Battery diagnosis method and battery diagnosis apparatus

Abstract

Disclosed are a battery diagnosis method and a battery diagnosis apparatus. The battery diagnosis method according to the present invention comprises the steps of: executing a procedure of intermittent application of electrical stimulation to a battery cell; acquiring 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 by the procedure of intermittent application; on the basis of the state history data, generating a measured full cell profile indicating the correspondence between the capacity and voltage of the battery cell; and analyzing the measured full cell profile to generate first diagnosis information including at least one diagnosis factor associated with the charge / discharge performance of the target cell.

Description

Battery diagnostic method and battery diagnostic device

[0001] The present invention relates to a technique for diagnosing the condition of a battery in a non-destructive manner.

[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, all of which are incorporated herein by reference in their entirety.

[0003] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has rapidly increased, and the development of electric vehicles, energy storage batteries, robots, and satellites has been in full swing, research into high-performance batteries capable of repeated charging and discharging is actively being conducted.

[0004] Currently commercialized batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium batteries. Among these, lithium batteries are receiving attention for their advantages of being able to charge and discharge freely, having a very low self-discharge rate, and having a high energy density, as they have almost no memory effect compared to nickel-based batteries.

[0005] While extensive research is being conducted on these batteries to improve capacity and density, improving lifespan and safety is also crucial. To improve battery safety, the current condition of the battery must be accurately diagnosed.

[0006] Accurately diagnosing the internal condition of a battery cell is essential for its safety and longevity. To diagnose the internal condition of a battery cell without disassembly, relational data (such as a full cell profile) that indicates the correspondence between capacity and voltage is primarily utilized.

[0007] Conventionally, the full-cell profile is acquired by repeatedly measuring the voltage and capacity of a battery cell at short intervals while a constant electrical stimulus (e.g., constant current charging or discharging) is applied to the battery cell. However, to minimize polarization (or overvoltage) that causes a decrease in diagnostic accuracy, it is advantageous to lower the level of electrical stimulus applied to the battery cell as much as possible. However, this has the limitation that it takes excessive time to acquire the full-cell profile. Conversely, while high-level electrical stimulus is advantageous in terms of shortening the time, it cannot guarantee the accuracy of the diagnostic result because it is accompanied by a severe polarization phenomenon.

[0008] The present invention has been made to solve the above problems, and its purpose is to provide a battery diagnosis method and a battery diagnosis device that acquire relationship data that directly or indirectly indicates the correspondence between the capacity and voltage of a battery cell by executing an intermittent electrical stimulation application procedure in which the application and removal of the electrical stimulation are alternately repeated. The polarization induced in a battery cell during the electrical stimulation application period naturally decreases during the electrical stimulation rest period. Therefore, even if the electrical stimulation used in the intermittent application procedure has a high level, the actual charge / discharge characteristics of the battery cell can be sufficiently reflected in the acquired relationship data.

[0009] In addition, the present invention aims to provide a battery diagnosis method and a battery diagnosis device capable of generating diagnostic information related to the charge / discharge performance of a battery cell based on relationship data acquired by executing an intermittent authorization procedure.

[0010] Other objects and advantages of the present invention can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0011] A battery diagnosis method according to one aspect of the present invention comprises the steps of: obtaining state history data of a battery cell corresponding to a state change period until an electrical state of the battery cell reaches a second state from a first state by an intermittent application procedure of an electrical stimulus to the battery cell; generating a measurement full-cell profile indicating a correspondence between a capacity and a voltage of the battery cell based on the state history data; and generating first diagnostic information including at least one diagnostic factor related to charge / discharge performance of the battery cell by analyzing the measurement full-cell profile.

[0012] The electrical stimulation may be a current stimulation that causes an instantaneous voltage change exceeding a threshold value in the battery cell.

[0013] The above electrical stimulation may be a current stimulation that causes an overvoltage exceeding a threshold value to the battery cell when the electrical stimulation is continuously applied for a predetermined period of time.

[0014] The above electrical stimulation may be a charging current having a predetermined current rate.

[0015] The above electrical stimulation may be a discharge current having a predetermined current rate.

[0016] The above state history data may include voltage values ​​representing the voltage of the battery cell measured at least once during each of the rest periods of the electrical stimulation applied within the state change period.

[0017] The intermittent application procedure may include a procedure of removing the electrical stimulation to the battery cell so that a rest period is applied to the battery cell whenever the current integration value of the battery cell changes by a threshold integration value during the application of the electrical stimulation.

[0018] The intermittent application procedure may further include a procedure for resuming application of the electrical stimulation when the duration of the pause period reaches a reference time.

[0019] The above first diagnostic information may include at least one of a positive electrode participation start point, a positive electrode participation end point, a positive electrode scale factor, and a positive electrode loading amount, which indicate the charge / discharge performance of the positive electrode of the battery cell, as the diagnostic factor.

[0020] The above battery diagnosis method may further include a step of applying a mathematical operation to the first diagnosis information to generate second diagnosis information including at least one deterioration parameter regarding the positive electrode or available lithium of the battery cell.

[0021] The above first diagnostic information may include at least one of a negative electrode participation start point, a negative electrode participation end point, a negative electrode scale factor, and a negative electrode loading amount, which indicate the charge / discharge performance of the negative electrode of the battery cell, as the diagnostic factor.

[0022] The above battery diagnosis method may further include a step of applying a mathematical operation to the first diagnostic information to generate second diagnostic information including at least one deterioration parameter regarding the negative electrode of the battery cell.

[0023] The above battery diagnosis method may further include a step of updating charge / discharge allowance condition information indicating at least one of a voltage range, SOC range, and current range allowed for the battery cell, based on at least one of the first diagnostic information and the second diagnostic information.

[0024] According to another aspect of the present invention, a battery diagnostic device includes a data acquisition unit configured to acquire state history data of a battery cell corresponding to a state change period until an electrical state of the battery cell reaches a second state from a first state by an intermittent application procedure of an electrical stimulus to the battery cell, and a processor configured to generate a measurement full-cell profile indicating a correspondence between a capacity and a voltage of the battery cell based on the state history data. The processor is configured to analyze the measurement full-cell profile to generate first diagnostic information including at least one diagnostic factor related to a charge / discharge performance of the battery cell.

[0025] The intermittent application procedure may include a procedure of removing the electrical stimulation to the battery cell so that a rest period is applied to the battery cell whenever the current integration value of the battery cell changes by a threshold integration value during the application of the electrical stimulation.

[0026] The intermittent application procedure may further include a procedure for resuming application of the electrical stimulation whenever the duration of the pause reaches a reference time.

[0027] The above first diagnostic information may include at least one of a positive electrode participation start point, a positive electrode participation end point, a positive electrode scale factor, and a positive electrode loading amount, which indicate the charge / discharge performance of the positive electrode of the battery cell, as the diagnostic factor.

[0028] The above first diagnostic information may include at least one of a negative electrode participation start point, a negative electrode participation end point, a negative electrode scale factor, and a negative electrode loading amount, which indicate the charge / discharge performance of the negative electrode of the battery cell, as the diagnostic factor.

[0029] A charging station according to another aspect of the present invention includes the battery diagnostic device.

[0030] A cloud server according to another aspect of the present invention includes the battery diagnostic device.

[0031] According to at least one of the embodiments of the present invention, by applying a method of intermittently applying electrical stimulation to a battery cell, relationship data indicating a correspondence between the capacity and voltage of the battery cell can be acquired, and diagnostic information indicating the charge / discharge performance of the battery cell can be generated based on the acquired relationship data.

[0032] Accordingly, even when high-level electrical stimulation is used to change the electrical state of a battery cell, not only can a decrease in diagnostic accuracy due to excessive polarization be prevented, but the time required to acquire relational data can also be shortened.

[0033] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0034] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0035] FIG. 1 is a drawing for reference in explaining a battery diagnostic device according to the present invention.

[0036] Figure 2 is a graph referenced to explain an example of each of a reference anode profile and a reference cathode profile.

[0037] FIG. 3a and FIG. 3b are graphs that are referenced to exemplarily explain the process of obtaining a measurement full cell profile of a battery cell.

[0038] FIGS. 4 to 6 are drawings for reference in explaining an example of a procedure for generating a comparison full-cell profile used for comparison with a measured full-cell profile according to one embodiment of the present invention.

[0039] FIGS. 7 to 9 are drawings for reference in explaining another example of a procedure for generating a comparison full-cell profile used for comparison with a measured full-cell profile according to one embodiment of the present invention.

[0040] FIG. 10 is a flowchart for reference in schematically explaining a battery diagnosis method according to the first embodiment of the present invention.

[0041] FIG. 11 is a flowchart for reference in schematically explaining a battery diagnosis method according to a second embodiment of the present invention.

[0042] FIG. 12 is a drawing for reference in explaining the correction procedure of voltage history data performed in step S1122 of FIG. 11.

[0043] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that conforms to the technical spirit of the present invention.

[0044] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0045] Terms that include ordinal numbers, such as first, second, etc., are used to distinguish one of the various components from the rest, and are not used to limit the components by such terms.

[0046] Throughout the specification, when a part is said to "include" a component, this does not exclude other components, unless otherwise stated, but rather implies that other components may be included. Furthermore, terms such as "unit" used throughout the specification mean a unit that processes at least one function or operation, and may be implemented using hardware, software, or a combination of hardware and software.

[0047] Additionally, throughout the specification, when we say that a part is "connected" to another part, this includes not only cases where it is "directly connected" but also cases where it is "indirectly connected" with other elements in between.

[0048] FIG. 1 is a drawing for reference in explaining a battery diagnostic device according to the present invention.

[0049] Referring to Fig. 1, a battery system (1) includes a system controller (2), a battery pack (10), an inverter (30), and an electrical load (40). The charge / discharge terminals (P+, P-) of the battery pack (10) can be electrically coupled to a charging station (300) via a charging cable or the like.

[0050] The system controller (2) (e.g., ECU: Electronic Control Unit) is configured to transmit a key-on signal to the battery management system (100) in response to a start button (not shown) provided in the battery system (1) being turned to the ON position by a user. The system controller (2) is configured to transmit a key-off signal to the battery management system (100) in response to a start button being turned to the OFF position by a user. The charging station (300) can communicate with the system controller (2) and supply charging power selected from among constant power, constant current, and constant voltage through the charge / discharge terminals (P+, P-) of the battery pack (10).

[0051] 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).

[0052] The battery (11) includes at least one battery cell (BC). In Fig. 1, the battery (11) includes a plurality of battery cells (BC1 to BC) connected in series. N , N is a natural number greater than or equal to 2) is illustrated as an example. Multiple battery cells (BC1 to BC N ) may be provided to have the same electrochemical specifications. Hereinafter, a plurality of battery cells (BC1 to BC N ), the symbol 'BC' is assigned to the battery cell. The charging station (300) can execute the charge / discharge cycle required to diagnose the battery cell (BC) through collaboration with an inverter (30) having a discharge function.

