Battery diagnosis method and battery diagnosis device

Abstract

The invention discloses a battery diagnosis method and device. The battery diagnostic method includes: performing an intermittent application process of electrical stimulation to a battery cell; obtaining state history data of the battery cell corresponding to a state change period until the electrical state of the battery cell reaches the second state from the first state; generating, based on the state history data, a measurement full cell profile representing a correspondence between a capacity and a voltage of the battery cell; and generating first diagnostic information by analytically measuring the full cell profile, the first diagnostic information including at least one diagnostic factor related to the charge / discharge performance of the battery cell.

Description

Technical Field

[0001] The present disclosure relates to techniques for non-destructively diagnosing the condition of a battery.

[0002] This application claims priority to Korean Patent Application No. 10-2023-0154875 filed on November 9, 2023, Korean Patent Application No. 10-2024-0057162 filed on April 29, 2024, and Korean Patent Application No. 10-2023-0133644 filed on October 6, 2023, filed in Korea, the disclosures of which are incorporated herein by reference. Background Art

[0003] In recent years, demand for portable electronic products such as laptop computers, cameras, and mobile phones has rapidly increased, and with the widespread development of electric vehicles, accumulators for energy storage, robots, and satellites, much research is being conducted on high-performance batteries that can be repeatedly recharged.

[0004] Currently, commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium batteries, etc., and among them, lithium batteries have little or no memory effect, and therefore they have received more attention than nickel-based batteries because they have the advantages of being rechargeable whenever convenient, having a very low self-discharge rate and a high energy density.

[0005] While much research is being conducted on these batteries in terms of increasing capacity and density, improvements in lifespan and safety are also important. In order to improve battery safety, the current state of the battery must be accurately diagnosed.

[0006] Accurately diagnosing the internal state of a battery cell is crucial to its safety and longevity. To diagnose the internal state of a battery cell without disassembling it, relational data (such as a full-cell profile) showing the corresponding relationship between capacity and voltage is primarily used.

[0007] Traditionally, full-cell profiles are obtained by repeatedly measuring the voltage and capacity of a battery cell at short intervals while applying a constant electrical stimulus (e.g., constant-current charging or discharging) to the cell. However, to minimize polarization (or overpotential) that can reduce diagnostic accuracy, it's advantageous to lower the level of electrical stimulus applied to the cell. This has the limitation of requiring excessive time to obtain a full-cell profile. Furthermore, while higher levels of electrical stimulation are advantageous in terms of time reduction, they are accompanied by severe polarization, making diagnostic accuracy unreliable. Summary of the Invention

[0008] Technical issues

[0009] The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure aims to provide a battery diagnostic method and a battery diagnostic device for obtaining relationship data that directly and indirectly represents the corresponding relationship between the capacity and voltage of a battery cell by performing an intermittent application process of electrical stimulation, wherein the application and removal of the electrical stimulation are repeated alternately. The polarization induced in the battery cell during the application period of the electrical stimulation is naturally reduced during the rest period of the electrical stimulation. Therefore, even if the electrical stimulation used in the intermittent application process has a high level, the actual charge / discharge characteristics of the battery cell can be fully reflected in the obtained relationship data.

[0010] Furthermore, the present disclosure is directed to providing a battery diagnosis method and a battery diagnosis apparatus capable of generating diagnosis information related to charge / discharge performance of a battery cell based on relationship data obtained by performing an intermittent application process.

[0011] These and other purposes and advantages of the present disclosure can be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of the present disclosure. Moreover, it will be readily understood that the purposes and advantages of the present disclosure can be achieved by the means shown in the appended claims and their combinations.

[0012] Technical Solution

[0013] In one aspect of the present disclosure, a battery diagnosis method is provided, comprising: obtaining, through an intermittent application process of electrical stimulation to a battery cell, state history data of the battery cell corresponding to a state change period until the electrical state of the battery cell reaches a second state from a first state; generating, based on the state history data, a measured full-cell profile representing a correspondence between the capacity and voltage of the battery cell; and generating first diagnostic information by analyzing the measured full-cell profile, the first diagnostic information including at least one diagnostic factor related to the charge / discharge performance of the battery cell.

[0014] The electrical stimulation may be a current stimulation that causes a transient voltage change exceeding a threshold value on the battery cell.

[0015] The electrical stimulation may be a current stimulation that causes an overpotential exceeding a threshold value to the battery cell when the electrical stimulation is continuously applied for a certain time.

[0016] The electrical stimulus may be a charging current at a predetermined current rate.

[0017] The electrical stimulation may be a discharge current at a predetermined current rate.

[0018] The state history data may include a voltage value representing a voltage of a battery cell measured at least once during each rest period of the electrical stimulus applied within the state change period.

[0019] The intermittent application process may include a process for removing the electrical stimulus to the battery cell so that a rest period is provided to the battery cell whenever a current integrated value of the battery cell changes by a threshold integrated value during application of the electrical stimulus.

[0020] The intermittent application process may further include a process for resuming application of electrical stimulation whenever the duration of the rest period reaches a reference time.

[0021] The first diagnostic information may include at least one of a positive electrode participation start point, a positive electrode participation end point, a positive electrode scaling factor, and a positive electrode load amount representing charge / discharge performance of the positive electrode of the battery cell as a diagnostic factor.

[0022] The battery diagnostic method may further include generating second diagnostic information by applying a mathematical operation to the first diagnostic information, the second diagnostic information including at least one degradation parameter regarding a positive electrode or available lithium of the battery cell.

[0023] The first diagnostic information may include at least one of a negative electrode participation start point, a negative electrode participation end point, a negative electrode scaling factor, and a negative electrode load amount representing charge / discharge performance of the negative electrode of the battery cell as a diagnostic factor.

[0024] The battery diagnostic method may further include generating second diagnostic information by applying a mathematical operation to the first diagnostic information, the second diagnostic information including at least one degradation parameter regarding the negative electrode of the battery cell.

[0025] The battery diagnostic method may further include updating charge / discharge permission condition information indicating at least one of a voltage range, an SOC range, and a current range allowed for the battery cell based on at least one of the first diagnostic information and the second diagnostic information.

[0026] In another aspect of the present disclosure, a battery diagnostic device is provided, including: a data acquisition unit, which is configured to obtain state history data of the battery cell corresponding to the state change period until the electrical state of the battery cell reaches the second state from the first state through an intermittent application process of electrical stimulation to the battery cell; and a processor, which is configured to generate a measured full-cell profile representing the correspondence between the capacity and voltage of the battery cell based on the state history data, wherein the processor is configured to generate first diagnostic information by analyzing the measured full-cell profile, and the first diagnostic information includes at least one diagnostic factor related to the charge / discharge performance of the battery cell.

[0027] The intermittent application process may include a process for removing the electrical stimulus to the battery cell so that a rest period is provided to the battery cell whenever a current integrated value of the battery cell changes by a threshold integrated value during application of the electrical stimulus.

[0028] The intermittent application process may further include a process for resuming application of electrical stimulation whenever the duration of the rest period reaches a reference time.

[0029] The first diagnostic information may include at least one of a positive electrode participation start point, a positive electrode participation end point, a positive electrode scaling factor, and a positive electrode load amount representing charge / discharge performance of the positive electrode of the battery cell as a diagnostic factor.

[0030] The first diagnostic information may include at least one of a negative electrode participation start point, a negative electrode participation end point, a negative electrode scaling factor, and a negative electrode load amount representing charge / discharge performance of the negative electrode of the battery cell as a diagnostic factor.

[0031] In yet another aspect of the present disclosure, a charging station is provided, comprising the battery diagnostic device.

[0032] In yet another aspect of the present disclosure, a cloud server is provided, comprising a battery diagnosis device.

[0033] Beneficial effects

[0034] According to at least one embodiment of the present disclosure, by applying a method of intermittently applying electrical stimulation to a battery cell, relational data representing the corresponding relationship between the capacity and voltage of the battery cell can be obtained, and diagnostic information representing the charge / discharge performance of the battery cell can be generated based on the obtained relational data.

[0035] Therefore, even if a high level of electrical stimulation is used to change the electrical state of the battery cell, a decrease in diagnostic accuracy due to excessive polarization can be prevented, and the time required to obtain relationship data can also be shortened.

[0036] The effects of the present disclosure are not limited to the above-described effects, and those skilled in the art will clearly understand these and other effects from the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, serve to provide a further understanding of the technical features of the present disclosure, and therefore, the present disclosure is not to be construed as being limited to the accompanying drawings.

[0038] Figure 1 2 is a diagram referred to to explain a battery diagnosis device according to the present disclosure.

[0039] Figure 2 are graphs referred to to describe examples of a reference positive electrode profile and a reference negative electrode profile, respectively.

[0040] Figure 3a and Figure 3b is a graph referred to to exemplarily describe a process of obtaining a measured full-cell profile of a battery cell.

[0041] Figures 4 to 6 is a diagram referred to to describe an example of a process of generating a comparative full-monobody profile line for comparison with a measured full-monobody profile line according to one embodiment of the present disclosure.

[0042] Figures 7 to 9 is a diagram referred to to describe another example of a process for generating a comparative full-monobody profile line for comparison with a measured full-monobody profile line according to one embodiment of the present disclosure.

[0043] Figure 10 is a flowchart referred to to exemplarily describe a battery diagnosis method according to a first embodiment of the present disclosure.

[0044] Figure 11 is a flowchart referred to to exemplarily describe a battery diagnosis method according to a second embodiment of the present disclosure.

[0045] Figure 12 is referred to in the description Figure 11 FIG. 1 is a diagram of a process of correcting voltage history data performed in step S1122 . DETAILED DESCRIPTION

[0046] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be interpreted as limited to the general and dictionary meanings, but should be interpreted based on the meanings and concepts corresponding to the technical aspects of the present disclosure on the principle of allowing the inventor to appropriately define the terms for the best interpretation.

[0047] Therefore, the descriptions presented herein are merely preferred examples for illustrative purposes, and are not intended to limit the scope of the present disclosure, and it should be understood that other equivalents and modifications may be made thereto without departing from the scope of the present disclosure.

[0048] Terms including ordinal numbers such as “first,” “second,” etc. are used to distinguish one element from another among various elements, but are not intended to limit the elements by the terms.

[0049] Unless the context clearly indicates otherwise, the terms "comprise" and "include" when used in this specification specify the presence of the stated elements, but do not exclude the presence or addition of one or more other elements. In addition, the term "unit" as used herein refers to a processing unit of at least one function or operation, and can be implemented by hardware and software alone or in combination.

[0050] Furthermore, throughout the specification, it will be understood that when an element is referred to as being “connected to” another element, it can be directly connected to the other element or intervening elements may be present.

[0051] Figure 1 2 is a diagram referred to to explain a battery diagnosis device according to the present disclosure.

[0052] refer to Figure 1 The battery system 1 includes a system controller 2, a battery pack 10, an inverter 30, and an electric load 40. The charging terminal P+ and the discharging terminal P- of the battery pack 10 can be electrically connected to the charging station 300 through a charging cable or the like.

[0053] The system controller 2 (e.g., an ECU: Electronic Control Unit) is configured to transmit a key-on signal to the battery management system 100 in response to a user switching a start button (not shown) provided in the battery system 1 to the on position. The system controller 2 is also configured to transmit a key-off signal to the battery management system 100 in response to a user switching the start button to the off position. The charging station 300 can communicate with the system controller 2 and supply charging power selected from constant power, constant current, and constant voltage via the charge terminal P+ and discharge terminal P− of the battery pack 10.

[0054] The battery pack 10 includes a battery 11 and may further include at least one of a relay 20 and a battery management system 100 .

[0055] The battery 11 includes at least one battery cell BC. Figure 1 In the embodiment, the battery 11 is exemplarily shown as including a plurality of battery cells (BC1 to BC N , N is a natural number of 2 or greater). Multiple battery cells (BC1 to BC N ) can be provided with the same electrochemical specifications. In the following, when multiple battery cells (BC1 to BC N ) When common features are found in the battery cells, the reference symbol “BC” will be given to the battery cells. The charging station 300 can perform charging and discharging cycles required for diagnosing the battery cells BC by cooperating with the inverter 30 having a discharging function.

