Method and system for testing electrical flow of battery

Abstract

Disclosed are a method and a system for testing an electrical flow of a waste battery. The method for testing an electrical flow of a waste battery performed by an electrical flow testing system according to one embodiment of the present invention comprises the steps of: obtaining at least one of a set voltage range, a lower limit of insulation resistance, an upper limit of electrical flow, impedance for each temperature, and an appropriate state of charge (SOC) range, corresponding to information related to the waste battery; obtaining at least one of voltage, insulation resistance, temperature, and impedance of the waste battery; and determining suitability for the waste battery by using at least one of the voltage, insulation resistance, temperature, and impedance of the waste battery, wherein the step of obtaining impedance uses a method of correcting impedance measured at an arbitrary temperature to impedance of a reference temperature.

Description

Method and system for testing electrical flow in a battery

[0001] The present invention relates to a method and system for inspecting the electrical flow of a waste battery (i.e., a used battery), and more particularly, to a method and system for inspecting the electrical flow of a battery for checking the state of charge and chargeability of a waste battery before reusing or recycling the battery, and for checking the presence or absence of an abnormality in the electrical flow through an electrical inspection.

[0002] According to the "Specific Compliance Matters for Those Recycling Waste" based on Article 13-2, Paragraph 3 of the Waste Management Act, Article 13-2, Paragraph 3 of the Enforcement Decree of the same Act, and Appendix 5-4, Subparagraph 3 of the Enforcement Decree of the same Act, "Any person who intends to recycle waste batteries from electric vehicles must conduct an external inspection and an electrical current inspection of the waste batteries from electric vehicles prior to recycling."

[0003] According to the announced content, “electrical flow test of a used battery” is to check the current charging status and whether charging is possible by connecting to a charging device, and to check for abnormalities in the electric flow through an electrical test.

[0004] However, to date, no system or device has been provided to perform electrical flow testing of waste batteries through connection to charging equipment.

[0005] Meanwhile, electrochemical impedance spectroscopy (EIS) can be used to test the electrical current in waste batteries. However, impedance based on EIS is highly temperature-dependent due to its influence on charge movement, making direct comparisons between data measured at different temperatures difficult. Therefore, to accurately measure impedance, it is recommended to set the impedance measurement temperature to a reference temperature (i.e., under identical temperature conditions) before measuring impedance.

[0006] However, since waste batteries must be discharged to eliminate stored energy for recycling / reuse, or must undergo various safety tests to check the remaining capacity, it is very difficult to always maintain waste batteries at a standard temperature, and thus there is a problem in that accurate impedance cannot be measured.

[0007] The first problem to be solved by the present invention is to provide a battery electrical flow inspection method and system capable of inspecting the electrical flow of a waste battery.

[0008] The second problem to be solved by the present invention is to provide a battery electric flow inspection system and method capable of performing an electric flow inspection on a used battery of an electric vehicle.

[0009] The purposes of the present invention are not limited to those mentioned above, and other unmentioned purposes and advantages of the present invention can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the purposes and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0010] In order to solve the above problem, the present invention provides a method for testing an electric flow of a waste battery performed by an electric flow testing system, and specifically, the method comprises the steps of: obtaining at least one of a set voltage range, an insulation resistance lower limit, an electric flow upper limit, an impedance for each temperature, and an appropriate SOC (state of charge) range corresponding to information related to the waste battery; obtaining at least one of a voltage, an insulation resistance, an electric flow upper limit, a temperature, and an impedance of the waste battery; and determining whether the waste battery is suitable using at least one of the voltage, the insulation resistance, the temperature, and the impedance of the waste battery, wherein the step of obtaining the impedance uses a method of correcting an impedance measured at an arbitrary temperature to an impedance of a reference temperature, and the method of correcting the impedance comprises: obtaining an equation of a shape related to the impedance for each temperature based on a plurality of coordinates corresponding to the impedance for each temperature; extracting a specific coordinate for each temperature from a plurality of coordinates constituting the equation of the obtained shape; And, the present invention provides a method for examining the electric flow of a waste battery, including a step of extracting information on the relationship between temperature and impedance based on specific coordinates extracted by temperature, and correcting the impedance at an arbitrary temperature to the impedance at a reference temperature through the extracted information.

[0011] In one embodiment of the present invention, the equation of the shape is an equation of a circle or an equation of an ellipse, and the step of obtaining the equation of the shape includes the step of identifying at least one coordinate that can form an arc among a plurality of coordinates corresponding to impedances according to temperature; and the step of obtaining the equation of the shape based on the identified at least one coordinate, wherein the specific coordinate extracted according to temperature may be the coordinate of the center of the circle or the center of the ellipse in the equation of the obtained shape.

[0012] In one embodiment of the present invention, the step of obtaining the impedance of the waste battery may include the steps of sequentially inputting input frequencies to the waste battery at varying levels and outputting output frequencies for each input frequency; and the step of identifying a resonant frequency of a high frequency using a phase difference between the input frequency input to the waste battery and the output frequency corresponding to the input frequency, and obtaining the impedance of the waste battery corresponding to the identified resonant frequency of the high frequency.