[0053] As long as the electrochemical device is capable of repeated charging and discharging, the type of battery cell (BC) is not specifically limited. The battery cell (BC) is subject to diagnosis by the charging station.

[0054] The relay (20) is electrically connected in series to the battery (11) via a power path connecting the battery (11) and the inverter (30). In Fig. 1, the relay (20) is illustrated as being connected between the positive terminal of the battery (11) and the charge / discharge terminal (P+). The relay (20) is turned on and off in response to a switching signal from the battery management system (100). The relay (20) may be a mechanical contactor that is turned on and off by the magnetic force of a coil, or a semiconductor switch such as a MOSFET (Metal Oxide Semiconductor Field Effect transistor).

[0055] An inverter (30) is provided to convert direct current from a battery (11) included in a battery pack (10) into alternating current in response to a command from a battery management system (100) or a system controller (2). An electric load (40) can be driven using alternating current power from the inverter (30). For example, a three-phase alternating current motor can be used as the electric load (40). Components within the battery system (1) that receive discharge power from the battery (11), including the inverter (30) and the electric load (40), can be collectively referred to as an electric load.

[0056] 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).

[0057] The sensing unit (110) includes a voltage sensor (111). The sensing unit (110) may further include a current sensor (112).

[0058] A voltage sensor (111) is connected to the positive and negative terminals of a battery cell (BC), measures the voltage across both ends of the battery cell (BC) (which may be referred to as a 'full cell voltage' or a 'cell voltage'), and is configured to generate a voltage signal representing a measurement value of the measured voltage. The voltage sensor (111) may be implemented as one or a combination of two or more of known voltage measuring elements, such as a voltage measuring IC.

[0059] The current sensor (112) is connected in series to the battery (11) through a current path between the battery (11) and the inverter (30). The current sensor (112) is configured to measure the current flowing through the battery (11) (which may be referred to as a 'charge / discharge current') and generate a current signal representing the measured current. A plurality of battery cells (BC1 to BC) N ) are connected in series, the current flowing in the battery (11) is the same as the current flowing in the battery cell (BC). The current sensor (112) can be implemented with one or a combination of two or more of known current measuring elements such as a shunt resistor, a Hall effect element, etc.

[0060] The communication circuit (150) is configured to support wired or wireless communication between the control circuit (130) and the system controller (2). The wired communication may be, for example, CAN (control area network) communication, and the wireless communication may be, for example, Zigbee or Bluetooth communication. Of course, as long as it supports wired or wireless communication between the control circuit (130) and the system controller (2), the type of communication protocol is not particularly limited. 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).

[0061] The control circuit (130) is operably coupled to a relay (20), a voltage sensor (111), and a communication circuit (150). When two components are operably coupled, it means that the two components are directly or indirectly connected so as to be capable of transmitting and receiving signals in one or both directions.

[0062] The control circuit (130) can collect a voltage signal from the voltage sensor (111) and a current signal from the current sensor (112). In this specification, the measurement signal may refer only to the voltage signal, or may be a term that collectively refers to both the voltage signal and the current signal. That is, the control circuit (130) can convert and record each analog signal collected from the sensors (111, 112) into a digital value using an ADC (Analog to Digital Converter) provided therein. Alternatively, each of the voltage sensor (111) and the current sensor (112) may include an ADC therein and transmit the digital value to the control circuit (130).

[0063] The control circuit (130) may be referred to as a 'battery controller' and may be implemented in hardware using at least one of application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), microprocessors, and other electrical units for performing functions.

[0064] The memory (131) may include at least one type of storage medium among, for example, a flash memory type, a hard disk type, an SSD (Solid State Disk type), an SDD (Silicon Disk Drive 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), and a programmable read-only memory (PROM). The memory (131) may store data and a program required for an operation by the control circuit (130). The memory (131) may store data indicating a result of an operation by the control circuit (130).

[0065] The control circuit (130) can control the charging and discharging of the battery cell (BC) according to the charge and discharge allowable condition information (including at least one of an allowable voltage range, an allowable SOC range, and an allowable current range) to be described later. For example, if the full-cell voltage of the battery cell (BC) is outside the allowable voltage range or the SOC of the battery cell (BC) is outside the SOC range, the control circuit (130) can prohibit the turning on of the relay (20), and otherwise allow the turning on of the relay (20). In addition, the control circuit (130) can control the relay (20) and / or the inverter (30) so that the magnitude of the current flowing through the battery cell (BC) does not exceed the allowable current range.

[0066] When the relay (20) is turned on, the battery (11) enters the charging mode or the discharging mode. When the relay (20) is turned off while the battery (11) is in use in the charging mode or the discharging mode, the battery (11) switches to the idle mode.

[0067] 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 transition from idle to charging or discharging. The key-off signal is a signal requesting a transition from charging or discharging to idle. Alternatively, the on / off control of the relay (20) may be handled by the system controller (2) instead of the control circuit (130).

[0068] In this specification, the history data of any parameter represents the history of changes in that parameter over time. In addition, a profile (or curve) representing the correspondence between any two parameters (e.g., 'voltage' and 'capacity', or 'voltage' and 'current') obtained at the same timing during the same period may be a mapping of the history data of the two parameters so that it can be expressed in the form of a two-dimensional graph, or may be a polynomial equation obtained by applying a predetermined curve fitting logic to a set of two mapped history data. Here, the degree of the highest term of the polynomial equation may be predetermined.

[0069] The battery diagnostic device (302) includes a data acquisition unit (310), a processor (320), and a memory unit (330).

[0070] The charging station (300) may include a stimulus application device (301) and a battery diagnosis device (302), as shown in FIG. 1. Of course, the battery diagnosis device (302) may be implemented to operate independently of the charging station (300). For example, the battery diagnosis device (302) may be provided in a form included in a cloud server (not shown). The cloud server may be located remotely from the charging station (300). In this case, the data acquisition unit (310) of the battery diagnosis device (302) may perform diagnostic procedures on the battery cell (BC) through remote communication with the stimulus application device (301) and / or the battery system (1). Hereinafter, the battery cell (BC) to be diagnosed may be simply referred to as a 'target cell'.

[0071] Alternatively, the battery diagnostic device (302) may be included in the battery pack (10) as a replacement 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).

[0072] The stimulation application device (301) may include a charger that provides charging power for normal charging of the battery pack (10). The stimulation application device (301), alone or in cooperation with an inverter (30), may apply or remove at least one type of electrical stimulus to the battery cell (BC) for diagnosis of the battery cell (BC).

[0073] 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) can transmit the results of the diagnosis of the battery cell (BC) performed by the processor (320) to the battery system (1). The data acquisition unit (310) can be included as a sub-component of the processor (320).

[0074] The processor (320) may be implemented in hardware using at least one of application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), microprocessors, and other electrical units for performing functions.

[0075] The memory unit (330) may include at least one type of storage medium, for example, a flash memory type, a hard disk type, an SSD (Solid State Disk type), an SDD (Silicon Disk Drive 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 unit (330) may store data and programs required for diagnostic procedures performed by the processor (320). The memory unit (330) may store data representing the results of an operation performed by the processor (320). The memory unit (330) may store data sets and software used to diagnose the deterioration state of the battery cell (BC).

[0076] Fig. 2 is a graph for reference in explaining an example of each of a reference anode profile and a reference cathode profile. In the graph of Fig. 2, the horizontal axis (X-axis) represents capacity (Ah) and the vertical axis (Y-axis) represents voltage.

[0077] Referring to FIG. 2, the memory unit (330) can store a reference positive electrode profile (Rp) and a reference negative electrode profile (Rn). The reference cell may be a coin-type cell including a positive electrode half-cell and a negative electrode half-cell, or a three-electrode cell. Hereinafter, the positive electrode and positive electrode half-cell of the reference cell will be described in equivalent terms, and the negative electrode and negative electrode half-cell of the reference cell will be described in equivalent terms.

[0078] The reference anode profile (Rp) may be a profile representing the correspondence between the anode voltage and capacity of a reference cell. The anode voltage of the reference cell refers to the potential difference between the potential of a reference electrode (not shown) and the potential of the anode of the reference cell. The anode profile may also be referred to as an anode half-cell profile.

[0079] The reference cathode profile (Rn) may be a profile representing the correspondence between the cathode voltage and capacity of a reference cell. The cathode voltage of the reference cell refers to the potential difference between the potential of the reference electrode and the potential of the cathode of the reference cell. The cathode profile may also be referred to as a cathode half-cell profile.

[0080] The potential of the reference electrode may be, for example, the redox potential of lithium. The anode voltage may be referred to simply as the anode potential, and the cathode voltage may be referred to simply as the cathode potential.

[0081] Each of the positive voltage and negative voltage can be an open circuit voltage (OCV) or a closed circuit voltage (CCV).

[0082] A first charge protocol or a first discharge protocol can be utilized to obtain the closed-loop voltages of the positive and negative electrodes of the reference cell, respectively. The first charge protocol can be a constant current charge method using a first current rate. The first discharge protocol can be a constant current discharge method using a first current rate (e.g., 0.05 C). For example, while the reference cell is continuously charged by the first charge protocol or while the reference cell is continuously discharged by the first discharge protocol, the closed-loop voltages of the positive and negative electrodes of the reference cell, which are measured periodically or aperiodically, can be recorded as the positive voltage and the negative voltage of the reference cell, respectively.

[0083] When comparing the open-circuit voltage with the closed-circuit voltage, a second charging protocol or a second discharging protocol can be utilized to obtain the open-circuit voltage of each of the positive and negative electrodes of the reference cell. The second charging protocol can be an intermittent charging method in which constant current charging using a second current rate (e.g., 3.0 C) and pauses are alternately performed. The second discharging protocol can be an intermittent charging method in which constant current discharging using a second current rate and pauses are alternately performed.

[0084] For example, when the charging time by constant current charging of the second charging protocol has elapsed by a set amount of time or the charge capacity of the reference cell has increased by a set amount of time, charging of the reference cell may be stopped for a set pause time and then constant current charging may be resumed. The charge capacity may be calculated by periodically or aperiodically accumulating sample values ​​of the charge current.

[0085] As another example, whenever the discharge time due to the constant current discharge of the second discharge protocol elapses by a set amount of time or the discharge capacity of the reference cell decreases by a set amount of time, the discharge of the reference cell may be stopped for a set amount of time and then the constant current discharge may be resumed. The discharge capacity may be calculated by periodically or aperiodically accumulating sample values ​​of the discharge current (i.e., measurements of the cell current).

[0086] At this time, multiple pauses may 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, respectively, measured at specific timings within each pause, may be recorded as the positive voltage and negative voltage of the reference cell.

[0087] In this specification, a low level electrical stimulation may be referred to as a 'first electrical stimulation', and a high level electrical stimulation may be referred to as a 'second electrical stimulation'.

