Apparatus and method for diagnosing battery

Abstract

A battery diagnostic method may include collecting battery-related measurements during a discharge period included in each cycle of a battery charge / discharge test; determining a reference value of the state variation in the discharge period; comparing the state change amount in the discharge period measured for each cycle with a reference value; and performing a battery diagnosis based on a result of the comparison.

Description

Technical Field

[0001] This application claims priority and benefit to Korean Patent Application No. 10-2024-0102278, filed on August 1, 2024, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.

[0002] This invention relates to apparatus and methods for diagnosing batteries, and more particularly, to apparatus and methods for diagnosing lithium-sulfur batteries under performance testing. Background Technology

[0003] Rechargeable and reusable secondary batteries are manufactured into battery modules or battery packs by connecting multiple battery cells in series based on the output capacity required by the corresponding device, serving as a power source for various applications. Recently, with the development of portable electronic devices, electric vehicles, and high-capacity power storage systems, the demand for high-capacity batteries has been increasing.

[0004] Lithium-sulfur batteries are secondary batteries that use sulfur-based materials with sulfur-sulfur bonds as the positive electrode active material and lithium metal as the negative electrode active material. Lithium-sulfur batteries exhibit higher energy density characteristics than other types of batteries. A typical lithium-sulfur battery consists of an anode made of lithium metal or a lithium metal alloy and a cathode made of elemental sulfur or other electroactive sulfur materials. When the state of charge (SOC) of a lithium-sulfur battery reaches a certain value (approximately 70%), the electrochemical reaction changes, and from this point onward, the open-circuit voltage (OCV) of the lithium-sulfur battery becomes disproportionate to the SOC.

[0005] Meanwhile, the secondary batteries undergo performance testing in the final stage of the manufacturing process before transportation. However, due to charging delays, lithium-sulfur batteries are prone to frequent fires during performance testing. In this situation, it is difficult to predict the ignition time and accurately analyze the cause after a fire, making it difficult to take measures to prevent fires in advance. Summary of the Invention

[0006] [Technical Issues]

[0007] To avoid one or more problems in related technologies, embodiments of this disclosure provide an apparatus for diagnosing batteries, particularly lithium-sulfur batteries under performance testing.

[0008] To address one or more problems in the related technologies, embodiments of this disclosure also provide a battery diagnostic method used by a battery diagnostic device.

[0009] [Technical Solution]

[0010] To achieve the purposes of this disclosure, a battery diagnostic device may include: at least one processor; and a memory configured to store at least one instruction executed by the at least one processor.

[0011] Here, at least one instruction may include: instructions for collecting battery-related measurements during a discharge period included in each cycle of the battery charge / discharge test; instructions for determining a reference value for the amount of state change during the discharge period; instructions for comparing the amount of state change during the discharge period measured for each cycle with the reference value; and instructions for performing battery diagnostics based on the comparison results.

[0012] Battery-related measurements may include one or more of the following: battery discharge capacity, open-circuit voltage (OCV), current, and temperature.

[0013] A reference value for the change in OCV can be calculated using the OCV from the previous cycle and a weighting factor that is set differently depending on the battery type.

[0014] A reference value for the OCV change can be determined using probability density function analysis of the OCV change measured during each cycle of a charge / discharge test that includes multiple cycles.

[0015] A reference value for the change in discharge capacity can be calculated using the discharge capacity of the previous cycle and a weighting factor that varies depending on the battery type.

[0016] A reference value for the change in discharge capacity can be determined by probability density function analysis of the change in discharge capacity measured in each cycle during a charge / discharge test that includes multiple cycles.

[0017] Instructions for performing battery diagnostics based on the comparison results may include instructions for determining that if the amount of state change in the corresponding discharge period is greater than or equal to a reference value, the probability of a charging delay occurring during the charging period following the corresponding discharge period is high.

[0018] At least one instruction may also include: an instruction to check whether there are changes in the current and temperature used in the battery charge / discharge test during the corresponding cycle; and an instruction to terminate the diagnostic if the changes in current and temperature are greater than or equal to a predetermined threshold.