[0013] In one embodiment of the present invention, the step of determining suitability for the waste battery may include a step of determining the electric flow of the waste battery as abnormal when the impedance of the corrected waste battery is higher than the upper limit of the electric flow, determining the electric flow of the waste battery as abnormal when the voltage of the waste battery is outside the set voltage range, or determining the electric flow of the waste battery as abnormal when the insulation resistance of the waste battery is lower than the lower limit of the insulation resistance.

[0014] In one embodiment of the present invention, the method further includes a step of estimating the state of charge (SOC) of the waste battery based on the voltage of the waste battery, and the step of determining whether the waste battery is suitable may further include a step of determining that the electric flow of the waste battery is abnormal if the SOC of the waste battery exceeds the appropriate SOC range.

[0015] According to the present invention, it is possible to perform an electric flow test on a used battery of an electric vehicle in accordance with the Ministry of Environment's notice.

[0016] According to the present invention, a system and method can be provided that can perform an electric flow test on a used battery of an electric vehicle at a low cost using an AC power source.

[0017] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0018] FIG. 1 is a block diagram of a battery current flow inspection system according to one embodiment of the present invention.

[0019] FIG. 2 is a drawing showing in detail an impedance measurement configuration in a battery current flow test system according to an embodiment of the present invention.

[0020] FIGS. 3 and 4 are drawings for explaining an impedance measurement operation in a battery current flow test system according to one embodiment of the present invention.

[0021] FIG. 5 is a flowchart illustrating a method for performing a battery current flow test according to one embodiment of the present invention.

[0022] FIG. 6 illustrates an example of impedance measured by an electrical flow test system according to one embodiment of the present invention.

[0023] FIG. 7 is a diagram for explaining a process in which an electric current inspection system, according to one embodiment of the present invention, derives an equation of a shape based on coordinates of impedance acquired for each temperature.

[0024] FIG. 8 is a drawing for explaining a method for an electrical flow inspection system to produce coordinates having linearity according to one embodiment of the present invention.

[0025] FIG. 9 is a diagram illustrating a process for obtaining an impedance estimation value at an arbitrary temperature by an electrical flow inspection system according to one embodiment of the present invention.

[0026] FIG. 10 is an example comparing the error rate between the impedance and the derived correction value at any temperature according to one embodiment of the present invention.

[0027] FIG. 11 and FIG. 12 are drawings showing screens displaying inspection items and inspection results in a battery current flow inspection system according to one embodiment of the present invention.

[0028] The principles of preferred embodiments of the present invention will be described in detail with reference to the attached drawings and descriptions below. However, the drawings and descriptions below are intended to illustrate preferred implementation methods among various methods for effectively explaining the features of the present invention, and the present invention is not limited to the drawings and descriptions below.

[0029] While terms such as "first" or "second" may be used to describe various components, these terms should be interpreted solely to distinguish one component from another. For example, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

[0030] Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "has" should be understood to indicate the presence of a described feature, number, step, operation, component, part, or combination thereof, but not to exclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0031] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art. Terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0032] Hereinafter, a method and system for inspecting the electric flow of a battery according to one embodiment of the present invention will be described with reference to the attached drawings.

[0033] In describing the present invention, the term "waste battery" may collectively refer to a waste battery that has been used and then recovered for various reasons. For example, the term "waste battery" may include, but is not limited to, a vehicle waste battery that was used in an eco-friendly vehicle (e.g., an electric vehicle, a hydrogen vehicle, etc.) and then recovered for various reasons (e.g., inspection, repair, expiration, accident, scrapping, etc.).

[0034] FIG. 1 is a block diagram of a battery current flow inspection system according to an embodiment of the present invention.

[0035] Referring to FIG. 1, a battery current flow inspection system (100) according to an embodiment of the present invention may include an inspection item management unit (110), a setting value storage unit (120), a battery voltage identification unit (130), an insulation resistance identification unit (140), an impedance identification unit (150), a voltage diagnosis unit (160), an insulation resistance diagnosis unit (170), an electric current diagnosis unit (180), a suitability diagnosis unit (190), and an impedance measuring device (230).

[0036] Here, if the impedance measuring device (230) is manufactured in a form that can be detachably attached to the system (100) of the present invention, the system (100) according to the embodiment of the present invention can omit the impedance measuring device (230).

[0037] The above inspection item management unit (110) can manage the setting values, measurement values, diagnosis values, and final inspection values ​​for each battery inspection item.

[0038] Here, the set value for each battery inspection item means a reference value for each inspection item for comparison with the measured value, and the measured value means a value measured for each inspection item, such as the measured battery voltage, the measured insulation resistance of the battery, and the measured electrochemical impedance of the battery.

[0039] The diagnostic value is the comparison result between the reference value and the measured value for each test item, indicating normal (pass) or abnormal (fail). Furthermore, the final test value indicates the final suitability of the battery based on the diagnostic value, for example, whether it is suitable or unsuitable.

