Electronic device and lithium-sulfur battery state of charge diagnosis method thereof

Abstract

Provided is an electronic device for diagnosing the state of charge of a lithium-sulfur battery. The electronic device may be configured to: acquire, for the lithium-sulfur battery, a plurality of first voltages measured during a first time period and a plurality of second voltages measured during a second time period following the first time period; identify a first change amount of an average voltage over time on the basis of a first average voltage, which is an average of the plurality of first voltages, and a second average voltage, which is an average of the plurality of second voltages; determine, on the basis of the first change amount, whether to accumulate the number of times for diagnosing the state of charge of the lithium-sulfur battery; and diagnose the state of charge of the lithium-sulfur battery on the basis of the accumulated number of times.

Description

Electronic device and method for diagnosing the state of charge of a lithium-sulfur battery thereof

[0001] The present disclosure relates to an electronic device and a method for diagnosing a state of charge of a lithium-sulfur battery thereof, and more particularly, to a technique for diagnosing a state in which charging of a lithium-sulfur battery is severely delayed.

[0002] This application claims the benefit of priority to Republic of Korea Patent Application No. 2024-0103139, dated August 2, 2024, the entire contents of which are incorporated herein by reference.

[0003] Lithium-sulfur batteries have the characteristic that the voltage does not increase during charging or increases at a relatively slow rate. This characteristic of lithium-sulfur batteries is different from that of conventional batteries (e.g., lithium-ion batteries (LIBs)), and the safety diagnostic techniques used for conventional batteries cannot be applied in the same way. Accordingly, a method has been proposed to diagnose abnormal voltage behavior by checking the charge / discharge profile during the charge / discharge cycle and comparing it with the profile data of the previous cycle. However, even according to this method, if a charge delay occurs during the initial cycle when little voltage data is collected, the diagnosis of abnormal behavior is practically impossible because the previous cycle data is insufficient. Therefore, the need for a method that can diagnose the charge delay issue that occurs during the charge / discharge of lithium-sulfur batteries at an early stage has arisen.

[0004] The present disclosure is proposed to solve the above-described problems, and provides an electronic device and a method for diagnosing a state of charge of a lithium-sulfur battery thereof.

[0005] The technical task to be achieved by this embodiment is not limited to the task described above, and other technical tasks can be inferred from the following examples.

[0006] An electronic device according to one embodiment includes a transceiver; a processor; and one or more memories storing one or more instructions, wherein the one or more instructions, when executed, cause the processor to obtain, for a lithium-sulfur battery, a plurality of first voltages measured during a first time interval and a plurality of second voltages measured during a second time interval after the first time interval, determine a first amount of change in the average voltage over time based on the first average voltage, which is an average of the plurality of first voltages, and the second average voltage, which is an average of the plurality of second voltages, determine whether to accumulate a number of times for diagnosing a state of charge of the lithium-sulfur battery based on the first amount of change, and diagnose the state of charge of the lithium-sulfur battery based on the accumulated number of times.

[0007] One or more instructions according to one embodiment may be configured to cause the processor, when executed, to determine to accumulate a count if the first variation is a negative value.

[0008] One or more instructions according to one embodiment may be configured to cause the processor, when executed, to calculate a first variation based on a difference between an average value of points in time included in a first time interval and an average value of points in time included in a second time interval and a difference between a first average voltage and a second average voltage.

[0009] According to one embodiment, the difference between the average value of the points in the first time interval and the average value of the points in the second time interval may be a value obtained by subtracting the average value of the points in the first time interval from the average value of the points in the second time interval, and the difference between the first average voltage and the second average voltage may be a value obtained by subtracting the first average voltage from the second average voltage.

[0010] One or more instructions according to one embodiment may be configured to cause the processor, when executed, to diagnose a state of charge of a lithium-sulfur battery if a sum of the accumulated counts corresponds to a threshold value.

[0011] In one embodiment, the diagnosed charging state may be a delayed charging state with a high risk of ignition.

[0012] One or more instructions according to one embodiment may be configured to cause the processor, when executed, to repeat an operation of determining whether to accumulate a count based on an amount of change in average voltage over time until the sum of the counts corresponds to a threshold value.

[0013] According to one embodiment, each of the plurality of first voltages and the plurality of second voltages may include a predetermined number of voltages measured at predetermined intervals.

