Battery diagnosis apparatus and battery diagnosis method

Abstract

Disclosed are a battery diagnosis apparatus and a battery diagnosis method. The battery diagnosing apparatus according to the present invention comprises: a processor that controls a stimulus application apparatus to intermittently apply a second electrical stimulus greater than a first electrical stimulus to a target cell during a state change period; and a communication unit that acquires current time-series data during the state change period and voltage time-series data indicating a change history of a full-cell voltage of the target cell at dormancies of the second electrical stimulus applied during the state change period. The processor generates a measurement full-cell profile on the basis of the current time-series data and the voltage time-series data, and estimates a positive electrode scale factor by analyzing the measurement full-cell profile.

Description

Battery diagnostic device and battery diagnostic method

[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. 10-2023-0154877, filed on November 9, 2023, and Korean Patent Application No. 10-2023-0133644, filed on October 6, 2023, the entire contents of which are disclosed in the specification and drawings of the aforementioned applications are incorporated herein by reference.

[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 a battery's internal condition is essential for its safety and longevity. To diagnose a battery's internal condition without disassembly, relational data (such as a full-cell profile) that indicates the relationship 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 while a constant electrical stimulus (e.g., constant current charging or discharging) is applied to the battery at short intervals. However, to minimize polarization (or overvoltage), which causes a decrease in diagnostic accuracy, the level of electrical stimulus applied to the target cell must be reduced, which leads to excessive time required 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 results because it is accompanied by severe polarization.

[0008] The present invention has been devised to solve the above problems, and the purpose of the present invention is to provide a battery diagnosis device and a battery diagnosis method capable of acquiring relationship data indicating a correspondence between the capacity and voltage of a target cell by intermittently applying a high level of electrical stimulation to the target cell, and diagnosing the anode deterioration state of the target cell (anode scale factor, anode loss rate, etc. described below) based on the acquired relationship data.

[0009] 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.

[0010] According to one aspect of the present invention, a battery diagnosis device includes a processor for controlling a stimulus application device to intermittently apply a second electrical stimulus greater than a first electrical stimulus to a target cell during a state change period in which the electrical state of the target cell, which is a battery cell as a diagnosis target, changes from an initial state to a target state; and a communication unit configured to acquire current time series data representing a change history of a current of the target cell during the state change period and voltage time series data representing a change history of a full-cell voltage of the target cell during rest periods of the second electrical stimulus applied during the state change period. The processor is configured to generate a measured full-cell profile representing a correspondence between a capacity of the target cell and a full-cell voltage, based on the current time series data and the voltage time series data. The processor is configured to analyze the measured full-cell profile and estimate a positive electrode scale factor of the target cell.

[0011] The first electrical stimulation may be an electrical stimulation that induces a difference between the OCV and CCV below a reference value in the target cell. The second electrical stimulation may be an electrical stimulation that induces a difference between the OCV and CCV above a reference value in the target cell.

[0012] The first electrical stimulation may be charging using a first current rate, and the second electrical stimulation may be charging using a second current rate greater than the first current rate.

[0013] The first electrical stimulation may be a discharge using a first current rate, and the second electrical stimulation may be a discharge using a second current rate greater than the first current rate.

[0014] The above voltage time series data may be the measurements of the full cell voltage during the resting periods of the second electrical stimulation, arranged in time order as the OCV of the target cell.

[0015] The processor may be configured to control the stimulation application device to initiate a pause of the second electrical stimulation whenever the current integration value of the current changes by a threshold integration value.

[0016] The processor may be configured to control the stimulation application device to resume application of the second electrical stimulation when a reference time has elapsed from the start time of the pause period of the second electrical stimulation.

[0017] The processor may be configured to determine a bipolar loss rate of the target cell based on the estimated bipolar scale factor.

[0018] The processor may be configured to limit at least one of an allowable voltage range and an allowable SOC range for the target cell based on the estimated bipolar scale factor.

[0019] A charging station according to another aspect of the present invention includes the battery diagnostic device.

[0020] A cloud server according to another aspect of the present invention includes the battery diagnostic device.