[0040] In addition, the inspection item management unit (110) can register the setting value, which is the standard value for each inspection item, for each battery type according to the user's request entered through the user input unit (10), and perform management such as modification or deletion of the setting value.

[0041] The inspection item management unit (110) can create an item setting screen that is displayed externally through the electric current inspection system (100). The inspection item management unit (110) allows a user to input and register a new battery type and setting values ​​for the new battery type through the item setting screen.

[0042] The inspection item management unit (110) can check the inspection item-specific setting values, various diagnostic values, and final inspection values ​​for the battery to be inspected through the item setting screen.

[0043] Here, the item setting screen will be described with reference to FIGS. 11 and 12. FIGS. 11 and 12 are diagrams showing screens displaying inspection items and inspection results in a battery current flow inspection system according to an embodiment of the present invention.

[0044] Referring to FIGS. 11 and 12, on the left side of the item setting screen, there may be a field (①) for the user to input a battery ID (identification information) or to call and display a registered battery ID, a field (②) for the user to input a battery type or to call and display a registered battery type, a button (③) for calling a new item setting screen to enable recording of new battery information, a button (④) for deleting information of the currently displayed battery, a field (⑤) for the user to input a setting value for an inspection item or to call and display the corresponding registered setting value, and a button (⑥) for indicating the start of an inspection.

[0045] The button (⑥) indicating the start of the test may be changed to "Test Initialization" and displayed when the user clicks the button. In addition, the field (⑤) may include a field labeled "Voltage Range" that indicates the upper and lower limits of the battery voltage for the corresponding battery type, a field labeled "Capacity" that indicates the reference current value, a field labeled "Upper Limit of Electric Flow" that indicates the upper limit of the impedance, and a field labeled "Lower Limit of Insulation Resistance" that indicates the lower limit of the insulation resistance.

[0046] In addition, on the right side of the item setting screen, there are fields that display the measurement values ​​and measurement results for the inspection items. For example, referring to FIGS. 11 and 12, on the right side of the item setting screen, there may be a field (⑦) that displays the inspection progress, a field (⑧) that displays the measured battery voltage and SOC (state of charge) labeled “charge status,” a field (⑨) that displays the measured impedance labeled “electrical flow,” a field (⑩) that displays the measured insulation resistance labeled “insulation stability,” a field (⑪) that displays the diagnosis results according to each measurement value, and finally a field (⑫) that displays the electric flow inspection results.

[0047] At this time, the SOC can be calculated using the battery voltage or determined using a pre-generated SOC table based on the voltage / capacity of the battery.

[0048] In Fig. 11, looking at the measurement results on the right side of the item setting screen, the measured battery voltage is 27.72 V, which is within the set voltage range of 24.20 V to 29.40 V, and is therefore displayed as normal (pass). The impedance, i.e., the electric current, is 15.62 mΩ, which is below the set value of 20.00 mΩ, and is therefore displayed as normal (pass). The measured insulation resistance exceeds the set value of 1.00 MΩ, and is therefore displayed as normal (pass). Accordingly, the final inspection result is displayed as "suitable / chargeable" because all inspection items are normal.

[0049] On the other hand, in Fig. 12, looking at the measurement results on the right side of the item setting screen, the measured battery voltage is 27.71 V, which is outside the set voltage range of 288.00 V to 403.20 V, and is displayed as abnormal (FAIL). The impedance, i.e., the electric current, is 15.62 mΩ, which is lower than the set value of 416.65 Ω, and is displayed as normal (pass). The measured insulation resistance exceeds the set value of 1.00 MΩ, and is displayed as normal (pass). Accordingly, the final inspection result was displayed as “unsuitable / unchargeable” because there was an abnormality in one of all inspection items.

[0050] Meanwhile, the setting value storage unit (120) stores the setting values ​​for each inspection item registered by the inspection item management unit (110) by matching them to the corresponding battery type. Of course, the setting value storage unit (120) can store the inspection results of a waste battery that has completed inspection.

[0051] The battery current flow inspection system (100) according to an embodiment of the present invention may have a measurement value identification unit (A) that identifies measurement values ​​for each inspection item. Each identification unit of the measurement value identification unit (A) operates according to instructions from the inspection item management unit (110) and provides the identified measurement values ​​to the inspection item management unit (110). The measurement value identification unit (A) may include a battery voltage identification unit (130), an insulation resistance identification unit (140), and an impedance identification unit (150).

[0052] The battery voltage detection unit (130) controls the operation of the battery voltage meter (210) to receive the measurement result measured by the battery voltage meter (210) and detect the battery voltage (e.g., voltage of a battery cell, a battery module, or a battery pack). Here, the battery voltage meter (210) is an electric current test system (100) that measures the voltage of the battery by having one measurement terminal connected to the negative pole of the battery and the other measurement terminal connected to the positive pole of the battery, and is a typical battery voltage measurement electric current test system (100).

