Patent Publication Number: US-2023140632-A1

Title: Power supply device and failure detection method for battery

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of PCT patent application no. PCT/JP2021/019193, filed on May 20, 2021, which claims priority to Japanese patent application no. JP2020-112016, filed on Jun. 29, 2020, the entire contents of which are herein incorporated by reference. 
    
    
     BACKGROUND 
     The present application relates to a power supply device and a failure detection method for a battery. 
     Conventionally, a technique for detecting a failure of a lithium ion battery by measuring a voltage or a current of the lithium ion battery has been studied. For example, a power supply device is proposed including: a voltage detection unit that detects the voltage between positive and negative terminals of the lithium ion battery; and a battery abnormality determination unit that determines occurrence of a micro-short circuit in which a detection value of the voltage detection unit instantaneously drops, and determines that the lithium ion battery is abnormal when an occurrence frequency of the micro-short circuit becomes equal to or higher than a setting frequency for abnormality determination. 
     SUMMARY 
     The present application relates to a power supply device and a failure detection method for a battery. 
     Conventionally, a use of lithium ion battery has been limited to technical fields such as notebook personal computers (PCs) and mobile phones, but in recent years, the lithium ion battery is expected to be used in various technical fields such as automobile including electric vehicles (EVs) and plug-in hybrid vehicles (PHVs), aircrafts, and power storage systems. For this reason, in recent years, development of a technique for detecting a failure of the lithium ion battery is more desired than ever before. 
     The present application relates to providing a power supply device and a failure detection method for a battery capable of detecting a failure of the lithium ion battery according to an embodiment. 
     In order to solve the problems described above, a power supply device is provided and including: a measurement unit that measures at least one of a voltage and a current of a lithium ion battery; a peak detection unit that detects at least one of a maximum value of the current and a minimum value of the voltage at regular time intervals using at least one of the voltage and the current measured by the measurement unit; and a determination unit that determines a failure of the lithium ion battery based on at least one of the maximum value of the current and the minimum value of the voltage detected at the regular time intervals by the peak detection unit according to an embodiment. 
     In an embodiment, the peak detection unit may be a peak holding unit that holds at least one of the maximum value of the current and the minimum value of the voltage at the regular time intervals from at least one of the voltage and the current measured by the measurement unit. 
     In an embodiment, the measurement unit may measure the voltage and the current, the peak detection unit may detect the maximum value of the current and the minimum value of the voltage at the regular time intervals using the voltage and the current measured by the measurement unit, and the determination unit may determine the failure of the lithium ion battery based on the maximum value of the current and the minimum value of the voltage detected at regular time intervals by the peak detection unit. 
     In an embodiment, a temperature measurement unit that measures a temperature of the lithium ion battery may be further included, and the determination unit may determine the failure of the lithium ion battery based on at least one of the maximum value of the current and the minimum value of the voltage detected by the peak detection unit, at least one of the voltage and the current measured by the measurement unit, and the temperature measured by the temperature measurement unit. 
     In an embodiment, a temperature measurement unit that measures a temperature of the lithium ion battery may be further included, and the determination unit may determine the failure of the lithium ion battery based on the maximum value of the current and the minimum value of the voltage detected by the peak detection unit, the voltage and the current measured by the measurement unit, and the temperature measured by the temperature measurement unit. 
     In an embodiment, the determination unit may determine the failure of the lithium ion battery using a learned model using a neural network. 
     In an embodiment, the regular time interval may be 1 minute or less. 
     A failure detection method for a battery is provided and including: measuring at least one of a voltage and a current of a lithium ion battery; detecting at least one of a maximum value of the current and a minimum value of the voltage at regular time intervals using at least one of the measured voltage and the measured current; and determining the failure of the lithium ion battery based on at least one of the maximum value of the current and the minimum value of the voltage detected at regular time intervals according to an embodiment. 
     According to the present application, it is possible to detect the failure of the lithium ion battery. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG.  1    is a block diagram illustrating an example of a configuration of a power supply device according to an embodiment of the present application. 
         FIG.  2    is a block diagram illustrating an example of a configuration of a data collection system. 
