DIAGNOSTIC DEVICE FOR A LITHIUM-ION BATTERY, DIAGNOSTIC PROCEDURES FOR A LITHIUM-ION BATTERY AND LITHIUM-ION BATTERY

Abstract

A system, a procedure, and a lithium-ion battery design for diagnosing battery performance using open-circuit voltage (OCV) measurements are described. A diagnostic device or procedure acquires a first OCV and a second OCV, calculates their difference (ΔV), and compares parameters—such as OCV or ΔV—to threshold values ​​(e.g., approximately 3.0 V or 0.12 V). If the second OCV occurs after approximately 200 charge / discharge cycles, or if ΔV is approximately 0.12 V or less, a longer battery lifespan is assumed. The lithium-ion battery includes an anode containing silicon (approximately 5 to 15 wt%) with a capacity of approximately 380 to 500 mAh / g, which contributes to improved cycle performance.

Description

TECHNICAL AREA

[0001] The present disclosure relates to a diagnostic device for a lithium-ion battery, a diagnostic method for a lithium-ion battery and a lithium-ion battery. BACKGROUND

[0002] With the rapid development of the electronics, communications, and computer industries, the application areas of energy storage technology are expanding to include camcorders, mobile phones, laptops, PCs, and electric vehicles. Consequently, the development of lightweight, durable, and highly reliable high-performance secondary batteries is underway.

[0003] Among the secondary batteries currently in use, the lithium-ion batteries developed in the early 1990s have a higher operating voltage and a significantly higher energy density than conventional batteries such as Ni-MH, Ni-Cd and lead-acid batteries, which use aqueous electrolytes, and have thus been used as a power source for many portable devices.

[0004] Materials containing graphite have been widely used as the active anode material in lithium-ion batteries. Since the average potential when graphite absorbs / releases lithium is approximately 0.1 to 0.2 V (relative to Li / Li+) and the discharge potential is relatively flat, one advantage is that the voltage of a battery using graphite is high and constant. However, the disadvantage is that graphite has a very low theoretical capacity of 372 mAh / g.

[0005] Therefore, various active anode materials are being investigated to further increase the capacity of lithium-ion batteries. Materials that form intermetallic compounds with lithium, such as silicon or tin, are considered promising active anode materials with high capacity. Silicon, in particular, is an alloy-like active anode material with a theoretical capacity (4,200 mAh / g) approximately ten times higher than that of graphite and is attracting attention as a next-generation active anode material.

[0006] However, silicon-based active anode materials undergo a large volume change (~300%) during charging and discharging. As a result, the physical contact between active materials is disrupted, and fragmentation occurs. Consequently, ionic conductivity, electrical conductivity, and other properties deteriorate rapidly, and the anode lifetime tends to decrease rapidly.

[0007] Therefore, there is a growing need for technologies that enable more accurate diagnosis and prediction of the performance of a lithium-ion battery using silicon as the active anode material. SUMMARY

[0008] Some embodiments of the present disclosure are said to provide a diagnostic device for a lithium-ion battery, a diagnostic method for a lithium-ion battery, and a lithium-ion battery.

[0009] According to some embodiments of the present disclosure, a diagnostic device for a lithium-ion battery may comprise: a data acquisition unit that acquires a first open circuit voltage (OCV) at a first time point and a second OCV at a second time point; a calculation unit that calculates ΔV, which is a difference between the first OCV and the second OCV; and a control unit that compares at least one of the first OCV, the inflection point, and ΔV with a threshold value.

[0010] In a diagnostic device for a lithium-ion battery according to some embodiments of the present disclosure, the first OCV can be a first OCV during an OCV measurement, and the second OCV can be an OCV at the turning point.

[0011] In a diagnostic device for a lithium-ion battery according to some embodiments of the present disclosure, the first OCV and the second OCV can be quiescent voltages after a discharge, provided that the discharge is carried out in a CC mode with a constant current of 1 C up to 2.5 V and then the charging is carried out in a CC / CV mode with a constant current of 1 C up to 4.2 V (0.1 C cutoff).

[0012] In a diagnostic device for a lithium-ion battery according to some embodiments of the present disclosure, the control unit can determine whether ΔV is 0.120 or less.

[0013] In a diagnostic device for a lithium-ion battery according to some embodiments of the present disclosure, the control unit can determine whether the first OCV is 3.0 V or more.

[0014] In a diagnostic device for a lithium-ion battery according to some embodiments of the present disclosure, the control unit can determine whether the turning point is after 200 cycles.