[0056] The type of the battery cell BC is not particularly limited as long as it is an electrochemical element that can be repeatedly charged and discharged. The battery cell BC is a diagnosis target of the charging station.

[0057] The relay 20 is electrically connected in series to the battery 11 through a power path connecting the battery 11 and the inverter 30. Figure 1 , a relay 20 is shown connected between the positive terminal of the battery 11 and the charge and discharge terminal P+. The relay 20 is controlled to switch on and off in response to a switching signal from the battery management system 100. The relay 20 may be a mechanical contactor that switches on and off by the magnetic force of a coil, or a semiconductor switch such as a MOSFET (metal oxide semiconductor field effect transistor).

[0058] The inverter 30 is configured to convert the DC current from the battery 11 included in the battery pack 10 into AC current in response to a command from the battery management system 100 or the system controller 2. The AC current power from the inverter 30 is used to drive the electric load 40. For example, a three-phase AC current motor can be used as the electric load 40. Components in the battery system 1 that receive discharge power from the battery 11, such as the inverter 30 and the electric load 40, can be collectively referred to as electric loads.

[0059] The battery management system 100 includes a sensing unit 110 and a control circuit 130. The battery management system 100 may further include a communication circuit 150.

[0060] The sensing unit 110 includes a voltage sensor 111 . The sensing unit 110 may further include a current sensor 112 .

[0061] The voltage sensor 111 is connected to the positive and negative terminals of the battery cell BC and is configured to measure the voltage across the battery cell BC (also referred to as the "full-cell voltage" or "cell voltage") and generate a voltage signal representing a measured value of the measured voltage. The voltage sensor 111 may be implemented as one or a combination of two or more known voltage measurement elements, such as a voltage measurement IC.

[0062] The current sensor 112 is connected in series to the battery 11 through the current path between the battery 11 and the inverter 30. The current sensor 112 is configured to measure the current (also referred to as "charging and discharging current") flowing through the battery 11 and generate a current signal representing a measured value of the measured current. N ) are connected in series, so the current flowing in the battery 11 is the same as the current flowing in the battery cell BC. The current sensor 112 may be implemented as one or a combination of two or more known current measuring elements such as a shunt resistor, a Hall effect element, etc.

[0063] The communication circuit 150 is configured to support wired or wireless communication between the control circuit 130 and the system controller 2. Wired communication may be, for example, CAN (Controller Area Network) communication, and wireless communication may be, for example, ZigBee or Bluetooth communication. The type of communication protocol is not particularly limited, as long as it supports both wired and wireless communication between the control circuit 130 and the system controller 2. The communication circuit 150 may include an output device (e.g., a display, a speaker) that provides information received from the control circuit 130 and / or the system controller 2 in a form recognizable to a user (driver).

[0064] The control circuit 130 is operatively coupled to the relay 20, the voltage sensor 111, and the communication circuit 150. Operable coupling of any two components means that the two components are directly or indirectly connected to enable sending and receiving signals in one direction or both directions.

[0065] Control circuit 130 can collect voltage signals from voltage sensor 111 and current signals from current sensor 112. In this specification, "measurement signal" can refer solely to the voltage signal or to both. Specifically, control circuit 130 can use an ADC (analog-to-digital converter) built into it to convert each analog signal collected from sensors 111 and 112 into a digital value and record the digital value. Alternatively, each of voltage sensor 111 and current sensor 112 can include an ADC and transmit the digital value to control circuit 130.

[0066] The control circuit 130 may be referred to as a "battery controller" and may be implemented in hardware using at least one of an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a microprocessor, or an electrical unit for performing other functions.

[0067] The memory 131 may include at least one type of storage medium, such as a flash memory type, a hard disk type, a solid-state drive (SSD) type, a silicon disk drive (SDD) type, a multimedia card micro type, a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), or a programmable read-only memory (PROM). The memory 131 may store data and programs required for the computational operations of the control circuit 130. The memory 131 may also store data representing the results of the computational operations performed by the control circuit 130.

[0068] The control circuit 130 can control the charging / discharging of the battery cells BC based on charge / discharge permission condition information (described later) (including at least one of an allowable voltage range, an allowable SOC range, and an allowable current range). For example, if the full-cell voltage of the battery cells BC exceeds the allowable voltage range or the SOC of the battery cells BC exceeds the SOC range, the control circuit 130 may prohibit the relay 20 from being turned on. Otherwise, the control circuit 130 may allow the relay 20 to be turned on. Furthermore, the control circuit 130 can control the relay 20 and / or the inverter 30 so that the current flowing through the battery cells BC does not exceed the allowable current range.

[0069] When the relay 20 is turned on, the battery 11 enters the charging mode or the discharging mode. If the relay 20 is turned off while the battery 11 is being used in the charging mode or the discharging mode, the battery 11 switches to the rest mode.

[0070] The control circuit 130 can turn on the relay 20 in response to a key-on signal. The control circuit 130 can turn off the relay 20 in response to a key-off signal. The key-on signal is a signal requesting a switch from the rest mode to the charging or discharging mode. The key-off signal is a signal requesting a switch from the charging or discharging mode to the rest mode. Alternatively, the system controller 2 may be responsible for turning on / off the relay 20 rather than the control circuit 130.

[0071] In this specification, historical data for a particular parameter indicates the history of changes in that parameter over time. Furthermore, a profile (or curve) representing the corresponding relationship between any two parameters (e.g., "voltage" and "capacity," or "voltage" and "current") obtained at the same timing in the same period can be a mapping of the two historical data for the two parameters, allowing them to be represented in a two-dimensional graph, or a polynomial equation obtained by applying a predetermined curve-fitting logic to a set of two mapped historical data. The degree of the highest term in the polynomial equation can be predetermined.

[0072] The battery diagnosis device 302 includes a data acquisition unit 310 , a processor 320 , and a memory unit 330 .

[0073] The charging station 300 may include: Figure 1 , the stimulation application device 301 and the battery diagnostic device 302 are shown in FIG. Of course, the battery diagnostic device 302 can also be configured to operate independently of the charging station 300. For example, the battery diagnostic device 302 can be configured to be included in a cloud server (not shown). The cloud server can be located remotely from the charging station 300. In this case, the data acquisition unit 310 of the battery diagnostic device 302 can perform a diagnostic process for the battery cell BC through remote communication with the stimulation application device 301 and / or the battery system 1. Hereinafter, the battery cell BC to be diagnosed may be referred to as a "target cell."

[0074] Alternatively, the battery diagnostic apparatus 302 may be included in the battery pack 10 as a replacement device for the battery management system 100, and the battery management system 100 may be omitted from the battery pack 10. In this case, the processor 320 may be responsible for all functions of the control circuit 130 of the battery management system 100, and the data acquisition unit 310 may be responsible for all functions of the communication circuit 150 of the battery management system 100. In addition, the data acquisition unit 310 may be implemented to include the sensing unit 110.

[0075] The stimulus applying device 301 may include a charger that provides charging power for normal charging of the battery pack 10. The stimulus applying device 301 may apply or remove at least one type of electrical stimulus to the battery cells BC alone or in cooperation with the inverter 30 for diagnosing the battery cells BC.

[0076] The data acquisition unit 310 is configured to support wired or wireless communication between the processor 320 and the system controller 2. The data acquisition unit 310 may transmit the result of diagnosis of the battery cells BC performed by the processor 320 to the battery system 1. The data acquisition unit 310 may be included as a subcomponent of the processor 320.

[0077] In terms of hardware, the processor 320 may be implemented using at least one of an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), a DSPD (Digital Signal Processing Device), a PLD (Programmable Logic Device), an FPGA (Field Programmable Gate Array), a microprocessor, and electrical units for performing other functions.

[0078] Memory unit 330 may include at least one type of storage medium, such as a flash memory type, a hard disk type, a solid-state drive (SSD) type, a silicon disk drive (SDD) type, a multimedia card micro type, a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), or a programmable read-only memory (PROM). Memory unit 330 may store data and programs required for diagnostic processes performed by processor 320. Memory unit 330 may also store data representing the results of computational operations performed by processor 320. Memory unit 330 may also store data sets and software used to diagnose the degradation state of battery cells BC.

[0079] Figure 2 is a graph referred to to describe an example of each of the reference positive electrode profile and the reference negative electrode profile. Figure 2 In the graph, the horizontal axis (X-axis) represents capacity (Ah), and the vertical axis (Y-axis) represents voltage.

[0080] refer to Figure 2 Memory unit 330 can store a reference positive electrode cross-sectional line Rp and a reference negative electrode cross-sectional line Rn. The reference cell can be a button-type cell including a positive electrode half cell and a negative electrode half cell, or can be a three-electrode cell. Hereinafter, the positive electrode and the positive electrode half cell of the reference cell will be described with equivalent terms, and the negative electrode and the negative electrode half cell of the reference cell will be described with equivalent terms.

[0081] The reference positive electrode profile Rp may be a profile that represents the relationship between the positive electrode voltage and capacity of a reference cell. The positive electrode voltage of a reference cell refers to the potential difference between the potential of a reference electrode (not shown) and the potential of the positive electrode of the reference cell. The positive electrode profile Rp may also be referred to as a positive electrode half-cell profile.

[0082] The reference negative electrode profile Rn may represent the relationship between the negative electrode voltage and capacity of a reference cell. The negative electrode voltage of a reference cell refers to the potential difference between the potential of the reference electrode and the potential of the negative electrode of the reference cell. The negative electrode profile Rn may also be referred to as a negative electrode half-cell profile.

[0083] The potential of the reference electrode may be, for example, the redox potential of lithium. The positive electrode voltage may be simply referred to as the positive electrode potential, and the negative electrode voltage may be simply referred to as the negative electrode potential.

[0084] Each of the positive electrode voltage and the negative electrode voltage may be an open circuit voltage (OCV) or a closed circuit voltage (CCV).

[0085] A first charging protocol or a first discharging protocol can be used to obtain the closed-circuit voltage of each of the positive and negative electrodes of the reference cell. The first charging protocol can be a constant current charging method using a first current rate. The first discharging protocol can be a constant current discharging method using a first current rate (e.g., 0.05C). For example, while the reference cell is continuously charged using the first charging protocol or continuously discharged using the first discharging protocol, the closed-circuit voltages of the positive and negative electrodes of the reference cell, measured periodically or aperiodically, can be recorded as the positive and negative electrode voltages of the reference cell.

[0086] When compared to the closed-circuit voltage, the open-circuit voltage of each of the positive and negative electrodes of the reference cell can be obtained using a second charging protocol or a second discharging protocol. The second charging protocol can be an intermittent charging method in which constant current charging using a second current rate (e.g., 3.0C) and rest periods are performed alternately. The second discharging protocol can be an intermittent charging method in which constant current discharging using the second current rate and rest periods are performed alternately.

[0087] For example, whenever the charging time of the constant current charging of the second charging protocol exceeds a set time or the charging capacity of the reference cell increases by a set capacity, charging of the reference cell may be stopped for a predetermined remaining time, and then constant current charging may be resumed. The charging capacity may be calculated by periodically or non-periodically accumulating sampled values ​​of the charging current.

[0088] As another example, whenever the discharge time of the constant current discharge of the second discharge protocol exceeds a set time or the discharge capacity of the reference cell decreases by a set capacity, the discharge of the reference cell may be stopped for a predetermined remaining time, and then the constant current discharge may be resumed. The discharge capacity may be calculated by periodically or non-periodically accumulating sampled values ​​of the discharge current (i.e., measured values ​​of the cell current).

[0089] At this time, multiple rest periods can be provided while the second charging protocol or the second discharging protocol is in progress, and the open circuit voltages of the positive and negative electrodes of the reference cell measured at specific timings within each rest period can be recorded as the positive electrode voltage and negative electrode voltage of the reference cell, respectively.