[0021] According to another aspect of the present invention, a battery diagnosis method includes the steps of: controlling a stimulus application device to intermittently apply a second electrical stimulus greater than a first electrical stimulus to a target cell during a state change period in which the electrical state of the target cell, which is a battery cell as a diagnosis target, changes from an initial state to a target state; acquiring current time series data representing a change history of a current of the target cell during the state change period and voltage time series data representing a change history of a full-cell voltage of the target cell during rest periods of the second electrical stimulus applied during the state change period; generating a measured full-cell profile representing a correspondence between a capacity of the target cell and a full-cell voltage based on the current time series data and the voltage time series data; and analyzing the measured full-cell profile to estimate a positive electrode scale factor of the target cell.

[0022] The above voltage time series data may be the measurements of the full cell voltage during the resting periods of the second electrical stimulation, arranged in time order as the OCV of the target cell.

[0023] The above battery diagnosis method may further include a step of determining a positive electrode loss rate of the target cell based on the estimated positive electrode scale factor.

[0024] The above battery diagnosis method may further include a step of limiting at least one of an allowable voltage range and an allowable SOC range for the target cell based on the estimated positive scale factor.

[0025] According to at least one of the embodiments of the present invention, by intermittently applying a high level of electrical stimulation to a target cell, relationship data indicating a correspondence between the capacity and voltage of the target cell can be acquired, and the bipolar deterioration state of the target cell (such as a bipolar scale factor described below) can be diagnosed based on the acquired relationship data.

[0026] That is, by using high-level electrical stimulation to change the electrical state of a target cell, it is possible to shorten the time required to acquire relational data, while also preventing a decrease in diagnostic accuracy due to excessive polarization caused by intermittent application of electrical stimulation.

[0027] 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.

[0028] 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.

[0029] FIG. 1 is a drawing exemplarily showing the configuration of a charging station including an electric vehicle and a battery diagnostic circuit according to the present invention.

[0030] Figure 2 is a graph referenced to explain an example of each of a reference anode profile and a reference cathode profile.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] FIG. 10 is a flowchart for reference in schematically explaining a battery management method according to the first embodiment of the present invention.

[0035] FIG. 11 is a flowchart for reference in schematically explaining a battery management method according to a second embodiment of the present invention.

[0036] FIG. 12 is a drawing for reference in explaining the correction procedure of voltage time series data performed in step S1122 of FIG. 11.

[0037] 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 aligns with the technical spirit of the present invention.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] FIG. 1 is a drawing exemplarily showing the configuration of a charging station including an electric vehicle and a battery diagnostic circuit according to the present invention.

[0043] Referring to FIG. 1, an electric vehicle (1) includes a vehicle controller (2), a battery pack (10), an inverter (30), and an electric motor (40). The charge / discharge terminals (P+, P-) of the battery pack (10) can be electrically connected to a charging station (300) via a charging cable or the like.

[0044] The vehicle 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 electric vehicle (1) being turned to the ON position by a user. The vehicle 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 vehicle 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).

[0045] The battery pack (10) includes a battery (11), a relay (20), and a battery management system (100).

[0046] 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.

[0047] 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.

[0048] 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).

[0049] 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 vehicle controller (2). An electric motor (40) is driven using alternating current power from the inverter (30). For example, a three-phase alternating current motor can be used as the electric motor (40). Components within an electric vehicle (1) that receive discharge power from the battery (11), including the inverter (30) and the electric motor (40), can be collectively referred to as an electric load.

[0050] The battery management system (100) includes a sensing unit (110) and a processor (130). The battery management system (100) may further include a communication circuit (150).

[0051] The sensing unit (110) includes a voltage sensor (111). The sensing unit (110) may further include a current sensor (112).

[0052] A voltage sensor (111) is connected to the positive and negative terminals of a battery cell (BC), and is configured to detect a voltage across both ends of the battery cell (BC) (which may be referred to as a 'full cell voltage') and generate a voltage signal representing a detected value of the detected voltage. The voltage sensor (111) may be implemented as one or a combination of two or more of known voltage detection elements, such as a voltage measurement IC.

[0053] 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 detect a current flowing through the battery (11) (which may be referred to as a 'charge / discharge current') and generate a current signal representing the detected 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 detection elements such as a shunt resistor, a Hall effect element, etc.

[0054] The communication circuit (150) is configured to support wired or wireless communication between the processor (130) and the vehicle controller (2). The wired communication may be, for example, CAN (controller 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 processor (130) and the vehicle 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 processor (130) and / or the vehicle controller (2) in a form recognizable to a user (driver).

[0055] The processor (130) is operably coupled to a relay (20), a voltage sensor (111), and a communication circuit (150). The two components being operably coupled 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.