[0088] Assuming that the battery cell is in a new condition, the first electrical stimulus may be a current stimulus that induces an instantaneous voltage change in the battery cell below a threshold value (e.g., the difference between OCV and CCV), and the second electrical stimulus may be a current stimulus that induces an instantaneous voltage change in the battery cell above a threshold value. The instantaneous voltage change is determined by Ohm's law due to 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., the open circuit voltage: OCV) and the voltage of the battery cell immediately after the application (i.e., the closed circuit voltage: CCV). If the electrical stimulus is a charge-induced stimulus, the instantaneous voltage change may be referred to as a 'voltage rise'. Conversely, if the electrical stimulus is a discharge-induced stimulus, the instantaneous voltage change may be referred to as a 'voltage drop'.

[0089] Alternatively, assuming that the battery cell is in a new condition, the first electrical stimulus may refer to a current stimulus that causes an overvoltage below a threshold value in the battery cell when continuously applied for a predetermined period of time, and the second electrical stimulus may refer to a current stimulus that causes an overvoltage above a threshold value in the battery cell when continuously applied for a predetermined period of time. The overvoltage when an electrical stimulus is continuously applied for a predetermined period of time may indicate the difference between the amount of change in OCV and the amount of change in CCV during the same period of time.

[0090] For example, the first electrical stimulus may be a charging current having a predetermined current rate (e.g., the first current rate), and the second electrical stimulus may be a charging current having a current rate corresponding to a higher level than the first electrical stimulus (e.g., the second current rate).

[0091] As another example, the first electrical stimulus may be a discharge current having a predetermined current rate (e.g., a first current rate), and the second electrical stimulus may be a discharge current having a current rate corresponding to a higher level than the first electrical stimulus (e.g., a second current rate).

[0092] Implementing the first charging protocol or the first discharging protocol may mean continuously applying a first electrical stimulus to the battery cell. Implementing the second charging protocol or the second discharging protocol may mean intermittently applying a second electrical stimulus to the battery cell.

[0093] For convenience of explanation, it is assumed that the horizontal axis represents the charging capacity in FIGS. 2 to 9.

[0094] At least one of the reference positive electrode profile (Rp) and the reference negative electrode profile (Rn) can be aligned along the horizontal axis so that the result of synthesizing a portion of the common capacity range of the two profiles (5 to 50 Ah in FIG. 2) matches the reference full-cell profile (R). FIG. 2 illustrates a case where the reference negative electrode profile (Rn) is aligned by shifting to the right, with the starting point (the point corresponding to capacity 0) of the reference positive electrode profile (Rp) as the reference point.

[0095] It can be seen from Fig. 2 that the ends of the reference positive electrode profile (Rp) and the reference negative electrode profile (Rn) are misaligned. That is, 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) represents the full-cell voltage of the reference cell in a portion of the capacity range common to the reference positive electrode profile (Rp) and the reference negative electrode profile (Rn). That is, 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).

[0096] The reference full-cell profile (R) can represent the relationship between the capacity and full-cell voltage of a new, certified good battery cell. In other words, the reference cell has the same positive and negative performance levels as a new, certified good battery cell. The positive and negative performance of any battery cell can be collectively referred to as "charge / discharge performance."

[0097] A "new battery cell" refers to a battery cell in its "new" condition. "New" condition can be synonymous with "Beginning of Life" (BOL). For example, the period from the time of manufacturing completion until the cumulative charge / discharge capacity reaches a predetermined set capacity can be referred to as "BOL," while the period from the time the cumulative charge / discharge capacity reaches the set capacity can be referred to as "Middle of Life" (MOL).

[0098] The reference full-cell profile (R) can represent the relationship between the voltage and capacity of the reference cell over at least a voltage range of interest (e.g., 3.0 to 4.0 V). The lower and upper limits of the voltage range of interest can be a first set voltage (3.0 V in FIG. 2) and a second set voltage (4.0 V in FIG. 2).

[0099] The SOC may be set to 0% when the full-cell voltage of any battery cell, including the reference cell, is equal to the first set voltage. The SOC may be set to 100% when the full-cell voltage of any battery cell, including the reference cell, is equal to the second set voltage. According to Fig. 2, the reference cell can reach a fully charged state (SOC 100%) from a fully discharged state (SOC 0%) with a charge capacity of 45 Ah.

[0100] In the present specification, the positive electrode participation start point on the positive electrode profile of any battery cell represents the positive electrode voltage and positive electrode capacity (or positive electrode SOC) when the full cell voltage of the battery cell matches the first set voltage. In addition, the negative electrode participation start point on the negative electrode profile of the battery cell represents the negative electrode voltage and negative electrode capacity (or negative electrode SOC) when the full cell voltage of the battery cell matches the first set voltage. Therefore, the voltage difference between the positive electrode participation start point and the negative electrode participation start point may be equal to the first set voltage.

[0101] Additionally, the positive engagement endpoint on the positive profile of any battery cell represents the positive voltage and positive capacity (or positive SOC) when the full-cell voltage of the battery cell matches the second set voltage. Additionally, the negative engagement endpoint on the negative profile of the battery cell represents the negative voltage and negative capacity (or negative SOC) when the full-cell voltage of the battery cell matches the second set voltage. Therefore, the voltage difference between the positive engagement endpoint and the negative engagement endpoint may be equal to the second set voltage.

[0102] In the present specification, the anode capacity (capacity value) of a specific point on the anode profile of any battery cell may mean the capacity difference between either one of the two end points of the anode profile and the specific point. The anode SOC of a specific point on the anode profile of any battery cell may mean the ratio of the capacity difference between either one of the two end points of the anode profile (e.g., a low-capacity point) and the specific point to the capacity difference between the two end points of the anode profile. The capacity difference between the two end points of the anode profile may be referred to as the total anode capacity.

[0103] Similarly, the negative capacity (capacity value) of a specific point on the negative profile of any battery cell may mean the capacity difference between either one of the two end points of the negative profile (or the positive profile) and the specific point. The negative SOC of a specific point on the negative profile of any battery cell may mean the ratio of the capacity difference between either one of the two end points of the negative profile (e.g., a low-capacity point) and the specific point to the capacity difference between either one of the two end points of the negative profile (or the positive profile). The capacity difference between the two end points of the negative profile may be referred to as the total negative capacity.

[0104] The memory unit (330) may have information indicating voltages of each of a reference positive electrode participation start point (pi0), a reference positive electrode participation end point (pf0), a reference negative electrode participation start point (ni0), and a reference negative electrode participation end point (nf0) pre-recorded. The reference positive electrode participation start point (pi0) and the reference positive electrode participation end point (pf0) are the positive electrode participation start point and the positive electrode participation end point on the reference positive electrode profile (Rp), respectively. The reference negative electrode participation start point (ni0) and the reference negative electrode participation end point (nf0) are the negative electrode participation start point and the negative electrode participation end point on the reference negative electrode profile (Rn), respectively.

[0105] The voltage difference between the reference positive engagement start point (pi0) and the reference negative engagement start point (ni0) may be equal to a first set voltage (e.g., 3.0 V). The voltage difference between the reference positive engagement end point (pf0) and the reference negative engagement end point (nf0) may be equal to a second set voltage (e.g., 4.0 V).

[0106] Figures 3a and 3b are graphs that are referenced to exemplarily explain the process of obtaining a measurement full cell profile of a target cell.

[0107] The graph illustrated in Fig. 3a illustrates an example of a change in the full-cell voltage of a target cell over time due to intermittent application of an electrical stimulus (e.g., the second electrical stimulus described above). The target cell is a battery cell that is to be diagnosed by a battery diagnostic device. The target cell may be a new battery cell that requires verification of whether it is a good product or a battery cell that has deteriorated after being verified as a good product and is no longer a new product. In the following, the target cell will also be assigned the symbol BC.

[0108] The processor (320) can control the stimulus application device (301) to intermittently apply electrical stimulation to the target cell (BC).

[0109] The procedure for controlling the stimulus application device (301) for diagnosis of the target cell (BC) can be performed during a state change period until the electrical state of the target cell (BC) (e.g., 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).

[0110] Referring to the graph in Figure 3a, the full-cell voltage of the target cell (BC) exhibits an upward trend as the sawtooth-shaped deformation is repeated. Each sawtooth-shaped voltage rising segment is caused by the application of electrical stimulation, and the voltage falling segment is caused by the cessation of electrical stimulation. In other words, the voltage falling segment represents the change in the full-cell voltage of the target cell (BC) over the resting period.

[0111] During the state change period, the processor (320) can repeatedly record measurements of the current of the target cell (BC) to generate current history data.

[0112] The processor (320) may control the stimulation application device (301) to initiate a pause period of the electrical stimulation whenever a predetermined pause condition is satisfied within the state change period. That is, the procedure for applying the electrical stimulation may be temporarily suspended when the pause condition is satisfied. For example, at least one of (i) the current integration value changing by a threshold integration value, (ii) the SOC changing by a threshold SOC, and (iii) the time for which the electrical stimulation is applied reaching a threshold time may be preset as a pause condition. For example, if the total current integration value during the state change period is 40 Ah and the threshold integration value is 2 Ah, a total of 20 pause periods may be provided during the state change period.

[0113] The processor (320) may determine at least one of a critical integration value, a critical SOC, and a critical time based on the buffer capacity, the SOH, or the previous diagnosis result (e.g., the capacity value of the negative electrode participation end point, the negative electrode loss rate) of the target cell (BC). At least one of the critical integration value, the critical SOC, and the critical time may have a predetermined positive (or negative) correspondence with the buffer capacity, the SOH, or the previous diagnosis result, and relationship data (a data table for idle period control) defining such correspondence may be stored in advance in the memory unit (330). By the predetermined positive (or negative) correspondence, as the buffer capacity, the SOH, or the previous diagnosis result decreases, at least one of the critical integration value, the critical SOC, and the critical time decreases. Consequently, as the target cell (BC) deteriorates over time, the idle periods are provided at shorter time intervals within the state change period, thereby preventing a decrease in the number of data points included in the voltage history data representing the temporal change history of the full-cell voltage in the idle periods of the state change period.

[0114] The processor (320) can obtain at least one of a buffer capacity, a SOH, or a critical integration value mapped to a previous diagnosis result, a critical SOC, and a critical time from a data table for rest period control. The processor (320) can control an intermittent application procedure of an electrical stimulus over a state change period using at least one of a critical integration value, a critical SOC, and a critical time obtained from the data table for rest period control.

[0115] The processor (320) can control the stimulation application device (301) to resume application of the electrical stimulation when a reference time has elapsed from the start of the pause period of the electrical stimulation. The reference time may be predetermined to a length of time sufficient to allow the polarization caused by the electrical stimulation to sufficiently resolve. For example, the reference time, which is the length of the pause period, may be the time required for the polarization to be reduced to 10% or less of the polarization at the start of the pause period.