[0019] According to another embodiment of this disclosure, a battery diagnostic method may include: collecting battery-related measurements during a discharge period included in each cycle of a battery charge / discharge test; determining a reference value for the amount of state change during the discharge period; comparing the amount of state change measured for each cycle with the reference value; and performing battery diagnostics based on the comparison result.

[0020] Battery-related measurements may include one or more of the following: battery discharge capacity, open-circuit voltage (OCV), current, and temperature.

[0021] A reference value for the change in OCV can be calculated using the OCV from the previous cycle and a weighting factor that is set differently depending on the battery type.

[0022] A reference value for the OCV change can be determined using probability density function analysis of the OCV change measured during each cycle of a charge / discharge test that includes multiple cycles.

[0023] At the same time, a reference value for the change in discharge capacity can be calculated using the discharge capacity of the previous cycle and a weighting factor that is set differently depending on the battery type.

[0024] A reference value for the change in discharge capacity can be determined by probability density function analysis of the change in discharge capacity measured in each cycle during a charge / discharge test that includes multiple cycles.

[0025] Performing battery diagnostics based on the comparison results may include: if the amount of state change in the corresponding discharge period is greater than or equal to a reference value, then it is determined that there is a high probability of a charging delay occurring during the charging period following the corresponding discharge period.

[0026] The diagnostic method may also include checking for changes in the current and temperature used in the battery charge / discharge test during the corresponding cycle; and terminating the battery diagnostic if the changes in current and temperature are greater than or equal to a predetermined threshold.

[0027] Batteries can include lithium-sulfur batteries.

[0028] [Beneficial Effects]

[0029] According to embodiments of this disclosure, charging delay issues in lithium-sulfur batteries can be detected in real time, allowing for proactive fire prevention.

[0030] Furthermore, by diagnosing problems before they actually occur, accurate cause analysis of the problem is possible. Attached Figure Description

[0031] Figure 1 This is a graph illustrating the charging delay issues that occurred during performance testing of lithium-sulfur batteries.

[0032] Figure 2 This is a graph showing the diagnostic parameters used in the battery diagnostic method according to an embodiment of the present invention.

[0033] Figure 3 This is an operation flowchart of a battery diagnostic method according to an embodiment of the present invention.

[0034] Figure 4 This is a diagram illustrating a method for setting a reference value for one of the battery diagnostic parameters according to an embodiment of the present invention—the change in discharge OCV.

[0035] Figure 5 This is a block diagram of a battery diagnostic device according to an embodiment of the present invention.

[0036] 100: Battery diagnostic device

[0037] 110: Processor; 120: Memory

[0038] 130: Transceiver 140: Input Interface

[0039] 150: Output interface; 160: Storage device Detailed Implementation

[0040] This invention can be modified in various forms and has various embodiments, and specific embodiments thereof are shown by way of example in the accompanying drawings and will be described in detail below. However, it should be understood that the invention is not intended to be limited to the specific embodiments, but rather, the invention is intended to cover all modifications, equivalents, and substitutions falling within the spirit and technical scope of the invention. Throughout the description of the accompanying drawings, similar reference numerals refer to similar elements.

[0041] It should be understood that although terms such as first, second, A, B, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the invention. As used herein, the term "and / or" includes a combination of multiple associated listed items or any one of multiple associated listed items.

[0042] It should be understood that when a component is described as being “coupled” or “connected” to another component, it can be directly coupled or connected to the other component, or there can be intermediate components. Conversely, when a component is described as being “directly coupled” or “directly connected” to another component, there are no intermediate components.

[0043] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that the terms “comprising,” “including,” “containing,” “comprise,” and / or “having,” when used herein, specify the presence of stated features, integers, steps, operations, constituent elements, components, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, constituent elements, components, and / or combinations thereof.

[0044] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in common dictionaries should be interpreted as having the same meaning as their meaning in the context of the relevant field, and will not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0045] Some of the terms used in this article are defined as follows.

[0046] A battery cell is a basic unit used to store electricity, while a battery module is an assembly in which multiple battery cells are electrically connected.