[0056] The processor (130) can collect a voltage signal from the voltage sensor (111) and a current signal from the current sensor (112). In this specification, the detection 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 processor (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 processor (130).

[0057] The processor (130) may be referred to as a 'battery controller' and may be implemented in hardware using at least one of ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), microprocessors, and other electrical units for performing functions.

[0058] The memory (131) 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 (131) may store data and a program required for an operation by the processor (130). The memory (131) may store data indicating a result of an operation by the processor (130).

[0059] 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.

[0060] The processor (130) can turn on the relay (20) in response to a key-on signal. The processor (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 performed by the vehicle controller (2) instead of the processor (130).

[0061] In this specification, time series data of a parameter represents the temporal change history of that parameter. In addition, a profile (or curve) representing the correspondence between two parameters obtained at the same timing during the same period may be a mapping of the time series data of two parameters so that it can be expressed in the form of a two-dimensional graph, or a polynomial equation obtained by applying a predetermined curve fitting logic to a set of two mapped time series data. Here, the degree of the highest term of the polynomial equation may be predetermined.

[0062] The battery diagnostic device (302) includes a communication unit (310), a processor (320), and a memory unit (330).

[0063] The charging station (300) may include a stimulus application device (301) and a battery diagnosis device (302). Alternatively, the battery diagnosis device (302) may be configured independently from 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 communication unit (310) of the battery diagnosis device (302) may perform diagnostic procedures on the target cell through remote communication with the stimulus application device (301) and / or the electric vehicle (1).

[0064] The battery diagnostic device (302) may be included in the battery pack (10), in which case the battery management system (100) may be omitted from the battery pack (10). That is, the processor (320) may be responsible for all functions of the control circuit (130) of the battery management system (100). For example, the communication unit (310) may be included as a sub-component of the processor (320) and may be responsible for all functions of the communication circuit (150) of the battery management system (100). In addition, the communication unit (310) may collect voltage measurement information and current measurement information from the sensing unit (110).

[0065] 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), either alone or in cooperation with an inverter (30), may apply various electrical stimuli to the battery cell (BC) for diagnosis of the battery cell (BC).

[0066] The communication unit (310) is configured to support wired or wireless communication between the processor (320) and the vehicle controller (2). The communication unit (310) can transmit the results of the diagnosis of the battery cell (BC) performed by the processor (320) to the electric vehicle (1).

[0067] 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.

[0068] 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).

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] Each of the positive voltage and negative voltage can be an open circuit voltage (OCV) or a closed circuit voltage (CCV).

[0075] A first charge protocol or a first discharge protocol can be utilized to obtain the open circuit voltages of the positive and negative electrodes of the reference cell, respectively. The first charge protocol can be an intermittent charge method in which constant current charging using a first current rate and pauses are alternately performed. The first discharge protocol can be an intermittent charge method in which constant current discharging using a first current rate and pauses are alternately performed. The first current rate (e.g., 0.05 C) can be predetermined to be greater than the second current rate (e.g., 3.0 C) described below.

[0076] For example, when the charging time by constant current charging of the first 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.

[0077] As another example, whenever the discharge time due to the constant current discharge of the first 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).

[0078] At this time, multiple pauses may be provided while the first charging protocol or the first 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.

[0079] When comparing the open circuit voltage, a second charging protocol or a second discharging protocol can be utilized to obtain the closed circuit voltages of the positive and negative electrodes of the reference cell, respectively. The second charging protocol can be a constant current charging method using a second current rate. The second discharging protocol can be a constant current discharging method using a second current rate. For example, while the reference cell is continuously charged by the second charging protocol or while the reference cell is continuously discharged by the second discharging protocol, the closed circuit 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 negative voltage of the reference cell, respectively.

[0080]

[0081] In this specification, a first electrical stimulus refers to an electrical stimulus that causes a difference between an OCV and a CCV of a battery cell that is below a reference value, and a second electrical stimulus refers to an electrical stimulus that causes a difference between an OCV and a CCV of a battery cell that is above a reference value.

[0082] For example, the first electrical stimulation may be charging using a first current rate, and the second electrical stimulation may be charging using a second current rate greater than the first current rate.

[0083] As another example, the first electrical stimulation may be a discharge using a first current rate, and the second electrical stimulation may be a discharge using a second current rate greater than the first current rate.