[0116] In each pause period of the electrical stimulation, the full-cell voltage of the target cell (BC) is measured at least once. For example, the processor (320) may record the measurement of the full-cell voltage at the end of each pause period of the electrical stimulation as the OCV of the target cell (BC). In another example, the full-cell voltage may be measured at least three times in each pause period of the electrical stimulation, and the processor (320) may estimate the OCV of the target cell (BC) for each pause period based on the measurements of the three full-cell voltages for each pause period.

[0117] Accordingly, voltage history data can be generated by recording OCV multiple times with time differences during the state change period. Each OCV point (D) marked in Fig. 3a OCV ) is an example of an arbitrary data point in the voltage history data.

[0118] The inventor of the present invention has recognized through numerous experiments that voltage history data generated by the aforementioned intermittent application method using the second electrical stimulus has a high consistency with voltage history data generated when the first electrical stimulus is actually continuously applied to the target cell (BC).

[0119] From now on, we will explain the advantages of a diagnostic method based on intermittent application of a second electrical stimulus instead of continuous application of a first electrical stimulus.

[0120] Let us assume that the conditions related to the diagnosis of the target cell (BC) are as follows.

[0121] (i) First electrical stimulus = 0.05 C charge

[0122] (ii) Second electrical stimulation = 3.0 C charge

[0123] (iii) Length of rest period of second electrical stimulation = 12 minutes

[0124] (iv) Total capacity change during the state change period = 80% of the buffer capacity (FCC: Full Charge Capacity) of the target cell (BC).

[0125] (v) Critical accumulation value = 3% of the buffer capacity of the target cell (BC)

[0126] Then, the time required for the target cell (BC) to change from the first state to the second state by continuous application of the first electrical stimulus is 1 / 0.05*80% = 16 hours.

[0127] In comparison, the time required for the target cell (BC) to increase its charge capacity by the critical integration value due to the second electrical stimulation is 0.03 / 3*80% = 0.008 hours. In addition, since a rest period is provided for every 3% increase in charge capacity, a total of 26 rest periods are provided during the state change period. Therefore, the time required for the target cell (BC) to change from the first state to the second state by intermittent application of the second electrical stimulation is (0.008 hours + 0.2 hours)*26 = 5.4 hours.

[0128] That is, compared to the continuous application method of the first electrical stimulus, the intermittent application method of the second electrical stimulus is advantageous in shortening the acquisition time of the full-cell profile.

[0129] In the graph of Fig. 3b, the horizontal axis (X-axis) represents capacity (Ah) and the vertical axis (Y-axis) represents voltage.

[0130] Referring to FIG. 3B, the processor (320) can generate a measurement full-cell profile (M) indicating a correspondence between the capacity of the target cell (BC) and the full-cell voltage (which may also be referred to as a 'full-cell voltage'). The measurement full-cell profile may also be referred to as a QV profile or a Q-OCV profile.

[0131] Here, the full-cell voltage is the voltage across both ends of the target cell (BC), and is distinct from the anode voltage and cathode voltage described above. In other words, the full-cell voltage of the target cell (BC) can be said to be the difference between the anode voltage and cathode voltage of the target cell (BC).

[0132] To generate a measurement full-cell profile (M), state history data mapped to a state change period may be used. The state history data includes the voltage history data described above, and may further include current history data or capacity history data.

[0133] In detail, each data point of the current history data and the voltage history data is indexed in chronological order. Therefore, the processor (320) can generate capacity history data by sequentially accumulating the data points of the current history data. In addition, the processor (320) can generate a measured full-cell profile (M) by applying a curve fitting algorithm to a set of a plurality of Q-OCV pairs by mapping between the capacity history data and 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) may be polynomials in which the order of the highest term is predetermined.

[0134] Similar to the reference full-cell profile (R), the measured full-cell profile (M) can represent the correspondence between the capacity and OCV of the target cell (BC) at least over the voltage range of interest (e.g., 3.0 to 4.0 V).

[0135] Since there is bound to be some difference in charge / discharge performance between the reference cell and the target cell (BC), there is also some difference between the measured full cell profile (M) and the reference full cell profile (R), as shown in Fig. 3b.

[0136] For example, at the same capacity value, the voltage of the measured full-cell profile (M) is higher than that of the reference full-cell profile (R), which is caused by a manufacturing defect of the target cell (BC), anode capacity loss, cathode capacity loss, and / or available lithium loss. It is obvious that as the target cell (BC) deteriorates through repeated charge and discharge, the difference between the measured full-cell profile (M) and the reference full-cell profile (R) will gradually increase. According to Fig. 3b, unlike the reference cell described with reference to Fig. 2, a charge capacity of 40 Ah is required for the full-cell voltage of the target cell (BC) to reach the second set voltage from the first set voltage, which is 5 Ah less than the charge capacity of 50 Ah of the reference cell under the same conditions.

[0137]

[0138] Meanwhile, in the graphs of FIGS. 2 and 3b, Ah is used as the unit of the horizontal axis, but this unit may be expressed in other forms. For example, instead of Ah, a percentage % indicating SOC (State Of Charge) may be used as the unit of the horizontal axis.

[0139] When a measurement full-cell profile (M) is generated, the processor (320) may be configured to compare the measurement full-cell profile (M) with at least one comparison full-cell profile. Here, the comparison full-cell profile may be a result of generating an adjusted anode profile and an adjusted cathode profile by adjusting each of the reference anode profile (Rp) and the reference cathode profile (Rn) stored in the memory unit (330), and then synthesizing (combining) the adjusted anode profile and the adjusted cathode profile.

[0140] That is, when the reference full-cell profile (R) is a result of subtracting a portion of the reference cathode profile (Rn) from a portion of the reference anode profile (Rp), the comparison full-cell profile can be said to be a result of subtracting a portion of the adjusted cathode profile from a portion of the adjusted anode profile.

[0141] The processor (320) can generate at least one comparison full-cell profile by directly adjusting the reference positive electrode profile (Rp) and the reference negative electrode profile (Rn). Alternatively, the at least one comparison full-cell profile can be pre-secured based on the reference positive electrode profile (Rp) and the reference negative electrode profile (Rn) and stored in the memory unit (330). In this case, the processor (320) can also obtain the comparison full-cell profile by accessing the memory unit (330) and reading it.

[0142] The processor (320) can generate a plurality of comparison full-cell profiles from the reference anode profile (Rp) and the reference cathode profile (Rp) by repeating an adjustment procedure in which each of the reference anode profile (Rp) and the reference cathode profile (Rp) is adjusted to several levels and then synthesized. The comparison full-cell profile may also be referred to as an 'adjusted reference full-cell profile'.

[0143] The processor (320) can specify a comparison full-cell profile among a plurality of comparison full-cell profiles that has a minimum error with respect to the measured full-cell profile (M). Then, the processor (320) can determine that the adjusted positive profile and the adjusted negative profile mapped to the specified comparison full-cell profile are the positive profile and the negative profile of the target cell (BC).

[0144] In this regard, various methods known at the time of filing of the present invention can be employed to determine the error between two profiles, each expressible in a two-dimensional coordinate system. For example, the absolute integral of the area between the two profiles or the Root Mean Square Error (RMSE) can be used as the error between the two profiles.

[0145] According to this configuration of the present invention, various state information regarding the target cell (BC) can be obtained based on the finally determined adjusted anode profile and adjusted cathode profile. The finally determined adjusted anode profile and adjusted cathode profile may be mapped to a comparative full-cell profile mapped with a minimum error. In particular, the comparative full-cell profile based on the finally determined adjusted anode profile and adjusted cathode profile can be said to be almost identical to the measured full-cell profile (M) in terms of shape, etc.

[0146] Therefore, according to the present invention, the positive electrode profile and the negative electrode profile for the target cell (BC) can be obtained even without disassembling the target cell (BC) or manufacturing it in the form of a three-electrode battery.

[0147] If the target cell (BC) is a new battery cell, the adjusted positive profile and the adjusted negative profile can be analyzed to more easily diagnose whether a defect has occurred in the target cell (BC) and, if so, what type of defect it is.

[0148] If the target cell (BC) is a battery cell in use after being verified as good, the degree to which the target cell (BC) has deteriorated for each deterioration item can be determined through the adjusted positive profile and the adjusted negative profile.

[0149] Moreover, according to one embodiment of the present invention, the positive and negative profiles of the target cell (BC) can be obtained in a simple manner. The present invention can be implemented even if only one reference positive profile (Rp) and one reference negative profile (Rn) are stored in the memory unit (330). That is, there is no need to store a plurality of reference positive profiles (Rp) and / or a plurality of reference negative profiles (Rn) in the memory unit (330). Accordingly, there is no need for a high storage capacity of the memory unit (330), and there is no need to perform numerous preliminary tests required to secure a plurality of reference positive profiles (Rp) and / or a plurality of reference negative profiles (Rn).

[0150] Hereinafter, with reference to FIGS. 4 to 9, the analysis process of the measured full-cell profile (M) for estimating the negative electrode loading, which is one of the parameters involved in the current charge / discharge performance of the target cell (BC), will be described. The negative electrode loading 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 is mAh / cm 2or mg / cm 2 It could be.

[0151] FIGS. 4 to 6 are drawings for reference in explaining an example of a procedure for generating a comparison full-cell profile used for comparison with a measured full-cell profile according to one embodiment of the present invention.

[0152] The procedure for generating a comparative full-cell profile, which will be described with reference to FIGS. 4 to 6, proceeds in the following order: a first routine (see FIG. 4) for setting four points (positive engagement start point, positive engagement end point, negative engagement start point, negative engagement end point) to correspond to a voltage range of interest, a second routine (see FIG. 5) for performing profile shifting, and a third routine (see FIG. 6) for performing capacity scaling. That is, the procedure for generating a comparative full-cell profile according to one embodiment of the present invention includes the first to third routines.

[0153] First, referring to FIG. 4, the reference anode profile (Rp) and the reference cathode profile (Rp) are the same as those shown in FIG. 2.

[0154] The processor (320) determines the positive engagement start point (pi), the positive engagement end point (pf), the negative engagement start point (ni), and the negative engagement end point (nf) on the reference positive profile (Rp) and the reference negative profile (Rp).

[0155] Either the positive engagement initiation point (pi) or the negative engagement initiation point (ni) depends on the other.

[0156] For example, the processor (320) may divide the positive voltage range from the starting point of the reference positive profile (Rp) to the ending point (or the second set voltage) into a plurality of micro-voltage sections, and then determine the boundary point of two adjacent micro-voltage sections among the plurality of micro-voltage sections as the positive engagement start point (pi). Each micro-voltage section may have a predetermined size (e.g., 0.01 V). Then, the processor (320) may determine the point on the reference negative profile (Rn) that is smaller by the first set voltage (e.g., 3 V) than the positive engagement start point (pi) as the negative engagement start point (ni).