[0047] A battery pack is a single-structure system assembled from connected modular units arranged in series / parallel by the battery manufacturer, and can be monitored and controlled by a battery management system (BMS). A battery pack includes several battery modules and battery protection units or any other protection devices.

[0048] A battery rack refers to a battery system comprising one or more battery packs, while a battery bank refers to a large battery rack system configured by connecting multiple battery racks in parallel. A battery bank BMS can monitor and control several BMSs, with each BMS managing the battery rack.

[0049] A battery assembly may include multiple electrically connected battery cells and refers to an assembly used as a power supply source by application to a particular system or device. Here, a battery assembly may mean a battery module, battery pack, battery rack, or battery bank, but the scope of this invention is not limited to these entities.

[0050] In the following, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0051] Figure 1 This is a graph illustrating the charging delay issues that occurred during performance testing of lithium-sulfur batteries.

[0052] Batteries are typically manufactured through electrode fabrication, assembly, and activation / inspection processes. Complete batteries that have undergone these processes are shipped in the form of battery packs (or battery modules) comprising multiple individual cells connected in series. The battery packs are connected to a load via positive and negative terminals and can perform charge / discharge operations. Depending on the requirements of the system using the batteries, the battery packs can be connected in series or parallel.

[0053] In various battery manufacturing processes, the activation / inspection process activates electrical energy and verifies stability. The activation process involves repeated aging and charge / discharge cycles. Following activation, the batteries undergo an inspection process to test their charge capacity and screen for defective batteries before shipping.

[0054] The battery inspection process may include charge / discharge tests to evaluate battery performance. These tests typically involve repeated charge and / or discharge cycles.

[0055] Typically, as shown in the figure, a constant current is applied to the battery cell under test, and the test is performed over several cycles in a charge-discharge test. Figure 1 In the graph, the x-axis represents time, and the y-axis represents voltage (V). The x-axis can also represent capacity (mAh). A single charge-discharge cycle typically consists of one or more "discharge" steps and one or more "charge" steps, with a rest period after each "discharge" and "charge" step. Figure 1 The graph in the figure shows two superimposed discharge steps and one charge step.

[0056] During normal cycling, the cell voltage tends to decrease over time during the discharge phase using negative current. During the charging phase using positive current, the voltage tends to increase with increasing current application time.

[0057] However, as Figure 1 As shown in the charging delay cycle, even when current is applied, cells with internal short circuits or other problems exhibit a delayed voltage increase or even a full voltage drop during the charging step. When such a charging delay (charging delay cycle) occurs, the charging time increases rapidly, potentially leading to misfires during performance testing.

[0058] This invention addresses the problem by providing a diagnostic method that detects charging delay before it occurs, enabling real-time pre-detection and prevention of fires caused by charging delay.

[0059] Figure 2 This is a graph illustrating the diagnostic parameters used in the battery diagnostic method according to an embodiment of the present invention.

[0060] Figure 2 The upper curve in the graph represents the voltage value (V) over time during the normal cycle and the charging delay cycle, while the lower curve represents the current value (A) over time during the normal cycle and the charging delay cycle. Figure 2 The graphs in the figure are composed of voltage and current values ​​measured in normal cycles and charging delay cycles obtained from the experiment.

[0061] Figure 2Each cycle in the upper and lower curves comprises a charging / discharging current, which is sequentially composed of a discharging period, a rest period, and a charging period. Here, each segment of the normal cycle represented in the upper curve (voltage) is time-synchronized with each segment of the normal cycle represented in the lower curve. Furthermore, each segment of the charging delay cycle represented in the lower curve (current) is time-synchronized with each segment of the charging delay cycle represented in the upper curve.

[0062] Observing the upper curve (voltage), it can be seen that the voltage (OCV) measured at the end of the rest period (0 charging current) after the discharge period in the "charging delay cycle" is lower than the voltage (OCV) measured at the end of the rest period (0 charging current) after the discharge period in the "normal cycle". In other words, if the voltage measured at the end of the rest period (0 charging current) after the discharge period in the normal cycle is the first OCV value, and the voltage measured at the end of the rest period (0 charging current) after the discharge period in the charging delay cycle is the second OCV value, then it can be understood that the second OCV value is lower than the first OCV value.