[0015] According to another embodiment of the present disclosure, a diagnostic method for a lithium-ion battery may comprise: sensing a first open circuit voltage (OCV) at a first time point and a second OCV at a second time point; calculating ΔV, which is a difference between the first OCV and the second OCV; and comparing at least one of the first OCV, the inflection point, and ΔV with a threshold value.

[0016] In a diagnostic procedure for a lithium-ion battery according to some embodiments of the present disclosure, the first OCV may be a first OCV during an OCV measurement, and the second OCV may be an OCV at the turning point.

[0017] In a diagnostic procedure for a lithium-ion battery according to some embodiments of the present disclosure, the first OCV and the second OCV can be quiescent voltages after a discharge, provided that the discharge is carried out in a CC mode with a constant current of 1 C up to 2.5 V and then the charging is carried out in a CC / CV mode with a constant current of 1 C up to 4.2 V (0.1 C cutoff).

[0018] In a diagnostic procedure for a lithium-ion battery according to some embodiments of the present disclosure, it can be determined by comparison whether ΔV is 0.120 or less.

[0019] In a diagnostic procedure for a lithium-ion battery according to some embodiments of the present disclosure, it can be determined by comparison whether the first OCV is 3.0 V or more.

[0020] In a diagnostic procedure for a lithium-ion battery according to some embodiments of the present disclosure, it can be determined by comparison whether the turning point is after 200 cycles.

[0021] According to some embodiments of the present disclosure, a lithium-ion battery comprises: a Si-containing anode in which a first open circuit voltage (OCV) may be defined at a first time and a second OCV at a second time, and if a difference between the first OCV and the second OCV is defined as ΔV, ΔV may be 0.12 or less.

[0022] In a lithium-ion battery according to some embodiments of the present disclosure, the first OCV may be a first OCV during an OCV measurement, and the second OCV may be an OCV at the turning point.

[0023] In a lithium-ion battery according to some embodiments of the present disclosure, the first OCV and the second OCV can be quiescent voltages after a discharge, provided that the discharge is carried out in a CC mode with a constant current of 1 C up to 2.5 V and then the charging is carried out in a CC / CV mode with a constant current of 1 C up to 4.2 V (0.1 C cutoff).

[0024] In a lithium-ion battery according to some embodiments of the present disclosure, the first OCV may be 3.0 V or more.

[0025] In a lithium-ion battery according to some embodiments of the present disclosure, the second OCV can be generated after 200 cycles.

[0026] In a lithium-ion battery according to some embodiments of the present disclosure, the number of charge and discharge cycles remaining until the end of life (EOL) can be 300 cycles or more.

[0027] In a lithium-ion battery according to some embodiments of the present disclosure, the lithium-ion battery may have a Si anode, and the Si anode may have 5 to 15 wt% Si in relation to a total composition of the Si anode.

[0028] According to a further embodiment of the present disclosure, a lithium-ion battery may have: a Si-containing anode in which, under the condition that a discharge in a CC mode with a constant current of 1 C up to 2.5 V and a subsequent charging in a CC / CV mode with a constant current of 1 C up to 4.2 V (0.1 C cutoff) is carried out, a graphical representation obtained when measuring a final voltage of a quiescent period after discharge may have an inflection point.

[0029] As explained, the method and the system appropriately include the use of a controller or processor.

[0030] In another embodiment, vehicles are provided which have a device disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other embodiments, features, and advantages of the present disclosure will become apparent from the detailed description of the following embodiments in conjunction with the accompanying drawings. The figures show: Fig. 1 shows a block diagram of a diagnostic device according to various embodiments of the present disclosure; Fig. Figure 2 shows a diagram illustrating an example of data captured by a data acquisition unit; Fig. Figure 3 shows a flowchart of a diagnostic procedure according to various embodiments of the present disclosure; Fig. Figure 4 shows a diagram representing a measurement result of the open-circuit voltage in the rest state of a lithium-ion battery containing only graphite; Fig. Figure 5 shows a graphical representation of the relationship between ΔV and an end of life (EOL); Fig.Figure 6 shows a graphical representation of the relationship between V1 and EOL; and Fig. Figure 7 shows a graphical representation of the relationship between an inflection point and the EOL. DETAILED DESCRIPTION

[0032] The embodiments disclosed in this patent specification are described in detail below with reference to the accompanying drawings. In the following description, identical or similar components are identified by the same or similar reference numerals, and overlapping descriptions may be omitted.

[0033] The embodiments disclosed in this patent specification are described in detail below with reference to the accompanying drawings. In the following description, identical or similar components are identified by the same or similar reference numerals, and overlapping descriptions may be omitted.

[0034] In this patent specification, “comprise” or “have / include” indicate the presence of features, numbers, steps, operations or processes, components, parts or combinations thereof that are described in the patent specification, but do not exclude any of the following: features, numbers, steps, operations or processes, components, parts or combinations thereof.