[0090] In this specification, the low-level electrical stimulation may be referred to as "first electrical stimulation", and the high-level electrical stimulation may be referred to as "second electrical stimulation".

[0091] When the battery cell is assumed to be in a new product state, the first electrical stimulus may refer to a current stimulus that induces a transient voltage change equal to or less than a threshold value (e.g., the difference between OCV and CCV) in the battery cell, and the second electrical stimulus may refer to a current stimulus that induces a transient voltage change greater than the threshold value in the battery cell. Based on Ohm's law, the transient voltage change is a function of the internal resistance of the battery cell and the current flowing in the battery cell, and may represent the difference between the voltage of the battery cell immediately before the application of the electrical stimulus (i.e., OCV: open circuit voltage) and the voltage of the battery cell immediately after the application of the electrical stimulus (i.e., CCV: closed circuit voltage). If the electrical stimulus is a charge-induced stimulus, the transient voltage change may be referred to as a "voltage rise." Conversely, if the electrical stimulus is a discharge-induced stimulus, the transient voltage change may be referred to as a "voltage drop."

[0092] Alternatively, when the battery cell is assumed to be in a new product state, the first electrical stimulation may refer to a current stimulation that induces an overpotential less than a threshold value in the battery cell when the current stimulation is continuously applied for a specific period of time, and the second electrical stimulation may refer to a current stimulation that induces an overpotential greater than the threshold value in the battery cell when the current stimulation is continuously applied for the specific period of time. When the electrical stimulation is continuously applied for the specific period of time, the overpotential may represent the difference between the amount of change in OCV and the amount of change in CCV during the same period of time.

[0093] For example, the first electrical stimulation may be a charging current at a predetermined current rate (eg, a first current rate), and the second electrical stimulation may be a charging current at a current rate (eg, a second current rate) corresponding to a higher level than the first electrical stimulation.

[0094] As another example, the first electrical stimulation may be a discharge current at a predetermined current rate (eg, a first current rate), and the second electrical stimulation may be a discharge current corresponding to a current rate (eg, a second current rate) at a higher level than the first electrical stimulation.

[0095] Implementing the first charging protocol or the first discharging protocol may mean continuously applying the first electrical stimulus to the battery cells. Implementing the second charging protocol or the second discharging protocol may mean intermittently applying the second electrical stimulus to the battery cells.

[0096] For the sake of explanation, assume Figures 2 to 9 The middle horizontal axis represents the charging capacity.

[0097] At least one of the reference positive electrode section line Rp and the reference negative electrode section line Rn may be aligned along the horizontal axis so that the common capacity range ( Figure 2 The synthesized results of a portion of the 5 to 50 Ah) match the reference full monomer profile R. Figure 2 An example is shown in which the reference negative electrode section line Rn is aligned to be shifted to the right based on the starting point (the point corresponding to the capacity 0) of the reference positive electrode section line Rp.

[0098] from Figure 2 It can be seen that the ends of the reference positive electrode profile Rp and the reference negative electrode profile Rn are offset from each other. In other words, the capacity range of the reference positive electrode profile Rp and the capacity range of the reference negative electrode profile Rn do not match and only partially overlap. Therefore, the reference full-cell profile R indicates the full-cell voltage of the reference cell within a portion of the capacity range shared by the reference positive electrode profile Rp and the reference negative electrode profile Rn. In other words, the reference full-cell profile R is an example of a full-cell voltage profile obtained by directly subtracting a portion of the reference negative electrode profile Rn from a portion of the reference positive electrode profile Rp.

[0099] The reference full-cell profile R represents the relationship between the capacity and full-cell voltage of a new, verified good battery cell. In other words, the reference cell has the same positive and negative electrode performance as a new, verified good battery cell. The positive and negative electrode performance of any battery cell can be collectively referred to as "charge / discharge performance."

[0100] A new battery cell refers to a battery cell in a new state. This new state can be the same concept as BOL (Beginning of Life). For example, the period from the time the cumulative charge / discharge capacity reaches the set capacity after manufacturing completion is called BOL, and from the time the cumulative charge / discharge capacity reaches the set capacity, it is called MOL (Middle of Life).

[0101] The reference full cell profile R may represent the corresponding relationship between the voltage and capacity of the reference cell within at least the voltage range of interest (eg, 3.0 V to 4.0 V). The lower limit and upper limit of the voltage range of interest may be the first set voltage ( Figure 2 3.0V) and the second set voltage ( Figure 2 4.0V in the CMOS).

[0102] If the total cell voltage of any battery cell, including the reference cell, is equal to the first set voltage, the SOC may be set to 0%. When the total cell voltage of any battery cell, including the reference cell, is equal to the second set voltage, the SOC may be set to 100%. Figure 2 , the reference cell can reach a fully charged state (SOC 100%) from a fully discharged state (SOC 0%) through a charging capacity of 45Ah.

[0103] In this specification, the positive electrode participation starting point on the positive electrode section line of any battery cell indicates the positive electrode voltage and positive electrode capacity (or positive electrode SOC) when the total cell voltage of the corresponding battery cell matches the first set voltage. Furthermore, the negative electrode participation starting point on the negative electrode section line of the corresponding battery cell indicates the negative electrode voltage and negative electrode capacity (or negative electrode SOC) when the total cell voltage of the corresponding battery cell matches the first set voltage. Therefore, the voltage difference between the positive electrode participation starting point and the negative electrode participation starting point can be equal to the first set voltage.

[0104] Furthermore, the positive electrode participation endpoint on the positive electrode section line of any battery cell indicates the positive electrode voltage and positive electrode capacity (or positive electrode SOC) when the full cell voltage of the corresponding battery cell matches the second set voltage. Furthermore, the negative electrode participation endpoint on the negative electrode section line of the corresponding battery cell indicates the negative electrode voltage and negative electrode capacity (or negative electrode SOC) when the full cell voltage of the corresponding battery cell matches the second set voltage. Therefore, the voltage difference between the positive electrode participation endpoint and the negative electrode participation endpoint can be equal to the second set voltage.

[0105] In this specification, the positive electrode capacity (capacity value) at a specific point on the positive electrode section line of any battery cell may refer to the capacity difference between either of the two endpoints of the positive electrode section line and the specific point. The positive electrode SOC at a specific point on the positive electrode section line of any battery cell may refer to the ratio of the capacity difference between either of the two endpoints of the positive electrode section line (e.g., the low-capacity point) and the specific point to the capacity difference between the two endpoints of the positive electrode section line. The capacity difference between the two endpoints of the positive electrode section line may be referred to as the total positive electrode capacity.

[0106] Similarly, the negative electrode capacity (capacity value) at a specific point on the negative electrode section line of any battery cell can refer to the capacity difference between either of the two endpoints of the negative electrode section line (or the positive electrode section line) and the specific point. The negative electrode SOC at a specific point on the negative electrode section line of any battery cell can refer to the ratio of the capacity difference between either of the two endpoints (e.g., the low-capacity point) of the negative electrode section line (or the positive electrode section line) and the specific point to the capacity difference between the two endpoints of the negative electrode section line. The capacity difference between the two endpoints of the negative electrode section line can be referred to as the total negative electrode capacity.

[0107] In memory unit 330, information indicating the voltage at each of the reference positive electrode participation starting point (pi0), the reference positive electrode participation end point (pf0), the reference negative electrode participation starting point (ni0), and the reference negative electrode participation end point (nf0) may be pre-recorded. The reference positive electrode participation starting point (pi0) and the reference positive electrode participation end point (pf0) are the positive electrode participation starting point and the positive electrode participation end point, respectively, on reference positive electrode profile line Rp. The reference negative electrode participation starting point (ni0) and the reference negative electrode participation end point (nf0) are the negative electrode participation starting point and the negative electrode participation end point, respectively, on reference negative electrode profile line Rn.

[0108] The voltage difference between the reference positive electrode participation starting point (pi0) and the reference negative electrode participation starting point (ni0) may be equal to a first set voltage (e.g., 3.0 V). The voltage difference between the reference positive electrode participation end point (pf0) and the reference negative electrode participation end point (nf0) may be equal to a second set voltage (e.g., 4.0 V).

[0109] Figure 3a and Figure 3b is a graph referred to to exemplarily describe a process of obtaining a measured whole-cell profile of a target cell.

[0110] Figure 3a The graph depicted in FIG. 1 shows an example of the change in the full-cell voltage of a target cell over time due to the intermittent application of an electrical stimulus (e.g., the second electrical stimulus described above). The target cell is a battery cell to be diagnosed by the battery diagnostic device. The target cell may be a new battery cell that needs to be verified as a good product, or a battery cell that has been verified as a good product and is no longer new due to deterioration. Hereinafter, the target cell is also denoted by the reference symbol BC.

[0111] The processor 320 may control the stimulation applying device 301 to intermittently apply electrical stimulation to the target cell BC.

[0112] The process for controlling the stimulation applying device 301 to diagnose the target cell BC may be performed during a state change period until the electrical state of the target cell BC (e.g., the full cell voltage corresponding to OCV) changes from a first state (e.g., a first set voltage) to a second state (e.g., a second set voltage).

[0113] refer to Figure 3a In the graph, the voltage across all target cells BC shows an upward trend as it repeats a sawtooth pattern. Each rising segment of the sawtooth voltage is caused by the application of electrical stimulation, while the falling segment is caused by the interruption of electrical stimulation. In other words, the falling voltage segment represents the change in the voltage across all target cells BC during each rest period.

[0114] During the state change period, the processor 320 may repeatedly record the current measurement value of the target cell BC to generate current history data.

[0115] Processor 320 can control stimulation application device 301 to initiate a rest period of electrical stimulation whenever a predetermined rest condition is met during the state change period. In other words, when the rest condition is met, the process of applying electrical stimulation can be temporarily stopped. For example, at least one of (i) a change in the current integrated value to a threshold integrated value, (ii) a change in the state of charge (SOC) to a threshold SOC, and (iii) the duration of the application of electrical stimulation reaching a threshold time can be preset as a rest condition. For example, if the total current integrated value during the state change period is 40Ah and the threshold integrated value is 2Ah, a total of 20 rest periods can be permitted during the state change period.

[0116] The processor 320 may determine at least one of a threshold integral value, a threshold SOC, and a threshold time based on the target cell BC's full charge capacity, SOH, or previous diagnostic results (e.g., the capacity value at the negative electrode end point, the negative electrode loss rate). At least one of the threshold integral value, SOC, and time may have a predetermined positive (or negative) correspondence with the full charge capacity, SOH, or previous diagnostic results, and relationship data defining this correspondence (a data table for controlling the rest period) may be pre-stored in the memory unit 330. Due to the predetermined positive (or negative) correspondence, as the full charge capacity, SOH, or previous diagnostic results decrease, at least one of the threshold integral value, SOC, and time also decreases. Therefore, as the target cell BC degrades over time, rest periods are provided at short intervals within the state change period, thereby preventing a decrease in the number of data points included in the voltage history data indicating the temporal change history of all-cell voltages during the rest period of the state change period.

[0117] The processor 320 may obtain at least one of a threshold integral value, a threshold SOC, and a threshold time mapped to the full charge capacity, SOH, or a previous diagnosis result from the data table for rest period control. The processor 320 may control the intermittent application process of electrical stimulation during the state change period using at least one of the threshold integral value, the threshold SOC, and the threshold time obtained from the data table for rest period control.

[0118] When a reference time has passed since the start time of the rest period of electrical stimulation, the processor 320 may control the stimulation application device 301 to resume application of electrical stimulation. The reference time may be predetermined so that the polarization caused by electrical stimulation can be sufficiently resolved. For example, the reference time, which serves as the length of the rest period, may be the time required for the polarization at the start time of the rest period to become 10% or less.

[0119] During each rest period of electrical stimulation, the full-cell voltage of the target cell BC is measured at least once. As an example, the processor 320 may record the measured full-cell voltage at the end of each rest period of electrical stimulation as the OCV of the target cell BC. As another example, the full-cell voltage may be measured at least three times during each rest period of electrical stimulation, and the processor 320 may estimate the OCV of the target cell BC for each rest period based on the three full-cell voltage measurements during each rest period.