[0053] The insulation resistance detection unit (140) can control the operation of the battery voltage meter (210) to receive and detect the insulation resistance of the battery measured by the insulation resistance meter (220). Here, the insulation resistance meter (220) is a typical electric flow test system (100) that measures the insulation resistance of a battery, and for example, can be an electric flow test system (100) that measures the insulation resistance of a battery by having one terminal connected to one of the positive or negative terminals of the battery and the other terminal connected to the body of the battery.

[0054] The impedance detection unit (150) controls the operation of the impedance measuring device (230) to receive the frequency of a plurality of currents supplied from the impedance measuring device (230) and the frequency of the voltage measured in response to the frequency of the supplied current, and after detecting the phase difference between the frequencies for the currents and voltages of the same frequency, the impedance can be detected using the voltage and current of the frequency without the phase difference. Here, the impedance can exhibit the same value as the DC impedance for the DC power by using the voltage and current of the frequency without the phase difference.

[0055] The battery current flow inspection system (100) according to an embodiment of the present invention may have a measurement value diagnosis unit (B) that diagnoses whether the measurement value for each inspection item is normal or abnormal. Each diagnosis unit of the measurement value diagnosis unit (B) may provide the diagnosis result to the inspection item management unit (110). The measurement value diagnosis unit identification unit (B) may include a voltage identification unit (160), an insulation resistance diagnosis unit (170), and an electric current diagnosis unit (180).

[0056] The voltage diagnosis unit (160) compares the voltage detected by the battery voltage detection unit (130) with a set voltage, i.e., a set voltage range, and diagnoses whether the detected voltage is within the set voltage range. The voltage diagnosis unit (160) can diagnose the detected voltage as normal if it is within the set voltage range, and can diagnose it as abnormal if it is not.

[0057] The insulation resistance diagnosis unit (170) compares the insulation resistance identified by the insulation resistance identification unit (140) with the set insulation resistance, and if the identified insulation resistance is higher than the set insulation resistance, it diagnoses it as normal, and if not, it diagnoses it as abnormal.

[0058] The electric flow diagnosis unit (180) can compare the impedance identified by the impedance identification unit (150) with the set impedance, and if the identified impedance is lower than the set insulation resistance, it can be diagnosed as normal, and if not, it can be diagnosed as abnormal.

[0059] The suitability diagnosis unit (190) receives each diagnosis result output from the voltage diagnosis unit (160), the insulation resistance diagnosis unit (170), and the electric flow diagnosis unit (180), determines the final suitability, and provides the result of suitability to the inspection item management unit (110).

[0060] The impedance measuring device (230) can sequentially generate frequencies in the set frequency band in the order of minimum frequency to maximum frequency or maximum frequency to minimum frequency and input them to the waste battery (30), and provide an output frequency corresponding to the input frequency to the impedance detection unit (150).

[0061] Meanwhile, current flow testing examines the flow of alternating current, which is affected by impedance. However, batteries are electrochemical devices that utilize direct current (DC), and since the measurement involves assessing the suitability of this current flow, DC resistance exhibits the most similar DC resistance value when there is no phase difference between current and voltage when measured using AC.

[0062] To explain this specifically, the impedance (Z) in direct current is calculated as "Z = resistance (R)", and the impedance (Z) in alternating current is calculated as "Z = R (resistance) + jX (impedance)". That is, in alternating current, unlike in direct current, the flow of alternating current is affected by impedance (X), and reactance (X) is inductive reactance (X L ) and capacitive reactance (X C ) exists.

[0063] Inductive reactance (X L ) and capacitive reactance (X C ) can be expressed as the following mathematical equations 1 and 2.

[0064]

[0065] [Mathematical Formula 1]

[0066]

[0067] [Equation 2]

[0068]

[0069] In the above mathematical equations 1 and 2, f is frequency, L is inductance, and C is capacitance.

[0070] Looking at mathematical equations 1 and 2, the inductive reactance (X L ) and capacitive reactance (X C ) can be seen to be affected by frequency. That is, inductive reactance (X(L)) and capacitive reactance (X(C)) are factors that affect the frequency of current and voltage, creating a phase difference between the voltage and current frequencies and affecting the period and rate of change for the voltage and current frequencies. These inductive reactance (X(L)) and capacitive reactance (X(C)) cause the magnitudes to move in opposite directions depending on the frequency.

[0071] The phase difference (φ) between the frequency of the current and the frequency of the voltage can be expressed by the following mathematical expression 3.

[0072] [Equation 3]

[0073]

[0074] Therefore, when the impedances of inductive reactance (X(L)) and capacitive reactance (X(C)) become equal, the phase difference between the current frequency and the voltage frequency becomes '0', and accordingly, the impedance becomes equal to the DC impedance. The frequency at which the phase difference between the current frequency and the voltage frequency in an electric circuit becomes '0' is called the resonant frequency.

[0075] Therefore, the present invention finds the resonant frequency when measuring electric flow, and uses the impedance at the resonant frequency as the measured impedance.

[0076] According to the principle of measuring electric current of the present invention, the impedance detection unit (150) and the impedance measuring device (230) are configured as shown in Fig. 2. Fig. 2 is a drawing showing in detail the impedance measurement configuration in the battery electric current testing system according to an embodiment of the present invention.