[0035] When any (e.g., first) component is referred to in the present patent specification as a "connection point", "coupling" or "connection or connection" or as "coupled" or "connected" to another (e.g., second) component with or without the term "functional" or "communicative", this means that any component can be connected to another component directly (e.g., in a wired manner), wirelessly, or via a third component.

[0036] It is understood that the term "vehicle" or "vehicle-" or a similar term as used herein includes motor vehicles in general, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft and the like, and hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other vehicles using alternative fuels (e.g., fuels derived from resources other than petroleum). As defined herein, a hybrid vehicle is a vehicle that has two or more sources of propulsion, for example, both gasoline-powered and electric-powered vehicles.

[0037] The terminology used herein serves solely to describe certain embodiments and is not to be construed as limiting the disclosure. As used herein, the singular forms "a" and "the" are intended to include the plural forms unless the context clearly indicates otherwise. These terms serve only to distinguish one component from another and do not restrict the nature, sequence, or order of the individual components. It is further understood that the terms "has" and / or "having" when used in this patent specification indicate the presence of certain features, integers, steps, operations, or processes, elements, and / or components, but do not include the presence or addition of one or more other features, integers, steps, operations, or processes.This does not exclude processes, elements, components, and / or groups thereof. As used herein, the term "and / or" includes all combinations of one or more of the listed elements. Throughout this patent, unless expressly stated otherwise, the word "include" and variations such as "includes" or "including" are to be understood as including the elements mentioned, but not excluding other elements. Furthermore, the terms "unit," "-er," "-or," and "module" as described in this patent refer to units for processing at least one function and operation and may be implemented by hardware components or software components and combinations thereof.

[0038] Although one embodiment is described as using a plurality of units to perform the exemplary process, it is understood that the exemplary processes can also be performed by one or a plurality of modules. Furthermore, it is understood that the term controller refers to a hardware device comprising memory and a processor, and specifically programmed to execute the processes described herein. The memory is configured to store the modules, and the processor is specifically configured to execute said modules to perform one or more processes described below.

[0039] Furthermore, the control logic of the present disclosure can be implemented as a non-transient, computer-readable medium on a computer-readable medium containing executable program instructions that are executed by a processor, controller, or the like. Examples of computer-readable media include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards, and optical data storage devices. The computer-readable medium can also be distributed across networked computer systems, such that the computer-readable medium is stored and executed in a distributed manner, for example, by a telematics server or a controller area network (CAN).

[0040] Unless explicitly stated or evident from the context, the term "approximately" as used herein means within a standard tolerance range, for example, within two standard deviations from the mean. "Approximately" can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise indicated by the context, all numerical values ​​stated herein are modified by the term "approximately".

[0041] According to some embodiments, the methods of the various embodiments disclosed in this patent specification can be included and provided in a computer program product. The computer program product can be traded as a product between a seller and a buyer. The computer program product can be distributed in the form of a machine-readable storage medium (e.g., read-only compact disc (CD-ROM)), or it can be distributed or passed on via an application store (e.g., by downloading or uploading), or it can be distributed or passed on directly online between two user devices (e.g., by downloading or uploading).In a case of online distribution, at least sections of the computer program product can be stored or temporarily created, at least temporarily, in the machine-readable storage medium, such as a manufacturer's server memory, an application storage server, or a relay server.

[0042] According to various embodiments, each component (e.g., a module or a program) of the components described above can comprise a single unit or a plurality of units, and some of the plurality of units can be arranged separately in another component. According to various embodiments, one or more of the corresponding components and their operations described above can be omitted, or one or more other components or their operations can be added. Alternatively or additionally, a plurality of components (e.g., modules or programs) can be integrated into a single component. In this case, the integrated component can perform one or more functions of each component of the plurality of components in such a way that these functions are performed by the corresponding component of the plurality of components prior to integration.According to various embodiments, the operations performed by the modules, programs or other components can be carried out in a sequential manner, in a parallel manner, in an iterative manner or in a heuristic manner, wherein at least some of the operations can be performed in a different order or omitted, or one or more operations can be added. DIAGNOSTIC DEVICE FOR A LITHIUM-ION BATTERY

[0043] A diagnostic device for a lithium-ion battery according to various embodiments of the present disclosure is described below.

[0044] Fig. Figure 1 shows a block diagram of a diagnostic device 100 according to various embodiments of the present disclosure. Fig. Figure 2 shows a diagram representing an example of data collected by a data acquisition unit.

[0045] With reference to Fig. 1 The diagnostic device 100 for a lithium-ion battery according to various embodiments of the present disclosure can comprise a data acquisition unit 110, a calculation unit 120 and a control unit 130.

