Method and system for detecting defective cell

Abstract

To provide a defective cell detection method for detecting a defective cell without disassembling the cell.SOLUTION: The method includes: a step S720 of performing at least one of a charge or a discharge of a cell so that a state of charge (SOC) of the cell falls within a predetermined range; a step of obtaining first charge / discharge data including information on voltage and temperature during the charge or discharge of the cell; a step S730 of calculating an entropy value of the cell on the basis of the first charge / discharge data; a step S740 of estimating a state of a graphite interface of the cell on the basis of the calculated entropy value; and steps S750 and S770 of determining whether or not the cell is defective on the basis of the estimated state of the graphite interface of the cell.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a method and apparatus for detecting defective cells. [Background technology]

[0002] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries that can be charged and discharged. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, laptop computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as motor drive power sources and power storage batteries in hybrid vehicles, electric vehicles, and the like. Such secondary batteries include an electrode assembly consisting of a positive electrode and a negative electrode, a case that houses the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] On the other hand, defects in secondary batteries can lead to problems such as fires. In order to detect defects in secondary batteries, conventional techniques have involved dismantling the secondary batteries and then examining the negative electrode condition of the cells using an electron microscope or the like. However, this conventional technique requires dismantling the cells to diagnose the internal condition of the secondary batteries, which has the disadvantage of discarding normal cells as well.

[0004] The foregoing information disclosed in this Background of the Invention section is intended solely to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Korean Patent Registration No. 10-2558017 (2023.07.17) Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure provides a method and apparatus (system) for detecting defective cells to solve the above technical problems.

[0007] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned should be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0008] To solve the above technical problem, a method for detecting a defective cell according to one embodiment of the present invention includes the steps of: conducting at least one of charging or discharging a cell so that the cell's State of Charge (SOC) falls within a predetermined range; acquiring first charging / discharging data including voltage and temperature information while the cell is being charged / discharged; calculating an entropy value of the cell based on the first charging / discharging data; estimating a graphite interface state of the cell based on the calculated entropy value; and determining whether the cell is defective based on the estimated graphite interface state of the cell.

[0009] According to another embodiment of the present disclosure for solving the technical problem, a computer-readable computer program can be provided for executing the defective cell detection method on a computer.

[0010] An apparatus according to yet another embodiment of the present invention for solving the technical problems includes a communication module, a memory, and at least one processor coupled to the memory and configured to execute at least one computer-readable program stored in the memory, wherein the at least one program includes instructions for: conducting at least one of charging or discharging a cell so that a state of charge of the cell falls within a predetermined range; acquiring first charge / discharge data including voltage and temperature information while the charging / discharging of the cell is progressing; calculating an entropy value of the cell based on the first charge / discharge data; estimating a graphite interface state of the cell based on the calculated entropy value; and determining whether the cell is defective based on the estimated graphite interface state of the cell. [Effects of the Invention]

[0011] According to some embodiments of the present disclosure, defective cells can be detected by electrochemical analysis without disassembling the cells, which allows users to easily detect defective cells by simply charging and discharging the cells, thereby improving the reliability of defective cell detection.

[0012] According to some embodiments of the present disclosure, defective cells can be detected non-destructively. Furthermore, defective cells can be reactivated to stabilize the defective graphite interface, and cells that do not improve even after the reactivation process can be treated as defective. This improves the reliability of defective cell detection.

[0013] However, the effects obtained by the present invention are not limited to the effects described above, and other technical effects not mentioned herein should be clearly understood by those skilled in the art from the description of the invention described below. [Brief explanation of the drawings]

[0014] The following drawings and the like attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention to be given later, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be analyzed by being limited to the matters depicted in such drawings. [Figure 1] FIG. 10 is a diagram illustrating an example of a method for detecting a defective cell according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic diagram illustrating a configuration in which an information processing system is connected to multiple user terminals so as to be able to communicate with each other in order to detect a faulty cell according to one embodiment of the present disclosure. [Figure 3] 1 is a block diagram showing an internal configuration of a user terminal and an information processing system according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is a diagram illustrating an example of an internal configuration of a processor of an information processing system according to an embodiment of the present disclosure. [Figure 5] FIG. 10 is a diagram illustrating an example of a graph showing changes in entropy value depending on the C rate according to an embodiment of the present disclosure. [Figure 6] FIG. 1 is a diagram showing an example of a graph illustrating the change in entropy value due to an additive according to an embodiment of the present disclosure. [Figure 7] FIG. 10 is a diagram illustrating an example of a method for detecting a defective cell according to an embodiment of the present disclosure. [Figure 8] 1 is a flowchart illustrating an example of a method according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] <Summary of the Invention> According to one embodiment, the method may further include outputting information associated with the cell in response to the cell being determined to be bad.

[0016] According to one embodiment, the graphite interface condition of the cell can indicate degradation of the interface of the graphite negative electrode of the cell.

[0017] According to one embodiment, the predetermined range may be related to the graphite interface state of the cell.

[0018] According to one embodiment, the predetermined range may be SOC 22% to 50%.

[0019] According to one embodiment, charging and discharging of the cell may proceed at a constant C-rate.

[0020] According to one embodiment, the constant C-rate may be greater than or equal to a predetermined threshold.