[0120] Therefore, voltage history data may be generated by recording OCV a plurality of times with a time difference during a state change period. Figure 3a Each OCV point marked in OCV ) is an example of a data point representing voltage history data.

[0121] The inventors of the present disclosure have recognized through numerous experiments that voltage history data generated using the second electrical stimulation in the intermittent application manner described above has high consistency with voltage history data generated when the first electrical stimulation is actually continuously applied to the target cell BC.

[0122] From now on, the advantages of the diagnosis method based on the intermittent application of the second electrical stimulation rather than the continuous application of the first electrical stimulation will be described.

[0123] The conditions related to the diagnosis of target monosomic BC are assumed to be as follows.

[0124] (i) First electrical stimulation = charging at 0.05 C

[0125] (ii) Second electrical stimulation = charging at 3.0 C

[0126] (iii) Length of rest period of second electrical stimulation = 12 minutes

[0127] (iv) Total capacity change during the state change period = 80% of the full charge capacity (FCC) of the target cell BC

[0128] (v) Threshold integral value = 3% of the fully charged capacity of the target cell BC

[0129] Then, the time taken for the target cell BC to change from the first state to the second state by continuously applying the first electrical stimulus is 1 / 0.05*80%=16 hours.

[0130] In contrast, the time required for the target cell BC's charge capacity to increase by the threshold integral value through the second electrical stimulation is 0.03 / 3 * 80% = 0.008 hours. Furthermore, since a rest period is granted each time the charge capacity increases by 3%, a total of 26 rest periods are permitted during the state change period. Therefore, the time required for the target cell BC to change from the first state to the second state through the intermittent application of the second electrical stimulation is (0.008 hours + 0.2 hours) * 26 = 5.4 hours.

[0131] In other words, compared with the method of continuously applying the first electrical stimulation, the method of intermittently applying the second electrical stimulation is advantageous in shortening the time for obtaining the entire monomer section line.

[0132] exist Figure 3b In the graph, the horizontal axis (X-axis) represents capacity (Ah), and the vertical axis (Y-axis) represents voltage.

[0133] refer to Figure 3b The processor 320 may generate a measured full-cell profile M representing a corresponding relationship between the capacity and voltage (also referred to as “full-cell voltage”) of the target cell BC. The measured full-cell profile may also be referred to as a QV profile or a Q-OCV profile.

[0134] Here, the full cell voltage is the voltage across the target cell BC and is distinguished from the positive and negative voltages described above. In other words, the full cell voltage of the target cell BC can be regarded as the difference between the positive and negative voltages of the target cell BC.

[0135] In order to generate the measurement full-cell profile M, the state history data mapped to the state change period can be used. The state history data includes the voltage history data mentioned above, and may also include current history data or capacity history data.

[0136] Specifically, each data point of the current history data and the voltage history data is indexed in chronological order. Thus, the processor 320 can generate the capacity history data by sequentially integrating the data points of the current history data. Furthermore, the processor 320 can generate a measured full-cell profile M by applying a curve fitting algorithm to a set of multiple Q-OCV pairs obtained by mapping the capacity history data to the voltage history data. The reference full-cell profile R, the reference positive electrode profile Rp, the reference negative electrode profile Rn, and the measured full-cell profile M can be polynomial equations in which the order of the highest term is predetermined.

[0137] Similar to the reference full-cell profile R, the measured full-cell profile M may represent the corresponding relationship between the capacity and OCV of the target cell BC within at least a voltage range of interest (eg, 3.0 V to 4.0 V).

[0138] Since there are inevitably some differences in the charge / discharge performance between the reference cell and the target cell BC, there are also some differences between the measured full-cell profile M and the reference full-cell profile R, such as Figure 3b As shown in .

[0139] For example, at the same capacity value, the voltage of the measured full-cell profile M is higher than the voltage of the reference full-cell profile R, which is caused by manufacturing defects of the target cell BC, loss of positive electrode capacity, loss of negative electrode capacity and / or loss of available lithium. Obviously, as the target cell BC deteriorates through repeated charge / discharge, the difference between the measured full-cell profile M and the reference full-cell profile R will gradually increase. Figure 3b , and reference Figure 2 Unlike the reference cell described, the full cell voltage of the target cell BC requires a charging capacity of 40 Ah to reach the second set voltage from the first set voltage, which is 5 Ah less than the charging capacity of 50 Ah of the reference cell under the same conditions.

[0140] At the same time, Figure 2 and Figure 3b In the graph of , Ah is used as the unit on the horizontal axis, but the unit can be expressed in other forms. For example, the unit on the horizontal axis can be percentage %, which represents SOC (state of charge) instead of Ah.

[0141] When generating the measured full-cell profile M, the processor 320 may be configured to compare the measured full-cell profile M with at least one comparative full-cell profile. Here, the comparative full-cell profile may be a result of adjusting each of the reference positive electrode profile Rp and the reference negative electrode profile Rn stored in the memory unit 330 to generate an adjusted positive electrode profile and an adjusted negative electrode profile, and then synthesizing (combining) the adjusted positive electrode profile and the adjusted negative electrode profile.

[0142] In other words, when the reference full cell profile R is the result of subtracting a portion of the reference negative electrode profile Rn from a portion of the reference positive electrode profile Rp, the comparative full cell profile can be regarded as the result of subtracting a portion of the adjusted negative electrode profile from a portion of the adjusted positive electrode profile.

[0143] Processor 320 can generate at least one comparative full-cell profile by directly adjusting reference positive electrode profile Rp and reference negative electrode profile Rn. Alternatively, at least one comparative full-cell profile can be pre-determined based on reference positive electrode profile Rp and reference negative electrode profile Rn and stored in memory unit 330. In this case, processor 320 can also obtain the comparative full-cell profile by accessing memory unit 330 and reading the comparative full-cell profile.

[0144] The processor 320 can generate multiple comparative full-cell profiles based on the reference positive profile Rp and the reference negative profile Rp by repeatedly adjusting each of the reference positive profile Rp and the reference negative profile Rp to several levels and then synthesizing them. The comparative full-cell profiles can also be referred to as "adjusted reference full-cell profiles."

[0145] The processor 320 may designate any one of the plurality of comparative full-cell profiles that has the smallest error relative to the measured full-cell profile M. The processor 320 may then determine that the adjusted positive and negative electrode profiles mapped to the designated comparative full-cell profiles are the positive and negative electrode profiles of the target cell BC.

[0146] In this regard, various methods known at the time of filing this application can be used to determine the error between two section lines, each of which can be represented in a two-dimensional coordinate system. For example, the integral of the absolute value of the area between the two section lines or the RMSE (root mean square error) can be used as the error between the two section lines.

[0147] According to this configuration of the present disclosure, various state information regarding the target cell BC can be obtained based on the finalized adjusted positive and negative electrode profiles. The finalized adjusted positive and negative electrode profiles can be mapped to a comparison full-cell profile with minimal error. In particular, the comparison full-cell profile obtained using the finalized adjusted positive and negative electrode profiles can be nearly identical in shape to the measured full-cell profile M.

[0148] Therefore, according to the present disclosure, even without disassembling the target cell BC or manufacturing the target cell BC in the form of a three-electrode battery, the positive electrode cross-sectional line and the negative electrode cross-sectional line of the target cell BC can be obtained.

[0149] If the target cell BC is a new battery cell, the adjusted positive electrode profile and the adjusted negative electrode profile can be more easily analyzed and utilized to diagnose whether a defect occurs in the target cell BC, and if so, what type of defect it is.

[0150] If the battery cell is used after the target cell BC is verified as a good product, how much the target cell BC has deteriorated can be determined for each degradation item through the adjusted positive electrode profile and the adjusted negative electrode profile.

[0151] Furthermore, according to one embodiment of the present disclosure, the positive and negative electrode profiles of the target cell BC can be obtained in a simple manner. This disclosure can be implemented even if only one reference positive electrode profile Rp and one reference negative electrode profile Rn are stored in the memory unit 330. In other words, there is no need to store multiple reference positive electrode profiles Rp and / or multiple reference negative electrode profiles Rn in the memory unit 330. Therefore, the storage capacity of the memory unit 330 does not need to be high, and the extensive preliminary testing required to ensure the availability of multiple reference positive electrode profiles Rp and / or multiple reference negative electrode profiles Rn is not necessary.

[0152] In the following, reference Figures 4 to 9 , the process of analyzing and measuring the full-cell profile M to estimate the negative electrode loading capacity will be described. The negative electrode loading capacity is one of the parameters involved in the current charge / discharge performance of the target cell BC. The negative electrode loading capacity of any battery cell is a term indicating the amount of negative electrode active material per unit area of ​​the negative electrode of the battery cell, and its unit can be mAh / cm 2 or mg / cm 2 .

[0153] Figures 4 to 6 is a diagram referred to to describe an example of a process of generating a comparative full-monobody profile line for comparison with a measured full-monobody profile line according to one embodiment of the present disclosure.

[0154] Will refer to Figures 4 to 6 The described process for generating comparative full-cell profiles proceeds in the following order: a first routine (see Figure 4 ), a second routine for performing the section line shift (see Figure 5 ) and a third routine for performing capacity scaling (see Figure 6 ). That is, the process for generating a comparative full-body section line according to one embodiment of the present disclosure includes first to third routines.

[0155] First, refer to Figure 4 , reference positive electrode section line Rp and reference negative electrode section line Rn and Figure 2The same as those shown in .

[0156] The processor 320 determines the positive electrode participation starting point (pi), the positive electrode participation end point (pf), the negative electrode participation starting point (ni), and the negative electrode participation end point (nf) on the reference positive electrode profile line Rp and the reference negative electrode profile line Rn.

[0157] Either one of the positive electrode participation starting point (pi) and the negative electrode participation starting point (ni) depends on the other.

[0158] As an example, processor 320 may divide the positive electrode voltage range from the starting point to the end point (or the second set voltage) of reference positive electrode profile Rp into multiple small voltage segments and then determine the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the positive electrode participation starting point (pi). Each small voltage segment may have a predetermined size (e.g., 0.01V). Next, processor 320 may determine a point on reference negative electrode profile Rn that is a first set voltage (e.g., 3V) lower than the positive electrode participation starting point (pi) as the negative electrode participation starting point (ni).

[0159] As another example, processor 320 may divide the negative electrode voltage range from the start point to the end point of reference negative electrode profile Rn into multiple small voltage segments of predetermined sizes, and then determine the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the negative electrode participation starting point (ni). Next, processor 320 may search for a point on reference positive electrode profile Rp that is greater than the negative electrode participation starting point (ni) by a first set voltage, and determine the searched point as the positive electrode participation starting point (pi).

[0160] Either the positive electrode participation endpoint (pf) or the negative electrode participation endpoint (nf) depends on the other.

[0161] As an example, processor 320 may divide the voltage range from the second set voltage to the end point of reference positive electrode profile Rp into multiple small voltage segments of predetermined sizes, and then determine the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the positive electrode participation end point (pf). Next, processor 320 may determine a point on reference negative electrode profile Rn that is lower than the positive electrode participation end point (pf) by a second set voltage (e.g., 4V) as the negative electrode participation end point (nf).

[0162] As another example, processor 320 may divide the negative electrode voltage range from the start point to the end point of reference negative electrode profile Rn into multiple small voltage segments of predetermined sizes, and then determine the boundary point between two adjacent small voltage segments among the multiple small voltage segments as the negative electrode participation end point (nf). Next, processor 320 may search for a point on reference positive electrode profile Rp that is a second set voltage greater than the negative electrode participation end point (nf), and determine the searched point as the positive electrode participation end point (pf).

[0163] If the positive pole participation starting point (pi), the positive pole participation end point (pf), the negative pole participation starting point (ni) and the negative pole participation end point (nf) are completely determined, the processor 320 shifts at least one of the reference positive pole profile line Rp and the reference negative pole profile line Rn to the left or right along the horizontal axis.