[0014] A method for diagnosing a state of charge of a lithium-sulfur battery, performed by an electronic device according to one embodiment, includes the steps of: obtaining, for a lithium-sulfur battery, a plurality of first voltages measured during a first time interval and a plurality of second voltages measured during a second time interval after the first time interval; determining a first change amount in an average voltage over time based on a first average voltage which is an average of the plurality of first voltages and a second average voltage which is an average of the plurality of second voltages; determining, based on the first change amount, whether to accumulate a number of times for diagnosing a state of charge of the lithium-sulfur battery; and diagnosing the state of charge of the lithium-sulfur battery based on the accumulated number of times, wherein the second average voltage may be an average of a plurality of second voltages of the lithium-sulfur battery measured during a second time interval before the first time interval.

[0015] A non-transitory computer-readable recording medium having recorded thereon a program for executing a method for diagnosing a state of charge of a lithium-sulfur battery according to one embodiment of the present invention, the method for diagnosing a state of charge of a lithium-sulfur battery comprises: obtaining, for a lithium-sulfur battery, a plurality of first voltages measured during a first time interval and a plurality of second voltages measured during a second time interval after the first time interval; confirming a first change amount in an average voltage over time based on a first average voltage which is an average of the plurality of first voltages and a second average voltage which is an average of the plurality of second voltages; determining, based on the first change amount, whether to accumulate a number of times for diagnosing a state of charge of the lithium-sulfur battery; and diagnosing the state of charge of the lithium-sulfur battery based on the accumulated number of times, wherein the second average voltage may be an average of a plurality of second voltages of the lithium-sulfur battery measured during a second time interval before the first time interval.

[0016] According to the present disclosure, even if a charge delay occurs at the initial stage of charging a lithium-sulfur battery, a state of extreme charge delay with a high risk of fire can be diagnosed.

[0017] Additionally, according to the present disclosure, the charging delay state of a lithium-sulfur battery can be diagnosed in real time.

[0018] The effects of the 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 of the claims.

[0019] Figure 1 illustrates a block diagram of an electronic device according to one embodiment.

[0020] Figure 2 shows a flowchart of a method for diagnosing a state of charge of a lithium sulfur battery according to one embodiment.

[0021] Figure 3 shows a capacity graph according to a charge / discharge test of a lithium-sulfur battery according to one embodiment.

[0022] Figure 4 shows a graph of voltage change according to a method for diagnosing the state of charge of a lithium-sulfur battery according to one embodiment.

[0023] Figure 5 illustrates a charge state diagnosis logic of a lithium sulfur battery according to one embodiment.

[0024] The terms used in the examples have been selected from widely used, current terms, taking into account the functions of the present disclosure. However, these terms may vary depending on the intentions of those skilled in the art, precedents, the emergence of new technologies, etc. Furthermore, in certain cases, terms may be arbitrarily selected by the applicant, in which case their meanings will be described in detail in the relevant description. Therefore, the terms used in this disclosure should not be defined simply as names, but rather based on the meanings of the terms and the overall content of the present disclosure.

[0025] When a part of the specification is said to "include" a component, this does not exclude other components, but rather implies the inclusion of other components, unless otherwise specifically stated. Furthermore, terms such as "part" and "module" used in the specification mean a unit that processes at least one function or operation, which may be implemented in hardware, software, or a combination of hardware and software.

[0026] The expression "at least one of a, b, and c" described throughout the specification may encompass 'a alone', 'b alone', 'c alone', 'a and b', 'a and c', 'b and c', or 'all of a, b, and c'.

[0027] Below, embodiments of the present disclosure are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein.

[0028] Hereinafter, embodiments of the present disclosure relating to an electronic device for diagnosing a state of charge of a lithium-sulfur battery will be described in detail with reference to the drawings.

[0029] Figure 1 illustrates a block diagram of an electronic device according to one embodiment.

[0030] Referring to FIG. 1, an electronic device (100) may include, according to one embodiment, a transceiver (110), a processor (120), and a memory (130). The electronic device (100) illustrated in FIG. 1 only includes components related to the present embodiment. Therefore, it will be understood by those skilled in the art related to the present embodiment that other general components may be included in addition to the components illustrated in FIG. 1.