[0157] As another example, the processor (320) may divide the negative voltage range from the starting point to the ending point of the reference negative profile (Rn) into a plurality of micro-voltage sections of a predetermined size, and then determine the boundary point of two adjacent micro-voltage sections among the plurality of micro-voltage sections as a negative engagement start point (ni). Then, the processor (320) may search for a point that is greater than the negative engagement start point (ni) by a first set voltage from the reference positive profile (Rp), and determine the searched point as the positive engagement start point (pi).

[0158] Either the positive engagement end point (pf) or the negative engagement end point (nf) depends on the other.

[0159] For example, the processor (320) may divide the voltage range from the second set voltage to the end point of the reference positive profile (Rp) into a plurality of micro-voltage sections of a predetermined size, and then determine the boundary point of two adjacent micro-voltage sections among the plurality of micro-voltage sections as the positive participation end point (pf). Then, the processor (320) may determine the point on the reference negative profile (Rn) that is smaller by the second set voltage (e.g., 4 V) than the positive participation end point (pf) as the negative participation end point (nf).

[0160] As another example, the processor (320) may divide the negative voltage range from the start point to the end point of the reference negative profile (Rn) into a plurality of micro-voltage sections of a predetermined size, and then determine the boundary point of two adjacent micro-voltage sections among the plurality of micro-voltage sections as a negative participation end point (nf). Then, the processor (320) may search for a point that is greater than the negative participation end point (nf) by a second set voltage from the reference positive profile (Rp), and determine the searched point as the positive participation end point (pf).

[0161] Once the determination of the positive engagement start point (pi), the positive engagement end point (pf), the negative engagement start point (ni), and the negative engagement end point (nf) is completed, the processor (320) shifts at least one of the reference positive profile (Rp) and the reference negative profile (Rp) to the left or right along the horizontal axis.

[0162] Referring to FIG. 5, the processor (320) can shift the reference positive electrode profile (Rp) to the left (low capacity side), shift the reference negative electrode profile (Rp) to the right (high capacity side), or both, so that the capacity values ​​of the positive electrode participation start point (pi) and the negative electrode participation start point (ni) match.

[0163] Alternatively, the processor (320) may shift the reference positive profile (Rp) to the left, shift the reference negative profile (Rp) to the right, or both, so that the capacitance values ​​of the positive engagement end point (pf) and the negative engagement end point (nf) match.

[0164] Fig. 5 illustrates a situation where only the reference anode profile (Rp) is shifted to the left to generate an adjusted reference anode profile (Rp'), resulting in the capacity value of the anode engagement initiation point (pi') matching the capacity value of the cathode engagement initiation point (ni). The adjusted reference anode profile (Rp') is the result of applying an adjustment procedure to the reference anode profile (Rp) that shifts to the left by the voltage difference between the anode engagement initiation point (pi) and the cathode engagement initiation point (ni). Therefore, the two points (pi, pi') differ only in the capacity value, and have the same voltage. The two points (pf, pf') also differ only in the capacity value, and have the same voltage.

[0165] When adjustment result profiles (Rp', Rn) in which at least one of the reference positive profile (Rp) and the reference negative profile (Rp) is shifted are secured, the processor (320) scales the capacity range of at least one of the adjustment result profiles (Rp', Rn).

[0166] According to the example illustrated in FIG. 5, the processor (320) performs an additional adjustment procedure to contract or expand at least one of the adjusted reference positive profile (Rp') and the reference negative profile (Rp) along the horizontal axis.

[0167] Referring to FIG. 6, the processor (320) may generate an adjusted reference anode profile (Rp') by shrinking or expanding the adjusted reference anode profile (Rp') so that the size of the capacity range between two points (pi', pf') of the adjusted reference anode profile (Rp') matches the size of the capacity range of the measured full-cell profile (M). At this time, one of the two points (pi', pf') may be fixed. Accordingly, the capacity difference between the two points (pi', pf'') of the adjusted reference anode profile (Rp'') may match the capacity range of the measured full-cell profile (M).

[0168] In addition, the processor (320) may generate an adjusted reference cathode profile (Rn') by shrinking or expanding the reference cathode profile (Rn) so that the size of the capacity range between two points (ni, nf) of the reference cathode profile (Rn) matches the size of the capacity range of the measured full-cell profile (M). At this time, one of the two points (ni, nf) may be fixed. Accordingly, the capacity difference between the two points (ni, nf') of the adjusted reference cathode profile (Rn') may match the capacity range of the measured full-cell profile (M).

[0169] In Fig. 6, the adjusted reference anode profile (Rp'') is a result of shrinking the adjusted reference anode profile (Rp') shown in Fig. 5, and the adjusted reference cathode profile (Rn') is a result of expanding the reference cathode profile (Rn) shown in Fig. 5.

[0170] The positive participation endpoint (pf'') on the adjusted reference positive profile (Rp'') corresponds to the positive participation endpoint (pf) on the adjusted reference positive profile (Rp'). The negative participation endpoint (nf') on the adjusted reference negative profile (Rn') corresponds to the negative participation endpoint (nf) on the reference negative profile (Rn).

[0171] The capacity difference between the positive engagement start point (pi') and the positive engagement end point (pf'') of the adjusted reference positive electrode profile (Rp'') corresponds to the size of the capacity range of the measured full-cell profile (M). Similarly, the capacity difference between the negative engagement start point (ni) and the negative engagement end point (nf') of the adjusted reference negative electrode profile (Rn') corresponds to the size of the capacity range of the measured full-cell profile (M).

[0172] In addition, the capacity range by two points (pi', pf'') of the adjusted reference positive electrode profile (Rp'') matches the capacity range by two points (ni, nf') of the adjusted reference negative electrode profile (Rn'). The processor (320) can generate a comparison 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').

[0173] The processor (320) can calculate the error (profile error) between the comparison full-cell profile (S) and the measured full-cell profile (M).

[0174] The processor (320) can map at least two of the adjusted reference positive profile (Rp''), the adjusted reference negative profile (Rn'), the positive engagement start point (pi'), the positive engagement end point (pf''), the negative engagement start point (ni), the negative engagement end point (nf'), the positive scale factor, the negative scale factor, the comparison full-cell profile (S), and the profile error to each other and record them in the memory unit (330).

[0175] The anode scale factor can represent the ratio of the capacity difference between the two ends of the adjusted reference anode profile (Rp'') to the capacity difference between the two ends of the reference anode profile (Rp). Alternatively, the anode scale factor can represent the ratio of the capacity difference between two points (pi', pf'') to the capacity difference between two points (pi0, pf0). Alternatively, the anode scale factor can represent the ratio of the anode capacity difference between two points (pi', pf'') to the anode capacity difference between two points (pi0, pf0). Alternatively, the anode scale factor can represent the ratio of the anode SOC difference between two points (pi', pf'') to the anode SOC difference between two points (pi0, pf0).

[0176] The cathode scale factor can represent the ratio of the capacity difference between the two ends of the adjusted reference cathode profile (Rn') to the capacity difference between the two ends of the reference cathode profile (Rn). Alternatively, the cathode scale factor can represent the ratio of the capacity difference between two points (ni0, nf') to the capacity difference between two points (ni0, nf0). Alternatively, the cathode scale factor can represent the ratio of the cathode capacity difference between two points (ni0, nf') to the cathode capacity difference between two points (ni0, nf0). Alternatively, the cathode scale factor can represent the ratio of the cathode SOC difference between two points (ni0, nf') to the cathode SOC difference between two points (ni0, nf0).

[0177]

[0178] Meanwhile, as described above, when the anode voltage range of the reference anode profile (Rp) is divided into a plurality of micro-voltage sections, the boundary points of two adjacent micro-voltage sections among the plurality of micro-voltage sections can be set as the anode participation start point (pi).

[0179] For example, if the anode voltage range of the reference anode profile (Rp) is divided into 100 microvoltage ranges, there may be 100 boundary points that can be set as anode participation start points (pi). Furthermore, if the voltage range that is higher than the second set voltage in the reference anode profile (Rp) is divided into 40 microvoltage ranges, there may be 40 boundary points that can be set as anode participation end points (pf). In this case, up to 4,000 different comparison full-cell profiles can be generated.

[0180] Of course, those skilled in the art will easily understand that as the size of the micro-voltage section decreases, the number of comparative full-cell profiles that can be generated at maximum increases, and conversely, as the size of the micro-voltage section increases, the number of comparative full-cell profiles that can be generated at maximum decreases.

[0181] The processor (320) can identify a minimum value among the profile errors of the plurality of comparative full-cell profiles generated as described above, and then obtain information mapped to the minimum profile error (e.g., at least one of a positive engagement start point, a positive engagement end point, a negative engagement start point, a negative engagement end point, a positive scale factor, and a negative scale factor) from the memory unit (330).

[0182] FIGS. 7 to 9 are diagrams that are referenced to explain another example of a procedure for generating a comparison full-cell profile used for comparison with a measured full-cell profile according to one embodiment of the present invention. Note that the embodiments according to FIGS. 7 to 9 are independent of the embodiments according to FIGS. 4 to 6. Therefore, terms or symbols commonly described in describing the embodiments according to FIGS. 4 to 6 and the embodiments according to FIGS. 7 to 9 should be understood as being limited to each embodiment.

[0183] The procedure for generating a comparative full-cell profile, which will be described with reference to FIGS. 7 to 9, proceeds in the following order: a fourth routine (see FIG. 7) for performing capacity scaling, a fifth routine (see FIG. 8) for setting four points (positive participation start point, positive participation end point, negative participation start point, negative participation end point), and a sixth routine (see FIG. 9) for performing profile shifting. That is, the procedure for generating a comparative full-cell profile according to another embodiment of the present invention includes the fourth to sixth routines.

[0184] Referring to FIG. 7, the processor (320) applies a positive scale factor and a negative scale factor selected from a scaling value range to a reference positive profile (Rp) and a reference negative profile (Rp), respectively, to generate an adjusted reference positive profile (Rp') and an adjusted reference negative profile (Rn').

[0185] The scaling value range may be predetermined or may vary depending 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). For example, when values ​​spaced by 0.1% of the scaling value range (e.g., 90-99%) (i.e., 90%, 90.1%, 90.2%, ... 98.9%, 99%) can be selected as the positive scale factor and the negative scale factor, respectively, 91 values ​​can be selected as the positive scale factor and the negative scale factor. In this case, a maximum of 8,281 adjusted profile pairs can be generated according to 91 × 91 = 8,281 adjustment levels (combinations of positive scale factors and negative scale factors). An adjusted profile pair means a combination of an adjusted positive profile and an adjusted negative profile.

[0186] The adjusted reference anode profile (Rp') and the adjusted reference cathode profile (Rn') illustrated in FIG. 7 illustrate the results of applying a cathode scale factor and anode scale factor of less than 100% to the reference anode profile (Rp) and the reference cathode profile (Rn), respectively.