[0063] Furthermore, examining the lower curve (current), it can be seen that the rest period following the discharge period begins earlier in the charging delay period than in the normal period. Considering that the battery's discharge capacity is determined at the maximum discharge point (i.e., the end of the discharge period), it is understandable that the discharge capacity during the charging delay period is lower than that during the normal period.

[0064] The present invention provides a method for early diagnosis of charging delay by using OCV and / or discharge capacity characteristics as diagnostic parameters during a rest period following a discharge period preceding a charging period with charging delay, wherein the discharge period is included in the cycle to which the charging period belongs.

[0065] Figure 3 This is an operation flowchart of a battery diagnostic method according to an embodiment of the present invention.

[0066] Battery diagnostics according to embodiments of the present invention can be performed during a charge / discharge test for performance testing. When a charge / discharge test for performance testing of a target battery (e.g., a single cell) is initiated (S310), battery-related measurements can be collected during the discharge period within each charge / discharge cycle (S320).

[0067] Measurements may include the mode used in the test cycle (e.g., charging current), battery temperature, and state values ​​for the discharge period within each charge / discharge cycle.

[0068] More specifically, the state value of the discharge period may include one or more of the OCV at the end of the rest period following the discharge period and the discharge capacity value. Here, the discharge capacity can be calculated at the end of the discharge period (i.e., at the beginning of the rest period following the discharge). More specifically, the discharge capacity can be calculated by integrating the current from the beginning to the end of the discharge period.

[0069] Meanwhile, the OCV and discharge capacity used as diagnostic parameters in this invention can be significantly affected by variations in cycling mode (e.g., charge / discharge current) and temperature. Therefore, cycling mode and temperature can serve as diagnostic influencing factors in this invention.

[0070] Reflecting on this, the present invention can first monitor changes in the cycle pattern (charging current) or temperature, which are diagnostic influencing factors, before performing diagnostics using diagnostic parameters. Specifically, it checks whether there are changes in the cycle pattern (charging current) or temperature compared to the previous cycle (S330).

[0071] If the test results show significant changes in the cycle mode and temperature, i.e., changes exceeding a certain threshold (Yes in S330), the diagnostics using the diagnostic parameters can be stopped, or the process can return to the step of collecting battery-related measurement data.

[0072] If the cycle pattern and temperature are unchanged (or only slightly changed) compared to the previous cycle, a diagnostic process using diagnostic parameters can be initiated (S350). In the diagnostic process (S350) according to an embodiment of the invention, a reference value for the diagnostic parameters is determined for each cycle, and the diagnostic parameters may be reference values ​​for the amount of state change during the discharge period. In other words, the reference value for the amount of state change during the discharge period can be set as the diagnostic parameters (S351).

[0073] Here, the state value of the discharge period may include one or more of the OCV at the end of the rest period following the discharge period and the discharge capacity. Furthermore, the state change during the discharge period may include one or more of the change in OCV at the end of the rest period following the discharge period compared to the previous cycle and the change in discharge capacity during the discharge period compared to the previous cycle.

[0074] Therefore, according to an embodiment, the reference value for the state change during the discharge period may include a reference value for the OCV change at the end of the rest period following the discharge period. According to another embodiment, the reference value for the state change during the discharge period may include a reference value for the discharge capacity change. According to yet another embodiment, the reference value for the state change during the discharge period may include both a reference value for the OCV change at the end of the rest period following the discharge period and a reference value for the discharge capacity change.

[0075] Here, the reference value (△OCV_th) of the OCV change at the end of the rest period after the discharge period can be determined according to the following equation 1: [Equation 1] ΔOCV th = max (OCV (n-1) Ⅹβ, σ) In Equation 1, OCV （n-1） σ is the OCV of the previous cycle, and β is the discharge OCV delay rate, which is a weighting factor that can be set differently depending on the type of lithium-sulfur battery (e.g., capacity). Additionally, σ is the minimum threshold related to OCV, which is set for anomaly diagnosis.