[0031] For example, the electronic device (100) may include a communication device including one or more transceivers (110), an input unit, and an output unit. The communication unit is a device for performing wired / wireless communication and may communicate with an external electronic device. The external electronic device may be a terminal or a server. In addition, communication technologies used by the communication unit may include GSM (Global System for Mobile communication), CDMA (Code Division Multi Access), LTE (Long Term Evolution), 5G, WLAN (Wireless LAN), Wi-Fi (Wireless-Fidelity), Bluetooth, RFID (Radio Frequency Identification), Infrared Data Association (IrDA), ZigBee, NFC (Near Field Communication), etc. The input unit may be, for example, a traditional keypad or keyboard, a mouse, a microphone for inputting voice signals, a camera, and various other input means for detecting or receiving various types of user input. The output unit may be, for example, a display that outputs images, a speaker that outputs sounds, a haptic device that generates vibrations, and various other forms of output means.

[0032] According to one embodiment, the electronic device (100) may be a device for charging and discharging a lithium-sulfur battery. Specifically, the electronic device (100) may be connected to a lithium-sulfur battery and may activate the battery by charging and discharging the battery by applying a charge or discharge current to the battery. The electronic device (100) may perform charging and discharging of the lithium-sulfur battery, and may simultaneously conduct performance and life evaluation of the lithium-sulfur battery and may also perform tests on the operation of the lithium-sulfur battery. In addition, the electronic device (100) may obtain voltage data of the battery during the process of charging and discharging the lithium-sulfur battery. The voltage data may be obtained, for example, from a BMS or the like through a transceiver (110).

[0033] According to another embodiment, the electronic device (100) may be a battery management system (BMS) or a server for analyzing various battery information.

[0034] The processor (120) can control the overall operation of the electronic device (100) and process data and signals. The processor (120) can be composed of at least one hardware unit. In addition, the processor (120) can operate by one or more software modules generated by executing program codes stored in the memory (130). The processor (120) can include a memory, and the processor (120) can control the overall operation of the electronic device (100) and process data and signals by executing the program codes stored in the memory.

[0035] The processor (120) may be implemented as a computer or similar device according to hardware, software, or a combination thereof. In terms of hardware, the processor (120) may be implemented in the form of an electronic circuit that processes electrical signals to perform a control function, and in terms of software, the processor (120) may be implemented in the form of a program that drives the hardware processor (120). Meanwhile, unless otherwise specified in the following description, the operation of the electronic device may be interpreted as being performed under the control of the processor (120). That is, when modules implemented in a system for diagnosing the state of charge of a lithium-sulfur battery are executed, the modules may be interpreted as controlling the processor (120) to perform the operations of the electronic device (100) below.

[0036] The memory (130) can store various types of information. The memory (130) can store data temporarily or semi-permanently. For example, the memory (130) of the electronic device (100) can store data related to an operating program (OS: Operating System) for operating the electronic device (100). Examples of the memory (130) may include a hard disk drive (HDD: Hard Disk Drive), a solid state drive (SSD), flash memory, read-only memory (ROM: Read-Only Memory), random access memory (RAM: Random Access Memory), etc. The memory (130) may be provided as a built-in type or a detachable type.

[0037] In summary, the various embodiments may be implemented through various means. For example, the various embodiments may be implemented through hardware, firmware, software, or a combination thereof.

[0038] In the case of hardware implementation, the methods according to various embodiments may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

[0039] When implemented via firmware or software, the methods according to various embodiments may be implemented in the form of modules, procedures, or functions that perform the functions or operations described above. For example, software code may be stored in memory and executed by a processor. The memory may be located within or external to the processor and may exchange data with the processor via various known means.

[0040] Figure 2 shows a flowchart of a method for diagnosing a state of charge of a lithium sulfur battery according to one embodiment.

[0041] In step S210, the electronic device (100) may obtain a plurality of first voltages measured during a first time interval and a plurality of second voltages measured during a second time interval after the first time interval for the lithium-sulfur battery. Each of the plurality of first voltages and the plurality of second voltages may include, for example, a preset number of voltages measured at predetermined intervals. Here, the preset number may be, for example, 10. In another example, each of the plurality of first voltages and the plurality of second voltages may include a preset number of voltages, but the intervals between the time points at which each voltage is measured may not be constant.