[0164] refer to Figure 5 , the processor 320 may shift the reference positive electrode profile Rp to the left (towards low capacity) or the reference negative electrode profile Rn to the right (towards high capacity) or both of them so that the capacity values ​​of the positive electrode participation starting point (pi) and the negative electrode participation starting point (ni) match.

[0165] Alternatively, the processor 320 shifts the reference positive profile Rp to the left or the reference negative profile Rn to the right or both of them so that the capacity values ​​of the positive electrode participation endpoint (pf) and the negative electrode participation endpoint (nf) match.

[0166] Figure 5 The diagram shows a case where only the reference positive electrode profile Rp is shifted leftward to generate an adjusted reference positive electrode profile (Rp'). Consequently, the capacity value at the positive electrode participation starting point (pi') matches the capacity value at the negative electrode participation starting point (ni). The adjusted reference positive electrode profile (Rp') is the result of applying the voltage adjustment process between the left-shifted positive electrode participation starting point (pi) and the negative electrode participation starting point (ni) to the reference positive electrode profile Rp. As a result, the two points (pi, pi') differ only in capacity value and have the same voltage. The two points (pf, pf') also differ only in capacity value and have the same voltage.

[0167] If the adjustment result profile (Rp′, Rn) in which at least one of the reference positive electrode profile Rp and the reference negative electrode profile Rn is shifted is ensured, the processor 320 scales the capacity range of at least one of the adjustment result profiles (Rp′, Rn).

[0168] according to Figure 5 In the example shown in , the processor 320 performs an additional adjustment process to shrink or expand at least one of the adjusted reference positive profile line (Rp′) and the reference negative profile line Rn along the horizontal axis.

[0169] refer to Figure 6, processor 320 can generate an adjusted reference positive electrode profile (Rp') by contracting or expanding the adjusted reference positive electrode profile (Rp') so that the capacity range between the two points (pi', pf') of the adjusted reference positive electrode profile (Rp') matches the capacity range of the full-cell profile M. In this case, any one of the two points (pi', pf') can be fixed. Therefore, the capacity difference between the two points (pi', pf') of the adjusted reference positive electrode profile (Rp') can match the capacity range of the full-cell profile M.

[0170] Furthermore, processor 320 can generate an adjusted reference negative electrode profile (Rn') by shrinking or expanding reference negative electrode profile Rn, such that the capacity range between two points (ni, nf) on reference positive electrode profile Rn matches the capacity range of full-cell profile M. In this case, any one of the two points (ni, nf) can be fixed. Therefore, the capacity difference between the two points (ni, nf') on the adjusted reference negative electrode profile (Rn') can match the capacity range of full-cell profile M.

[0171] exist Figure 6 The adjusted reference positive electrode profile (Rp'') is the contraction Figure 5 The results of the adjusted reference positive profile (Rp') shown in the figure and the adjusted reference negative profile (Rn') are the expansion Figure 5 The results for the reference negative electrode profile Rn are shown in FIG.

[0172] The positive electrode participation endpoint (pf'') on the adjusted reference positive electrode profile (Rp'') corresponds to the positive electrode participation endpoint (pf) on the adjusted reference positive electrode profile (Rp'). The negative electrode participation endpoint (nf') on the adjusted reference negative electrode profile (Rn') corresponds to the negative electrode participation endpoint (nf) on the reference negative electrode profile (Rn).

[0173] The capacity difference between the positive electrode participation starting point (pi') and the positive electrode participation end point (pf'') of the adjusted reference positive electrode profile (Rp'') corresponds to the size of the capacity range of the full-cell profile M. Similarly, the capacity difference between the negative electrode participation starting point (ni) and the negative electrode participation end point (nf') of the adjusted reference negative electrode profile (Rn') corresponds to the size of the capacity range of the full-cell profile M.

[0174] In addition, the capacity range of the two points (pi', pf') of the adjusted reference positive electrode profile (Rp') matches the capacity range of the two points (ni, nf') of the adjusted reference negative electrode profile (Rn'). Processor 320 can generate a comparative full-cell profile S by subtracting the profile between the two points (pi, pf') of the adjusted reference positive electrode profile (Rp') from the profile between the two points (ni, nf') of the adjusted reference negative electrode profile (Rn').

[0175] The processor 320 may calculate an error (section line error) between the comparison values ​​between the comparison full-unit section line S and the measured full-unit section line M.

[0176] The processor 320 can map and record at least two of the adjusted reference positive electrode profile (Rp''), the adjusted reference negative electrode profile (Rn'), the positive electrode participation starting point (pi'), the positive electrode participation end point (pf''), the negative electrode participation starting point (ni), the negative electrode participation end point (nf'), the positive electrode scaling factor, the negative electrode scaling factor, the comparison full monomer profile S and the profile error to each other in the memory unit 330.

[0177] The positive electrode scaling factor may represent the ratio of the capacity difference between the two ends of the adjusted reference positive electrode profile (Rp'') to the capacity difference between the two ends of the reference positive electrode profile Rp. Alternatively, the positive electrode scaling factor may represent the ratio of the capacity difference between two points (pi', pf'') to the capacity difference between two points (pi0, pf0). Alternatively, the positive electrode scaling factor may represent the ratio of the positive electrode capacity difference between two points (pi', pf'') to the positive electrode capacity difference between two points (pi0, pf0). Alternatively, the positive electrode scaling factor may represent the ratio of the positive electrode SOC difference between two points (pi', pf'') to the positive electrode SOC difference between two points (pi0, pf0).

[0178] The negative electrode scaling factor may represent the ratio of the capacity difference between the two ends of the adjusted reference negative electrode profile (Rn') to the capacity difference between the two ends of the reference negative electrode profile Rn. Alternatively, the negative electrode scaling factor may represent the ratio of the capacity difference between two points (ni, nf') to the capacity difference between two points (ni0, nf0). Alternatively, the negative electrode scaling factor may represent the ratio of the negative electrode capacity difference between two points (ni, nf') to the negative electrode capacity difference between two points (ni0, nf0). Alternatively, the negative electrode scaling factor may represent the ratio of the negative electrode SOC difference between two points (ni, nf') to the negative electrode SOC difference between two points (ni0, nf0).

[0179] Meanwhile, as described above, when the positive voltage range of the reference positive profile line Rp is divided into a plurality of small voltage sections, boundary points of two adjacent small voltage sections among the plurality of small voltage sections may be set as positive participation starting points (pi).

[0180] For example, if the positive electrode voltage range of the reference positive electrode profile Rp is divided into 100 small voltage ranges, there can be 100 boundary points that can be set as the positive electrode participation starting point (pi). Furthermore, if the voltage range greater than or equal to the second set voltage in the reference positive electrode profile Rp is divided into 40 small voltage ranges, there can be 40 boundary points that can be set as the positive electrode participation end point (pf). In this case, at least 4,000 different comparative full-cell profiles can be generated.

[0181] Of course, those skilled in the art will readily appreciate that as the size of the low voltage segment decreases, the maximum number of comparative full-cell profiles that can be generated increases, and conversely, as the size of the low voltage segment increases, the maximum number of comparative full-cell profiles that can be generated decreases.

[0182] The processor 320 can identify the minimum value among the profile errors of multiple comparative full-monomer profiles generated as described above, and then obtain information mapped to the minimum profile error from the memory unit 330 (for example, at least one of the positive pole participation starting point, the positive pole participation end point, the negative pole participation starting point, the negative pole participation end point, the positive pole scaling factor, and the negative pole scaling factor).

[0183] Figures 7 to 9 is a diagram referred to to describe another example of a process of generating a comparative full-monobody profile for comparison with a measured full-monobody profile according to one embodiment of the present disclosure. For reference, Figures 7 to 9 The embodiment shown in Figures 4 to 6 Therefore, it is usually used to describe Figures 4 to 6 The embodiments shown in Figures 7 to 9 The terms or reference numerals of the embodiments shown in FIG should be understood as being limited to each embodiment.

[0184] To refer to Figures 7 to 9 The explained process of generating comparative full-cell profiles proceeds in the following order: The fourth routine of capacity scaling is executed (see Figure 7 ), set the fourth point (positive electrode participation start point, positive electrode participation end point, negative electrode participation start point and negative electrode participation end point) of the fifth routine (see Figure 8 ) and a sixth routine that performs section line shifting (see Figure 9 ). That is, the process of generating a comparative full-body cross-section line according to another embodiment of the present disclosure includes fourth to sixth routines.

[0185] refer to Figure 7, the processor 320 generates an adjusted reference positive profile line (Rp′) and an adjusted reference negative profile line (Rn′) by applying a positive scaling factor and a negative scaling factor selected from the scaling value range to the reference positive profile line Rp and the reference negative profile line (Rn), respectively.

[0186] The scaling value range can be predetermined or can vary based on the ratio of the size of the capacity range of the measured full-cell profile M to the size of the capacity range of the reference full-cell profile (R). As an example, assuming that the positive and negative scaling factors can be selected from values ​​with intervals of 0.1% in the scaling value range (e.g., 90 to 99%) (i.e., 90%, 90.1%, 90.2%, ... 98.9%, 99%), 91 values ​​can be selected as the positive and negative scaling factors, respectively. In this case, based on 91×91=8281 adjustment levels (combinations of positive and negative scaling factors), a maximum of 8281 adjusted profile pairs can be generated. An adjusted profile pair refers to a combination of an adjusted positive profile and an adjusted negative profile.

[0187] refer to Figure 7 , the adjusted reference positive profile (Rp') and the adjusted reference negative profile (Rn') show the results of applying the positive scaling factor and the negative scaling factor to the reference positive profile Rp and the reference negative profile Rn, respectively.

[0188] Since the positive and negative scaling factors are less than 100%, the reference positive cross-sectional line Rp is contracted along the horizontal axis to obtain an adjusted reference positive cross-sectional line (Rp'), and the reference negative cross-sectional line Rn is contracted along the horizontal axis to obtain an adjusted reference negative cross-sectional line (Rn'). For ease of understanding, the reference positive cross-sectional line Rp and the reference negative cross-sectional line Rn are shown with their starting points fixed and their remaining portions contracted to the left along the horizontal axis.

[0189] refer to Figure 8 The processor 320 determines the positive electrode participation starting point (pi'), the positive electrode participation end point (pf'), the negative electrode participation starting point (ni') and the negative electrode participation end point (nf') on the adjusted reference positive electrode profile line (Rp') and the adjusted reference negative electrode profile line (Rp').

[0190] Either the positive electrode participation starting point (pi') or the negative electrode participation starting point (ni') may depend on the other. Furthermore, either the positive electrode participation end point (pf') or the negative electrode participation end point (nf') may depend on the other. Furthermore, either the positive electrode participation starting point (pi') or the positive electrode participation end point (pf') may be set based on the other.

[0191] That is, if any one of the positive electrode participation starting point (pi'), the positive electrode participation end point (pf'), the negative electrode participation starting point (ni') and the negative electrode participation end point (nf') is set, the capacity range of the full-cell profile M can be measured by the first set voltage, the second set voltage and / or the size of the capacity range of the full-cell profile M (for example, Figure 3b The remaining three points are automatically set using the 45Ah-5Ah=40Ah in the figure.

[0192] As an example, the processor 320 may divide the positive electrode voltage range from the start point to the end point (or the second set voltage) of the adjusted reference positive electrode profile (Rp') into multiple small voltage segments, and then determine the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the positive electrode participation starting point (pi'). Next, the processor 320 may determine a point on the adjusted reference negative electrode profile (Rn) that is lower than the positive electrode participation starting point (pi') by a first set voltage (e.g., 3V) as the negative electrode participation starting point (ni').

[0193] As another example, processor 320 may divide the negative electrode voltage range from the start point to the end point of the adjusted reference negative electrode profile (Rn') into multiple small voltage segments of predetermined sizes, and then determine the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the negative electrode participation starting point (ni'). Next, processor 320 may search for a point on the reference positive electrode profile (Rp) that is greater than the negative electrode participation starting point (ni') by a first set voltage, and determine the searched point as the positive electrode participation starting point (pi').