[0084] Performing the first charging protocol or the first discharging protocol may mean applying a first electrical stimulus to the battery cell. Performing the second charging protocol or the second discharging protocol may mean applying a second electrical stimulus to the battery cell.

[0085] For convenience of explanation, it is assumed that the horizontal axis represents the charging capacity in FIGS. 2 to 9.

[0086] 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.

[0087] 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).

[0088] 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."

[0089] A "new battery cell" refers to a battery cell in its new condition. "New" condition is 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 considered BOL, while the period from the time the cumulative charge / discharge capacity reaches the set capacity can be considered MOL (Middle of Life).

[0090] 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).

[0091] 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.

[0092] 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.

[0093] Additionally, the positive engagement end point on the positive profile of any battery cell represents the positive voltage and positive capacity when the full-cell voltage of the battery cell matches the second set voltage. Additionally, the negative engagement end point on the negative profile of the battery cell represents the negative voltage and negative capacity when the full-cell voltage of the battery cell matches the second set voltage. Therefore, the voltage difference between the positive engagement end point and the negative engagement end point may be equal to the second set voltage.

[0094] 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.

[0095] 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).

[0096] 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.

[0097] 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).

[0098] FIG. 3a and FIG. 3b are graphs that are referenced to exemplarily explain the process of obtaining a measurement full cell profile of a target cell.

[0099] The graph illustrated in Fig. 3a illustrates an example of the variation in full-cell voltage over time of a target cell due to the intermittent application of a second electrical stimulus. The target cell is a battery cell that is being 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. Hereinafter, the target cell will also be assigned the symbol BC.

[0100] Referring to FIG. 3A, the processor (320) can control the stimulus application device (301) to intermittently apply a second electrical stimulus greater than the first electrical stimulus to the target cell (BC).

[0101] The procedure for controlling the stimulation application device (301) for diagnosis of the target cell (BC) can be performed during a state change period until the electrical state (e.g., full cell voltage) of the target cell (BC) changes from an initial state (e.g., first set voltage) to a target state (e.g., second set voltage).

[0102] 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 generated by the application of the second electrical stimulus, and the voltage falling segment is generated by the cessation of the second electrical stimulus. In other words, the voltage falling segment represents the change in the full-cell voltage of the target cell (BC) over the resting period.

[0103] During the state change period, the processor (320) can repeatedly record measurements of the current of the target cell (BC) to generate current time series data.

[0104] The processor (320) may control the stimulation application device (301) to initiate a pause period of the second electrical stimulation whenever a predetermined pause condition is satisfied within the state change period. That is, the procedure for applying the second 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 during which the second 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.

[0105] 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, SOH, or a previous diagnosis result (e.g., a potential and / or capacity value of a positive electrode end point, a positive 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 control) defining such correspondence may be stored in advance in the memory unit (310). 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, a decrease in the number of data points included in the voltage time series data representing the temporal history of full cell voltage changes during the rest periods of the state change period can be prevented by providing rest periods at shorter time intervals within the state change period.

[0106] 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 a second 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.

[0107] The processor (320) can control the stimulation application device (301) to resume application of the second electrical stimulation when a reference time has elapsed from the start of the pause period of the second electrical stimulation. The reference time may be predetermined to a length of time that allows the polarization caused by the second electrical stimulation to be sufficiently resolved. 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.

[0108] In each pause period of the second 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 second 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 second 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.

[0109] Accordingly, voltage time series 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 a data point in voltage time series data.

[0110] The inventor of the present invention has recognized through numerous experiments that the voltage time series data generated in the above-described manner using the second electrical stimulation has a high consistency with the voltage time series data generated when the first electrical stimulation is actually applied to the target cell (BC).

[0111] 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.

[0112] Let us assume that the conditions related to the diagnosis of the target cell (BC) are as follows.

[0113] (i) First electrical stimulus = 0.05 C charge

[0114] (ii) Second electrical stimulation = 3.0 C charge

[0115] (iii) Length of rest period of second electrical stimulation = 12 minutes

[0116] (iv) Total capacity change during the state change period = 80% of the buffer capacity (FCC: Full Charge Capacity) of the target cell (BC).

[0117] (v) Critical accumulation value = 3% of the buffer capacity of the target cell (BC)

[0118] Then, the time required for the target cell (BC) to change from the initial state to the target state by continuous application of the first electrical stimulus is 1 / 0.05*80% = 16 hours.