[0042] In step S220, the electronic device (100) can determine a first change amount in the average voltage over time based on a first average voltage, which is an average of a plurality of first voltages, and a second average voltage, which is an average of a plurality of second voltages. For example, the electronic device (100) can calculate the first change amount based on the difference between the average value of points in a first time section and the average value of points in a second time section and the difference between the first average voltage and the second average voltage. In this way, by deriving an average value of a certain number of voltages included in a specific time section to calculate the first change amount, noise due to a voltage spike phenomenon that may be included in the specific time section, etc., can be removed or alleviated. In addition, since the average value is derived based on a relatively small amount of data compared to using a large amount of data such as a charge / discharge cycle, the computational cost required for diagnosing the state of charge can be significantly reduced.

[0043] According to one embodiment, the difference between the average value of the points in the first time interval and the average value of the points in the second time interval may be, for example, a value obtained by subtracting the average value of the points in the first time interval from the average value of the points in the second time interval, and the difference between the first average voltage and the second average voltage may be, for example, a value obtained by subtracting the first average voltage from the second average voltage. Meanwhile, when a specific time interval is t, the calculation process of the average voltage change amount in the time interval t may be expressed, for example, as in Mathematical Expression 1 below.

[0044]

[0045] In the above mathematical formula, is the change over time interval t, is the average voltage over time interval t, is the average voltage of the previous time interval t-1 of the time interval t, is the average value of the points (T) included in the time interval t, represents the average value of the time points included in the time interval t-1. That is, when each time interval includes 10 time points and 10 voltage data measured at each time point, the average voltage of each time interval and the average value of the time points included in each time interval are calculated, and based on this, the amount of change in the average voltage over time can be derived. In other words, the amount of change in the average voltage over time calculated through the above process can have the meaning of the slope of the average voltage over time.

[0046] In step S230, the electronic device (100) may determine whether to accumulate the number of times for diagnosing the state of charge of the lithium-sulfur battery based on the first change amount. For example, the electronic device (100) may determine to accumulate the number of times if the first change amount is a negative value. That is, if the average voltage of a specific time interval has a lower value than the average voltage of a previous time interval, the number of times may be accumulated. This may be a condition for the number of times accumulation set in consideration of the fact that, in the case where the degree of charging delay described below is extreme, the amount of change in the average voltage generally has a negative value. Meanwhile, it will be clearly understood by those skilled in the art that the threshold value that serves as the criterion for accumulating the number of times is not limited thereto and may be set in various ways depending on the embodiment.

[0047] In step S240, the electronic device (100) can diagnose the state of charge of the lithium-sulfur battery based on the accumulated count. For example, the electronic device (100) can diagnose the state of charge of the lithium-sulfur battery when the sum total of the accumulated counts corresponds to a threshold value. Here, the diagnosed state of charge of the lithium-sulfur battery may be a charge delay state with a high risk of ignition. In other words, the electronic device (100) can diagnose whether the lithium-sulfur battery is in an extreme charge delay state with a high risk of ignition based on the sum total of the accumulated counts. The charge delay state may mean a state in which the voltage of the battery does not increase or increases slowly during charging, so that the charging capacity and time increase, and the voltage of the battery does not reach the target voltage, and the state of charge diagnosed according to the present disclosure may refer to an extreme charge delay state that is highly likely to lead to ignition among the charge delay states. Meanwhile, the threshold value as a condition for diagnosing the state of charge may be a value derived through experimentation, and may be, for example, 5.

[0048] According to one embodiment, the electronic device (100) may repeat an operation of determining whether to accumulate a number of times for diagnosing a state of charge of a lithium-sulfur battery based on the amount of change in the average voltage as described above until the sum of the numbers corresponds to a threshold value. In other words, the electronic device (100) may repeat steps S210 to S230 until the sum of the accumulated numbers corresponds to the threshold value. If the sum of the accumulated numbers corresponds to the threshold value, the electronic device (100) may diagnose that an extreme charging delay of the lithium-sulfur battery has occurred and provide a notification thereon.

[0049] Accordingly, the electronic device (100) can diagnose cells with extreme charging delay tendencies in real time based on voltage change trends of the lithium-sulfur battery within the current cycle, without the need for data acquisition and analysis of battery capacity over multiple charge / discharge cycles. Accordingly, even if a ignition risk situation occurs in the initial cycle, it can be diagnosed and addressed effectively and economically, and based on the present disclosure, more rapid responses to all charging delay situations can be achieved.