[0021] According to one embodiment, the estimating step may include comparing the calculated entropy value with a reference entropy value to estimate the graphite interface state of the cell.

[0022] According to one embodiment, the reference entropy value may be determined based on the entropy values ​​of a plurality of normal cells that have been determined to be normal.

[0023] According to one embodiment, the cells may be cells that have undergone an activation process.

[0024] According to one embodiment, the method may further include the step of proceeding with a reactivation process for the cell in response to the cell being determined to be bad.

[0025] According to one embodiment, the method may further include the steps of acquiring second charge / discharge data after performing the cell reactivation process, re-estimating the graphite interface state of the cell based on the second charge / discharge data, and determining whether the cell is defective based on the re-estimated graphite interface state.

[0026] According to one embodiment, the entropy value can be related to the arrangement of the lithium layers of the cell.

[0027] According to one embodiment, the at least one program may further include instructions for outputting information associated with the cell in response to the cell being determined to be bad.

[0028] According to one embodiment, the predetermined range may be related to the graphite interface state of the cell.

[0029] According to one embodiment, the predetermined range may be SOC 22% to 50%.

[0030] According to one embodiment, charging and discharging of the cell may proceed at a constant C-rate.

[0031] According to one embodiment, estimating may include comparing the calculated entropy value with a reference entropy value to estimate the graphite interface state of the cell.

[0032] <Detailed Description of the Invention> Preferred embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. First, the terms and phrases used in this specification and claims should not be interpreted in a limited manner based on their ordinary and dictionary meanings, but should be interpreted in a manner consistent with the technical concept of the present invention, based on the principle that the inventor may appropriately define the concepts of terms in order to best describe his or her invention. Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely preferred embodiments of the present invention and do not represent the entire technical concept of the present invention, and that various equivalents and modifications may exist as of the time of filing this application.

[0033] Furthermore, as used herein, "comprise," "comprising," "include," and "including" specify the presence of a stated shape, number, step, operation, member, element, and / or group, but do not exclude the presence or addition of one or more other shapes, numbers, operations, members, elements, and / or groups. Furthermore, when describing an embodiment of the present invention, "may" and "may be" can include "one or more embodiments of the present invention."

[0034] In order to facilitate understanding of the invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals are used to refer to the same components in different embodiments.

[0035] A statement that two comparison objects are "identical" means that they are "substantially identical." Therefore, being substantially identical can include cases where there is a deviation that is considered low in the art, for example, a deviation of 5% or less. Furthermore, a statement that a certain parameter is uniform in a given region can mean that the parameter is uniform on average.

[0036] Although terms such as "first" and "second" are used to describe various components, it is understood that these components are not limited by these terms. These terms are merely used to distinguish one component from another, and unless otherwise specified, a first component can be a second component.

[0037] Throughout the specification, unless specifically stated to the contrary, each element may be singular or plural.

[0038] The phrase "above (or below)" a component or "above (or below)" a component means that the component is not only placed in contact with the upper surface (or lower surface) of the component, but also means that other components may be interposed between the component and the component placed above (or below) the component.

[0039] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the components may be directly coupled or connected to each other, but that other components may be "intervening" between the components, or that each component may be "coupled," "coupled," or "connected" via other components.

[0040] Furthermore, when a part is said to be electrically coupled to another part, this includes not only a direct connection but also a connection via another element therebetween.

[0041] Throughout the specification, "A and / or B" means A, B, or A and B, unless expressly stated to the contrary. That is, "and / or" includes all or any combination of the listed items. "C through D" means at least C and at most D, unless expressly stated to the contrary.

[0042] Additionally, the terms "module" and "module" used herein refer to software or hardware components, each performing a specific function. However, the terms "module" and "module" are not limited to software or hardware. A "module" or "module" may reside on an addressable storage medium or execute one or more processors. Thus, by way of example, a "module" or "module" may include components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The components and "modules" or "modules" may be combined into fewer components and "modules" or "modules," or the functionality provided therein may be further separated into additional components and "modules" or "modules."

[0043] According to one embodiment of the present disclosure, a "module" or "unit" may be embodied with a processor and memory. "Processor" should be broadly interpreted to include a general-purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a controller, a microcontroller, a state machine, etc. In some environments, a "processor" may also refer to an application-specific semiconductor (ASIC), a programmable logic device (PLD), a field-programmable gate array (FPGA), etc. A "processor" may also refer to a combination of processing devices, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors in conjunction with a DSP core, or any other such configuration. Additionally, "memory" should be broadly interpreted to include any electronic component capable of storing electronic information. "Memory" can refer to various types of processor-readable media, such as RAM (Random Access Memory), ROM (Read Only Memory), NVRAM (Non-Volatile Random Access Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory, magnetic or optical data storage devices, registers, etc. Memory is said to be in electronic communication with a processor when the processor can read information from the memory and store information read into the memory. Memory that is integrated into a processor is in electronic communication with the processor.

[0044] In the present disclosure, a "system" may include at least one of a server device and a cloud device, but is not limited to this. For example, a system may be composed of one or more server devices. As another example, a system may be composed of one or more cloud devices. As yet another example, a system may be operated by comprising both a server device and a cloud device.