[0119] 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 initial state to the target state by intermittent application of the second electrical stimulation is (0.008 hours + 0.2 hours)*26 = 5.4 hours.

[0120] 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.

[0121] In the graph of Fig. 3b, the horizontal axis (X-axis) represents capacity (Ah) and the vertical axis (Y-axis) represents voltage.

[0122] 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.

[0123] 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).

[0124] To generate a measurement full cell profile (M), the current time series data and the voltage time series data mapped to the state change period can be used.

[0125] In detail, each data point of the current time series data and the voltage time series data is indexed in chronological order. Therefore, the processor (320) can generate capacity time series data by sequentially accumulating the data points of the current time series 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 time series data and the voltage time series 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 order term is predetermined.

[0126] 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).

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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'.

[0134] 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).

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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).

[0141] Hereinafter, with reference to FIGS. 4 to 9, the analysis process of the measured full cell profile (M) for estimating the bipolar scale factor of the target cell (BC) is described.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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).

[0146] Either the positive engagement initiation point (pi) or the negative engagement initiation point (ni) depends on the other.

[0147] 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 set the boundary points of two adjacent micro-voltage sections among the plurality of micro-voltage sections as positive engagement start points (pi). Each micro-voltage section may have a predetermined size (e.g., 0.01 V). Then, the processor (320) may set a point on the reference negative profile (Rn) that is smaller than the positive engagement start point (pi) by the first set voltage (e.g., 3 V) as the negative engagement start point (ni).

[0148] 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 set the boundary points of two adjacent micro-voltage sections among the plurality of micro-voltage sections as negative engagement start points (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 set the searched point as the positive engagement start point (pi).

[0149] Either the positive engagement end point (pf) or the negative engagement end point (nf) depends on the other.

[0150] 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 set 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 set 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).

[0151] 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 set 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 from the reference positive profile (Rp) that is greater than the negative participation end point (nf) by a second set voltage, and set the searched point as the positive participation end point (pf).

[0152] 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.

[0153] 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.

[0154] 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.

[0155] Figure 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 for shifting the reference anode profile (Rp) 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.

[0156] 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).

[0157] 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.

[0158] 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).

[0159] 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).

[0160] 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.

[0161] 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).

[0162] 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).

[0163] 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').

[0164] The processor (320) can calculate the error (profile error) between the comparison full-cell profile (S) and the measured full-cell profile (M).

[0165] 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).

[0166] 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).

[0167] The cathode scale factor can represent the ratio of the capacity difference between two points (ni, 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 (ni, 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 (ni, nf') to the cathode SOC difference between two points (ni0, nf0).

[0168] 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).

[0169] 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.

[0170] 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.

[0171] 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).

[0172] 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.

[0173] 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.

[0174] 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').

[0175] 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, 91 values ​​can be selected as the positive scale factor and the negative scale factor, respectively. In this case, up to 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.

[0176] 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.

[0177] 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, as an example.

[0178] 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').

[0179] 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.

[0180] 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).

[0181] 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 set the boundary points of two adjacent micro-voltage sections among the plurality of micro-voltage sections as positive engagement start points (pi'). Then, the processor (320) may set a point on the adjusted reference negative voltage profile (Rn) that is smaller than the positive engagement start point (pi') by a first set voltage (e.g., 3 V) as the negative engagement start point (ni').

[0182] 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 set 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 larger than the negative engagement start point (ni') by a first set voltage from the reference positive profile (Rp), and set the searched point as the positive engagement start point (pi').

[0183] 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 set the boundary point of two adjacent micro-voltage sections among the plurality of micro-voltage sections as a 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 set the searched point as a negative participation end point (nf').

[0184] 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 set 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 set the searched point as the positive participation end point (pf').

[0185] The processor (320) can additionally determine 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.

[0186] For example, when the positive participation start point (pi') is first determined, the processor (320) may set 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 set the searched point as the negative participation start point (ni'). In addition, the processor (320) may set 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').

[0187] As another example, when the positive participation end point (pf') is first determined, the processor (320) may set 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 from the adjusted reference negative profile (Rn') that is lower by a second set voltage than the positive participation end point (pf') and set the searched point as the negative participation end point (nf'). In addition, the processor (320) may set 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').

[0188] As another example, when the negative participation start point (ni') is determined, the processor (320) may set 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 set the searched point as the positive participation start point (pi'). In addition, the processor (320) may set 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').