         FIG.  3    is a block diagram illustrating an example of a configuration of a data collection device. 
         FIG.  4    is a schematic diagram illustrating an example of data collected by a peak hold circuit. 
     
    
    
     DETAILED DESCRIPTION 
     The present application will be described below in further detail including with reference to the figures according to an embodiment. 
       FIG.  1    is a block diagram illustrating an example of a configuration of a power supply device  10  according to an embodiment. The power supply device  10  is a power supply device having the neural network realized by an information processing device. The power supply device  10  includes a secondary battery  11 , a temperature measurement unit  12 , a current measurement unit  13 A, a current peak detection unit  13 B, a voltage measurement unit  14 A, a voltage peak detection unit  14 B, a determination unit  15 , a positive electrode terminal  16 A, and a negative electrode terminal  16 B. The power supply device  10  is preferably provided in electric vehicles (EV or PHV) or electric aircrafts. 
     The secondary battery  11  is a lithium ion battery. The positive electrode terminal of the secondary battery  11  is connected to the positive electrode terminal of a power supply source via the positive electrode terminal  16 A. Furthermore, the negative electrode terminal of the secondary battery  11  is connected to the negative electrode terminal of the power supply source via the negative electrode terminal  16 B. 
     The temperature measurement unit  12  includes a temperature detection element such as a thermocouple or a thermistor. The temperature detection element is disposed on or near a surface of the secondary battery  11 . The temperature measurement unit  12  detects the temperature of the secondary battery  11  by the temperature detection element and outputs the temperature to the determination unit  15 . 
     The current measurement unit  13 A measures the current of the secondary battery  11  and outputs the current to the current peak detection unit  13 B. The current measurement unit  13 A is, for example, a current measurement circuit. The current peak detection unit  13 B keeps the maximum value of the current at regular time intervals from the current measured by the current measurement unit  13 A, and outputs the maximum value to the determination unit  15 . The current peak detection unit  13 B is an example of a current peak detection unit that detects the maximum value of the current at regular time intervals. As the current peak detection unit  13 B, a current peak holding unit (the peak hold circuit) configured to be able to perform the peak hold for the maximum value of the current as an analog signal is used. From a viewpoint of early detection of the failure of the secondary battery  11 , the regular time interval of the current holding is preferably 1 minute or less, more preferably 10 seconds or less, and still more preferably 1 second or less. A lower limit value of the regular time interval is not particularly limited, but is, for example, 10 milliseconds or more. 
     From the viewpoint of early detection of the failure of the secondary battery  11 , the current peak detection unit  13 B is preferably configured to be able to detect a current rise (the current peak) having a half-value width of 1 second or less. A detection target by the current peak detection unit  13 B is the micro-short circuit derived from metal lithium. An instantaneous rise of the current of the secondary battery  11  and behavior of immediately recovering thereafter are characteristic behaviors observed in the micro-short circuit caused by a dendrite generation. The dendrite generation can be detected by detecting these characteristic behaviors (waveforms) by the current peak detection unit  13 B. Accordingly, the determination unit  15  can determine whether the secondary battery  11  is normal or abnormal based on the maximum value of the current input from the current peak detection unit  13 B. 
     The voltage measurement unit  14 A measures the voltage of the secondary battery  11  and outputs the voltage to the voltage peak detection unit  14 B. The voltage measurement unit  14 A is, for example, a voltage measurement circuit. The voltage peak detection unit  14 B holds the minimum value of the voltage at regular time intervals from the voltage measured by the voltage measurement unit  14 A, and outputs the minimum value thereof to the determination unit  15 . The voltage peak detection unit  14 B is an example of a voltage peak detection unit that detects the minimum value of the voltage at regular time intervals. As the voltage peak detection unit  14 B, a voltage peak holding unit (the peak hold circuit) configured to be able to perform the peak hold for the minimum value of the voltage as the analog signal is used. The regular time interval of voltage holding is preferably 1 minute or less, more preferably 10 seconds or less, and still more preferably 1 second or less from the viewpoint of early detection of the failure of the secondary battery  11 . A lower limit value of the regular time interval is not particularly limited, but is, for example, 10 milliseconds or more. 