[0194] As another example, processor 320 may divide the voltage range from the second set voltage to the endpoint of the adjusted reference positive electrode profile (Rp') into multiple small voltage segments of predetermined sizes, and then determine the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the positive electrode participation endpoint (pf'). Next, processor 320 may search for a point on the adjusted reference negative electrode profile (Rn') that is lower than the positive electrode participation endpoint (pf') by a second set voltage (e.g., 4V), and determine the searched point as the negative electrode participation endpoint (nf').

[0195] As another example, processor 320 may divide the negative electrode voltage range from the start point to the end point of the adjusted reference negative electrode profile (Rn') into multiple small voltage segments of predetermined sizes, and then determine the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the negative electrode participation end point (nf'). Next, processor 320 may search for a point on the adjusted reference positive electrode profile (Rp') that is a second set voltage greater than the negative electrode participation end point (nf'), and determine the searched point as the positive electrode participation end point (pf').

[0196] If any one of the positive pole participation starting point (pi'), the positive pole participation end point (pf'), the negative pole participation starting point (ni'), and the negative pole participation end point (nf') is determined, the processor 320 may additionally determine at least one of the remaining three points based on the determined point.

[0197] For example, if the positive electrode participation starting point (pi') is first determined, the processor 320 can determine a point on the adjusted reference positive electrode profile (Rp') having a capacity value greater than the capacity value of the positive electrode participation starting point (pi') by the size of the capacity range of the measured full-cell profile M as the positive electrode participation end point (pf'). In addition, the processor 320 can search for a point on the adjusted reference negative electrode profile (Rn') that is lower than the positive electrode participation starting point (pi') by a first set voltage and determine the searched point as the negative electrode participation starting point (ni'). In addition, the processor 320 can determine a point on the adjusted reference negative electrode profile (Rn') having a capacity value greater than the capacity value of the negative electrode participation starting point (ni') by the size of the capacity range of the measured full-cell profile M as the negative electrode participation end point (nf').

[0198] As another example, when the positive electrode participation endpoint (pf') is first determined, the processor 320 can determine a point on the adjusted reference positive electrode profile (Rp') having a capacity value that is smaller than the capacity value of the positive electrode participation endpoint (pf') by the size of the capacity range of the measured full-cell profile M as the positive electrode participation starting point (pi'). In addition, the processor 320 can search for a point on the adjusted reference negative electrode profile (Rn') that is lower than the positive electrode participation endpoint (pf') by a second set voltage and determine the searched point as the negative electrode participation endpoint (nf'). In addition, the processor 320 can determine a point on the adjusted reference negative electrode profile (Rn') having a capacity value that is smaller than the capacity value of the negative electrode participation endpoint (nf') by the size of the capacity range of the measured full-cell profile M as the negative electrode participation starting point (ni').

[0199] As another example, when the negative electrode participation starting point (ni') is determined, the processor 320 may determine a point on the adjusted reference negative electrode profile (Rn') having a capacity value greater than the capacity value of the negative electrode participation starting point (ni') by the size of the capacity range of the measured full-cell profile M as the negative electrode participation end point (nf'). Furthermore, the processor 320 may search the adjusted reference positive electrode profile (Rp') for a point that is higher than the negative electrode participation starting point (ni') by a first set voltage, and determine the searched point as the positive electrode participation starting point (pi'). Furthermore, the processor 320 may determine a point on the adjusted reference positive electrode profile (Rp') having a capacity value greater than the capacity value of the positive electrode participation starting point (pi') by the size of the capacity range of the measured full-cell profile M as the positive electrode participation end point (pf').

[0200] As another example, when the negative electrode participation endpoint (nf') is determined, the processor 320 may determine a point on the adjusted reference negative electrode profile (Rn') having a capacity value that is smaller than the capacity value of the negative electrode participation endpoint (nf') by the size of the capacity range of the measured full-cell profile M as the negative electrode participation starting point (ni'). Furthermore, the processor 320 may search the adjusted reference positive electrode profile (Rp') for a point that is higher than the negative electrode participation endpoint (nf') by a second set voltage, and determine the searched point as the positive electrode participation endpoint (pf'). Furthermore, the processor 320 may determine a point on the adjusted reference positive electrode profile (Rp') having a capacity value that is smaller than the capacity value of the positive electrode participation endpoint (pf') by the size of the capacity range of the measured full-cell profile M as the positive electrode participation starting point (pi').

[0201] If the positive electrode participation starting point (pi'), the positive electrode participation end point (pf'), the negative electrode participation starting point (ni') and the negative electrode participation end point (nf') are completely determined based on the positive electrode scaling factor and the negative electrode scaling factor, the processor 320 can shift at least one of the adjusted reference positive electrode profile (Rp') and the adjusted reference negative electrode profile (Rn') to the left or right along the horizontal axis so that the capacity values ​​of the positive electrode participation starting point (pi') and the negative electrode participation starting point (ni') match or the capacity values ​​of the positive electrode participation starting point (pf') and the negative electrode participation starting point (nf') match.

[0202] Figure 9 The adjusted reference negative profile (Rn'') shown in Figure 8 This is achieved by shifting the adjusted reference negative electrode profile (Rn') shown in the figure to the right. Therefore, the capacity values ​​at the positive electrode participation starting point (pi') and the negative electrode participation starting point (ni'') match each other on the horizontal axis. Relatedly, the capacity difference between the positive electrode participation starting point (pi') and the positive electrode participation end point (pf') is equal to the capacity difference between the negative electrode participation starting point (ni') and the negative electrode participation end point (nf'). Therefore, if the capacity values ​​at the positive electrode participation starting point (pi') and the negative electrode participation starting point (ni'') match each other, then the capacity values ​​at the positive electrode participation end point (pf') and the negative electrode participation end point (nf') also match each other on the horizontal axis.

[0203] refer to Figure 9 , the processor 320 may generate a comparative full-cell profile U by subtracting a partial profile between two points (pi', pf') of the adjusted reference positive profile (Rp') from a partial profile between two points (ni'', nf'') of the adjusted reference negative profile (Rn'').

[0204] The processor 320 may calculate and compare the error (section line error) between the entire section line U and the measured section line M.

[0205] The processor 320 can map and record at least two of the adjusted reference positive electrode profile (Rp'), the adjusted reference negative electrode profile (Rn''), the positive electrode participation starting point (pi'), the positive electrode participation end point (pf'), the negative electrode participation starting point (ni''), the negative electrode participation end point (nf''), the positive electrode scaling factor, the negative electrode scaling factor, the comparison full monomer profile U and the profile error to each other in the memory unit 330.

[0206] As described above, processor 320 can generate a comparative full-cell cross-section corresponding to each pair of a positive and negative scale factor selected from the scale value range. Since there are multiple pairs of positive and negative scale factors, it is obvious that multiple comparative cross-sections will also be generated. Processor 320 can identify the minimum cross-section error among the multiple comparative full-cell cross-sections and then obtain information mapped to the minimum cross-section error from memory unit 330.

[0207] Processor 320 can determine the negative electrode loading of the target cell BC based on the information mapped to the minimum profile error. Processor 320 can estimate the negative electrode loading of the target cell BC based on the extracted negative electrode scaling factor. For reference, at least one of the positive electrode participation start point, positive electrode participation end point, negative electrode participation start point, negative electrode participation end point, positive electrode scaling factor, and negative electrode scaling factor when the target cell BC is in a new state may have been recorded in memory unit 330 by performing the above-described analysis process when the target cell BC is in a new state.

[0208] The processor 320 may determine at least one degradation parameter (eg, negative electrode loading) based on the information mapped to the minimum profile error. Table 1 below summarizes the degradation parameters and formulas that may be used to determine each degradation parameter.

[0209] Table 1

[0210]

[0211] Each variable listed in Table 1 is a diagnostic factor that can be determined through the above analysis process. The definitions of the degradation parameters and variables in Table 1 can be as follows.

[0212] <Degradation Parameters>

[0213] P SOH : Cathode SOH (healthy state) of target cell BC

[0214] N SOH : Negative electrode SOH of target monomer BC

[0215] L SOH : Available lithium SOH of target monomer BC

[0216] FSOH : All monomer SOH of target monomer BC

[0217] P LOSS : Positive electrode loss rate of target monomer BC

[0218] N LOSS : Negative electrode loss rate of target monomer BC

[0219] L LOSS : Available lithium loss rate of target monomer BC

[0220] F LOSS : Total monomer loss rate of target monomer BC

[0221] P loading_MOL : Target monomer BC cathode loading

[0222] N loading_MOL : Negative electrode loading of target monomer BC

[0223] The positive electrode loading of any battery cell represents the amount of positive electrode active material (or available capacity) per unit area of ​​the positive electrode of the battery cell. The negative electrode loading of any battery cell represents the amount of negative electrode active material (or available capacity) per unit area of ​​the negative electrode of the battery cell. The unit of loading can be mAh / cm 2 or mg / cm 2 In Table 1, P loading_ref represents the reference positive electrode loading, and N loading_ref Represents a reference negative electrode loading amount. The reference positive electrode loading amount is a predetermined value representing the amount of positive electrode active material (or available capacity) per unit area of ​​the positive electrode of a reference cell. The reference positive electrode loading amount may be a value obtained by dividing the reference positive electrode capacity by the reference positive electrode area. Here, the reference positive electrode capacity may be a value preset to the total positive electrode capacity of the reference cell. The reference positive electrode area may be a value preset to the area of ​​the positive electrode of the reference cell. The reference negative electrode loading amount is a predetermined value representing the amount of negative electrode active material (or available capacity) per unit area of ​​the negative electrode of the reference cell. The reference negative electrode loading amount may be a value obtained by dividing the reference negative electrode capacity by the reference negative electrode area. Here, the reference negative electrode capacity may be a value preset to the total negative electrode capacity of the reference cell. The reference negative electrode area may be a value preset to the negative electrode area of ​​the reference cell.

[0224] <variable>

[0225] pi BOL : The positive electrode capacity (positive electrode SOC) at the starting point of positive electrode participation when the target monomer BC is in the BOL state

[0226] pi MOL : The current cathode participation starting point of the target monomer BC (e.g., Figure 6 The positive electrode capacity (positive electrode SOC) of pi') shown in

[0227] pf BOL : The positive electrode capacity (positive electrode SOC) at the end point when the target monomer BC is in the BOL state

[0228] pf MOL : The current cathode participation endpoint of the target monomer BC (e.g., Figure 6 The positive electrode capacity (positive electrode SOC) of the pf') shown in

[0229] ni BOL : Negative electrode capacity (negative electrode SOC) at the starting point of negative electrode participation when the target monomer BC is in the BOL state

[0230] ni MOL : The current negative electrode participation starting point of the target monomer BC (e.g., Figure 6 The negative electrode capacity (negative electrode SOC) of ni) is shown in

[0231] nf BOL : When the target monomer BC is in the BOL state, the negative electrode capacity of the negative electrode at the end point (negative electrode SOC)

[0232] nf MOL : The current negative electrode participation endpoint of the target monomer BC (e.g., Figure 6 The negative electrode capacity (negative electrode SOC) of nf') is shown in

[0233] ps BOL : positive electrode scaling factor when the target monomer BC is in the BOL state

[0234] ps MOL : Current positive scaling factor of the target monomer BC

[0235] ns BOL : Negative scaling factor when the target monomer BC is in the BOL state

[0236] ns MOL : Current negative scaling factor of target cell BC

[0237] The process of determining diagnostic factors for a target monomer BC may be repeated periodically or aperiodically throughout the life of the target monomer BC.

[0238] As the available lithium capacity, total positive electrode capacity, and / or total negative electrode capacity of a battery cell decrease, the positive electrode capacity (positive electrode SOC) corresponding to the starting point of positive electrode participation of the battery cell may have a gradually increasing characteristic. The available lithium amount of a battery cell may be a parameter that represents the total amount of lithium that can contribute to the charging and discharging of the battery cell. Due to side reactions that occur within the battery cell during charging and discharging, the available lithium amount may gradually decrease from a new product state.