[0189] As another example, when the negative participation end point (nf') is determined, the processor (320) may set 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 set the searched point as the positive participation end point (pf'). In addition, the processor (320) may set 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').

[0190] 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.

[0191] 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. 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') are also matched with each other.

[0192] 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'').

[0193] The processor (320) can calculate the error (profile error) between the comparison full cell profile (U) and the measured full cell profile (M).

[0194] 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).

[0195] 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).

[0196]

[0197] The processor (320) can extract at least an anode scale factor from information mapped to a minimum profile error. The processor (300) can estimate the anode loading amount of the target cell (BC) based on the extracted anode scale factor. Specifically, the processor (320) can determine the anode loading amount of the target cell (BC) based on the anode scale factor and the reference anode loading amount. For reference, at least one of the anode participation start point, the anode participation end point, the cathode participation start point, the cathode participation end point, the anode 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.

[0198] The processor (320) can determine at least one degradation parameter based on information (e.g., a bipolar scale factor) mapped to a minimum profile error. Table 1 below summarizes the degradation parameters and formulas that can be used to determine each degradation parameter.

[0199] Table 1

[0200]

[0201] 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.

[0202] <Deterioration parameters>

[0203] P SOH : The anode SOH (State Of Heat) of the target cell (BC)

[0204] N SOH : Cathode SOH of the target cell (BC)

[0205] L SOH : Available lithium SOH of target cell (BC)

[0206] F SOH : Full-cell SOH of the target cell (BC)

[0207] P LOSS : Anode loss rate of target cell (BC)

[0208] N LOSS : Cathode loss rate of target cell (BC)

[0209] L LOSS : Available lithium loss rate of target cell (BC)

[0210] F LOSS : Full cell loss rate of target cell (BC)

[0211] P loading_MOL : Anode loading of the target cell (BC)

[0212] N loading_MOL : Cathode loading of target cell (BC)

[0213]

[0214] As any battery cell deteriorates, at least one of the total positive electrode capacity, total negative electrode capacity, available lithium content, and total full cell capacity of the battery cell may gradually decrease from the value when the battery cell was in the BOL state. The total full cell capacity may represent the capacity difference between the two end points of the full cell profile. For example, the total full cell capacity may mean the full charge capacity (FCC). The available lithium content may represent the total amount of lithium that can contribute to charging and discharging the battery cell. P SOH can represent the retention rate of the total anode capacity. N SOH can represent the retention rate of the total cathode capacity. L SOH can represent the retention rate of available lithium. F SOH can represent the retention rate of the total full cell capacity.

[0215] P SOH and P LOSS The sum of, N SOH and N LOSS The sum of L SOH and L LOSS The sum of, F SOH and F LOSS The sum of each of F can be equal to 1. LOSS is P LOSS and L LOSS may be equal to the sum of

[0216] 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.

[0217]

[0218] <variables>

[0219] pi BOL : Anode capacity at the start of anode participation when the target cell (BC) was in BOL state (anode SOC)

[0220] 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).

[0221] pf BOL : Anode capacity (anode SOC) at the anode participation end point when the target cell (BC) was in BOL state

[0222] 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).

[0223] ni BOL : Cathode capacity (cathode SOC) at the start of cathode participation when the target cell (BC) was in BOL state

[0224] 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).

[0225] nf BOL : Cathode capacity (cathode SOC) at the end point of cathode participation when the target cell (BC) was in BOL state

[0226] 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).

[0227] ps BOL : Bipolar scale factor when the target cell (BC) was in BOL state

[0228] ps MOL : Current bipolar scale factor of the target cell (BC)

[0229] ns BOL : Cathode scale factor when the target cell (BC) was in BOL state

[0230] ns MOL : Current cathode scale factor of the target cell (BC)

[0231]

[0232] 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).

[0233] 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 reduction amount limit level from a BOL state of the positive scale factor may be stored in advance in the memory unit (330). That is, according to the relationship data, a reduction in the positive scale factor results 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 a lower limit of the range and decreasing an upper limit of the range.

[0234] For example, let's say that the allowable voltage range and allowable SOC range are 2.5~4.5V and 5~95%, respectively. If the current positive scale factor of the target cell (BC) is ns MOL Bipolar scale factor ns 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%.