[0187] Since the positive scale factor and the negative scale factor are less than 100%, the adjusted reference positive profile (Rp') is the reference positive profile (Rp) shrunk along the horizontal axis, and the adjusted reference negative profile (Rn') is also the reference negative profile (Rp) shrunk along the horizontal axis. To facilitate understanding, the starting points of the reference positive profile (Rp) and the reference negative profile (Rp) are fixed, and only the remaining portion is shrunk to the left along the horizontal axis.

[0188] Referring to FIG. 8, the processor (320) determines the positive engagement start point (pi'), the positive engagement end point (pf'), the negative engagement start point (ni'), and the negative engagement end point (nf') on the adjusted reference positive profile (Rp') and the adjusted reference negative profile (Rp').

[0189] Either the positive engagement start point (pi') or the negative engagement start point (ni') may depend on the other. Furthermore, either the positive engagement end point (pf') or the negative engagement end point (nf') may depend on the other. Furthermore, either the positive engagement start point (pi') or the positive engagement end point (pf') may be set based on the other.

[0190] That is, when any one of the positive engagement start point (pi'), positive engagement end point (pf'), negative engagement start point (ni') and negative engagement end point (nf') is set, the remaining three points can be automatically set by the size of the capacity range of the first set voltage, the second set voltage and / or the measured full-cell profile (M) (e.g., 45 Ah - 5 Ah = 40 Ah in FIG. 3b).

[0191] For example, the processor (320) may divide the positive voltage range from the starting point to the ending point (or the second set voltage) of the adjusted reference positive voltage profile (Rp') into a plurality of micro-voltage sections, and then determine the boundary point of two adjacent micro-voltage sections among the plurality of micro-voltage sections as the positive engagement start point (pi'). Then, the processor (320) may determine the point on the adjusted reference negative voltage profile (Rn) that is smaller by the first set voltage (e.g., 3 V) than the positive engagement start point (pi') as the negative engagement start point (ni').

[0192] As another example, the processor (320) may divide the negative voltage range from the start point to the end point of the adjusted reference negative profile (Rn') into a plurality of micro-voltage sections of a predetermined size, and then determine the boundary point of two adjacent micro-voltage sections among the plurality of micro-voltage sections as a negative engagement start point (ni'). Then, the processor (320) may search for a point that is greater than the negative engagement start point (ni') by a first set voltage from the reference positive profile (Rp), and determine the searched point as the positive engagement start point (pi').

[0193] As another example, the processor (320) may divide the voltage range from the second set voltage to the end point of the adjusted reference positive profile (Rp') into a plurality of micro-voltage sections of a predetermined size, and then determine the boundary point of two adjacent micro-voltage sections among the plurality of micro-voltage sections as the positive participation end point (pf'). Then, the processor (320) may search for a point in the adjusted reference negative profile (Rn') that is smaller than the positive participation end point (pf') by the second set voltage (e.g., 4 V), and determine the searched point as the negative participation end point (nf').

[0194] As another example, the processor (320) may divide the negative voltage range from the start point to the end point of the adjusted reference negative profile (Rn') into a plurality of micro-voltage sections of a predetermined size, and then determine the boundary point of two adjacent micro-voltage sections among the plurality of micro-voltage sections as a negative participation end point (nf'). Then, the processor (320) may search for a point that is larger than the negative participation end point (nf') by a second set voltage from the adjusted reference positive profile (Rp') and determine the searched point as the positive participation end point (pf').

[0195]

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

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

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

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

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

[0201] When the determination of the positive engagement start point (pi'), the positive engagement end point (pf'), the negative engagement start point (ni') and the negative engagement end point (nf') is completed based on the pair of positive scale factors and negative scale factors, the processor (320) may shift at least one of the adjusted reference positive profile (Rp') and the adjusted reference negative profile (Rn') to the left or right along the horizontal axis so that the capacity values ​​of the positive engagement start point (pi') and the negative engagement start point (ni') match or so that the capacity values ​​of the positive engagement start point (pf') and the negative engagement start point (nf') match.

[0202] The adjusted reference cathode profile (Rn'') illustrated in Fig. 9 is only the adjusted reference cathode profile (Rn') illustrated in Fig. 8 shifted to the right. Accordingly, the capacity values ​​of the positive participation start point (pi') and the negative participation start point (ni'') are matched with each other on the horizontal axis. In this regard, since the capacity difference between the positive participation start point (pi') and the positive participation end point (pf') is the same as the capacity difference between the negative participation start point (ni') and the negative participation end point (nf'), when the capacity values ​​of the positive participation start point (pi') and the negative participation start point (ni'') are matched with each other, the capacity values ​​of the positive participation end point (pf') and the negative participation end point (nf') also become matched with each other on the horizontal axis.

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

[0204] The processor (320) can calculate the error (profile error) between the comparison full cell profile (U) and the measured full cell profile (M).

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

[0206] As described above, the processor (320) can generate a corresponding comparison full-cell profile for each pair of positive and negative scale factors selected from a range of scaling values. Since there are multiple pairs of positive and negative scale factors, it is obvious that multiple comparison full-cell profiles will also be generated. The processor (320) can identify a minimum value among the profile errors of the multiple comparison full-cell profiles, and then obtain information mapped to the minimum profile error from the memory unit (330).

[0207] The processor (320) can determine the cathode loading of the target cell (BC) from information mapped to the minimum profile error. The processor (320) can estimate the cathode loading of the target cell (BC) based on the extracted cathode scale factor. For reference, at least one of the cathode participation start point, the cathode participation end point, the cathode participation start point, the cathode participation end point, the cathode scale factor, and the cathode scale factor when the target cell (BC) was in a new state may have already been recorded in the memory unit (330) by executing the aforementioned analysis process when the target cell (BC) was in a new state.

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

[0209] Table 1

[0210]

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

[0212] <Deterioration parameters>

[0213] P SOH: The anode SOH (State Of Heat) of the target cell (BC)

[0214] N SOH : Cathode SOH of the target cell (BC)

[0215] L SOH : Available lithium SOH of target cell (BC)

[0216] F SOH : Full-cell SOH of the target cell (BC)

[0217] P LOSS : Anode loss rate of target cell (BC)

[0218] N LOSS : Cathode loss rate of target cell (BC)

[0219] L LOSS : Available lithium loss rate of target cell (BC)

[0220] F LOSS : Full cell loss rate of target cell (BC)

[0221] P loading_MOL : Anode loading of the target cell (BC)

[0222] N loading_MOL : Cathode loading of target cell (BC)

[0223]

[0224] The positive electrode loading of a battery cell refers to 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 a battery cell refers to 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 is mAh / cm 2 or mg / cm 2 It can be. In Table 1, P loading_ref represents the standard anode loading, and N loading_refrepresents the 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 the 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 as the total positive electrode capacity of the reference cell. The reference positive electrode area may be a value preset as 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 as the total negative electrode capacity of the reference cell. The reference negative electrode area may be a value preset as the area of ​​the negative electrode of the reference cell.

[0225]

[0226] <variables>

[0227] pi BOL : Anode capacity at the start of anode participation when the target cell (BC) was in BOL state (anode SOC)

[0228] pi MOL : The anode capacity (anode SOC) of the current anode participation starting point of the target cell (BC) (e.g., pi' shown in Fig. 6).

[0229] pf BOL : Anode capacity (anode SOC) at the anode participation end point when the target cell (BC) was in BOL state

[0230] pf MOL : The anode capacity (anode SOC) of the current anode participation end point (e.g., pf'' shown in Fig. 6) of the target cell (BC).

[0231] ni BOL : Cathode capacity (cathode SOC) at the start of cathode participation when the target cell (BC) was in BOL state

[0232] ni MOL: The cathode capacity (cathode SOC) of the current cathode participation starting point of the target cell (BC) (e.g., ni as shown in Fig. 6).

[0233] nf BOL : Cathode capacity (cathode SOC) at the end point of cathode participation when the target cell (BC) was in BOL state

[0234] nf MOL : The cathode capacity (cathode SOC) of the current cathode participation end point (e.g., nf' shown in Fig. 6) of the target cell (BC).

[0235] ps BOL : Bipolar scale factor when the target cell (BC) was in BOL state

[0236] ps MOL : Current bipolar scale factor of the target cell (BC)

[0237] ns BOL : Cathode scale factor when the target cell (BC) was in BOL state

[0238] ns MOL : Current cathode scale factor of the target cell (BC)

[0239]

[0240] The process of determining diagnostic factors for a target cell (BC) can be repeated periodically or aperiodically throughout the life of the target cell (BC).

[0241] As the available lithium capacity, total anode capacity, and / or total cathode capacity of a battery cell decreases, the anode capacity (anode SOC) at the anode participation start point of the battery cell may exhibit a characteristic of gradually increasing. The available lithium capacity of a battery cell may be a parameter indicating the total amount of lithium that can contribute to the charging and discharging of the battery cell. The available lithium capacity may gradually decrease from its new state due to side reactions occurring within the battery cell during charging and discharging.

[0242] In view of these characteristics, the processor (320) can determine whether a loss of available lithium of the target cell (BC) occurs due to a loss of at least one of the available lithium amount and the total positive electrode capacity, based on the estimation result of the positive electrode participation start point of the target cell (BC).

[0243] The processor (320) can diagnose that available lithium loss has occurred in response to an increase in the anode capacity (or anode SOC) at the anode engagement start point from its value in a new state.

[0244] There may be a situation where the change in the positive electrode capacity (or positive electrode SOC) at the positive electrode participation start point of the target cell (BC) and the negative electrode capacity (or negative electrode SOC) at the negative electrode participation end point from the new state are less than a predetermined set value. If so, the processor (320) may determine that the greater the increase in the negative electrode capacity (or negative electrode SOC) at the negative electrode participation start point from the new state, the more the capacity loss in at least one of the positive electrode and the negative electrode has contributed to the change in the negative electrode participation start point of the target cell (BC) from the new state than the loss of available lithium amount.

[0245] The processor (320) may limit at least one of the allowable voltage range and the allowable SOC range for the target cell (BC) based on the estimated positive engagement start point for the target cell (BC). Relationship data indicating a predetermined positive correlation between the change (e.g., increase) of the positive electrode capacity (or positive electrode SOC) from the new state of the positive electrode engagement start point and the limit level may be stored in advance in the memory unit (330). That is, according to the relationship data, a decrease or increase in the capacity value (positive electrode capacity or positive electrode SOC) of the positive electrode engagement start point may result in a reduction in at least one of the allowable voltage range and the allowable SOC range. Reducing a range means at least one of increasing the lower limit of the range and lowering the upper limit of the range. For example, let's say that the allowable voltage range and the allowable SOC range are 2.5 to 4.5 V and 5 to 95%, respectively. If the anode capacity at the start of the anode participation is estimated to be 110% of the value when it was in the BOL state, the allowable voltage range can be reduced to 2.75 to 4.05 V, and the allowable SOC range can be reduced to 5.5 to 85.5%.