     From the viewpoint of early detection of the failure of the secondary battery  11 , the voltage peak detection unit  14 B is preferably configured to be able to detect a voltage drop (the voltage peak) having the half-value width of 1 second or less. The detection target by the voltage peak detection unit  14 B is the micro-short circuit derived from metal lithium. An instantaneous drop of the voltage of the secondary battery  11  and behavior of immediately recovering thereafter are characteristic behaviors observed in the micro-short circuit caused by the dendrite generation. The dendrite generation can be detected by detecting these characteristic behaviors (the waveforms) by the voltage peak detection unit  14 B. Accordingly, the determination unit  15  can determine whether the secondary battery  11  is normal or abnormal based on the minimum value of the voltage input from voltage peak detection unit  14 B. 
     The determination unit  15  determines the failure of the secondary battery  11  based on the temperature measured by the temperature measurement unit  12 , the current measured by the current measurement unit  13 A, the voltage measured by the voltage measurement unit  14 A, a maximum current value held by the current peak detection unit  13 B, and a minimum voltage value held by the voltage peak detection unit  14 B. The determination unit  15  is a processor that executes the above determination by the learned model using the neural network, or an integrated circuit such as an application specific integrated circuit (ASIC). 
     Specifically, the determination unit  15  includes a storage unit that stores the learned model using the neural network, and determines a failure of the secondary battery  11  using the learned model stored in the storage unit. The neural network includes an input layer and an output layer. Input data of the input layer is (1) the temperature measured by the temperature measurement unit  12 , (2) the current measured by the current measurement unit  13 A, (3) the voltage measured by the voltage measurement unit  14 A, (4) the maximum current value held by the current peak detection unit  13 B, and (5) the minimum voltage value held by the voltage peak detection unit  14 B. Output data of the output layer is presence or absence of the failure of the secondary battery  11 . The presence or absence of the failure of the secondary battery  11  is determined by inputting the data of (1) to (5) to the neural network. The storage unit included in the determination unit  15  is, for example, a nonvolatile memory. 
     Hereinafter, an example of a failure detection method for battery using the power supply device  10  having the configuration above will be described according to an embodiment. 
     To start with, the current measurement unit  13 A and the voltage measurement unit  14 A measure the voltage and the current of the secondary battery  11  respectively, and output the voltage and the current to the current peak detection unit  13 B as well as the voltage peak detection unit  14 B, and to the determination unit  15 . In addition, the temperature measurement unit  12  measures the temperature of the secondary battery  11  and outputs the temperature to the determination unit  15 . 
     Next, the current peak detection unit  13 B holds the maximum value of the current at regular time intervals from the current measured by the current measurement unit  13 A, and outputs the maximum value to the determination unit  15 . In addition, the voltage peak detection unit  14 B holds the minimum value of the voltage at regular time intervals from the voltage measured by the voltage measurement unit  14 A, and outputs the minimum value thereof to the determination unit  15 . 
     The determination unit  15  inputs, to the neural network, the temperature measured by the temperature measurement unit  12 , the current measured by the current measurement unit  13 A, the voltage measured by the voltage measurement unit  14 A, the maximum current value held by the current peak detection unit  13 B, and the minimum voltage value held by the voltage peak detection unit  14 B as data to determine the presence or absence of the failure of the secondary battery  11 , and outputs a determination result to an external device by, for example, serial communication. 
     Hereinafter, an example of a configuration of a data collection system used for generating the learned model will be described according to an embodiment. 
       FIG.  2    is a block diagram illustrating an example of a configuration of a data collection system. The data collection system includes a data collection device  20 , a source measure unit  31 , a timed internal short-circuit cell  32 , and a control PC  33 . The data collection device  20  and the timed internal short-circuit cell  32  are connected by a cable. The data collection device  20  and the source measure unit  31  are connected by a cable. The control PC  33  and the data collection device  20  are connected by a cable such as a universal serial bus (USB). The control PC  33  and the source measure unit  31  are connected by a cable such as a general purpose interface bus (GPIB). 