[0235] Fig. 10 is a flowchart schematically illustrating a battery management method according to a first embodiment of the present invention. The method according to Fig. 10 may be executable by a battery diagnostic device.

[0236] In step S1010, the processor (320) controls the stimulus application device (301) to intermittently apply a second electrical stimulus greater than the first electrical stimulus to the target cell (BC) during a state change period until the electrical state of the target cell (BC) changes from an initial state to a target state.

[0237] In step S1020, the processor (320) uses the communication unit (310) to obtain current time series data representing the change history of the current of the target cell (BC) during the state change period and voltage time series data representing the change history of the full-cell voltage of the target cell (BC) during the rest periods of the second electrical stimulation applied during the state change period. The voltage time series data is a measurement value of the full-cell voltage at the end point of each rest period (D in FIG. 3a). OCV (reference) may be included. For example,

[0238] The communication unit (310) can collect current time series data and voltage time series data generated by the electric vehicle (1) from the electric vehicle (1) after the end of the state change period.

[0239] Alternatively, the communication 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 electric vehicle (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 current time series data and voltage time series data from a set of measurements collected over the state change period.

[0240] 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 current time series data and the voltage time series data.

[0241] In step S1040, the processor (320) analyzes the measured full cell profile to estimate the bipolar scale factor of the target cell (BC).

[0242] In step S1050, the processor (320) determines the anode loss rate (which may also be referred to as 'anode capacity loss rate') of the target cell (BC) based on the estimated anode scale factor.

[0243] In step S1060, the processor (320) limits at least one of the allowable voltage range and the allowable SOC range for the target cell (BC) based on the estimated bipolar scale factor. Alternatively or alternatively, the allowable current for the target cell (BC) may also be limited (down-regulated).

[0244] In the method according to FIG. 10, only one of step S1050 and step S1060 may be executed.

[0245] In step S1070, the processor (320) can transmit the diagnosis result of the target cell (BC) to the electric vehicle (1) using the communication unit (310). The diagnosis result includes at least one of a positive scale factor, a positive loading amount, a positive loss rate, a limited allowable voltage range, and a limited allowable SOC range.

[0246] Fig. 11 is a flowchart schematically illustrating a battery management method according to a second embodiment of the present invention. The method according to Fig. 11 may be executable by a battery diagnostic device.

[0247] In step S1110, the processor (320) controls the stimulus application device (301) to intermittently apply a second electrical stimulus greater than the first electrical stimulus to the target cell (BC) during a state change period until the electrical state of the target cell (BC) changes from an initial state to a target state.

[0248] In step S1120, the processor (320) uses the communication unit (310) to obtain current time series data representing a change history of the current of the target cell (BC) during a state change period and voltage time series data representing a change history of the full-cell voltage of the target cell (BC) during rest periods of the second electrical stimulation applied during the state change period.

[0249] Unlike the first embodiment described above, the voltage time series data acquired in step S1120 includes measurements of full cell voltage measured three or more times per rest period.

[0250] In step S1122, the processor (320) applies OCV estimation logic to the voltage time series data acquired in step S1120 to generate corrected voltage time series 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 time series 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 time series data acquired in step S1120 will include 3X full-cell voltage measurements, and the corrected voltage time series data will include X OCV values.

[0251] 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 current time series data and the corrected voltage time series data.

[0252] In step S1140, the processor (320) analyzes the measured full cell profile to estimate the positive loading amount of the target cell (BC).

[0253] In step S1150, the processor (320) determines the anode loss rate of the target cell (BC) based on the estimate of the anode loading amount.

[0254] In step S1160, the processor (320) limits at least one of the allowable voltage range and the allowable SOC range for the target cell (BC) based on the estimated positive loading amount. Alternatively or alternatively, the allowable current for the target cell (BC) may also be limited (down-regulated).

[0255] In the method according to FIG. 11, only one of step S1150 and step S1160 may be executed.

[0256] In step S1170, the processor (320) can transmit the diagnosis result of the target cell (BC) to the electric vehicle (1) through the communication unit (310). The diagnosis result includes at least one of a positive electrode scale factor, a positive electrode loading amount, a positive electrode loss rate, a limited allowable voltage range, and a limited allowable SOC range.

[0257] FIG. 12 is a drawing for reference in explaining the correction procedure of voltage time series data performed in step S1122 of FIG. 11.

[0258] 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.

[0259] Referring to Figure 12, during each rest period, the target cell (BC) is placed in a no-load state with neither charging nor discharging.