[0050] Figure 3 shows a capacity graph (300) according to a charge / discharge test of a lithium sulfur battery according to one embodiment.

[0051] Referring to FIG. 3, the capacity graph (300) may represent a portion of the charge profile during the charge / discharge cycle of a cell that ignited after a charge delay phenomenon occurred during a charge / discharge test on a lithium-sulfur battery. The capacity graph (300) is a graph in which the capacity (mAh) of the battery is represented on the x-axis and the voltage (V) is represented on the y-axis. On the graph, charge profile B may be a profile in which a slight charge delay occurred based on charge profile A, and a profile in which an extreme charge delay occurred and led to ignition may be charge profile C. Various safety diagnosis methods are being discussed to prevent ignition such as charge profile C. However, in most cases, since the voltage abnormality of the current cycle is diagnosed based on a comparison with the previous charge / discharge cycle data, there is a limitation in that it is difficult to diagnose a problem of a charge delay that occurs at the beginning of the cycle because there is insufficient data from the previous cycle.

[0052] FIG. 4 shows a voltage change graph (400) according to a method for diagnosing a state of charge of a lithium sulfur battery according to one embodiment.

[0053] The voltage change graph (400) of FIG. 4 shows the trend (slope) of the average voltage change over time according to the charging state diagnosis method of the present disclosure, based on the same charging profile data as FIG. 3. In the voltage change graph (400), the x-axis represents a time interval t composed of a plurality of time points (T), and the y-axis can represent the voltage change (V / s) obtained by dividing the voltage value by time. The voltage change graph (400) shows that the average voltage change over time of each of charging profiles A and B has a negative value less than 5 times, whereas the average voltage change over time of charging profile C has a negative value more than 5 times. That is, by using the voltage change graph (400) as described above, it is possible to quickly diagnose the occurrence of an extreme charging delay at an early stage.

[0054] Figure 5 illustrates a charge state diagnosis logic of a lithium sulfur battery according to one embodiment.

[0055] In step S510, the electronic device (100) can check whether the number of acquired voltage data of the lithium-sulfur battery is greater than or equal to a first threshold value. The first threshold value can be set to, for example, 70. That is, in an example where 10 voltage data are included in one time interval, the electronic device (100) can check whether voltage data of the lithium-sulfur battery corresponding to at least 7 time intervals have been acquired. In this way, the electronic device (100) can check whether a minimum amount of voltage data has been acquired prior to diagnosing the state of charge.

[0056] If it is confirmed that the minimum data for diagnosing the state of charge has been acquired, the electronic device (100) can check the voltage change amount of the lithium-sulfur battery over time in step S520. On the other hand, if the voltage data exceeding the first threshold value has not been acquired, the electronic device (100) can continuously acquire voltage data without performing operations below step S520.

[0057] At step S530, the electronic device (100) can check whether the voltage change amount is negative.

[0058] If the confirmed voltage change amount is negative, in step S540, the electronic device (100) can accumulate the number of times to diagnose the charging state once. On the other hand, if the confirmed voltage change amount is not negative, the electronic device (100) can perform step S520 again.

[0059] At step S550, the electronic device (100) can check whether the total of the accumulated counts corresponds to a second threshold. The second threshold may be, for example, 5.

[0060] If the sum total of the accumulated counts corresponds to the second threshold, the electronic device (100) can diagnose the state of charge of the lithium-sulfur battery at step S560. On the other hand, if the sum total of the accumulated counts does not correspond to the second threshold, the electronic device (100) can perform steps S520 and below again. That is, the electronic device (100) can repeatedly perform steps S520 to S550 until the sum total of the accumulated counts corresponds to the second threshold.

[0061] The electronic device according to the above-described embodiments may include a processor, a memory for storing and executing program data, permanent storage such as a disk drive, a communication port for communicating with an external device, a user interface device such as a touch panel, a key, a button, etc. The methods implemented as software modules or algorithms may be stored on a computer-readable recording medium as computer-readable codes or program instructions executable on the processor. Here, the computer-readable recording medium includes a magnetic storage medium (e.g., read-only memory (ROM), random-access memory (RAM), floppy disk, hard disk, etc.) and an optical reading medium (e.g., CD-ROM, DVD: Digital Versatile Disc)). The computer-readable recording medium may be distributed to computer systems connected to a network, so that the computer-readable code may be stored and executed in a distributed manner. The medium may be readable by a computer, stored in a memory, and executed by a processor.