[0046] The data acquisition unit 110 can acquire data relating to the open-circuit voltage (OCV) of a battery 10 under diagnosis or analysis. The data acquisition unit 110 can also acquire data relating to the final voltage (defined as "resting OCV," and the terms "OCV" and "resting OCV" are used synonymously hereafter) after a resting period following discharge, provided that the battery 10 under analysis is discharged in constant current (CC) mode with a constant current of 1C up to 2.5V and then charged in constant current / continuous charge (CC / CV) mode with a constant current of 1C up to 4.2V (0.1C cutoff). The resting period can be between 10 and 20 minutes. The measurement temperature can be room temperature, for example, 25°C.

[0047] With reference to Fig.2. The data acquisition unit 110 can acquire data relating to a first OCV (V1) at a first time point and a second OCV (V2) at a second time point. During the resting OCV measurement, the data acquisition unit 110 can acquire a first OCV (V1) value, which is a first resting OCV value, and the second OCV (V2) value, which is a resting OCV at an inflection point.

[0048] Data acquisition unit 110 can collect data relating to the second time point at which the second OCV (V2) occurs. Data acquisition unit 110 can collect data relating to the turning point, which represents the time at which the second OCV (V2) occurs.

[0049] Although not shown in the drawing, the data acquired by the data acquisition unit 110 can be stored in the memory.

[0050] The computation unit 120 can receive data from the data acquisition unit 110 and / or the memory. The computation unit 120 can perform a calculation based on the received data. For example, the computation unit 120 can calculate ΔV, which is the difference between the first OCV (V1) and the second OCV (V2).

[0051] The control unit 130 can receive data and calculation data from the data acquisition unit 110 and / or the calculation unit 120. The control unit 130 can receive data relating to at least one of the first OCV, the inflection point, and ΔV. The control unit 130 can analyze the lithium-ion battery based on the received data.

[0052] The control unit 130 can compare at least one of the first OCV, the inflection point, and ΔV with a threshold value. Alternatively, the control unit 130 can compare at least two of the first OCV, the inflection point, and ΔV with the threshold value. Alternatively, the control unit 130 can also compare all values ​​of the first OCV, the inflection point, and ΔV with the threshold value.

[0053] The control unit 130 can analyze the lithium-ion battery based on data relating to the first OCV (V1) received from the data acquisition unit 110. For example, the control unit 130 can determine whether the first OCV (V1) is 3.0 V or higher. If the control unit 130 determines that the first OCV (V1) is 3.0 V or higher, it can determine that the performance of the battery 10 being analyzed is higher than or equal to a standard or norm. If the control unit 130 determines that the first OCV (V1) is 3.0 V or higher, it can determine that the performance of the battery 10 being analyzed is excellent. If the control unit 130 determines that the first OCV (V1) is below 3.0 V, the control unit 130 can determine that the performance of the battery 10 being analyzed is below the norm.If the control unit 130 determines that the first OCV (V1) is below 3.0 V, the control unit 130 can determine that the performance of the battery 10 being analyzed is below the norm.

[0054] The control unit 130 can analyze the lithium-ion battery based on inflection point data received from the data acquisition unit 110. For example, the control unit 130 can determine whether the inflection point occurs after 200 cycles. If the control unit 130 determines that the inflection point is at 200 cycles or more, it can determine that the performance of the battery being analyzed is higher than or equal to the norm. If the control unit 130 determines that the inflection point is at 200 cycles or more, it can determine that the performance of the battery being analyzed is excellent. If the control unit 130 determines that the inflection point is below 200 cycles, it can determine that the performance of the battery being analyzed is below the norm.If the control unit 130 determines that the turning point is below 200 cycles, the control unit 130 can determine that the performance of the battery 10 being analyzed is below the norm.

[0055] Alternatively, the control unit 130 can determine whether the inflection point is after 150 cycles. If the control unit 130 determines that the inflection point is at 150 cycles or more, it can determine that the performance of the battery 10 being analyzed is higher than or equal to the norm. If the control unit 130 determines that the inflection point is at 150 cycles or more, it can determine that the performance of the battery 10 being analyzed is excellent. If the control unit 130 determines that the inflection point is below 150 cycles, it can determine that the performance of the battery 10 being analyzed is below the norm. If the control unit 130 determines that the inflection point is below 150 cycles, it can determine that the performance of the battery 10 being analyzed is below the norm.