[0045] In this disclosure, "display" may refer to any display device associated with a computing device, for example, any display device capable of displaying any information / data controlled by or provided by a computing device.

[0046] In the present disclosure, "entropy value" can refer to an entropy change value (i.e., Δentropy) calculated based on a voltage change and a temperature change of a cell. Similarly, "entropy" shown in Figures 5 and 6 can also refer to an entropy change value calculated based on a voltage change and a temperature change of a cell.

[0047] 1 is a diagram illustrating an example of a method for detecting a defective cell according to an embodiment of the present disclosure. In one embodiment, a cell 110 undergoing an activation process may be connected to a charger / discharger 120 and a sensor 130. The charger / discharger 120 may charge or discharge the cell 110 so that the state of charge (SOC) of the cell 110 falls within a predetermined range. Here, the predetermined range may be related to the graphite interface state of the cell 110. The sensor 130 may also measure the voltage and temperature of the cell 110 while the cell 110 is being charged or discharged.

[0048] In one embodiment, a processor (at least one processor of an information processing system) can acquire charge / discharge data, including voltage and temperature information, during charge / discharge of the cell 110. The processor can also calculate an entropy value of the cell 110 based on the charge / discharge data. The entropy value can be related to the arrangement of lithium layers in the graphite anode 140 of the cell 110. Specifically, the graphite anode 140 can include lithium 144 disposed between the graphite layers 142. If the graphite interface, where the lithium 144 migrates and the graphite layers 142 meet, is poor, the arrangement of the lithium 144 can become unstable due to uneven surface reactions within a predetermined SOC range. This can increase the entropy value of the cell 110. The relationship between the entropy value of the cell 110 and the graphite interface state will be described in detail below with reference to FIGS. 5 and 6.

[0049] In one embodiment, the processor can estimate the graphite interface state of the cell 110 based on the calculated entropy value. Here, the graphite interface state may indicate interface degradation of the graphite anode 140 of the cell 110. The processor can also determine whether the cell 110 is defective based on the estimated graphite interface state of the cell 110. Specifically, the processor can estimate whether there is a change in the arrangement of lithium 144 in the graphite anode 140 by comparing the calculated entropy value with a reference entropy value. In this case, the reference entropy value can be determined based on the entropy values ​​of multiple normal cells determined to be normal. Such changes in the arrangement of lithium 144 are due to differences in lithium intercalation, which in turn are due to differences in the graphite interface. Therefore, the graphite interface state of the cell 110 can be estimated based on the entropy value. That is, if the graphite interface is uneven, changes in the arrangement of the lithium layers occur, and the entropy value may differ from the reference entropy value.

[0050] In one embodiment, the processor may output information related to the cell 110 in response to determining that the cell 110 is defective. Here, the information related to the cell 110 may include, but is not limited to, identification information of the cell 110, location information of the cell 110, temperature information of the cell 110, voltage information of the cell 110, entropy value of the cell 110, whether the cell 110 is defective, whether a revitalization process is required, etc. Thus, a user can easily identify cells that should be treated as defective, cells that require a revitalization process, etc. using the information related to the cell 110 output on the display.

[0051] This configuration allows defective cells to be detected by electrochemical analysis without disassembling the cells, allowing users to easily detect defective cells simply by charging and discharging the cells, thereby improving the reliability of defective cell detection.

[0052] 2 is a schematic diagram illustrating a configuration in which an information processing system 230 is connected to a plurality of user terminals 210_1, 210_2, and 210_3 so as to be able to communicate with each other in order to detect a bad cell according to one embodiment of the present disclosure. As shown in the figure, the plurality of user terminals 210_1, 210_2, and 210_3 may be connected to the information processing system 230, which can provide a bad cell determination service via a network 220. Here, the plurality of user terminals 210_1, 210_2, and 210_3 may include terminals of users who will receive the bad cell determination service.

[0053] In one embodiment, the information processing system 230 may include one or more server devices and / or databases capable of storing, providing, and executing computer-executable programs (e.g., downloadable applications) and data related to providing the defective cell determination service, and one or more distributed computing devices and / or distributed databases based on a cloud computing service.

[0054] The bad cell determination service provided by the information processing system 230 may be provided to users via a bad cell determination application, a web browser, a web browser extension program, etc. installed in each of the user terminals 210_1, 210_2, and 210_3. For example, the information processing system 230 may provide information or perform a corresponding process in response to a bad cell determination request received from the user terminals 210_1, 210_2, and 210_3 via the bad cell determination application, etc.

[0055] A plurality of user terminals 210_1, 210_2, and 210_3 can communicate with the information processing system 230 via a network 220. The network 220 can be configured to enable communication between the plurality of user terminals 210_1, 210_2, and 210_3 and the information processing system 230. Depending on the installation environment, the network 220 can be composed of a wired network such as Ethernet (registered trademark), PLC (Power Line Communication), telephone line communication device, and RS-serial communication, a mobile communication network, a wireless network such as WLAN (Wireless LAN), Wi-Fi (registered trademark), Bluetooth (registered trademark), and ZigBee (registered trademark), or a combination thereof. The communication method is not limited and can include not only a communication method utilizing a communication network (e.g., a mobile communication network, a wired Internet, a wireless Internet, a broadcast network, a satellite network, etc.) that can include the network 220, but also short-range wireless communication between the user terminals 210_1, 210_2, and 210_3.