[0077] Referring to FIG. 2, the impedance detection unit (150) may be configured to include a measurement control unit (151), a phase difference detection unit (152), and an impedance calculation unit (153), and the impedance measuring device (230) may be configured to include a frequency adjustment unit (231), an input frequency generation unit (232), and an output frequency measurement unit (233).

[0078] The measurement control unit (151) operates the impedance measuring device (230) according to the instructions of the inspection item management unit (110), and the phase difference detection unit (152) receives the input frequency input to the waste battery (30) and the output frequency output from the waste battery (30) to detect the phase difference between the two frequencies.

[0079] Here, the input frequency is the frequency of the current, and the output frequency is the frequency of the voltage. The impedance calculation unit (153) can determine the point in time when the value of the phase difference continuously received from the phase difference detection unit (152) is '0', and can calculate the impedance (Z) using the amplitude of the input frequency and the output frequency, that is, the current value and the voltage value, at the point in time when the value of the phase difference is '0'.

[0080] At this time, since the impedance (Z) has a phase difference value of '0', only the resistance (R) can be calculated. The operation of the phase difference detection unit (152) and the impedance calculation unit (153) is described with reference to FIGS. 3 and 4.

[0081] FIG. 3 and FIG. 4 are diagrams for explaining an impedance measurement operation in a battery current flow inspection system according to an embodiment of the present invention. FIG. 3 is a Bode plot showing a phase difference and impedance change according to a frequency change, and FIG. 4 is a Nyquist plot for the real part and the imaginary part.

[0082] Referring to the board diagram shown in (a) of Fig. 3, when the frequency is changed by the impedance measuring device (230), the phase difference between the current and voltage detected by the impedance calculating unit (153), theta (φ), changes from a negative value to a positive value as shown in the g1 graph.

[0083] Among these changes, at least one resonant frequency is found where the phase difference becomes '0', and the impedance calculation unit (153) finds the highest frequency among at least one resonant frequency, that is, the high-frequency resonant frequency.

[0084] And the impedance calculation unit (153) can calculate the impedance at the high frequency resonant frequency found in (a) of FIG. 3 as shown in (b) of FIG. 3, and can calculate the impedance while sweeping the frequency from high frequency to low frequency depending on the waste battery.

[0085] Meanwhile, when calculating impedance by sweeping the frequency from high frequency to low frequency, impedance information that can be obtained in the low frequency region, such as charge transfer resistance (R ct ) factor, capacitance (C dl ) can obtain information on various factors such as the factor, Warburg factor, etc., thereby expanding the scope of electrical flow examination / diagnosis. In some examples, the impedance calculation unit (153) can calculate impedance in a high frequency region of less than 100 kHz, preferably less than 1 kHz, to a low frequency region of 100 Hz or more, preferably 1 mHz or more.

[0086] Meanwhile, when the contents of Fig. 3 are explained through the Nyquist diagram of Fig. 4, when the frequency is changed, the impedance of the waste battery (30) is displayed in a section where the value of the vertical axis, which is the imaginary part, is '0' and only the value of the horizontal axis, which is the real part, exists, and a section where the values ​​of the imaginary part and the real part appear simultaneously is displayed.

[0087] At this time, the section where the value of the vertical axis, which is the imaginary part, is '0' and only the value of the horizontal axis, which is the real part, exists is the section where the phase difference between voltage and current is '0', and the impedance at the point where the value of the real part is the highest among this section is the impedance calculated by the impedance calculation section (153).

[0088] FIG. 5 is a flowchart illustrating a method for performing a battery current flow test according to one embodiment of the present invention.

[0089] In one embodiment of the present invention, the electric current inspection system (100) can obtain at least one of a set voltage range, an insulation resistance lower limit, an electric current upper limit, an impedance by temperature, and an appropriate SOC (state of charge) range corresponding to information related to a waste battery (S100).

[0090] Specifically, when a battery flow test is requested through the user input unit (10), the test item management unit (110) of the electric flow test system (100) can display an item setting screen, which is a setting window, through the electric flow test system (100).

[0091] Additionally, the electrical flow inspection system (100) can receive information related to a waste battery through a user input unit (10). Here, the information related to the waste battery can include a battery type and / or a battery ID.

[0092] The inspection item management unit (110) can call up the setting values ​​for each inspection item from the storage unit (120) through the battery type and / or battery ID. For example, the setting values ​​for each inspection item can include a setting voltage range, insulation resistance lower limit, electric flow upper limit, temperature-dependent impedance, and appropriate SOC range corresponding to the waste battery type and / or battery ID.

[0093] Meanwhile, the electric flow inspection system (100) can obtain at least one of the voltage, insulation resistance, upper limit of electric flow, temperature, and impedance of the waste battery (S200).

[0094] Specifically, when the inspection start button (⑥) is clicked, the inspection item management unit (110) can notify each identification unit (130, 140, 150) of the start of the inspection. Accordingly, the battery voltage identification unit (130) can operate the battery voltage measuring device (210) to measure the voltage of the waste battery (30), and can identify the voltage of the battery through the measured result and provide it to the voltage diagnosis unit (160).