     In an abnormality detection technique using machine learning, when only time series data in the normal time is used as teacher data, it is possible to determine as not normal, but it is not possible to determine whether it leads to a thermal runaway. In order to reliably determine that the thermal runaway occurs, it is necessary to prepare the time series data of a case where the thermal runaway occurs as the teacher data and to perform the learning using the data. Thereupon, the timed internal short-circuit cell  32  in which an internal short-circuit will soon occur is produced. 
     Furthermore, the timed internal short-circuit cell  32  is not obviously different from a commercially available lithium ion battery, but is a cell subjected to processing for causing an internal short-circuit at a predetermined intended timing. There are several preparation methods thereof, and a battery cell can be prepared by, for example, performing continuous charging, high temperature storage, overcharge cycle, or the like, or processing a short source inside the battery cell when assembling the battery cell. The timed internal short-circuit cell  32  is housed within a refractory chamber  32 A. 
       FIG.  3    is a block diagram illustrating an example of a configuration of the data collection device  20 . The data collection device  20  measures a charge/discharge current, the voltage, and the temperature of the timed internal short-circuit cell  32 . In addition, the data collection device  20  detects the minimum value and the maximum value of the current of the timed internal short-circuit cell  32  at regular time intervals and the minimum value and the maximum value of the voltage of the timed internal short-circuit cell  32  at regular time intervals. 
     The data collection device  20  includes a microcontroller  21  as a control device, a display device  22 , positive electrode terminals  23 A 1 ,  24 A 1 ,  23 B 1 , and  24 B 1 , negative electrode terminals  23 A 2 ,  24 A 2 ,  23 B 2 , and  24 B 2 , a current measurement unit  25 A, an upper peak hold circuit  25 B, a lower peak hold circuit  25 C, a voltage measurement unit  26 A, an upper peak hold circuit  26 B, a lower peak hold circuit  26 C, a thermocouple  27 A as a temperature detection element, a temperature measurement unit  27 B, a USB connector  28 A, and a USB serial converter  28 B. 
     The positive electrode terminal  23 A 1  and the positive electrode terminal  24 A 1  are connected to each other. The negative electrode terminal  23 A 2  and the negative electrode terminal  24 A 2  are connected to each other. The positive electrode terminal  23 A 1  and the negative electrode terminal  23 A 2  are connected to a positive electrode terminal and a negative electrode terminal of the timed internal short-circuit cell  32  respectively, and the positive electrode terminal  24 A 1  and the negative electrode terminal  24 A 2  are connected to a positive electrode terminal and a negative electrode terminal for current control of the source measure unit  31  respectively. 
     The positive electrode terminal  23 B 1  and the positive electrode terminal  24 B 1  are connected to each other. The negative electrode terminal  23 B 2  and the negative electrode terminal  24 B 2  are connected to each other. The positive electrode terminal  23 B 1  and the negative electrode terminal  23 B 2  are connected to a positive electrode terminal and a negative electrode terminal of the timed internal short-circuit cell  32  respectively, and the positive electrode terminal  24 B 1  and the negative electrode terminal  24 B 2  are connected to a positive electrode terminal and a negative electrode terminal for a voltage control of the source measure unit  31  respectively. 
     The current measurement unit  25 A measures a current flowing between the positive electrode terminal  23 A 1  and the positive electrode terminal  24 A 1 , and outputs the current to the upper peak hold circuit  25 B, the lower peak hold circuit  25 C, and the microcontroller  21 . The upper peak hold circuit  25 B holds the maximum current value at regular time intervals from the current measured by the current measurement unit  25 A, and outputs the maximum current value to the microcontroller  21 . The lower peak hold circuit  25 C holds a minimum current value at regular time intervals from the current measured by the current measurement unit  25 A, and outputs the minimum current value to the microcontroller  21 . 
     The voltage measurement unit  26 A measures a voltage applied between the positive electrode terminal  23 B 1  and the negative electrode terminal  23 B 2 , and outputs the voltage to the upper peak hold circuit  26 B, the lower peak hold circuit  26 C, and the microcontroller  21 . The upper peak hold circuit  26 B holds a maximum voltage value at regular time intervals from the voltage measured by the voltage measurement unit  26 A, and outputs the maximum voltage value to the microcontroller  21 . The lower peak hold circuit  25 C holds the minimum voltage value at regular time intervals from the voltage measured by the voltage measurement unit  26 A, and outputs the minimum voltage value to the microcontroller  21 . 