[0076] In addition, the reference value (△Capacity_th) of the change in discharge capacity during the discharge period can be determined according to Equation 2 below.

[0077] [Equation 2]

[0078] △Capacity_ th = Capacity (n-1) Xα

[0079] In Equation 2, Capacity （n-1） α is the discharge capacity of the previous cycle, and α is the discharge capacity lag rate, which is a weighting factor that can be set differently depending on the type of lithium-sulfur battery (e.g., capacity).

[0080] Once a reference value for the amount of state change during the discharge period is set, the amount of state change during the discharge period of each cycle is compared with the reference value (S352), and any abnormal battery is diagnosed (S360). Specifically, if the amount of state change during the discharge period of each cycle is lower than the reference value (Yes at S350), the corresponding cycle is determined to be a normal cycle, and the next cycle is executed to collect measurement values. Conversely, if the amount of state change during the discharge period of each cycle is equal to or higher than the reference value (No at S350), a high probability of charging delay in the subsequent charging period is determined, and therefore a battery abnormality is diagnosed and the charging / discharging test is terminated (S370).

[0081] In summary, according to a first embodiment of the present invention, the diagnostic process using diagnostic parameters may include the following steps: setting a reference value for the change in OCV at the end of the rest period after the discharge period compared to the previous cycle; and comparing the amount of OCV change measured for each cycle with the reference value for the OCV change.

[0082] Furthermore, according to a second embodiment of the present invention, the diagnostic process using diagnostic parameters may include the following steps: setting a reference value for the change in discharge capacity during the discharge period compared to the previous cycle; and comparing the amount of change in discharge capacity measured for each cycle with the reference value for the change in discharge capacity.

[0083] Furthermore, according to a third embodiment of the present invention, the diagnostic process using diagnostic parameters may include the following steps: setting a reference value for the change in OCV at the end of the rest period after the discharge period compared to the previous cycle; setting a reference value for the change in discharge capacity during the discharge period compared to the previous cycle; comparing the OCV change measured for each cycle with the reference value for the OCV change; and comparing the discharge capacity change measured for each cycle with the reference value for the discharge capacity change. Here, when both the OCV change and the discharge capacity change exceed their respective reference values, a cell abnormality (e.g., internal short circuit) can be determined.

[0084] Figure 4 This is a diagram illustrating a method for setting a reference value for one of the battery diagnostic parameters—OCV change—according to an embodiment of the present invention.

[0085] Figure 4 A graph is shown of a standard normal distribution configured by measuring the change in OCV (delta-OCV) over all loops (2,397 loops) included in the pre-execution test and representing the probability density function indicating the value of the change in OCV.

[0086] Based on the results of the normal distribution analysis of the OCV variation, the OCV variation (delta-OCV) during the charging delay cycle was observed at a position where the deviation from the mean of 0.0 is -2σ (94.5%) or below. Therefore, the reference value of the OCV variation according to an embodiment of the present invention can be determined by referring to the OCV variation at a deviation of -2σ.

[0087] For example, in Figure 4 In the curve graph, the reference value for the change in OCV can be derived from either the change in OCV at deviation -2σ or any OCV change located to the left of deviation -2σ. Furthermore, from... Figure 4 The value of the OCV change derived from the curve can be used as Figure 3 The initial value of the reference value for the change in OCV during the diagnostic process, or used to determine the discharge OCV delay rate (β) or the minimum threshold (σ) related to OCV in Equation 1.

[0088] In summary, one of the diagnostic parameters in this invention—a reference value for the change in OCV—can be selected by analyzing the probability density function of the cycle-by-cycle OCV change measured during a charge / discharge test that includes multiple cycles.

[0089] Meanwhile, the reference value for the change in discharge capacity can also be determined through testing and the derivation of the probability density function distribution curve, such as... Figure 4 As shown, a similar analytical process can be used to determine a reference value for the discharge capacity change. In other words, one of the diagnostic parameters in this invention—the reference value for the discharge capacity change—can be selected through probability density function analysis of the cycle-by-cycle discharge capacity change measured during multiple charge / discharge tests.

[0090] Figure 5 This is a block diagram of a battery diagnostic device according to an embodiment of the present invention.