[0239] Based on this characteristic, the processor 320 may determine whether the loss of available lithium of the target cell BC occurs due to a loss of at least one of available lithium amount and total positive electrode capacity based on the estimation result of the positive electrode participation starting point of the target cell BC.

[0240] Processor 320 may diagnose that a loss of available lithium has occurred in response to the positive electrode capacity (or positive electrode SOC) at the positive electrode participation starting point increasing from a value in a new product state.

[0241] There may be cases where the change in the positive electrode capacity (or positive electrode SOC) at the positive electrode participation starting point and the negative electrode capacity (or negative electrode SOC) at the negative electrode participation end point of the target cell BC relative to the new product state is less than a predetermined set value. If so, processor 320 may determine that the capacity loss in at least one of the positive and negative electrodes contributes more to the change in the negative electrode participation starting point of the target cell BC relative to the new product state than the available lithium loss, because the increase in the negative electrode capacity (or negative electrode SOC) at the negative electrode participation starting point relative to the new product state is greater.

[0242] Processor 320 can limit at least one of the allowable voltage range and the allowable SOC range of the target cell BC based on the estimated positive electrode participation starting point for the target cell BC. Relationship data indicating a predetermined positive correlation between the change (e.g., increase) in the positive electrode capacity (or positive electrode SOC) at the positive electrode participation starting point relative to the new product state and a limit level can be pre-stored in memory unit 330. In other words, according to the relationship data, a decrease or increase in the capacity value (positive electrode capacity or positive electrode SOC) at the positive electrode participation starting point can cause at least one of the allowable voltage range and the allowable SOC range to decrease. Decreasing the range means at least one of increasing the lower limit of the range or decreasing the upper limit of the range. For example, assuming the allowable voltage range and the allowable SOC range are 2.5 V to 4.5 V and 5% to 95%, respectively. If the positive electrode capacity at the positive electrode participation starting point is estimated to be 110% of the value in the BOL state, the allowable voltage range can be reduced to 2.75 V to 4.05 V, and the allowable SOC range can be reduced to 5.5% to 85.5%.

[0243] The processor 320 may diagnose that a capacity loss occurs at the positive electrode of the target cell BC in response to a decrease in the positive electrode capacity (or positive electrode SOC) at the positive electrode participation endpoint relative to a value in a new product state.

[0244] The processor 320 may limit at least one of the allowable voltage range and the allowable SOC range of the target battery cell (BC) based on the positive electrode participation endpoint. Relationship data indicating a predetermined positive correlation between the change (e.g., reduction) in the positive electrode capacity (or positive electrode SOC) at the positive electrode participation endpoint relative to the new product state and the limit level may be pre-stored in the memory unit 330. In other words, according to the relationship data, a decrease in the capacity value (positive electrode capacity, positive electrode SOC) at the positive electrode participation endpoint may result in a decrease in at least one of the allowable voltage range and the allowable SOC range. For example, assuming the allowable voltage range and the allowable SOC range are 2.5 V to 4.5 V and 5% to 95%, respectively. If the positive electrode participation endpoint is estimated to be 90% of the value at the BOL state, the allowable voltage range may be reduced to 2.75 V to 4.05 V, and the allowable SOC range may be reduced to 5.5% to 85.5%.

[0245] Processor 320 can limit at least one of the permissible voltage range and the permissible SOC range of the target cell BC based on the estimated positive scaling factor of the target cell BC. Relationship data representing a predetermined positive correlation between the amount of change (e.g., decrease) in the positive scaling factor relative to the BOL state and a limit level can be pre-stored in memory unit 330. That is, according to the relationship data, a decrease in the positive scaling factor can cause a decrease in at least one of the permissible voltage range and the permissible SOC range. For example, assuming the permissible voltage range and the permissible SOC range are 2.5 V to 4.5 V and 5% to 95%, respectively. If the current positive scaling factor ps of the target cell BC is MOL is estimated as the positive scaling factor p in the new product state sBOL If the allowed voltage range is reduced to 2.75 V to 4.05 V, the allowed SOC range can be reduced to 5.5% to 85.5%.

[0246] Processor 320 can limit at least one of the permissible voltage range and the permissible SOC range of the target cell BC based on an estimated value of the target cell BC's positive electrode loading capacity. Relationship data representing a predetermined positive correlation between the positive electrode loading capacity and a limit level can be pre-stored in memory unit 330. That is, based on the relationship data, a decrease in the positive electrode loading capacity can cause a decrease in at least one of the permissible voltage range and the permissible SOC range. For example, assuming the permissible voltage range and the permissible SOC range are 2.5 V to 4.5 V and 5% to 95%, respectively. If the positive electrode loading capacity is estimated to be 90% of the reference positive electrode loading capacity, the permissible voltage range can be reduced to 2.75 V to 4.05 V, and the permissible SOC range can be reduced to 5.5% to 85.5%.

[0247] The processor 320 can limit at least one of the allowable voltage range and the allowable SOC range of the target cell BC based on the negative electrode participation starting point of the target cell BC. Relationship data indicating a predetermined positive correlation between the change (e.g., decrease) in the negative electrode capacity (or negative electrode SOC) at the negative electrode participation starting point relative to the new product state and a limit level can be pre-stored in the memory unit 330. In other words, according to the relationship data, a decrease or increase in the capacity value (negative electrode capacity or negative electrode SOC) at the negative electrode participation starting point can cause a decrease in at least one of the allowable voltage range and the allowable SOC range. For example, assuming the allowable voltage range and the allowable SOC range are 2.5 V to 4.5 V and 5% to 95%, respectively. If the negative electrode capacity at the current negative electrode participation starting point is estimated to be 90% of the value in the BOL state, the allowable voltage range can be reduced to 2.75 V to 4.05 V, and the allowable SOC range can be reduced to 5.5% to 85.5%.

[0248] Processor 320 can diagnose capacity loss at the negative electrode of the target cell BC in response to a decrease in the negative electrode capacity (or negative electrode SOC) at the negative electrode participation endpoint from the value in the new product state. Processor 320 can limit at least one of the target cell BC's allowable voltage range and allowable SOC range based on the estimated negative electrode participation endpoint. Relationship data indicating a predetermined positive correlation between the amount of change (e.g., decrease) in the negative electrode capacity (or negative electrode SOC) at the negative electrode participation endpoint relative to the new product state and a limit level can be pre-stored in memory unit 330. That is, according to the relationship data, a decrease in the capacity value (negative electrode capacity, negative electrode SOC) at the negative electrode participation endpoint can cause a decrease in at least one of the allowable voltage range and the allowable SOC range. For example, assuming the allowable voltage range and allowable SOC range are 2.5 V to 4.5 V and 5% to 95%, respectively. If the current negative electrode participation endpoint is estimated to be 90% of the value in the BOL state, the allowable voltage range can be reduced to 2.75 V to 4.05 V, and the allowable SOC range can be reduced to 5.5% to 85.5%.

[0249] The processor 320 may limit at least one of the permissible voltage range and the permissible SOC range of the target cell BC based on the estimated negative scaling factor of the target cell BC. Relationship data representing a predetermined positive correlation between the amount of reduction in the negative scaling factor relative to the BOL state and the limit level may be pre-stored in the memory unit 330. That is, according to the relationship data, a reduction in the negative scaling factor may cause a reduction in at least one of the permissible voltage range and the permissible SOC range. For example, assuming that the permissible voltage range and the permissible SOC range are 2.5 V to 4.5 V and 5% to 95%, respectively. If the current negative scaling factor n of the target cell BC is sMOL is estimated as the negative scaling factor n in the new product state sBOL 90%, the allowable voltage range can be reduced to 2.75 V to 4.05 V, and the allowable SOC range can be reduced to 5.5% to 85.5%. The processor 320 can limit at least one of the allowable voltage range and the allowable SOC range of the target cell BC based on the estimated value of the negative load amount of the target cell BC. Relationship data indicating a predetermined positive correlation between the reduction amount of the negative load amount relative to the BOL state and the limit level can be pre-stored in the memory unit 330. That is, according to the relationship data, the reduction in the negative load amount can cause a reduction in at least one of the allowable voltage range and the allowable SOC range. For example, assuming that the allowable voltage range and the allowable SOC range are 2.5 V to 4.5 V and 5% to 95% respectively. If the current negative load amount N loading_MOL Estimated to be the value N in the BOL state loading_BOLIf the allowed voltage range is reduced to 2.75 V to 4.05 V, the allowed SOC range can be reduced to 5.5% to 85.5%.

[0250] Figure 10 is a flowchart exemplarily describing a battery diagnosis method according to a first embodiment of the present disclosure. Figure 10 The method may be executed by the battery diagnostic device 302 .

[0251] In step S1010, the processor 320 performs an intermittent application process of electrical stimulation to the target cell BC. Specifically, the processor 320 may control the stimulation application device 301 to intermittently apply electrical stimulation (e.g., second electrical stimulation) to the target cell BC during a state change period until the electrical state of the target cell BC changes from the first state to the second state.

[0252] The intermittent application of electrical stimulation may be a process in which periods of electrical stimulation application and rest periods are repeated. In other words, the intermittent application process includes at least two application processes and at least two rest periods. When the current integral value of the target cell BC changes by a threshold integral value while applying electrical stimulation in each application process, the electrical stimulation to the target cell BC may be removed (output may be stopped) to provide a rest period. When the rest period of each rest process reaches a reference time, the application of electrical stimulation may be resumed.

[0253] Step S1010 may be performed by the battery management system 100 or the system controller 2 instead of the processor 320, and in this case, step S1010 may be performed from Figure 10 Omitted from the method.

[0254] In step S1020, the processor 320 obtains the state history data corresponding to the state change period of the target cell BC using the data obtaining unit 310. The state history data includes voltage history data, and may also include current history data or capacity history data.

[0255] The voltage history data may include a voltage value representing the full-cell voltage of the target cell BC measured at least once in each rest period of the electrical stimulation applied during the state change period. In other words, the voltage history data may represent a change history of the full-cell voltage of the target cell BC during the state change period. The voltage history data may include a measured value of the full-cell voltage of the target cell BC at the end of each rest period (see Figure 3a D OCV ). The data obtaining unit 310 may collect the state history data generated by the battery system 1 from the battery system 1 after the state change period ends.

[0256] Alternatively, the data acquisition unit 310 may periodically collect measurement data representing at least one measurement value of the current of the target cell BC and the full-cell voltage from the battery system 1 during the state change period. In this case, each measurement value collected multiple times during the state change period may be recorded in chronological order in the memory unit 330. The processor 320 may generate state history data based on the collection of measurement values ​​collected during the state change period.

[0257] In step S1030, the processor 320 generates a measured full-cell profile indicating a corresponding relationship between the capacity of the target cell BC and the full-cell voltage based on the state history data (see Figure 3b in the text).

[0258] In step S1040 , the processor 320 analyzes the measured full-cell profile to generate first diagnostic information, the first diagnostic information including at least one diagnostic factor related to the charge / discharge performance of the target cell BC.

[0259] The first diagnostic information may include at least one of a positive electrode participation starting point, a positive electrode participation end point, a positive electrode scaling factor, and a positive electrode loading amount, which represent the charge / discharge performance of the positive electrode of the target cell BC. The positive electrode loading amount represents the amount of positive electrode active material per unit area of ​​the positive electrode.

[0260] The first diagnostic information may include at least one of a negative electrode participation starting point, a negative electrode participation end point, a negative electrode scaling factor, and a negative electrode loading amount, which represent the charge / discharge performance of the negative electrode of the target cell BC. The negative electrode loading amount represents the amount of negative electrode active material per unit area of ​​the negative electrode.

[0261] In step S1050, the processor 320 generates second diagnostic information of the target cell BC by applying at least one mathematical operation to the first diagnostic information. The second diagnostic information may include at least one degradation parameter (see Table 1, etc.) regarding at least one of the positive electrode, the negative electrode, and the available lithium.

[0262] The second diagnostic information may include whether available lithium loss occurs and / or the available lithium loss rate of the target cell BC determined based on the cathode participation starting point of the first diagnostic information.