     The thermocouple  27 A is disposed on or near a surface of the timed internal short-circuit cell  32 . The temperature measurement unit  27 B measures the temperature of the timed internal short-circuit cell  32  by the thermocouple  27 A and outputs the temperature to the microcontroller  21 . 
     A USB connector  28 A is connected to the microcontroller  21  via a USB serial converter  28 B. A USB cable is connected to the USB connector  28 A. The data collection device  20  and the control PC  33  are connected via the USB cable. 
     The microcontroller  21  acquires a voltage, a current, a temperature, a minimum voltage value at regular time intervals, the maximum voltage value at regular time intervals, the minimum current value at regular time intervals, and the maximum current value at regular time intervals, and outputs the acquired values to the control PC  33 . The microcontroller  21  resets each of the upper peak hold circuits  25 B and  26 B and the lower peak hold circuits  25 C and  26 C at regular time intervals. Accordingly, it is possible to read the minimum current value, the maximum current value, the minimum voltage value, and the maximum voltage value at a regular period after a previous reset. The display device  22  displays information related to collected data and the like. 
     The data collection device  20  is configured to be able to measure, for example, a peak value of a peak having a half-value width of 1 μs or more with an accuracy of 5% or less. The data collection device  20  is equipped with a continuous data transmission function. This is a function of transmitting (1) the value (Present) at that time, (2) the maximum value (Upper) in the latest 500 milliseconds, and (3) the minimum value (Lower) at regular time intervals (for example, every 500 milliseconds) (see  FIG.  4   ). 
     The source measure unit  31  charges and discharges the timed internal short-circuit cell  32 . 
     The control PC  33  controls the source measure unit  31  to charge and discharge the timed internal short-circuit cell  32 . Furthermore, the control PC  33  controls the data collection device  20  to collect data on the timed internal short-circuit cell  32 . 
     Hereinafter, an example of a data collection method using the data collection system having the configuration above will be described according to an embodiment. 
     The control PC  33  controls the source measure unit  31  to perform a cycle test of the timed internal short-circuit cell  32 . Charge conditions in the cycle test are, for example, 1C charge, and discharge conditions are, for example, a current pattern actually applied to the battery in the electric aircrafts. Then, the data collection device  20  measures time-series data of the current, the voltage, the temperature, the minimum current value, the maximum current value, the minimum voltage value, and the maximum voltage value until the timed internal short-circuit cell  32  reaches the thermal runaway. The control PC  33  collects the time-series data measured by the data collection device  20 . This charge-discharge cycle test is performed until the timed internal short-circuit cell  32  undergoes an exothermic runaway. This series of data collection is performed using, for example, 200 timed internal short-circuit cells  32 . 
     The time series data of the current, the voltage, the temperature, the minimum current value, the maximum current value, the minimum voltage value, and the maximum voltage value collected by the data collection device  20  is used as the teacher data by using a machine learning platform TensorFlow to create a neural network for abnormality detection. 
     A neural network created on TensorFlow using Renesas integrated development environment e2 studio is converted into a source code for a microprocessor, and the source code is written into the microprocessor. Then, in combination with the current measurement unit  13 A, the current peak detection unit  13 B, the voltage measurement unit  14 A, the voltage peak detection unit  14 B, and the temperature measurement unit  12 , the power supply device  10  (see  FIG.  1   ) on which the learned neural network is mounted is prepared. 
     The power supply device  10  is configured to be able to output (1) how many seconds after which an abnormality occurs and (2) the percentage of certainty of the abnormality. 
     For example, specifically when a data acquisition interval of the power supply device  10  is every 500 milliseconds, in a case where the current peak detection unit  13 B and the voltage peak detection unit  14 B capable of detecting the peak value of the peak having the half-value width of 1 μs or more are provided, the current abnormality and the voltage abnormality can be detected in an early stage. 
     In learning and estimation of the neural network, not only voltage but also current and temperature information are used. Since a voltage waveform for determining the presence or absence of the failure of the secondary battery  11  depends on an internal resistance, and the internal resistance depends on the current and the temperature, more accurate determination can be made by using these three physical quantities. 