[0091] Reference Figure 5 According to an embodiment of the present invention, the battery diagnostic device 100 may include a processor 110 and a memory 120 storing at least one instruction executed by the processor. Here, the processor may be, for example, a microcontroller unit (MCU) or other form of controller.

[0092] The battery diagnostic device 100 according to an embodiment of the present invention can be connected to a charger / discharger that repeatedly performs multiple charge / discharge cycles according to a charge / discharge mode, and can receive information about the charge / discharge mode from the charger / discharger. The battery diagnostic device 100 can also be connected to various measuring devices (temperature sensors, voltage sensors, etc.) and receive measurement data related to the battery state.

[0093] Here, at least one instruction executed by the processor may include: instructions for collecting battery-related measurements during a discharge period included in each cycle of the battery charge / discharge test; instructions for determining a reference value for the amount of state change during the discharge period; instructions for comparing the amount of state change during the discharge period measured for each cycle with the reference value; and instructions for performing battery diagnostics based on the comparison results.

[0094] Battery-related measurements may include one or more of the following: battery discharge capacity, open-circuit voltage (OCV), current, and temperature.

[0095] A reference value for the change in OCV can be calculated using the OCV from the previous cycle and a weighting factor that is set differently depending on the battery type.

[0096] A reference value for the OCV change can be determined using probability density function analysis of the OCV change measured during each cycle of a charge / discharge test that includes multiple cycles.

[0097] At the same time, a reference value for the change in discharge capacity can be calculated using the discharge capacity of the previous cycle and a weighting factor that is set differently depending on the battery type.

[0098] A reference value for the change in discharge capacity can be determined by probability density function analysis of the change in discharge capacity measured in each cycle during a charge / discharge test that includes multiple cycles.

[0099] Instructions for performing battery diagnostics based on the comparison results may include instructions for determining that if the amount of state change in the corresponding discharge period is greater than or equal to a reference value, the probability of a charging delay occurring during the charging period following the corresponding discharge period is high.

[0100] At least one instruction may also include: an instruction to check whether there are changes in the current and temperature used in the battery charge / discharge test during the corresponding cycle; and an instruction to terminate the diagnostic if the changes in current and temperature are greater than or equal to a predetermined threshold.

[0101] Batteries can include lithium-sulfur batteries.

[0102] Meanwhile, the battery diagnostic device 100 according to an embodiment of the present invention may also include a transceiver 130, an input interface 140, an output interface 150, a storage device 160, etc. The various components included in the battery diagnostic device 100 can be connected via a bus 170 and can communicate with each other.

[0103] Furthermore, the memory 120 (or storage device) may include at least one of volatile storage media and non-volatile storage media. For example, the memory may include at least one of read-only memory (ROM) and random access memory (RAM), and may include electrically erasable programmable read-only memory (EEPROM).

[0104] According to embodiments of this disclosure, charging delay issues in lithium-sulfur batteries can be detected in real time, allowing for proactive fire prevention. Furthermore, by diagnosing the problem before it actually occurs, accurate root cause analysis is possible.

[0105] The operation of the method according to embodiments of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes all types of recording devices in which computer systems store data readable by the computer. Furthermore, the computer-readable recording medium can be distributed across network-connected computer systems to store and execute computer-readable programs or code in a distributed manner.

[0106] Although some aspects of the invention have been described in the context of apparatus, they may also refer to, according to the description of the corresponding method, a block or apparatus corresponding to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also refer to features of a corresponding block or item or a corresponding apparatus. Some or all of the method steps may be performed by (or using) hardware devices such as, for example, microprocessors, programmable computers, or electronic circuits. In some embodiments, one or more of the most important method steps may be performed by such apparatus.

[0107] In the foregoing, the present invention has been described with reference to exemplary embodiments thereof. However, those skilled in the art will understand that various modifications and variations may be made to the invention within the scope of the appended claims without departing from the spirit and scope of the invention as described therein.