[0095] The voltage diagnostic unit (160) calculates the SOC (State Of Charge) of the used battery using the received battery voltage and provides the voltage of the battery and the calculated SOC information of the battery to the inspection item management unit (110) so that each piece of information can be displayed on the item setting screen.

[0096] The insulation resistance detection unit (140) operates the insulation resistance meter (220) to measure the insulation resistance of the waste battery (30), and the measurement results can be used to detect the insulation resistance of the battery and provide the results to the insulation resistance diagnosis unit (170).

[0097] Additionally, the impedance detection unit (150) operates the impedance measuring device (230), and the impedance measuring device (230) can vary the frequency so that the input frequency increases to a set frequency.

[0098] The input frequency input to the battery (30) and the corresponding output frequency are provided to the impedance detection unit (150), so that the impedance detection unit (150) can detect the phase difference between the input frequency and the output frequency.

[0099] And the impedance identification unit (150) can identify the resonant frequency of high frequency with a phase difference of '0', identify the impedance using the voltage value and current value of the identified resonant frequency of high frequency, and provide the identified impedance to the electric flow diagnosis unit (180) and the inspection item management unit (110).

[0100] Meanwhile, the impedance detection unit (150) can measure impedance at any temperature without being restricted to a specific temperature, such as a temperature higher or lower than the reference temperature, as well as impedance at a reference temperature (e.g., 25°C).

[0101] The electrical flow test system (100) can correct the impedance measured at any temperature to the impedance at a reference temperature (e.g., 25°C) (S300).

[0102] Impedance varies significantly depending on the measurement temperature. Therefore, when using impedance to determine the suitability of a used battery, it is advisable to measure and utilize impedance at the same reference temperature.

[0103] However, it is not easy to measure the temperature of spent batteries after setting them to the same reference temperature. This is particularly challenging because spent batteries may be discharged to eliminate stored energy for recycling / reuse or undergo various safety inspections. Maintaining a constant reference temperature for spent batteries presents significant challenges.

[0104] To solve this problem, the inventors of the present invention developed a method for accurately estimating impedance at an arbitrary temperature based on previously measured impedance, or a method for converting (correcting) impedance acquired at an arbitrary temperature into impedance acquired at a reference temperature (e.g., 25°C).

[0105] Below, a method for correcting impedance measured at an arbitrary temperature to impedance corresponding to a reference temperature (e.g., 25℃) is described.

[0106] In the present invention, the reference temperature means the same reference temperature set to compare impedance, and is not limited to a specific temperature.

[0107] Specifically, the impedance detection unit (150) can load information on temperature-dependent impedance corresponding to the type of the waste battery from the storage unit (120).

[0108] At this time, the information on the temperature-dependent impedance may be obtained by measuring the electrochemical impedance of the battery at different temperatures.

[0109] For example, a method of obtaining impedance according to temperature can be performed by maintaining the temperature of a space where a battery is located at a first temperature and measuring electrochemical impedance for the battery to obtain impedance according to the first temperature, and changing the temperature of the space where the battery is located to a second temperature and then maintaining it, and measuring electrochemical impedance for the battery to obtain impedance according to the second temperature.

[0110] As described above, the temperature-dependent impedance can be obtained / collected by measuring the electrochemical impedance for the battery at different temperatures. The impedance can be separated by frequency, and the absolute value of the impedance for the frequency, the real component (real part, Z) real ) and imaginary component (imaginary part, Z img ) can be obtained and plotted as a Nyquist plot.

[0111] For example, as illustrated in (a) of FIG. 6, the electrical flow inspection system (100) can plot the impedance measured at each temperature (310) as a Nyquist plot. As the measurement temperature decreases, a larger semicircle appears on the Nyquist plot, indicating that the impedance has a large temperature dependence. Meanwhile, as illustrated in (b) of FIG. 6, the electrical flow inspection system (100) can normalize the impedance at each temperature and then plot it as a Nyquist plot.

[0112] The electrical flow inspection system (100) can obtain an equation of a shape related to impedance at each temperature based on a plurality of coordinates corresponding to impedance at each measured temperature.

[0113] At this time, the equation of the shape can be the equation of a circle or the equation of an ellipse.

[0114] In one embodiment of the present invention, the electrical flow inspection system (100) can identify at least one coordinate that can form an arc shape among a plurality of coordinates corresponding to impedance according to temperature.

[0115] Referring to (a) of Fig. 6, among a plurality of coordinates corresponding to impedance by temperature, there may be at least one coordinate that can form an arc shape.

[0116] In another embodiment of the present invention, the electrical flow inspection system (100) can normalize a plurality of coordinates corresponding to impedance according to temperature and then identify at least one coordinate.

[0117] Referring to (b) of Fig. 6, after normalizing multiple coordinates corresponding to impedance by temperature to the origin of the Zreal axis (x-axis), at least one coordinate can be identified.