[0263] The second diagnostic information may include whether the positive electrode capacity loss of the target cell BC occurs and / or the positive electrode loss rate determined based on the positive electrode participation endpoint, positive electrode scaling factor and / or positive electrode loading amount of the first diagnostic information.

[0264] The second diagnostic information may include whether available lithium loss occurs in the target cell BC, whether capacity loss occurs in the positive electrode, whether capacity loss occurs in the negative electrode, and / or the negative electrode loss rate determined based on the negative electrode participation starting point, negative electrode participation end point, and / or negative electrode scaling factor of the first diagnostic information.

[0265] The second diagnostic information may include a negative electrode loss rate (which may also be referred to as a “negative electrode capacity loss rate”) of a target cell BC determined based on the negative electrode loading amount of the first diagnostic information.

[0266] In step S1060 , processor 320 updates charge / discharge permission condition information indicating at least one of a voltage range, an SOC range, and a current range permitted for the target cell BC based on at least one of the first diagnostic information and the second diagnostic information.

[0267] For example, the processor 320 may determine updated charge / discharge permission condition information by limiting (e.g., downwardly adjusting) at least one of a voltage range, an SOC range, and a current range of a target cell BC of previous charge / discharge permission condition information based on at least one degradation parameter (e.g., a negative electrode load amount) of the first diagnostic information.

[0268] In step S1070, the processor 320 may transmit the diagnosis result of the target cell BC to the battery system 1 using the data obtaining unit 310. The diagnosis result includes at least one of the first diagnosis information, the second diagnosis information, and the updated charge / discharge permission condition information.

[0269] In accordance with Figure 10 In the method, at least one of steps S1050, S1060 and S1070 can be obtained from the Figure 10 Omitted from the method.

[0270] Figure 11 FIG. 1 is a flowchart exemplarily describing a battery diagnosis method according to a second embodiment of the present disclosure. Figure 11 The method may be executed by the battery diagnostic device 302 .

[0271] In step S1110 , the processor 320 performs an intermittent application process of electrical stimulation to the target cell BC.

[0272] In step S1120 , the processor 320 obtains the state history data corresponding to the state change period using the data obtaining unit 310 .

[0273] Compared with the above-mentioned first embodiment Figure 10Different from S1020 , the voltage history data of the state history data obtained in step S1120 includes measurement values ​​of the full-cell voltage measured three or more times in each rest period during the state change period.

[0274] In step S1122, processor 320 applies OCV estimation logic to the voltage history data of the state history data acquired in step S1120 to generate corrected state history data. The OCV estimation logic can be provided to replace the set of three full-cell voltage measurements for each rest period included in the state history data acquired in step S1120 with a single OCV value. Therefore, if a total of X rest periods are permitted during the state change period and the full-cell voltage is measured three times during each rest period, those skilled in the art will readily appreciate that the voltage history data acquired in step S1120 will include 3X full-cell voltage measurements, and the corrected voltage history data will include X OCV values.

[0275] In step S1130, the processor 320 generates a measured full-cell profile indicating a corresponding relationship between the capacity of the target cell BC and the full-cell voltage based on the corrected state history data (see Figure 3b in the text).

[0276] In step S1140 , the processor 320 analyzes the measured full-cell profile to generate first diagnostic information including at least one diagnostic factor associated with the charge / discharge performance of the target cell BC.

[0277] In step S1150 , the processor 320 generates second diagnostic information of the target cell BC by applying at least one mathematical operation to the first diagnostic information.

[0278] In step S1160 , processor 320 updates charge / discharge permission condition information indicating at least one of a voltage range, an SOC range, and a current range permitted for the target cell BC based on at least one of the first diagnostic information and the second diagnostic information.

[0279] In step S1170 , the processor 320 may transmit the diagnosis result of the target cell BC to the battery system 1 through the data obtaining unit 310 .

[0280] In accordance with Figure 11 In the method, steps S1110, S1140, S1150, S1160 and S1170 can be respectively Figure 10 Steps S1010, S1040, S1050, S1060 and S1070 of the method are substantially the same. Figure 11 In the method, at least one of steps S1150, S1160 and S1170 can be obtained from the Figure 10 Omitted from the method.

[0281] Figure 12 is referred to in the description Figure 11 FIG. 1 is a diagram of a process of correcting voltage history data performed in step S1122 .

[0282] Figure 12 The symbol 1200 indicates Figure 3a One of the voltage drop segments shown in t R Indicates the time point at which the reference time has passed since the start time point of the rest period. R The part is depicted as a solid line, and at t R The subsequent portion is depicted as a dotted line.

[0283] refer to Figure 12 , during each rest period, the target cell BC is placed in a no-load state in which it is neither charged nor discharged.

[0284] During the no-load state, the full-cell voltage of the target cell BC gradually converges toward the OCV corresponding to the SOC of the target cell BC. The behavior of the full-cell voltage of the target cell BC in a specific rest period can be equivalent to the voltage response of the primary RC circuit, such as the following formula 1.

[0285] <Formula 1>

[0286]

[0287] In formula 1, t is the time elapsed from the start time of a specific rest period, V full (t) is the total cell voltage at t, V OCV is the actual OCV, V S is the full-cell voltage at the starting time point of a specific rest period, and τ is a time constant determined by the internal resistance and capacity of the target cell BC.

[0288] In Formula 1, V full (t) is measurable, so V OCV 、V S and τ are unknown. Since there are three unknown values, we can use V full (t) to estimate the OCV of a specific rest period. The following formula 2 can be used to estimate the OCV of each rest period.

[0289] <Formula 2>

[0290]

[0291] In formula 2, t1, t2, and t3 are the sequential measurement timings of the voltage of all cells. The time difference between t1 and t2 can be the same as the time difference between t2 and t3. Figure 12 In, t R and t3 are shown to be different, but t R = t3 is also possible. In this case, V full (t3) = D OCV .

[0292] The processor 320 can calculate V OCV Determine D in the same way OCV_C .

[0293] The processor 320 may perform the above operations by repeatedly using a single OCV value (D OCV_C ) replaces the three full-cell voltage measurements (V full (t1), V full (t2), V full The voltage history data obtained in step S1120 is converted into corrected voltage history data in step S1130 by a process (t3). The corrected voltage history data includes X OCV values. The processor 320 may apply curve fitting logic to the corrected voltage history data to generate a measured full-cell profile M.

[0294] For reference, D OCV is the measured value of the full-cell voltage at the end of the rest period (before the polarization is fully resolved), and D OCV_C is the full cell voltage in a state where polarization is completely resolved (i.e., V OCV ). Therefore, it can be considered that D OCV_C than D OCV Closer to the actual OCV of the target monomer BC.

[0295] The embodiments of the present disclosure described above are not only implemented by the device and method, but can also be implemented by a program that executes functions corresponding to the configuration of the embodiments of the present disclosure or a recording medium having the program recorded thereon, and based on the disclosure content of the previously described embodiments, those skilled in the art can easily implement such an implementation.

[0296] While the present disclosure has been described above with respect to a limited number of embodiments and drawings, it is not limited thereto, and it will be apparent to those skilled in the art that various modifications and changes may be made thereto within the technical aspects of the present disclosure and the equivalent scope of the appended claims.

[0297] In addition, since those skilled in the art can make many substitutions, modifications and changes to the present disclosure without departing from the technical aspects of the present disclosure, the present disclosure is not limited to the above-mentioned embodiments and drawings, and some or all of the embodiments can be selectively combined to allow various modifications.

Claims

1. A battery diagnostic method, comprising: obtaining, through an intermittent application process of an electrical stimulus to a battery cell, state history data of the battery cell corresponding to a state change period until the electrical state of the battery cell reaches a second state from a first state; generating a measured full-cell profile representing a corresponding relationship between the capacity and voltage of the battery cell based on the state history data; as well as First diagnostic information is generated by analyzing the measured full-cell profile, the first diagnostic information including at least one diagnostic factor related to charge / discharge performance of the battery cell.

2. The battery diagnosis method according to claim 1, in, The electrical stimulation is a current stimulation that causes a transient voltage change exceeding a threshold value on the battery cell.

3. The battery diagnosis method according to claim 1, in, The electrical stimulation is a current stimulation that causes an overpotential exceeding a threshold value to the battery cell when the electrical stimulation is continuously applied for a specific time.

4. The battery diagnosis method according to claim 1, in, The electrical stimulus is a charging current at a predetermined current rate.

5. The battery diagnosis method according to claim 1, in, The electrical stimulation is a discharge current at a predetermined current rate.

6. The battery diagnosis method according to claim 1, in, The state history data includes a voltage value representing the voltage of the battery cell measured at least once during each rest period of the electrical stimulus applied within the state change period.

7. The battery diagnosis method according to claim 1, in, The intermittent application process includes a process for removing the electrical stimulus to the battery cell so that a rest period is provided to the battery cell each time a current integrated value of the battery cell changes by a threshold integrated value during application of the electrical stimulus.

8. The battery diagnosis method according to claim 7, in, The intermittent application process further includes a process for resuming the application of the electrical stimulation whenever the duration of the rest period reaches a reference time.

9. The battery diagnosis method according to claim 1, in, The first diagnostic information includes at least one of a positive electrode participation starting point, a positive electrode participation end point, a positive electrode scaling factor, and a positive electrode load amount representing charge / discharge performance of the positive electrode of the battery cell as the diagnostic factor.

10. The battery diagnosis method according to claim 9, further comprising: Second diagnostic information is generated by applying a mathematical operation to the first diagnostic information, the second diagnostic information including at least one degradation parameter regarding the positive electrode or available lithium of the battery cell.

11. The battery diagnosis method according to claim 1, in, The first diagnostic information includes at least one of a negative electrode participation starting point, a negative electrode participation end point, a negative electrode scaling factor, and a negative electrode load amount representing charge / discharge performance of the negative electrode of the battery cell as the diagnostic factor.

12. The battery diagnosis method according to claim 11, further comprising: Second diagnostic information is generated by applying a mathematical operation to the first diagnostic information, the second diagnostic information including at least one degradation parameter regarding the negative electrode of the battery cell.

13. The battery diagnosis method according to claim 10 or 12, further comprising: Charge / discharge permission condition information indicating at least one of a voltage range, an SOC range, and a current range permitted for the battery cell is updated based on at least one of the first diagnostic information and the second diagnostic information.

14. A battery diagnostic device comprising: a data obtaining unit configured to obtain, through an intermittent application process of an electrical stimulus to the battery cell, state history data of the battery cell corresponding to a state change period until the electrical state of the battery cell reaches a second state from a first state; as well as a processor configured to generate a measured full-cell profile representing a corresponding relationship between capacity and voltage of the battery cell based on the state history data; The processor is configured to generate first diagnostic information by analyzing the measured full-cell profile, wherein the first diagnostic information includes at least one diagnostic factor related to charge / discharge performance of the battery cell.

15. The battery diagnostic device according to claim 14, in, The intermittent application process includes a process for removing the electrical stimulus to the battery cell so that a rest period is provided to the battery cell each time a current integrated value of the battery cell changes by a threshold integrated value during application of the electrical stimulus.

16. The battery diagnostic device according to claim 15, in, The intermittent application process further includes a process for resuming the application of the electrical stimulation whenever the duration of the rest period reaches a reference time.

17. The battery diagnostic device according to claim 14, in, The first diagnostic information includes at least one of a positive electrode participation starting point, a positive electrode participation end point, a positive electrode scaling factor, and a positive electrode load amount representing charge / discharge performance of the positive electrode of the battery cell as the diagnostic factor.

18. The battery diagnostic device according to claim 14, in, The first diagnostic information includes at least one of a negative electrode participation starting point, a negative electrode participation end point, a negative electrode scaling factor, and a negative electrode load amount representing charge / discharge performance of the negative electrode of the battery cell as the diagnostic factor.

19. A charging station comprising the battery diagnostic device according to any one of claims 14 to 18. 20 . A cloud server comprising the battery diagnosis device according to claim 14 .

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