Claims

1. A device for diagnosing a battery, comprising: At least one processor; as well as A memory configured to store at least one instruction executed by the at least one processor; Wherein, the at least one instruction includes: Instructions for collecting battery-related measurements during the discharge period included in each cycle of battery charge / discharge testing; Instructions for determining reference values ​​of state changes during the discharge period; Instructions for comparing the amount of state change during the discharge period for each cycle measurement with the reference value; and Instructions used to perform battery diagnostics based on the comparison results.

2. The apparatus according to claim 1, wherein, The battery-related measurements include one or more of the following: the battery's discharge capacity, discharge OCV, current, and temperature.

3. The apparatus according to claim 1, wherein, The state change during the discharge period includes one or more of the following: The change in OCV at the end of the rest period following the discharge period compared to the previous cycle; as well as The change in discharge capacity during the discharge period compared to the previous cycle.

4. The apparatus according to claim 3, wherein, A reference value for the change in OCV is calculated using the OCV from the previous cycle and a weighting factor that is set differently depending on the battery type.

5. The apparatus according to claim 3, wherein, A reference value for the OCV change is determined using probability density function analysis of the change in OCV measured during each cycle of a charge / discharge test that includes multiple cycles.

6. The apparatus according to claim 3, wherein, A reference value for the change in discharge capacity is calculated using the discharge capacity of the previous cycle and a weighting factor that varies depending on the type of battery.

7. The apparatus according to claim 3, wherein, A reference value for the change in discharge capacity is determined by probability density function analysis of the change in discharge capacity measured in each cycle during a charge / discharge test that includes multiple cycles.

8. The apparatus according to claim 1, wherein, Instructions for performing battery diagnostics based on the results of the comparison include: An instruction is used to determine that if the state change amount in the corresponding discharge period is greater than or equal to the reference value, the probability of a charging delay occurring during the charging period following the corresponding discharge period is high.

9. The apparatus according to claim 1, wherein, The at least one instruction further includes: Instructions for checking whether there are changes in the current and temperature used in the battery charge / discharge test during the corresponding cycle; and This instruction is used to terminate the diagnosis if the changes in current and temperature are greater than or equal to a predetermined threshold.

10. The apparatus according to claim 1, wherein, The battery includes a lithium-sulfur battery.

11. A method for diagnosing a battery, comprising: Battery-related measurements are collected during the discharge period included in each cycle of the battery charge / discharge test; Determine reference values ​​for the state changes during the discharge period; The amount of state change measured during the discharge period for each cycle is compared with the reference value; as well as Battery diagnostics are performed based on the comparison results.

12. The method according to claim 11, wherein, The battery-related measurements include one or more of the following: the battery's discharge capacity, discharge OCV, current, and temperature.

13. The method according to claim 11, wherein, The state change during the discharge period includes one or more of the following: The change in OCV at the end of the rest period following the discharge period compared to the previous cycle; as well as The change in discharge capacity during the discharge period compared to the previous cycle.

14. The method according to claim 13, wherein, A reference value for the change in OCV is calculated using the OCV from the previous cycle and a weighting factor that is set differently depending on the battery type.

15. The method according to claim 13, wherein, A reference value for the OCV change is determined using probability density function analysis of the change in OCV measured during each cycle of a charge / discharge test that includes multiple cycles.

16. The method according to claim 13, wherein, A reference value for the change in discharge capacity is calculated using the discharge capacity of the previous cycle and a weighting factor that is set differently depending on the battery type.

17. The method according to claim 13, wherein, A reference value for the change in discharge capacity is determined by probability density function analysis of the change in discharge capacity measured in each cycle during a charge / discharge test that includes multiple cycles.

18. The method according to claim 11, wherein, Performing battery diagnostics based on the results of the comparison includes: If the state change during the corresponding discharge period is greater than or equal to the reference value, then it is determined that the probability of a charging delay occurring during the charging period following the corresponding discharge period is high.

19. The method of claim 11, further comprising: Check for any changes in the current and temperature used in the battery charge / discharge test during the corresponding cycle; as well as If the changes in current and temperature are greater than or equal to a predetermined threshold, the diagnosis is terminated.

20. The method according to claim 11, wherein, The battery includes a lithium-sulfur battery.

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