[0062] The present embodiment may be represented by functional block configurations and various processing steps. These functional blocks may be implemented by various hardware and / or software configurations that perform specific functions. For example, the embodiment may employ direct circuit configurations such as memory, processing, logic, look-up tables, etc., which may perform various functions under the control of one or more microprocessors or other control devices. Similarly, the present embodiment may be implemented in a programming or scripting language such as C, C++, Java, assembler, etc., including various algorithms implemented as a combination of data structures, processes, routines, or other programming configurations. Functional aspects may be implemented as algorithms that execute on one or more processors. Furthermore, the present embodiment may employ conventional techniques for electronic configuration, signal processing, and / or data processing. Terms like "mechanism," "element," "means," and "composition" can be used broadly and are not limited to mechanical or physical components. These terms can also encompass a series of software routines, such as those associated with a processor.

[0063] The above-described embodiments are merely examples, and other embodiments may be implemented within the scope of the claims set forth below.

Claims

1. In electronic devices, transceiver; processor; and Contains one or more memories that store one or more instructions, The one or more instructions, when executed, cause the processor to: For a lithium-sulfur battery, a plurality of first voltages measured during a first time interval and a plurality of second voltages measured during a second time interval after the first time interval are obtained, Based on the first average voltage, which is the average of the plurality of first voltages, and the second average voltage, which is the average of the plurality of second voltages, a first change amount of the average voltage over time is confirmed, Based on the first change amount, it is determined whether to accumulate the number of times to diagnose the state of charge of the lithium-sulfur battery, An electronic device configured to diagnose the state of charge of the lithium sulfur battery based on the accumulated number of times.

2. In paragraph 1, The one or more instructions, when executed, cause the processor to: An electronic device configured to determine that the number of times is accumulated when the first change amount is a negative value.

3. In paragraph 1, The one or more instructions, when executed, cause the processor to: An electronic device configured to calculate the first change amount based on a difference between an average value of points included in the first time interval and an average value of points included in the second time interval and a difference between the first average voltage and the second average voltage.

4. In paragraph 3, The difference between the average value of the points included in the first time interval and the average value of the points included in the second time interval is It is a value obtained by subtracting the average value of the time points included in the first time interval from the average value of the time points included in the second time interval, The difference between the first average voltage and the second average voltage is An electronic device, wherein the value is obtained by subtracting the first average voltage from the second average voltage.

5. In paragraph 1, The one or more instructions, when executed, cause the processor to: An electronic device configured to diagnose the state of charge of the lithium-sulfur battery when the sum of the accumulated counts corresponds to a threshold value.

6. In paragraph 1, The above-mentioned state of charge being diagnosed is a state of delayed charge with a high risk of ignition, an electronic device.

7. In paragraph 1, The one or more instructions, when executed, cause the processor to: An electronic device configured to repeat an operation of determining whether to accumulate the number of times based on the amount of change in the average voltage over the time until the sum of the number of times corresponds to a threshold value.

8. In paragraph 1, An electronic device, wherein each of the plurality of first voltages and the plurality of second voltages includes a preset number of voltages measured at predetermined intervals.

9. In a method for diagnosing the state of charge of a lithium-sulfur battery, performed by an electronic device, For a lithium sulfur battery, a step of obtaining a plurality of first voltages measured during a first time interval and a plurality of second voltages measured during a second time interval after the first time interval; A step of checking a first change amount of the average voltage over time based on a first average voltage which is an average of the plurality of first voltages and a second average voltage which is an average of the plurality of second voltages; A step of determining whether to accumulate the number of times to diagnose the state of charge of the lithium-sulfur battery based on the first change amount; and A step of diagnosing the state of charge of the lithium sulfur battery based on the accumulated number of times, A method for diagnosing a state of charge of a lithium-sulfur battery, wherein the second average voltage is an average of a plurality of second voltages of the lithium-sulfur battery measured during a second time period prior to the first time period.

10. A non-transitory computer-readable recording medium recording a program for executing the method of Article 9 on a computer.

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