[0056] The control unit 130 can analyze the lithium-ion battery based on ΔV data received from the processing unit 120. For example, the control unit 130 can determine whether ΔV is 0.120 or less. If the control unit 130 determines that ΔV is 0.120 or less, it can determine that the performance of the battery 10 being analyzed is higher than or equal to the norm. If the control unit 130 determines that ΔV is 0.120 or less, it can determine that the performance of the battery 10 being analyzed is excellent. If the control unit 130 determines that ΔV exceeds 0.120, it can determine that the performance of the battery 10 being analyzed is below the norm. If the control unit 130 determines that ΔV exceeds 0.120, the control unit 130 can determine that the performance of the battery 10 being analyzed is below the norm.

[0057] For a lithium-ion battery where at least one of the initial OCV, the inflection point, and ΔV meets the threshold, the number of charge and discharge cycles remaining until end of life (EOL) can be 300 cycles or more. Similarly, for a lithium-ion battery where at least one of the initial OCV, the inflection point, and ΔV meets the threshold, a state of health of 70% can be achieved for 300 cycles or more. Therefore, a lithium-ion battery where at least one of the OCV, the inflection point, and ΔV meets the threshold can be classified as having excellent performance.

[0058] According to the diagnostic device for a lithium-ion battery as described in various embodiments of the present disclosure, it is possible to introduce a new standard for predicting the exact performance of a lithium-ion battery. Specifically, according to the diagnostic device for a lithium-ion battery as described in various embodiments of the present disclosure, it is possible to introduce a new standard for predicting the exact performance, in particular of a lithium-ion battery with a silicon anode. This makes it possible to provide guidance for ensuring excellent performance when designing the anode, which contains silicon as the active anode material. DIAGNOSTIC PROCEDURES FOR A LITHIUM-ION BATTERY

[0059] A diagnostic procedure for a lithium-ion battery according to various embodiments of the present disclosure is described below.

[0060] Fig.Figure 3 shows a flowchart of a diagnostic procedure according to various embodiments of the present disclosure.

[0061] With reference to Fig. 3. According to various embodiments of this disclosure, the diagnostic method may comprise a step (S110) for acquiring a first OCV at a first time point and a second OCV at a second time point; a step (S120) for calculating ΔV; and a step (S130) for comparing at least one of the first OCV, the inflection point, and ΔV with a threshold value. The diagnostic method according to various embodiments of this disclosure may be performed by the diagnostic device described above.

[0062] In the acquisition step (S110), data regarding the final voltage after discharge can be acquired under the condition that the battery to be analyzed is discharged in CC mode with a constant current of 1C up to 2.5 V and then charged in CC / CV mode with a constant current of 1C up to 4.2 V (0.1C cutoff). The resting period can be 10 to 20 minutes. The measurement temperature can be room temperature, for example, 25°C.

[0063] In the acquisition step (S110), data relating to the first OCV (V1) at the first time point and the second OCV (V2) at the second time point can be acquired. In the acquisition step (S110), during the resting OCV measurement, the first OCV (V1) value, which is the first resting OCV value, and the second OCV (V2) value, which is the resting OCV at the turning point, can be acquired.

[0064] Meanwhile, in the data collection step (S110), the data relating to the second time point at which the second OCV (V2) occurs can be collected. In the data collection step (S110), the data relating to the turning point, which is the time at which the second OCV (V2) occurs, can be collected.

[0065] Next, in calculation step (S120) ΔV, which is the difference between the first OCV (V1) and the second OCV (V2), can be calculated.

[0066] In comparison step (S130), at least one of the first OCV, the inflection point, and ΔV can be compared with a threshold value. Alternatively, in comparison step (S130), at least two of the first OCV, the inflection point, and ΔV can be compared with the threshold value. Alternatively, in comparison step (S130), all values ​​of the first OCV, the inflection point, and ΔV can be compared with the threshold value.

[0067] For example, comparison step (S130) can determine whether the first OCV (V1) is 3.0 V or higher. If comparison step (S130) determines that the first OCV (V1) is 3.0 V or higher, it can be analyzed and determined that the performance of the battery being analyzed is higher than or equal to the standard. If comparison step (S130) determines that the first OCV (V1) is 3.0 V or higher, it can be determined that the performance of the battery being analyzed is excellent. If comparison step (S130) determines that the first OCV (V1) is below 3.0 V, it can be determined that the performance of the battery being analyzed is below the standard.

[0068] The comparison step (S130) determines whether the inflection point is after 200 cycles. If the comparison step (S130) determines that the inflection point is after 200 cycles or more, it can be determined that the performance of the battery being analyzed is higher than or equal to the norm. If the comparison step (S130) determines that the inflection point is after 200 cycles or more, it can be determined that the performance of the battery being analyzed is excellent. If the comparison step (S130) determines that the inflection point is below 200 cycles, it can be diagnosed that the performance of the battery being analyzed is below the standard.