[0056] 2 illustrates a mobile phone terminal 210_1, a tablet terminal 210_2, and a PC terminal 210_3 as examples of user terminals, but is not limited thereto. The user terminals 210_1, 210_2, and 210_3 may be any computing devices capable of wired and / or wireless communication and capable of installing and executing a poor cell determination application or a web browser. For example, the user terminals may include AI speakers, smartphones, mobile phones, navigation systems, desktop computers, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), tablet PCs, game consoles, wearable devices, internet of things (IoT) devices, virtual reality (VR) devices, augmented reality (AR) devices, set-top boxes, etc. Also, while FIG. 2 shows three user terminals 210_1, 210_2, and 210_3 communicating with the information processing system 230 via the network 220, this is not limited thereto, and a different number of user terminals may be configured to communicate with the information processing system 230 via the network 220.

[0057] FIG. 2 illustrates a configuration in which a user request (e.g., a request for determining a defective cell) is transmitted to the information processing system 230 via user terminals 210_1, 210_2, and 210_3, but is not limited to this. The user request may be provided to the information processing system 230 via an input device associated with the information processing system 230, rather than via the user terminals 210_1, 210_2, and 210_3, and the result of processing the user request (e.g., whether the cell is defective or not) may be provided to the user via an output device (e.g., a display, etc.) associated with the information processing system 230.

[0058] FIG. 3 is a block diagram showing the internal configuration of a user terminal 210 and an information processing system 230 according to an embodiment of the present disclosure. The user terminal 210 may refer to any computing device capable of executing applications, a web browser, and the like and capable of wired / wireless communication, and may include, for example, the mobile phone terminal 210_1, the tablet terminal 210_2, and the PC terminal 210_3 of FIG. 2. As shown in the figure, the user terminal 210 may include a memory 312, a processor 314, a communication module 316, and an input / output interface 318. Similarly, the information processing system 230 may include a memory 332, a processor 334, a communication module 336, and an input / output interface 338. As shown in FIG. 3, the user terminal 210 and the information processing system 230 may be configured to communicate information and / or data over the network 220 using their respective communication modules 316 and 336. Furthermore, the input / output device 320 may be configured to input information and / or data to the user terminal 210 and output information and / or data generated by the user terminal 210 via the input / output interface 318.

[0059] The memories 312 and 332 may include any non-transitory computer-readable recording medium. According to one embodiment, the memories 312 and 332 may include permanent mass storage devices such as read only memory (ROM), disk drives, solid state drives (SSDs), and flash memory. As another example, permanent mass storage devices such as ROM, SSDs, flash memory, and disk drives may be included in the user terminal 210 or the information processing system 230 as permanent storage devices separate from the memory. The memories 312 and 332 may also store an operating system and at least one program code.

[0060] Such software components may be loaded from a computer-readable recording medium separate from the memories 312, 332. Such separate computer-readable recording medium may include a recording medium directly connectable to the user terminal 210 and the information processing system 230, but may also include computer-readable recording media such as a floppy drive, a disk, a tape, a DVD / CD-ROM drive, and a memory card. As another example, the software components may be loaded into the memories 312, 332 via the communication modules 316, 336 rather than a computer-readable recording medium. For example, at least one program may be loaded into the memories 312, 332 based on a computer program to be installed from a file provided via the network 220 by a developer or a file distribution system that distributes application installation files.

[0061] The processors 314, 334 may be configured to process computer program instructions by performing basic arithmetic, logic, and input / output operations. The instructions may be provided to the processors 314, 334 by the memories 312, 332 or the communications modules 316, 336. For example, the processors 314, 334 may be configured to execute instructions received by program code stored in a storage device, such as the memories 312, 332.

[0062] The communication modules 316 and 336 may provide configurations and functions for the user terminal 210 and the information processing system 230 to communicate with each other via the network 220, and may also provide configurations and functions for the user terminal 210 and / or the information processing system 230 to communicate with other user terminals or other systems (e.g., another cloud system, etc.). For example, a request or data (e.g., a bad cell determination request) generated by the processor 314 of the user terminal 210 via program code stored in a storage device such as the memory 312 may be transmitted to the information processing system 230 via the network 220 under the control of the communication module 316. Conversely, a control signal or command provided under the control of the processor 334 of the information processing system 230 may be received by the user terminal 210 via the communication module 316 of the user terminal 210 via the communication module 336 and the network 220.

[0063] The input / output interface 318 may be a means for interfacing with the input / output device 320. For example, the input device may include a device such as a camera including an audio sensor and / or an image sensor, a keyboard, a microphone, a mouse, etc., and the output device may include a device such as a display, a speaker, a haptic feedback device, etc. As another example, the input / output interface 318 may be a means for interfacing with a device that integrates components or functions for performing input and output, such as a touch screen. For example, when the processor 314 of the user terminal 210 processes instructions of a computer program loaded in the memory 312, a service screen configured using information and / or data provided by the information processing system 230 or another user terminal may be displayed on the display via the input / output interface 318. Although the input / output device 320 is illustrated as not being included in the user terminal 210 in FIG. 3, the present invention is not limited thereto and may be configured integrally with the user terminal 210. Furthermore, the input / output interface 338 of the information processing system 230 may be a means for interfacing with an input or output device (not shown) that may be coupled to the information processing system 230 or may be included in the information processing system 230. While the input / output interfaces 318, 338 are shown in Figure 3 as elements configured separately from the processors 314, 334, this is not limiting, and the input / output interfaces 318, 338 may also be configured to be included in the processors 314, 334.