     It is possible to determine whether the battery is normal or abnormal by detecting an instantaneous voltage drop and a voltage behavior that recovers immediately thereafter. However, in the technique described in the Background section (e.g., Japanese Patent Application Laid-Open No. 2003-009405), particularly when a lithium ion battery is to be used as a battery for the electric aircrafts, there are insufficient points, for example, (1) a specific detection means for detecting a voltage waveform thereof; and (2) a specific determination means for determining an obtained waveform. 
     (1) With Respect to Detection Means 
     Regarding the instantaneous voltage drop caused by the dendrite generation and the voltage behavior that immediately recovers thereafter, paragraph 0045 of Japanese Patent Application Laid-Open No. 2003-009405 describes that voltage measurement is performed every several tens of milliseconds. 
     However, specifically when the interval of the voltage measurement is every several tens of milliseconds, it cannot be said that the interval is sufficiently fast. This is because, in the internal short circuit caused by the dendrite, to start with, an extremely thin dendrite is connected between the positive and negative electrodes to cause an internal short circuit, which fuses in an extremely short time, then a slightly thick dendrite is connected between the positive and negative electrodes to cause an internal short circuit, which fuses after a slightly long short circuit time, and then a slightly thicker dendrite is connected, so that the dendrite gradually becomes thicker, and the short circuit time gradually becomes longer. In other words, an earlier dendrite growth can be found, the more it is possible to measure the initial abnormal voltage behavior in an extremely short time. At a measurement interval of several tens of milliseconds, it is difficult to detect such initial dendrite generation, and when the dendrite generation can be detected, there is not much time left until the thermal runaway, and the dendrite generation is detected after a relatively late stage. How much time is needed depends on a use application of the battery. For example, in a battery for electric aircrafts, a time on an order of several tens of minutes at the minimum and a time on an order of several hours when possible are needed as a postponed time from the detection of the internal short circuit to a safe landing of the aircrafts. The measurement interval of every several tens of milliseconds was insufficient for such applications that particularly has high requirement for safety. 
     In order to be able to measure a high-speed current change and a voltage change that are much shorter than several tens of milliseconds, for example, there is a method of increasing a sampling frequency of an AD converter that reads current behavior and voltage behavior. However, attempting to perform high-speed sampling on a large number of batteries required to drive an electric aircraft would increase an overall cost of the system. In Japanese Patent Application Laid-Open No. 2003-009405, the detection means for preventing the increase in cost is not sufficiently devised. 
     On the other hand, the power supply device  10  according to an embodiment includes the current peak detection unit  13 B and the voltage peak detection unit  14 B in order to solve the problem above. The current peak detection unit  13 B and the voltage peak detection unit  14 B are circuits that continue to hold the maximum value and the minimum value at a regular time interval. Accordingly, this makes it possible to detect the minimum voltage value without increasing the sampling frequency of the AD converter specifically when the current rise or the voltage drop has a very narrow half-value width. 
     The current peak detection unit  13 B configured by a first peak hold circuit and the voltage peak detection unit  14 B configured by the second peak hold circuit can be relatively easily constructed by an analog circuit using a rectifier element, and the cost of the circuit can also be suppressed. This is particularly effective in a case where a large number of batteries such as in the electric aircrafts are used. 
     (2) With Respect to Determination Means 
     Next is a base voltage. Japanese Patent Application Laid-Open No. 2003-009405 describes a threshold voltage for determining that the detection value of the voltage detection unit has instantaneously dropped. However, a degree of a voltage minimal value of the voltage drop due to the micro-short circuit depends on the internal resistance of the battery, and the internal resistance depends on the degree of deterioration, the temperature, and the like. Therefore, when the base voltage is used as a determination reference, it is necessary to separately prepare a measurement means of the internal resistance of the battery and the like, and sequentially change the base voltage using an obtained internal resistance value. However, Japanese Patent Application Laid-Open No. 2003-009405, such discussion is not sufficiently made, and a scientific basis for determination criteria is insufficient. 