[0069] Alternatively, the comparison step (S130) can determine whether the inflection point is after 150 cycles. If the comparison step (S130) determines that the inflection point is 150 cycles or more, it can be determined that the performance of battery 10 under analysis is higher than or equal to the standard. If the comparison step (S130) determines that the inflection point is 150 cycles or more, it can be determined that the performance of battery 10 under analysis is excellent. If the comparison step (S130) determines that the inflection point is below 150 cycles, it can be determined that the performance of battery 10 under analysis is below the standard.

[0070] In comparison step (S130), it can be determined whether ΔV is 0.120 or less. If comparison step (S130) determines that ΔV is 0.120 or less, it can be determined that the performance of the battery being analyzed is higher than or equal to the standard. If comparison step (S130) determines that ΔV is 0.120 or less, it can be determined that the performance of the battery being analyzed is excellent. If comparison step (S130) determines that ΔV exceeds 0.120, it can be determined that the performance of the battery being analyzed is 10 times below the standard. If comparison step (S130) determines that ΔV exceeds 0.120, it can be determined that the performance of the battery being analyzed is below the standard.

[0071] In a lithium-ion battery where at least one of the OCV, inflection point, and ΔV values ​​meets the threshold, the number of charge and discharge cycles remaining until end of life (EOL) can be 300 cycles or more. A state of health (SOH) of 70% can also be achieved with 300 cycles or more in a lithium-ion battery where at least one of the OCV, inflection point, and ΔV values ​​meets the threshold. Therefore, it can be concluded that a lithium-ion battery where at least one of the OCV, inflection point, and ΔV values ​​meets the threshold exhibits excellent performance.

[0072] According to the diagnostic method for a lithium-ion battery as described in various embodiments of the present disclosure, it is possible to introduce a new standard for predicting the exact performance of a lithium-ion battery. This new standard, which includes a silicon anode, allows for the prediction of the exact performance of a lithium-ion battery with a silicon anode. Consequently, it is possible to provide guidance for ensuring excellent performance when designing the anode, which incorporates silicon as the active anode material. LITHIUM-ION BATTERY

[0073] A lithium-ion battery according to various embodiments of the present disclosure is described below. A lithium-ion battery according to various embodiments of the present disclosure can have a specific open-circuit voltage (OCV).

[0074] In particular, under the condition that the lithium-ion battery, according to various embodiments of the present disclosure, is discharged in CC mode with a constant current of 1 C up to 2.5 V and then charged in CC / CV mode with a constant current of 1 C up to 4.2 V (0.1 C cutoff), the final voltage after discharge can have a specific voltage value. The resting period can be 10 to 20 minutes. The temperature at which the resting OCV is measured can be room temperature.

[0075] With reference to Fig.2. According to various embodiments of the present disclosure, the lithium-ion battery can have at least one inflection point in the graphical representation obtained during the resting OCV measurement.

[0076] According to various embodiments of the present disclosure, the lithium-ion battery is defined such that it has the first OCV (V1) at the first time point and the second OCV (V2) at the second time point, and if the difference between the first OCV (V1) and the second OCV (V2) is defined as ΔV, ΔV is 0.12 or less. Preferably, ΔV can be between 0.03 and 0.12. Alternatively, ΔV can be between 0.04 and 0.12. Alternatively, ΔV can be between 0.05 and 0.12. Alternatively, ΔV can be between 0.06 and 0.12. Alternatively, ΔV can be between 0.065 and 0.12. Alternatively, ΔV can be between 0.065 and 0.11.

[0077] The first OCV (V1) may be the first OCV in the resting OCV measurement, and the second OCV (V2) may be the resting OCV at the inflection point.

[0078] The first OCV (V1) of the lithium-ion battery according to the various embodiments of the present disclosure can be 3.0 V or more.

[0079] The lithium-ion battery according to various embodiments of the present disclosure can cause the second OCV (V2) to occur after 200 cycles. That is, the turning point can occur after 200 cycles during the resting OCV measurement. Alternatively, the second OCV (V2) can occur after 150 cycles.

[0080] The lithium-ion battery according to the various embodiments of the present disclosure can satisfy at least one of the following conditions (1) to (3). The lithium-ion battery according to the various embodiments of the present disclosure can satisfy at least two of the following conditions (1) to (3). The lithium-ion battery according to the various embodiments of the present disclosure can satisfy all of the following conditions (1) to (3). V1≥3.0 V ΔV(V1−V2)≤0.120 V Turning point ≥ 200 cycles

[0081] In the case of the lithium-ion battery according to various embodiments of the present disclosure, the number of charge and discharge cycles remaining until end-of-life (EOL) can be 300 cycles or more. Alternatively, the number of charge and discharge cycles remaining until EOL can be 350 cycles or more. Alternatively, the number of charge and discharge cycles remaining until EOL can be 300 to 800 cycles.