[0260] 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.

[0261] <Formula 1>

[0262]

[0263] 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 S is 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).

[0264] 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.

[0265] <Formula 2>

[0266]

[0267] 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 .

[0268] The processor (320) calculates V using Equation 2 OCV Same as D OCV_C can be decided.

[0269] 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 rest periods, thereby converting the voltage time series data obtained in step S1120 into corrected voltage time series data for step S1130. The corrected voltage time series data includes X OCV values. The processor (320) can apply curve fitting logic to the corrected voltage time series data to generate a measured full-cell profile (M).

[0270] For reference, D OCVis 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).

[0271] 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.

[0272] 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.

[0273] 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 processor that controls a stimulation application device to intermittently apply a second electrical stimulus greater than a first electrical stimulus to the target cell during a state change period until the electrical state of the target cell, which is a battery cell as a diagnosis target, changes from an initial state to a target state; and A communication unit configured to obtain current time series data representing a change history of the current of the target cell during the state change period and voltage time series data representing a change history of the full-cell voltage of the target cell during the rest periods of the second electrical stimulation applied during the state change period, The above processor, Based on the current time series data and the voltage time series data, a measurement full-cell profile is generated that indicates the correspondence between the capacity of the target cell and the full-cell voltage, A battery diagnostic device configured to estimate a positive scale factor of the target cell by analyzing the above measured full cell profile.

2. In paragraph 1, The first electrical stimulation is an electrical stimulation that causes a difference between the OCV and CCV below a reference value in the target cell, A battery diagnostic device, wherein the second electrical stimulus is an electrical stimulus that causes a difference between the OCV and CCV exceeding the reference value in the target cell.

3. In paragraph 1, The above first electrical stimulation is charging using a first current rate, A battery diagnostic device, wherein the second electrical stimulation is charging using a second current rate greater than the first current rate.

4. In paragraph 1, The above first electrical stimulation is a discharge using a first current rate, A battery diagnostic device, wherein the second electrical stimulation is a discharge using a second current rate greater than the first current rate.

5. In paragraph 1, The above voltage time series data is, A battery diagnostic device, wherein the measurements of the full cell voltage during the rest periods of the second electrical stimulation are arranged in chronological order as the OCV of the target cell.

6. In paragraph 1, The above processor, A battery diagnostic device configured to control the stimulation application device to initiate a pause period of the second electrical stimulation whenever the current integration value of the above current changes by a threshold integration value.

7. In paragraph 6, The above processor, A battery diagnostic device configured to control the stimulation application device to resume application of the second electrical stimulation when a reference time has elapsed from the start time of the pause period of the second electrical stimulation.

8. In paragraph 1, The above processor, A battery diagnostic device configured to determine a positive electrode loss rate of the target cell based on the estimated positive electrode scale factor.

9. In paragraph 1, The above processor, A battery diagnostic device configured to limit at least one of an allowable voltage range and an allowable SOC range for the target cell based on the estimated positive scale factor.

10. A charging station including a battery diagnostic device according to any one of claims 1 to 9.

11. A cloud server including a battery diagnostic device according to any one of claims 1 to 9.

12. A step of controlling a stimulation application device to intermittently apply a second electrical stimulus greater than the first electrical stimulus to the target cell during a state change period until the electrical state of the target cell, which is a battery cell as a diagnosis target, changes from an initial state to a target state; A step of obtaining current time series data representing a change history of the current of the target cell during the state change period and voltage time series data representing a change history of the full-cell voltage of the target cell during the rest periods of the second electrical stimulation applied during the state change period; A step of generating a measurement full-cell profile indicating a correspondence between the capacity of the target cell and the full-cell voltage based on the current time series data and the voltage time series data; and A step of estimating the anode scale factor of the target cell by analyzing the above measured full cell profile; A battery diagnostic method comprising:

13. In paragraph 12, The above voltage time series data is, A battery diagnosis method, wherein the measurements of the full cell voltage during the rest periods of the second electrical stimulation are arranged in chronological order as the OCV of the target cell.

14. In paragraph 12, A step of determining a positive loss rate of the target cell based on the estimated positive scale factor; A battery diagnostic method further comprising:

15. In paragraph 12, A step of limiting at least one of an allowable voltage range and an allowable SOC range for the target cell based on the estimated positive scale factor; A battery diagnostic method further comprising:

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