[0118] As illustrated in (a) of FIG. 7, the electrical flow inspection system (100) can derive / obtain an equation of a shape related to impedance by temperature based on at least one coordinate (e.g., a and b) that can form the center of a circle and / or an arc shape.

[0119] As an example, Fig. 7(b) shows an example of an equation of a circle obtained from impedance at each measured temperature derived based on at least one coordinate (e.g., a and b) that can form the center of the circle and / or an arc shape.

[0120] However, at least one coordinate that can form the center of a circle or the center of an ellipse and an arc shape is only one embodiment, and the electric current inspection system (100) can derive an equation of a shape related to impedance for each measurement temperature by using one or more coordinates among a plurality of coordinates corresponding to impedance for each measurement temperature.

[0121] The electrical flow inspection system (100) can extract specific coordinates for each measurement temperature from a plurality of coordinates that constitute the equation of the acquired shape.

[0122] For example, the specific coordinate may be the center of a circle or the center of an ellipse. As another example, the specific coordinate may be any coordinate that satisfies the equation of the shape, for example, the real part (Z) that satisfies the equation of the shape. real ), imaginary part (Z img ) can be any coordinate.

[0123] At this time, the temperature-specific coordinates extracted by the electric flow inspection system (100) may have linearity with respect to temperature.

[0124] The electrical flow inspection system (100) can extract information on the relationship between temperature and impedance based on extracted specific coordinates, and estimate impedance at a reference temperature through the extracted information.

[0125] For example, referring to FIG. 8, the electrical flow inspection system (100) can extract specific coordinates, for example, the center of the circle (520-1, 520-2, 520-3, 520-4, 520-5, 520-6), from among a plurality of coordinates that constitute an equation of a circle related to impedance by temperature (510).

[0126] At this time, linearity may exist between specific coordinates extracted from the equation of the circle for each temperature, such as the center coordinates of the circle. That is, the electrical flow inspection system (100) may extract specific coordinates that may have linearity from each equation of the circle related to the impedance for each temperature.

[0127] In Fig. 8, the temperature-specific coordinates are illustrated as the center coordinates of a circle, which is a shape related to temperature-specific impedance, but are not limited thereto. The temperature-specific coordinates refer to coordinates that can have linearity among the multiple coordinates that constitute the equation of the temperature-specific shape.

[0128] Meanwhile, a relational expression representing the relationship between the measured temperature and impedance can be extracted / derived based on specific coordinates (e.g., the center of a circle) for each extracted temperature.

[0129] As illustrated in (a) of FIG. 9, the electrical flow inspection system (100) can obtain specific coordinates corresponding to the reference temperature (e.g., center coordinates of a circle corresponding to the reference temperature) through the extracted relational expression. Based on the specific coordinates corresponding to the obtained reference temperature (e.g., center coordinates of a circle), the electrical flow inspection system (100) can obtain an equation of a shape corresponding to the reference temperature and coordinates (620) according to the equation of the shape.

[0130] As shown in (b) of FIG. 9, the electric current inspection system (100) can calculate coordinates (630) representing the impedance of the reference temperature among the coordinates constituting the equation of the shape corresponding to the reference temperature based on a pattern of multiple coordinates corresponding to the impedance for each measured temperature.

[0131] Fig. 10 is an example comparing the error rate between an impedance value at an arbitrary temperature and a derived corrected impedance value according to one embodiment of the present invention. That is, Fig. 10 is an example comparing the error rate between an impedance value (measured at 7°C) actually measured by an electrical current inspection system (100) at an arbitrary temperature and an impedance value at a reference temperature corrected through a graph equation (impedance corrected to 25°C).

[0132] The error rate between the impedance value actually measured at any temperature and the correction value derived from the equation of the shape can be within 5%.

[0133] Meanwhile, the electrical flow inspection system (100) can determine the suitability of a waste battery by using at least one of the temperature, voltage, insulation resistance, and corrected impedance of the waste battery.

[0134] At this time, the corrected impedance means the impedance measured at any temperature corrected to the impedance corresponding to the reference temperature (e.g., 25℃).

[0135] Specifically, the voltage diagnosis unit (160) diagnoses whether the received battery voltage is within the set voltage range and whether the SOC of the battery is appropriate, and provides the diagnosis result to the inspection item management unit (110) so that the diagnosis result related to the battery voltage can be displayed on the item setting screen.

[0136] The insulation resistance diagnosis unit (170) can diagnose whether the received insulation resistance exceeds the set insulation resistance lower limit and provide the diagnosis result to the inspection item management unit so that the diagnosis result related to insulation resistance, i.e. insulation stability, is displayed on the item setting screen.

[0137] The electric flow diagnosis unit (180) compares the corrected impedance with the set electric flow upper limit, diagnoses it as normal if the impedance is lower than the electric flow upper limit, and diagnoses it as abnormal if it is higher, and provides the diagnosis results to the inspection item management unit (110) so that they can be displayed on the item setting screen.