[0246] The processor (320) can diagnose that a capacity loss has occurred in the anode of the target cell (BC) in response to a decrease in the anode capacity (or anode SOC) of the anode participation end point from its value in a new state.

[0247] The processor (320) may limit at least one of the allowable voltage range and the allowable SOC range for the target cell (BC) based on the positive engagement endpoint. Relationship data indicating a predetermined positive correlation between the change (e.g., reduction) of the positive electrode capacity (or positive electrode SOC) of the positive engagement endpoint from a new state and the limit level may be stored in advance in the memory unit (330). That is, according to the relationship data, a decrease in the capacity value (positive electrode capacity, positive electrode SOC) of the positive engagement endpoint may result in a reduction of at least one of the allowable voltage range and the allowable SOC range. For example, let's say that the allowable voltage range and the allowable SOC range are 2.5 to 4.5 V and 5 to 95%, respectively. If the positive engagement endpoint is estimated to be 90% of the value when it was in the BOL state, the allowable voltage range may be reduced to 2.75 to 4.05 V, and the allowable SOC range may be reduced to 5.5 to 85.5%.

[0248] The processor (320) may limit at least one of an allowable voltage range and an allowable SOC range for the target cell (BC) based on the estimated positive scale factor of the target cell (BC). Relationship data indicating a predetermined positive correlation between a BOL state (e.g., a reduction amount) of the positive scale factor and a limit level may be stored in advance in the memory unit (330). That is, according to the relationship data, a decrease in the positive scale factor may result in a reduction in at least one of the allowable voltage range and the allowable SOC range. For example, let's say that the allowable voltage range and the allowable SOC range are 2.5 to 4.5 V and 5 to 95%, respectively. If the current positive scale factor of the target cell (BC) is ps MOL Bipolar scale factor ps when new BOL If the allowable voltage range is estimated to be 90%, the allowable voltage range can be reduced to 2.75–4.05 V, and the allowable SOC range can be reduced to 5.5–85.5%.

[0249] The processor (320) may limit at least one of an allowable voltage range and an allowable SOC range for the target cell (BC) based on an estimate of the anode loading amount of the target cell (BC). Relationship data indicating a predetermined positive correlation between the anode loading amount and the limit level may be stored in advance in the memory unit (330). That is, according to the relationship data, a decrease in the anode loading amount may result in a reduction in at least one of the allowable voltage range and the allowable SOC range. For example, let's say that the allowable voltage range and the allowable SOC range are 2.5 to 4.5 V and 5 to 95%, respectively. If the anode loading amount is estimated to be 90% of the reference anode loading amount, the allowable voltage range may be reduced to 2.75 to 4.05 V, and the allowable SOC range may be reduced to 5.5 to 85.5%.

[0250] The processor (320) may limit at least one of the allowable voltage range and the allowable SOC range for the target cell (BC) based on the negative engagement start point of the target cell (BC). Relationship data indicating a predetermined positive correlation between the change (e.g., reduction) from the new state of the negative capacity (or negative SOC) of the negative engagement start point and the limit level may be stored in advance in the memory unit (330). That is, according to the relationship data, a decrease or increase in the capacity value (negative capacity, or negative SOC) of the negative engagement start point may result in a reduction in at least one of the allowable voltage range and the allowable SOC range. For example, let's say that the allowable voltage range and the allowable SOC range are 2.5 to 4.5 V and 5 to 95%, respectively. If the cathode capacity at the current cathode participation initiation point is estimated to be 90% of the value when it was in the BOL state, the allowable voltage range can be reduced to 2.75 to 4.05 V, and the allowable SOC range can be reduced to 5.5 to 85.5%.

[0251] The processor (320) may diagnose that capacity loss has occurred in the negative electrode of the target cell (BC) in response to a decrease in the negative electrode capacity (or negative electrode SOC) of the negative electrode engagement endpoint from a value in a new state. The processor (320) may limit at least one of an allowable voltage range and an allowable SOC range for the target cell (BC) based on the estimated negative electrode engagement endpoint for the target cell (BC). Relationship data indicating a predetermined positive correlation between the amount of change (e.g., decrease) in the negative electrode capacity (or negative electrode SOC) of the negative electrode engagement endpoint from a new state and a limiting level may be stored in advance in the memory unit (330). That is, according to the relationship data, a decrease in the capacity value (negative electrode capacity, negative electrode SOC) of the negative electrode engagement endpoint may result in a reduction in at least one of the allowable voltage range and the allowable SOC range. For example, let's say that the allowable voltage range and the allowable SOC range are 2.5 to 4.5 V and 5 to 95%, respectively. If the current cathode participation end point is estimated to be 90% of the value when the BOL state was reached, the allowable voltage range can be reduced to 2.75 to 4.05 V, and the allowable SOC range can be reduced to 5.5 to 85.5%.

[0252] The processor (320) may limit at least one of an allowable voltage range and an allowable SOC range for the target cell (BC) based on the estimated negative scale factor of the target cell (BC). Relationship data indicating a predetermined positive correlation between the reduction amount limit levels from the BOL state of the negative scale factor may be stored in advance in the memory unit (330). That is, according to the relationship data, a decrease in the negative scale factor may result in a reduction of at least one of the allowable voltage range and the allowable SOC range. For example, let's say that the allowable voltage range and the allowable SOC range are 2.5 to 4.5 V and 5 to 95%, respectively. If the current negative scale factor of the target cell (BC) is ns MOL ns, the negative scale factor when the product was in new condition BOLIf the estimated negative loading amount of the target cell (BC) is 90%, the allowable voltage range may be reduced to 2.75 to 4.05 V, and the allowable SOC range may be reduced to 5.5 to 85.5%. The processor (320) may limit at least one of the allowable voltage range and the allowable SOC range for the target cell (BC) based on the estimated negative loading amount of the target cell (BC). Relationship data indicating a predetermined positive correlation between the decrease amount of the negative loading amount from the BOL state and the limit level may be stored in advance in the memory unit (330). That is, according to the relationship data, a decrease in the negative loading amount may result in a reduction of at least one of the allowable voltage range and the allowable SOC range. For example, let's say that the allowable voltage range and the allowable SOC range are 2.5 to 4.5 V and 5 to 95%, respectively. If the current negative loading amount N loading_MOL N is the value when this BOL state was loading_BOL If the allowable voltage range is estimated to be 90%, the allowable voltage range can be reduced to 2.75–4.05 V, and the allowable SOC range can be reduced to 5.5–85.5%.

[0253] Fig. 10 is a flowchart for reference in schematically explaining a battery diagnosis method according to a first embodiment of the present invention. The method according to Fig. 10 may be executable by a battery diagnosis device (302).

[0254] In step S1010, the processor (320) executes a procedure for intermittently applying an electrical stimulus to the target cell (BC). Specifically, the processor (320) may control the stimulus application device (301) to intermittently apply an electrical stimulus (e.g., a second electrical stimulus) to the target cell (BC) during a state change period until the electrical state of the target cell (BC) changes from a first state to a second state.

[0255] The intermittent application procedure of electrical stimulation may be a procedure in which application periods and rest periods of electrical stimulation are repeated. That is, the intermittent application procedure includes at least two application procedures and at least two rest procedures. When the current integration value of the target cell (BC) changes by a threshold integration value during the application of electrical stimulation by each application procedure, the electrical stimulation to the target cell (BC) may be removed (output interrupted) to provide a rest period. When the duration of the rest period by each rest procedure reaches a reference time, the application procedure of the electrical stimulation may be resumed.

[0256] Step S1010 may be executed by the battery management system (100) or the system controller (2) instead of the processor (320), in which case step S1010 may be omitted from the method of FIG. 10.

[0257] In step S1020, the processor (320) acquires state history data of the target cell (BC) corresponding to the state change period using the data acquisition unit (310). The state history data includes voltage history data and may further include current history data or capacity history data.

[0258] The voltage history data may include voltage values ​​representing the full-cell voltage of the target cell (BC) measured at least once during each of the rest periods of the electrical stimulation applied during the state change period. That is, the voltage history data may represent the history of changes in the full-cell voltage of the target cell (BC) over the state change period. The voltage history data may include measurements of the full-cell voltage of the target cell (BC) at the end of each rest period (D in FIG. 3a). OCV The data acquisition unit (310) may collect the state history data generated by the battery system (1) from the battery system (1) after the end of the state change period.

[0259] Alternatively, the data acquisition unit (310) may periodically collect measurement data representing at least one measurement of the current and full cell voltage of the target cell (BC) from the battery system (1) during the state change period. In this case, each measurement collected multiple times over the state change period may be recorded chronologically in the memory unit (330). The processor (320) may generate state history data from a set of measurements collected over the state change period.

[0260] In step S1030, the processor (320) generates a measured full-cell profile (see symbol M in FIG. 3b) indicating a correspondence between the capacity of the target cell (BC) and the full-cell voltage based on the state history data.

[0261] In step S1040, the processor (320) analyzes the measured full cell profile to generate first diagnostic information including at least one diagnostic factor related to the charge / discharge performance of the target cell (BC).

[0262] The first diagnostic information may include at least one of a positive electrode engagement start point, a positive electrode engagement end point, a positive electrode scale factor, and a positive electrode loading amount as diagnostic factors, which indicate the charge / discharge performance of the positive electrode of the target cell (BC). The positive electrode loading amount indicates the amount of positive electrode active material per unit area of ​​the positive electrode.

[0263] The first diagnostic information may include at least one of a negative electrode engagement start point, a negative electrode engagement end point, a negative electrode scale factor, and a negative electrode loading amount as a diagnostic factor, which indicate the charge / discharge performance of the negative electrode of the target cell (BC). The negative electrode loading amount indicates the amount of negative electrode active material per unit area of ​​the negative electrode.

[0264] In step S1050, the processor (320) applies at least one mathematical operation to the first diagnostic information to generate second diagnostic information of the target cell (BC). The second diagnostic information may include at least one degradation parameter regarding at least one of the positive electrode, the negative electrode, and the available lithium (see Table 1, etc.).

[0265] The second diagnostic information may include whether or not available lithium loss has occurred in the target cell (BC) and / or the available lithium loss rate, determined based on the positive engagement start point of the first diagnostic information.

[0266] The second diagnostic information may include whether anode capacity loss of the target cell (BC) has occurred and / or anode loss rate, determined based on the anode participation end point, anode scale factor, and / or anode loading amount of the first diagnostic information.

[0267] The second diagnostic information may include whether the target cell (BC) has lost available lithium, whether a capacity loss has occurred in the positive electrode, whether a capacity loss has occurred in the negative electrode, and / or a negative electrode loss rate, which are determined based on the negative electrode participation start point, negative electrode participation end point, and / or negative electrode scale factor of the first diagnostic information.