[0064] The user terminal 210 and the information processing system 230 may include more components than those shown in FIG. 3 . However, it is not necessary to explicitly show most of the conventional components. According to one embodiment, the user terminal 210 may be embodied to include at least a portion of the input / output device 320 described above. The user terminal 210 may also include other components such as a transceiver, a global positioning system (GPS) module, a camera, various sensors, and a database. For example, if the user terminal 210 is a smartphone, it may include components typically found in smartphones. For example, the user terminal 210 may be embodied to further include various components such as an acceleration sensor, a gyro sensor, a microphone module, a camera module, various physical buttons, buttons using a touch panel, input / output ports, and a vibrator for vibration.

[0065] When a program or application for a bad cell determination service or the like is running, the processor 314 can receive text, images, videos, voice, and / or actions, etc., entered or selected through an input device such as a touch screen, keyboard, camera including an audio sensor and / or image sensor, microphone, etc. connected to the input / output interface 318, and can store the received text, images, videos, voice, and / or actions, etc. in the memory 312 or provide them to the information processing system 230 via the communication module 316 and the network 220.

[0066] The processor 314 of the user terminal 210 may be configured to manage, process, and / or store information and / or data received from the input / output device 320, other user terminals, the information processing system 230, and / or multiple external systems. The information and / or data processed by the processor 314 may be provided to the information processing system 230 via the communication module 316 and the network 220. The processor 314 of the user terminal 210 may transfer and output information and / or data to the input / output device 320 via the input / output interface 318. For example, the processor 314 may output or display the received information and / or data on a screen of the user terminal 210.

[0067] The processor 334 of the information processing system 230 may be configured to manage, process, and / or store information and / or data received from multiple user terminals 210 and / or multiple external systems. The information and / or data processed by the processor 334 may be provided to the user terminal 210 via the communication module 336 and the network 220.

[0068] 4 is a diagram illustrating an example of the internal configuration of a processor 334 of an information processing system according to an embodiment of the present disclosure. As shown in the figure, the processor 334 of the information processing system may include a charge / discharge data acquisition unit 410, an entropy calculation unit 420, a graphite interface state estimation unit 430, and a cell defect determination unit 440. While FIG. 4 illustrates a single processor, the present invention is not limited to this and may be configured with multiple processors.

[0069] The charge / discharge data acquisition unit 410 may acquire first charge / discharge data related to the cell while the cell is being charged or discharged. Here, the first charge / discharge data may include cell voltage information, temperature information, etc. The charge / discharge data acquired by the charge / discharge data acquisition unit 410 may be stored in the database 450.

[0070] In one embodiment, the charge / discharge data acquisition unit 410 may generate a control signal to be applied to a charger / discharger (e.g., 120 in FIG. 1) to acquire charge / discharge data and transmit the control signal to the charger / discharger. Here, the control signal may be a signal that controls the charge or discharge of the charger / discharger so that the state of charge of the cell falls within a predetermined range (e.g., SOC 22% to 50%), or a signal that controls the C rate (e.g., 0.33C) of the charge or discharge of the charger / discharger to a constant value. For example, if the state of charge of a cell is 10%, the charge / discharge data acquisition unit 410 may generate a signal to control the charge of the charger / discharger so that the state of charge of the cell becomes 50%, and transmit the signal to the charger / discharger. As another example, if the state of charge of a cell is 60%, the charge / discharge data acquisition unit 410 may generate a signal to control the discharge of the charger / discharger so that the state of charge of the cell becomes 22%, and transmit the signal to the charger / discharger.

[0071] The entropy calculation unit 420 may calculate the entropy value of the cell based on the charge / discharge data obtained by the charge / discharge data acquisition unit 410. Specifically, the entropy calculation unit 420 may calculate the entropy value based on the temperature and voltage at a specific state of charge of the cell. Here, the entropy value may be related to the arrangement of the lithium layers of the cell. For example, the entropy calculation unit 420 may calculate the entropy value in the SOC range of 22% to 50% based on the temperature and voltage collected during charge / discharge in the range. The entropy value calculated by the entropy calculation unit 420 may be stored in the database 450.

[0072] The graphite interface state estimation unit 430 can estimate the graphite interface state of the cell based on the entropy value calculated by the entropy calculation unit 420. Here, the graphite interface state of the cell can indicate interface deterioration of the graphite anode of the cell. Specifically, the graphite interface state estimation unit 430 can estimate the graphite interface state of the cell by comparing the calculated entropy value with a reference entropy value. In this case, the reference entropy value can be determined based on the entropy values ​​of multiple normal cells determined to be normal. For example, if the calculated entropy value differs by 1% or more from the average entropy value of multiple normal cells, the graphite interface state estimation unit 430 can estimate that the graphite interface state of the cell is abnormal, but is not limited to this.