[0138] In addition, if the impedance of the above-mentioned corrected waste battery is lower than the upper limit of the electric flow, the voltage of the waste battery is within the set voltage range, the insulation resistance of the waste battery is higher than the lower limit of the insulation resistance, and the SOC of the waste battery is within the appropriate SOC range, the electric flow inspection system (100) can determine that the waste battery is suitable.

[0139] Meanwhile, the embodiments of the present invention described above can be written as a program that can be executed on a computer, and the written program can be stored in a medium.

[0140] A medium may permanently store a computer-executable program, or may temporarily store it for execution or download. Furthermore, a medium may be a variety of recording or storage devices, including a single or multiple hardware devices. It is not limited to media directly connected to a computer system, but may also be distributed across a network.

[0141] Examples of media may include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; and ROM, RAM, flash memory, and other media configured to store program instructions. Furthermore, examples of other media may include recording or storage media managed by app stores that distribute applications, other sites that supply or distribute various software, servers, etc.

[0142] The embodiments described in the present invention and the accompanying drawings merely exemplify some of the technical concepts encompassed by the present invention. Therefore, the embodiments disclosed herein are intended to illustrate, rather than limit, the technical concepts of the present invention. Therefore, it is clear that the scope of the technical concepts of the present invention is not limited by these embodiments.

[0143] All modifications and specific embodiments that can be easily inferred by a person skilled in the art within the scope of the technical idea included in the specification and drawings of the present invention should be interpreted as being included in the scope of the present invention.

[0144] [Explanation of symbols]

[0145] 110: Inspection item management section 120: Setting value storage section

[0146] 130: Battery voltage detection unit 140: Insulation resistance detection unit

[0147] 150: Impedance detection section 160: Voltage diagnosis section

[0148] 170: Insulation resistance diagnostic section 180: Electric current diagnostic section

[0149] 190: Compatibility Diagnostic Unit 210: Battery Voltage Meter

[0150] 220: Insulation resistance meter 230: Impedance meter

[0151] 150: Measurement control unit 152: Phase difference detection unit

[0152] 153: Impedance calculation unit 231: Frequency control unit

[0153] 232: Input frequency generation unit 233: Output frequency measurement unit

Claims

1. A method for testing the electric flow of a waste battery by an electric flow testing system, A step of obtaining at least one of a set voltage range, an insulation resistance lower limit, an electric current upper limit, an impedance by temperature, and an appropriate SOC (state of charge) range corresponding to information related to the above-mentioned waste battery; A step of obtaining at least one of voltage, insulation resistance, upper limit of current flow, temperature and impedance of the above-mentioned waste battery; Comprising a step of determining suitability for the waste battery by using at least one of the voltage, insulation resistance, upper limit of electric flow, temperature, and impedance of the waste battery, The step of obtaining the above impedance uses a method of correcting the impedance measured at any temperature to the impedance at the reference temperature. How to compensate for the above impedance A step of obtaining an equation of a shape related to the temperature-dependent impedance based on a plurality of coordinates corresponding to the temperature-dependent impedance; A step of extracting specific coordinates by temperature from a plurality of coordinates constituting the equation of the acquired shape; and A method for examining the electric current of a waste battery, comprising the steps of extracting information on the relationship between temperature and impedance based on specific coordinates extracted by temperature, and correcting the impedance at an arbitrary temperature to the impedance at a reference temperature using the extracted information.

2. In paragraph 1, The equation of the above figure is the equation of a circle or an equation of an ellipse, The step of obtaining the equation of the above shape comprises the steps of: identifying at least one coordinate that can form an arc among a plurality of coordinates corresponding to the impedance according to temperature; and A step of obtaining an equation of the shape based on at least one identified coordinate, The specific coordinates extracted by temperature are the coordinates of the center of the circle or the center of the ellipse in the equation of the obtained shape. Method for testing the electrical flow of a waste battery.

3. In paragraph 1, The step of obtaining the impedance of the above-mentioned waste battery is: A step of sequentially inputting input frequencies to the above-mentioned waste batteries and outputting output frequencies for each input frequency; and A step of identifying a resonant frequency of high frequency by using the phase difference between the input frequency input to the waste battery and the output frequency corresponding to the input frequency, and obtaining the impedance of the waste battery corresponding to the identified resonant frequency of high frequency, Method for testing the electrical flow of a waste battery.

4. In paragraph 3, The steps for determining suitability for the above waste batteries are: If the impedance of the above-mentioned corrected waste battery is higher than the upper limit of the electric flow, the electric flow of the waste battery is judged as abnormal, or If the voltage of the above-mentioned waste battery is outside the set voltage range, the electric flow of the above-mentioned waste battery is judged to be abnormal, or A step of determining that the electric flow of the waste battery is abnormal when the insulation resistance of the waste battery is lower than the lower insulation resistance limit, Method for testing the electrical flow of a waste battery.

5. In paragraph 4, Further comprising a step of estimating the SOC (state of charge) of the waste battery based on the voltage of the waste battery, The steps for determining suitability for the above waste batteries are: If the SOC of the waste battery exceeds the appropriate SOC range, the method further includes a step of determining that the electric flow of the waste battery is abnormal. Method for testing the electrical flow of a waste battery.

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