[0082] Alternatively, in the lithium-ion battery according to various embodiments of the present disclosure, the SOH of 70% can be 300 cycles or more. Alternatively, the SOH of 70% can be 350 cycles or more. Alternatively, the SOH of 70% can be 300 to 800 cycles.

[0083] The anode of the lithium-ion battery according to various embodiments of the present disclosure can have a capacity of 380 to 500 mAh / g.

[0084] The anode of the lithium-ion battery according to various embodiments of the present disclosure can comprise silicon (Si) as the active anode material. Si can comprise 5 to 15 wt.% in relation to the total composition of the anode. The anode of the lithium-ion battery according to various embodiments of the present disclosure can further comprise graphite as an active anode material. The anode of the lithium-ion battery according to various embodiments of the present disclosure may not comprise only graphite as the active anode material.

[0085] The anode of the lithium-ion battery according to various embodiments of the present disclosure may further comprise a conductive material, a binder and a thickening agent.

[0086] The conductive material may include at least one selected from the group consisting of: natural graphite, synthetic graphite, carbon black, acetylene black, Ketjen black, canal black, Paneth black, lamp black, heat black, conductive fibers, fluorocarbon, aluminum powder, nickel powder, zinc oxide, potassium titanate, titanium oxide, polyphenylene derivatives, carbon nanotubes, sheet graphite, graphene, graphene oxide and graphite flakes.

[0087] The binder and / or thickener may comprise at least one selected from the group consisting of: polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene propylene diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluoroelastomer and polyacrylic acid, and may also comprise various copolymers thereof.

[0088] The lithium-ion battery according to various embodiments of the present disclosure can have a cathode. The cathode can comprise an active cathode material, a conductive material, and a binder. The active cathode material can comprise at least one selected from the group consisting, for example, of nickel-cobalt-manganese (NCM), nickel-cobalt-aluminum (NCA), lithium-manganese oxide (LMO), lithium-cobalt oxide (LCO), and lithium iron phosphate (LFP). Preferably, the active cathode material can comprise NCM.

[0089] The conductive material may include at least one selected from the group consisting of: natural graphite, synthetic graphite, carbon black, acetylene black, Ketjen black, canal black, Paneth black, lamp black, heat black, conductive fibers, fluorocarbon, aluminum powder, nickel powder, zinc oxide, potassium titanate, titanium oxide, polyphenylene derivatives, carbon nanotubes, sheet graphite, graphene, graphene oxide and graphite flakes.

[0090] The binder may contain at least one selected from the group consisting of: polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene propylene diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluoroelastomer and polyacrylic acid, and may also contain various copolymers thereof.

[0091] The lithium-ion battery according to various embodiments of the present disclosure can have a separator and an electrolyte between the cathode and the anode.

[0092] The separator can separate the anode and cathode and provide a passage through which the lithium ions can move. The separator can have a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof. Alternatively, the separator can have a nonwoven fabric made of high-melting-point glass fibers, polyethylene terephthalate fibers, and the like.

[0093] The electrolyte can be an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel-like polymer electrolyte, a solid inorganic electrolyte, a molten inorganic electrolyte, and the like.

[0094] According to the lithium-ion battery according to various embodiments of the present disclosure, it is possible to ensure excellent performance in a lithium-ion battery with a Si anode by fulfilling new characteristic values ​​or parameters. Example

[0095] Various lithium-ion batteries were fabricated using NCM as the active cathode material and Si as the active anode material. The Si content of the fabricated lithium-ion batteries ranged from 5 to 15 wt%, and the capacity was between 380 and 500 mAh / g. The resting OCV was measured for the batteries.

[0096] Under the condition that the quiescent OCV is discharged in CC mode with a constant current of 1 C down to 2.5 V and then charged in CC / CV mode with a constant current of 1 C down to 4.2 V (0.1 C cutoff), the final voltage of the quiescent time after discharge was measured.

[0097] When measuring the resting OCV, data relating to V1, the first OCV, V2, the resting OCV at the inflection point, the inflection point and ΔV were obtained based on the measurement results.