[0073] The cell defect determination unit 440 can determine whether a cell is defective based on the graphite interface state of the cell estimated by the graphite interface state estimation unit 430. When the cell defect determination unit 440 determines that a cell that has already undergone an activation process is defective, it can generate a control signal to perform a reactivation process on the cell or output information related to the cell.

[0074] In one embodiment, after performing a reactivation process on a cell determined to be defective, the charge / discharge data acquisition unit 410 may acquire second charge / discharge data associated with the cell while charging / discharging the cell so that the cell's state of charge falls within a predetermined range. The entropy calculation unit 420 may recalculate the entropy value of the cell based on the second charge / discharge data. The graphite interface state estimation unit 430 may re-estimate the graphite interface state of the cell based on the recalculated entropy value. The cell failure determination unit 440 may re-determine whether the cell is defective based on the re-estimated graphite interface state. If the cell failure determination unit 440 determines the cell to be defective, the cell may ultimately be disposed of as defective.

[0075] In one embodiment, the cell defect determination unit 440 may output information related to the cell in response to determining that the cell is defective (e.g., final defect determination after a reactivation process). Here, the information related to the cell may include, but is not limited to, information stored in the database 450, such as cell identification information, cell location information, cell temperature information, cell voltage information, and cell entropy value.

[0076] FIG. 5 illustrates an example graph 500 showing changes in entropy value with C-rate according to an embodiment of the present disclosure. In one embodiment, the entropy value of a cell may be related to the arrangement of the cell's lithium layers. Specifically, a graphite anode may include lithium disposed between graphite interfaces. If the graphite interface condition is poor, the arrangement of the lithium layers may become unstable due to non-uniform surface reactions in a predetermined SOC range 510. Here, the predetermined SOC range 510 is related to the cell's graphite interface condition and may be an SOC of 22% to 50%.

[0077] Graph 500 shows the change in entropy value with a constant C-rate (C-rate) for charging and discharging a cell. In one embodiment, in an SOC range lower than the predetermined SOC range 510 (i.e., a range below 22% SOC), the number of lithium atoms present in the lithium layer is small, so the effect of surface reactions on the lithium arrangement may be small. As a result, the difference in entropy value with the C-rate may be relatively small in this range. In contrast, in an SOC range higher than the predetermined SOC range 510 (i.e., a range above 50% SOC), the number of lithium atoms present in the lithium layer is large, so the change in the lithium layer arrangement may be minimal. As a result, the difference in entropy value with the C-rate may be relatively small in this range.

[0078] In one embodiment, in a predetermined SOC range 510, the lithium layer spacing is appropriately narrow, so the effect of surface reactions on lithium alignment may be relatively large. Specifically, when the cell is charged at a low C rate (e.g., 0.1 C), the lithium surface reactions are uniform, so the effect of surface reactions on lithium alignment may be small. In contrast, when the cell is charged at a high C rate (e.g., 0.5 C), the lithium surface reactions are non-uniform, so the effect of surface reactions on lithium alignment may be relatively large. Thus, referring to graph 500, it can be seen that the entropy value of the cell differs when only the C rate is changed within the predetermined SOC range 510. That is, the entropy value of the cell may be related to the alignment of the lithium layers of the cell and the graphite interface state.

[0079] 5, the predetermined SOC range 510 is illustrated as being SOC 22% to 50%, but is not limited thereto. For example, the predetermined SOC range 510 may include an SOC range in which the entropy value of a cell is observed to differ from a reference entropy value.

[0080] 6 illustrates example graphs 610 and 620 showing changes in entropy with additives according to an embodiment of the present disclosure. In one embodiment, the entropy of a cell can be related to the arrangement of the lithium layers in the cell. Specifically, a graphite anode can include lithium disposed between the graphite interfaces.

[0081] A first graph 610 shows the change in cell entropy value when VC (vinylene carbonate), a graphite interface modification additive, is added. A second graph 620 shows the change in cell entropy value when FEC (fluoroethylene carbonate), a graphite interface modification additive, is added. The graphite interface modification additive forms a uniform and robust interface at the graphite interface without changing the structure or ionic conductivity of the graphite except at the graphite interface. Furthermore, by referring to the predetermined SOC range 612 of the first graph 610 and the predetermined SOC range 622 of the second graph 620, it can be seen that the cell entropy value differs from the reference (Ref.) entropy value when a graphite interface modification additive is added. That is, the cell entropy value can be related to the graphite interface state.

[0082] FIG. 7 illustrates an example of a method for detecting a defective cell according to an embodiment of the present disclosure. In one embodiment, the method for detecting a defective cell begins by performing an activation process on a cell using activation process equipment (S710). Furthermore, at least one of charging and discharging of the cell may be performed based on a predetermined cell state of charge range (e.g., SOC 22% to 50%) (S720). At this time, charging or discharging of the cell may be performed at a constant C rate (e.g., 0.33C). A processor (e.g., 334 in FIG. 3) obtains first charging and discharging data including voltage and temperature information during the charging and discharging of the cell.