     On the other hand, in the power supply device  10  according to an embodiment, a neural network is used to solve the above problems. When the neural network is learned, not only voltage information but also current and temperature information are used. The internal resistance of the battery is a physical quantity dependent on the voltage, the current, and the temperature. Therefore, by using these three pieces of data for learning and estimation, more accurate determination based on the internal resistance can be made. 
     The data used for learning and estimation of the neural network is not limited to the three pieces of data of the voltage, the current, and the temperature. Data obtained by the current peak detection unit  13 B and the voltage peak detection unit  14 B is also used as information on the voltage rise and the voltage drop having a very narrow half-value width. Accordingly, a determination accuracy can be further improved. 
     In an embodiment described above, the power supply device  10  may not include the temperature measurement unit  12 . In this case, the data collection device  20  may not include the thermocouple  27 A and the temperature measurement unit  27 B. 
     In an embodiment described above, the power supply device  10  may not include the current measurement unit  13 A and the current peak detection unit  13 B. In this case, the data collection device  20  may not include the current measurement unit  25 A, the upper peak hold circuit  25 B, and the lower peak hold circuit  25 C. 
     In an embodiment described above, the power supply device  10  may not include the voltage measurement unit  14 A and the voltage peak detection unit  14 B. In this case, the data collection device  20  may not include the voltage measurement unit  26 A, the upper peak hold circuit  26 B, and the lower peak hold circuit  26 C. 
     In an embodiment described above, an example in which the power supply device  10  includes one secondary battery  11  and the data collection system includes one timed internal short-circuit cell  32  has been described. However, the power supply device  10  may include a plurality of secondary batteries  11  and the data collection system may include a plurality of timed internal short-circuit cells  32 . In this case, the current measurement unit  13 A of the power supply device  10  may measure the currents of the plurality of secondary batteries  11  connected, and the voltage measurement unit  14 A of the power supply device  10  may measure the voltage of each secondary battery  11 . In addition, the current measurement unit  25 A of the data collection device  20  may measure the currents of the plurality of timed internal short-circuit cells  32  connected, and the voltage measurement unit  26 A of the data collection device  20  may measure the voltage of each timed internal short-circuit cell  32 . 
     In an embodiment described above, an example in which the power supply device  10  includes the current measurement unit  13 A, the current peak detection unit  13 B, the voltage measurement unit  14 A, and the voltage peak detection unit  14 B has been described. However, the sampling frequency of the AD converter that reads the current behavior and the voltage behavior may be increased to detect the maximum current value and the minimum voltage value. 
     Although an embodiment including the modification examples of the present application have been described above, the present application is not limited thereto and various modifications can be made. 
     For example, the configurations, methods, steps, shapes, materials, numerical values, and the like described in an embodiment and modification examples described above are merely examples, and different configurations, methods, steps, shapes, materials, numerical values, and the like may be used as necessary. 
     In addition, the configurations, methods, steps, shapes, materials, numerical values, and the like of an embodiment including modification examples described above can be combined with each other without departing from the present application. 
     DESCRIPTION OF REFERENCE SYMBOLS 
     
         
         
           
               10 : Power supply device 
               11 : Secondary battery 
               12 ,  27 B: Temperature measurement unit 
               13 A,  25 A: Current measurement unit 
               13 B: Current peak detection unit 
               14 A,  26 A: Voltage measurement unit 
               14 B: Voltage peak detection unit 
               15 : Determination unit 
               16 A,  23 A 1 ,  23 B 1 ,  24 A 1 ,  24 B 1 : Positive electrode terminal 
               16 B,  23 A 2 ,  23 B 2 ,  24 A 2 ,  24 B 2 : Negative electrode terminal 
               20 : Data collection device 
               21 : Microcontroller 
               22 : Display device 
               25 B,  26 B: Upper peak hold circuit 
               25 C,  26 C: Lower peak hold circuit 
               27 A: Thermocouple 
               28 A: USB connector 
               28 B: USB serial converter 
               31 : Source measure unit 
               32 : Timed internal short-circuit cell 
               32 A: Refractory chamber 
               33 : Control PC 
           
         
       
    
     It should be understood that various changes and modifications to the presently preferred embodiments herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.