[0098] The results are listed in Table 1 below. [Table 1] Nr. v1 (V) Turning point (cycle) V2 (V) ΔV (V) EOL (cycle) Si content (wt.%) 1 3,03 400 3,03 0,07 700 5 2 3,03 300 3,03 0,07 680 5 3 3,04 400 3,03 0,08 620 6 4 3,03 400 3,01 0,09 600 7 5 3,01 320 2,99 0,09 600 8 6 3,03 300 3,035 0,065 580 9 7 3,03 300 3,02 0,08 550 9 8 3,02 300 3,02 0,07 550 10 9 3,02 300 3,02 0,07 520 10 10 3,01 280 3,015 0,065 500 11 11 3 220 2,98 0,09 490 12 12 3 240 2,97 0,1 460 14 13 3,01 200 2,97 0,11 430 14 14 3,03 220 2,98 0,12 370 15 15 2,99 120 2,93 0,13 240 5 16 2,98 120 2,92 0,13 220 5 17 2,97 150 2,93 0,14 220 6 18 2,96 150 2,94 0,15 220 7 19 2,99 120 2,92 0,14 210 8 20 2,96 140 2,9 0,17 210 9 21 2,99 140 2,85 0,21 200 9 22 2,99 140 2,88 0,18 200 10 23 2,96 130 2,92 0,17 200 10 24 2,99 130 2,85 0,21 190 11 25 2,97 130 2,87 0,17 190 12 26 2,98 125 2,87 0,18 180 14 27 2,97 120 2,85 0,19 180 14 28 2,98 120 2,86 0,19 160 15 29 2,97 110 2,85 0,19 160 15

[0099] Meanwhile, for comparison, the resting OCV was measured using the above method for a lithium-ion battery that contains no Si as the active anode material, but only graphite. Fig. Figure 4 shows a diagram representing a resting OCV measurement result of a lithium-ion battery containing only graphite. Referring to Fig.Figure 4 shows that there is no distinct inflection point and that the voltage gradually decreases as the cycle progresses, only to rise again at the end of the cycle. In other words, it can be seen that it exhibits a different trend than a battery containing silicon as the active anode material.

[0100] Fig. Figure 5 shows a graphical representation of the relationship between ΔV and EOL in the measurement results from Table 1 above.

[0101] If the number of charge and discharge cycles remaining until end-of-life (EOL) is 350 or more, it can be determined that the battery has excellent remaining lifespan and performance. With reference to Fig. 5. It can be confirmed that the EOL is 350 or more if ΔV is 0.120 or less, regardless of the Si content. That is, if ΔV exceeds 0.120, it can be confirmed that the EOL decreases.

[0102] Fig.Figure 6 shows a graphical representation of the relationship between V1 and EOL in the measurement results from Table 1 above.

[0103] With reference to Fig. 6. It can be confirmed that the EOL is 350 or more when V1 is 3.0 V or more, regardless of the Si content. That is, it can be confirmed that the EOL decreases when V1 is less than 3.0 V.

[0104] Fig. Figure 7 shows a graphical representation of the relationship between inflection point and EOL in the measurement results from Table 1 above.

[0105] With reference to Fig. 7. It can be confirmed that the EOL is 350 or more when the inflection point occurs after 200 cycles, regardless of the Si content. That is, it can be seen that the EOL decreases when the inflection point occurs before 200 cycles.

[0106] The results above demonstrate that excellent performance can be ensured by meeting new characteristic values ​​in a lithium-ion battery with a silicon anode. Furthermore, it is possible to provide a guideline for ensuring outstanding performance when designing the anode that incorporates silicon as the active anode material.

[0107] According to the diagnostic device and diagnostic method for a lithium-ion battery as described in various embodiments of the present disclosure, it is possible to introduce a new standard for predicting the exact performance of a lithium-ion battery with a silicon anode. According to the diagnostic device and diagnostic method for a lithium-ion battery as described in various embodiments of the present disclosure, it is possible to provide a guideline for ensuring excellent performance when designing an anode that incorporates silicon as the active anode material.

[0108] According to the lithium-ion battery according to various embodiments of the present disclosure, it is possible to ensure excellent performance in a lithium-ion battery with a Si anode by fulfilling new characteristic values.

[0109] The effects of the present disclosure are not limited to those mentioned above, and other, unmentioned effects can be clearly understood by a person skilled in the art from the following description.

[0110] The above description includes embodiments of the present disclosure with accompanying drawings. This is for illustrative purposes only, and the present disclosure is not limited to the content of the embodiments and drawings described above.

[0111] It is obvious to a person skilled in the art that the present disclosure can be modified within the scope of the disclosed technical idea. The described embodiments should be considered as part of the present disclosure, and the scope of the present disclosure should not be limited solely by the described embodiments.

[0112] The scope of this disclosure should be assessed based on the technical idea described in the claims. Furthermore, even if the actions or effects according to the arrangement are not expressly described in the description of the embodiments of this disclosure, it is obvious that the actions or effects foreseeable by the arrangement should be recognized as the present disclosure.

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