[0083] The processor can then calculate the entropy value of the cell based on the first charge / discharge data (S730). The processor can also determine whether the graphite interface of the cell is defective based on the entropy value of the cell (S740). Specifically, the processor can determine whether the graphite interface of the cell is defective by comparing the calculated entropy value with a reference entropy value. For example, the processor can determine that the graphite interface of the cell is defective if the calculated entropy value differs from the reference entropy value by 1% or more. If the processor determines that the graphite interface is not defective, the processor can determine that the cell is a normal cell (S750). At this time, information indicating that the cell is a normal cell can be output on a display.

[0084] If it is determined that the graphite interface is defective, the processor may determine whether the number of times the graphite interface of the cell has been determined to be defective is the second or greater (S760). If the number of times the graphite interface of the cell has been determined to be defective is the first, a reactivation process may be performed on the cell to stabilize the defective graphite interface (S710). For example, the reactivation process may be performed using activation process equipment. Thereafter, as described above, the cell that has undergone the reactivation process is charged and discharged based on a predetermined range. The processor may also obtain second charge and discharge data for the cell and recalculate the entropy value based on the second charge and discharge data (S730). The processor may then re-determine whether the graphite interface of the cell is defective based on the second charge and discharge data (S740).

[0085] If the graphite interface of the cell is still bad, the processor may determine that the cell is a bad cell because the determination count is second (S770). In response to determining that the cell is bad (e.g., a final bad determination), the processor may output information related to the cell. Here, the information related to the cell may include, but is not limited to, cell identification information, cell location information, cell temperature information, cell voltage information, and cell entropy value.

[0086] This configuration allows for non-destructive detection of defective cells. Furthermore, the defective cells are reactivated to stabilize the defective graphite interface, and cells that do not improve even after the reactivation process can be treated as defective. This improves the reliability of defective cell detection.

[0087] FIG. 8 is a flowchart illustrating an example of a method 800 according to an embodiment of the present disclosure. In one embodiment, the method 800 can be performed by at least one processor. The method 800 begins by the processor proceeding with at least one of charging or discharging the cell so that the cell's State of Charge (SOC) falls within a predetermined range (S810). Here, the predetermined range can be related to the graphite interface condition of the cell. For example, the predetermined range can be SOC 22% to 50%.

[0088] The processor may then acquire first charge / discharge data including voltage and temperature information during charging / discharging of the cell (S820). The processor may also calculate an entropy value of the cell based on the first charge / discharge data (S830). Here, the entropy value may be related to the arrangement of the lithium layers of the cell.

[0089] The processor can then estimate the graphite interface state of the cell based on the calculated entropy value (S840). Here, the graphite interface state of the cell can indicate interface degradation of the graphite negative electrode of the cell. Specifically, the processor can estimate the graphite interface state of the cell by comparing the calculated entropy value with a reference entropy value. In this case, the reference entropy value can be determined based on the entropy values ​​of multiple normal cells determined to be normal.

[0090] The processor may also determine whether the cell is defective based on the estimated graphite interface state of the cell (S850). If the cell is determined to be defective, the processor may output information related to the cell. For example, the information related to the cell may include cell identification information, a cell entropy value, cell voltage information, and cell temperature information.

[0091] In one embodiment, charging and discharging of the cell can proceed at a constant C-rate, where the constant C-rate can be equal to or greater than a predetermined threshold (e.g., 0.33 C).

[0092] In one embodiment, the cell may be a cell that has undergone an activation process. In this case, the processor may perform a reactivation process on the cell in response to determining that the cell is defective. The processor may also acquire second charge / discharge data after performing the cell reactivation process. Based on the second charge / discharge data, the processor may re-estimate the graphite interface state of the cell. Based on the re-estimated graphite interface state, the processor may further determine whether the cell is defective.

[0093] The above-described method may be provided as a computer program stored on a computer-readable recording medium for execution by a computer. The medium may continuously store a computer-executable program or temporarily store it for execution or download. The medium may also be various recording or storage means in the form of a single piece of hardware or multiple pieces of hardware combined together. The medium is not limited to media directly connected to a computer system but may also be distributed over a network. Examples of media include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; and ROM, RAM, flash memory, and other media configured to store program instructions. Other examples of media include recording or storage media managed by app stores that distribute applications and other sites or servers that provide or distribute various software.

[0094] The methods, operations, or techniques of the present disclosure can be implemented by a variety of means. For example, such techniques can be embodied in hardware, firmware, software, or a combination thereof. Those skilled in the art will appreciate that the various exemplary logical blocks, modules, circuits, and algorithm steps described in this disclosure can be embodied in electronic hardware, computer software, or a combination of both. To clearly illustrate this interchange between hardware and software, the various exemplary components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is embodied as hardware or software will vary depending on the particular application and design requirements imposed on the overall system. Those skilled in the art may implement the described functionality in various ways for each particular application, but such implementations should not be interpreted as departing from the scope of the present disclosure.

[0095] In a hardware implementation, the processing units utilized to perform the techniques may be embodied within one or more ASICs, DSPs, GPUs, digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units designed to perform the functions described in this disclosure, computers, or combinations thereof.