[0268] The second diagnostic information may include a cathode loss rate (which may also be referred to as a 'cathode capacity loss rate') of the target cell (BC), which is determined based on the cathode loading amount of the first diagnostic information.

[0269] In step S1060, the processor (320) updates charge / discharge allowable condition information indicating at least one of a voltage range, an SOC range, and a current range allowed for the target cell (BC) based on at least one of the first diagnostic information and the second diagnostic information.

[0270] For example, the processor (320) may determine updated charge / discharge allowance condition information by limiting (e.g., downwardly adjusting) at least one of the voltage range, SOC range, and current range for the target cell (BC) of the previous charge / discharge allowance condition information based on at least one degradation parameter (e.g., negative electrode loading) of the first diagnostic information.

[0271] In step S1070, the processor (320) may transmit the diagnosis result of the target cell (BC) to the battery system (1) using the data acquisition unit (310). The diagnosis result includes at least one of first diagnostic information, second diagnostic information, and updated charge / discharge allowance condition information.

[0272] In the method according to FIG. 10, at least one of steps S1050, S1060 and S1070 can be omitted from the method according to FIG. 10.

[0273] Fig. 11 is a flowchart for reference in schematically explaining a battery diagnosis method according to a second embodiment of the present invention. The method according to Fig. 11 can be executed by a battery diagnosis device (302).

[0274] In step S1110, the processor (320) executes a procedure for intermittently applying electrical stimulation to the target cell (BC).

[0275] In step S1120, the processor (320) acquires state history data corresponding to the state change period using the data acquisition unit (310).

[0276] Unlike step S1020 of FIG. 10 according to the first embodiment described above, the voltage history data of the state history data acquired in step S1120 includes measurements of the full cell voltage measured three or more times per rest period within the state change period.

[0277] In step S1122, the 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 may be provided to replace a set of three full-cell voltage measurements per idle period included in the voltage history data acquired in step S1120 with a single OCV value. Accordingly, if a total of X idle periods are granted during the state change period and the full-cell voltage is measured three times per idle period, it will be readily understood by those skilled in the art 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.

[0278] In step S1130, the processor (320) generates a measured full-cell profile (see symbol M in FIG. 3b) indicating a correspondence between the capacity of the target cell (BC) and the full-cell voltage based on the corrected state history data.

[0279] In step S1140, the processor (320) analyzes the measured full cell profile to generate first diagnostic information including at least one diagnostic factor related to the charge / discharge performance of the target cell (BC).

[0280] In step S1150, the processor (320) applies at least one mathematical operation to the first diagnostic information to generate second diagnostic information of the target cell (BC).

[0281] In step S1160, the processor (320) updates charge / discharge allowance condition information indicating at least one of a voltage range, an SOC range, and a current range allowed for the target cell (BC) based on at least one of the first diagnostic information and the second diagnostic information.

[0282] In step S1170, the processor (320) can transmit the diagnosis result of the target cell (BC) to the battery system (1) through the data acquisition unit (310).

[0283] In the method according to FIG. 11, steps S1110, S1140, S1150, S1160 and S1170 may be substantially the same as steps S1010, S1040, S1050, S1060 and S1070 of the method according to FIG. 10, respectively. In the method according to FIG. 11, at least one of steps S1150, S1160 and S1170 may be omitted from the method according to FIG. 10.

[0284] FIG. 12 is a drawing for reference in explaining the correction procedure of voltage history data performed in step S1122 of FIG. 11.

[0285] Reference numeral 1200 in FIG. 12 indicates one of the voltage drop segments illustrated in FIG. 3a. t R t indicates the point in time when the reference time has elapsed from the start of the rest period. R The part up to is a solid line, t R The subsequent parts are separated by dotted lines.

[0286] Referring to Figure 12, during each rest period, the target cell (BC) is placed in a no-load state with neither charging nor discharging.

[0287] In 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) at a specific rest period can be equivalent to the voltage response of a first-order RC circuit as shown in Equation 1 below.

[0288] <Formula 1>

[0289]

[0290] In Equation 1, t is the elapsed time from the start of a particular rest period, V full (t) is the full cell voltage at t, V OCV is the actual OCV, V Sis the full cell voltage at the start of a specific rest period, and τ is a time constant determined by the internal resistance and capacitance of the target cell (BC).

[0291] In Equation 1, V full (t) is measurable, so V OCV , V S and τ are unknowns. Since there are three unknowns, the OCV of a particular resting period is V measured at three different timings. full (t) can be estimated based on. The following equation 2 can be used to estimate the OCV for each rest period.

[0292] <Formula 2>

[0293]

[0294] In Equation 2, t1, t2, and t3 are sequential measurement timings of the full cell voltage. The time difference between t1 and t2 may be the same as the time difference between t2 and t3. Meanwhile, in Fig. 12, t R Although t3 is shown as different, t R = t3 may be. In this case, V full (t3) = D OCV .

[0295] The processor (320) calculates V using Equation 2 OCV Same as D OCV_C can be decided.

[0296] The processor (320) measures three full cell voltages (V) per idle period. full (t1), V full (t2), V full (t3)) as a single OCV value (D OCV_C) can be repeated for all idle periods, thereby converting the voltage history data obtained in step S1120 into corrected voltage history data for step S1130. The corrected voltage history data includes X OCV values. The processor (320) can apply curve fitting logic to the corrected voltage history data to generate a measured full-cell profile (M).

[0297] For reference, D OCV is a measurement of the full-cell voltage at the end of the resting period (before polarization is completely released), whereas D OCV_C is the full cell voltage (i.e., V) when the polarization is completely released. OCV ) is an estimate. Therefore, D OCV_C Go D OCV It can be said to be closer to the actual OCV of the target cell (BC).

[0298] The embodiments of the present invention described above are not implemented only through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded, and such implementation can be easily implemented by an expert in the technical field to which the present invention belongs based on the description of the embodiments described above.

[0299] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0300] In addition, the present invention described above is not limited to the above-described embodiments and the attached drawings, and all or part of each embodiment may be selectively combined and configured so that various modifications can be made, as those skilled in the art can make various substitutions, modifications, and changes within the scope of the technical idea of ​​the present invention.

Claims

1. A step of obtaining state history data of a battery cell corresponding to a state change period until the electrical state of the battery cell reaches a second state from a first state by a procedure of intermittently applying electrical stimulation to the battery cell; A step of generating a measurement full cell profile indicating a correspondence between the capacity and voltage of the battery cell based on the above state history data; and A step of analyzing the measured full cell profile to generate first diagnostic information including at least one diagnostic factor related to the charge / discharge performance of the battery cell; A battery diagnostic method comprising:

2. In paragraph 1, The above electrical stimulation is, A battery diagnostic method, wherein the current stimulus causes an instantaneous voltage change exceeding a threshold value to the battery cell.

3. In paragraph 1, The above electrical stimulation is, A battery diagnosis method, wherein the electrical stimulation is a current stimulation that causes an overvoltage exceeding a threshold value to the battery cell when the electrical stimulation is continuously applied for a predetermined period of time.

4. In paragraph 1, The above electrical stimulation is, A battery diagnosis method, wherein the charging current has a predetermined current rate.

5. In paragraph 1, The above electrical stimulation is, A battery diagnosis method, wherein the discharge current has a predetermined current rate.

6. In paragraph 1, The above status history data is, A battery diagnosis method, comprising voltage values ​​representing the voltage of the battery cell measured at least once during each of the rest periods of the electrical stimulation applied within the state change period.

7. In paragraph 1, The above intermittent authorization procedure is: A battery diagnosis method, comprising a procedure for removing the electrical stimulation to the battery cell so that a rest period is applied to the battery cell whenever the current integration value of the battery cell changes by a threshold integration value during application of the electrical stimulation.

8. In paragraph 7, The above intermittent authorization procedure is: A battery diagnostic method further comprising a procedure for resuming application of the electrical stimulation whenever the duration of the above pause reaches a reference time.

9. In paragraph 1, The above first diagnostic information is, A battery diagnosis method, comprising at least one of a positive electrode participation start point, a positive electrode participation end point, a positive electrode scale factor, and a positive electrode loading amount, which indicate the charge / discharge performance of the positive electrode of the battery cell, as the diagnosis factor.

10. In paragraph 9, A step of applying a mathematical operation to the first diagnostic information to generate second diagnostic information including at least one deterioration parameter regarding the positive electrode or available lithium of the battery cell; A battery diagnostic method further comprising:

11. In paragraph 1, The above first diagnostic information is, A battery diagnosis method, comprising at least one of a negative electrode participation start point, a negative electrode participation end point, a negative electrode scale factor, and a negative electrode loading amount, which indicate the charge / discharge performance of the negative electrode of the battery cell, as the diagnosis factor.

12. In paragraph 11, A step of applying a mathematical operation to the first diagnostic information to generate second diagnostic information including at least one deterioration parameter regarding the negative electrode of the battery cell; A battery diagnostic method further comprising:

13. In paragraph 10 or 12, A step of updating charge / discharge allowance condition information indicating at least one of a voltage range, a 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; A battery diagnostic method further comprising:

14. A data acquisition unit configured to acquire state history data of a battery cell corresponding to a state change period until the electrical state of the battery cell reaches a second state from a first state by an intermittent application procedure of electrical stimulation to the battery cell; A processor configured to generate a measurement full cell profile indicating a correspondence between the capacity and voltage of the battery cell based on the above state history data, The above processor, A battery diagnostic device configured to analyze the measured full cell profile to generate first diagnostic information including at least one diagnostic factor associated with the charge / discharge performance of the battery cell.

15. In paragraph 14, The above intermittent authorization procedure is: A battery diagnostic device, comprising a procedure for removing the electrical stimulation to the battery cell so that a rest period is applied to the battery cell whenever the current integration value of the battery cell changes by a threshold integration value during application of the electrical stimulation.

16. In paragraph 15, The above intermittent authorization procedure is: A battery diagnostic device further comprising a procedure for resuming application of the electrical stimulation whenever the duration of the above pause reaches a reference time.

17. In paragraph 14, The above first diagnostic information is, A battery diagnostic device comprising at least one of a positive electrode engagement start point, a positive electrode engagement end point, a positive electrode scale factor, and a positive electrode loading amount, which indicate the charge / discharge performance of the positive electrode of the battery cell, as the diagnostic factor.

18. In paragraph 14, The above first diagnostic information is, A battery diagnostic device comprising at least one of a negative electrode participation start point, a negative electrode participation end point, a negative electrode scale factor, and a negative electrode loading amount, which indicate the charge / discharge performance of the negative electrode of the battery cell, as the diagnostic factor.

19. A charging station comprising a battery diagnostic device according to any one of claims 14 to 18.

20. A cloud server including a battery diagnostic device according to any one of claims 14 to 18.

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