[0096] Accordingly, the various exemplary logic blocks, modules, and circuits described in this disclosure may be embodied or performed by any combination of general purpose processors, DSPs, ASICs, FPGAs or other programmable logic devices, discrete gate and transistor logic, discrete hardware components, or any combination designed to perform the functions described herein. A general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be embodied as a combination of computing devices, such as a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other configuration.

[0097] In a firmware and / or software implementation, the techniques may be embodied as instructions stored on a computer-readable medium such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable PROM (EEPROM), flash memory, compact disc (CD), magnetic or optical data storage device, etc. The instructions may be executable by one or more processors to cause the processors to perform certain aspects of the functions described in this disclosure.

[0098] If embodied as software, the techniques can be stored on or transmitted via a computer-readable medium as one or more instructions or code. Computer-readable media includes any medium that facilitates transfer of a computer program from one place to another, including both computer storage media and communication media. Storage media can be any available medium that can be accessed by a computer. By way of non-limiting example, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to transport or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection can be properly termed a computer-readable medium.

[0099] For example, if software is transferred from a website, server, or other remote source using coaxial cable, fiber optic cable, lead wire, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, fiber optic cable, lead wire, Digital Subscriber Line, or wireless technologies such as infrared, radio, and microwave are included within the definition of medium. As used herein, "disk" and "disc" include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically while discs reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable medium.

[0100] A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium may be coupled to the processor such that the processor reads information from, and writes information to, the storage medium. Alternatively, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. Alternatively, the processor and the storage medium may reside as discrete components in a user terminal.

[0101] Although the above-described embodiments are described as utilizing aspects of the presently disclosed subject matter on one or more stand-alone computer systems, the present disclosure is not limited thereto and may be implemented in any computing environment, such as a network or distributed computing environment. Furthermore, aspects of the subject matter in the present disclosure may be implemented on multiple processing chips or devices, and storage may be shared across multiple devices. Such devices may include PCs, network servers, and handheld devices.

[0102] Although the present invention has been described above using limited examples and drawings, it is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims. [Explanation of symbols]

[0103] 110 cells 120 Charger / discharger 130 sensors 140 Graphite anode 142 graphite layer 144 Lithium

Claims

1. proceeding with at least one of charging or discharging the cell so that the state of charge (SOC) of the cell falls within a predetermined range; acquiring first charge / discharge data including voltage and temperature information during charging / discharging of the cell; calculating an entropy value of the cell based on the first charge / discharge data; estimating a graphite interface state of the cell based on the calculated entropy value; and determining whether the cell is defective based on the estimated graphite interface state of the cell.

2. 2. The method of claim 1, further comprising the step of outputting information associated with the cell in response to the cell being determined to be defective.

3. 2. The method of claim 1, wherein the graphite interface condition of the cell indicates degradation of the interface of the graphite negative electrode of the cell.

4. The method of claim 1 , wherein the predetermined range is associated with a graphite interface state of the cell.

5. 5. The defective cell detection method according to claim 4, wherein the predetermined range is SOC 22% to 50%.

6. The method of claim 1 , wherein the cells are charged and discharged at a constant C rate.

7. The method of claim 6 , wherein the constant C-rate is equal to or greater than a predetermined threshold.

8. The defective cell detection method according to claim 1 , wherein the estimating step includes the step of comparing the calculated entropy value with a reference entropy value to estimate the graphite interface state of the cell.

9. The method of detecting a defective cell according to claim 8 , wherein the reference entropy value is determined based on entropy values ​​of a plurality of normal cells determined to be normal.

10. 2. The method of claim 1, wherein the cells are cells that have undergone an activation process.

11. The method of claim 10 , further comprising the step of: in response to determining that the cell is defective, proceeding with a reactivation process for the cell.

12. acquiring second charge / discharge data after performing the cell reactivation process; re-estimating the graphite interface state of the cell based on the second charge / discharge data; The defective cell detection method according to claim 11 , further comprising: determining whether the cell is defective based on the re-estimated graphite interface state.

13. 2. The method of claim 1, wherein the entropy value is related to the arrangement of the lithium layers of the cell.

14. A computer readable computer program for performing the method of any one of claims 1 to 13 on a computer.

15. a communication module; Memory and at least one processor coupled to the memory and configured to execute at least one computer-readable program contained in the memory; The at least one program proceeding with at least one of charging and discharging the cell so that the state of charge of the cell falls within a predetermined range; Acquiring first charge / discharge data including voltage and temperature information during charging / discharging of the cell; Calculating an entropy value of the cell based on the first charge / discharge data; Estimating the graphite interface state of the cell based on the calculated entropy value; The apparatus includes instructions for determining whether the cell is defective based on the estimated graphite interface state of the cell.

16. 16. The apparatus of claim 15, wherein the at least one program further comprises instructions for outputting information associated with the cell in response to the cell being determined to be bad.

17. The apparatus of claim 15 , wherein the predetermined range is associated with a graphite interface state of the cell.

18. The apparatus of claim 17, wherein the predetermined range is from 22% to 50% SOC.

19. 16. The device of claim 15, wherein charging and discharging of the cell proceeds at a constant C rate.

20. The apparatus of claim 15 , wherein the estimating comprises comparing the calculated entropy value with a reference entropy value to estimate a graphite interface state of the cell.

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