Battery diagnosis device and battery diagnosis method

Abstract

The invention discloses a battery diagnosis device and a battery diagnosis method. The battery diagnosis apparatus includes: a processor configured to control a stimulus applying device 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 configured to obtain current time series data during the state change period and voltage time series data representing a change history of a full cell voltage of the target cell during a rest period of the second electrical stimulation applied in the state change period. The processor generates a measured full cell profile based on the current time series data and the voltage time series data, and analyzes the measured full cell profile to estimate a cathode load.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a technology for non-destructively diagnosing a state of a battery.

[0002] This application claims priority to Korean Patent Application No. 10-2023-0154880 filed on November 9, 2023, and Korean Patent Application No. 10-2023-0133644 filed on October 6, 2023, the disclosures of which are incorporated herein by reference. BACKGROUND

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

[0004] Currently, commercially available batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, lithium batteries, and the like, and among them, lithium batteries have little or no memory effect, and thus they have received more attention than nickel-based batteries because they are advantageous in that they can be recharged whenever it is convenient, have a very low self-discharge rate, and have a high energy density.

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

[0006] Accurately diagnosing the internal state of a battery is crucial for the safety and long lifespan of the battery. In order to diagnose the internal state of a battery without disassembly, mainly relationship data showing the correspondence between capacity and voltage, which can be referred to as a full cell profile, etc., are used.

[0007] Conventionally, a full cell profile is obtained by a process of repeatedly measuring the voltage and capacity of a battery at short intervals while applying a constant electric stimulus (e.g., constant current charging or discharging) to the battery. However, in order to minimize polarization (or overpotential) that causes a decrease in diagnostic accuracy, it is necessary to reduce the level of the electric stimulus applied to the target cell, which has the limitation that it takes too much time to acquire the full cell profile. At the same time, while advanced electric stimuli are advantageous in terms of shortening the time, since the advanced electric stimuli are accompanied by a serious polarization phenomenon, it is not possible to guarantee the accuracy of the diagnostic results. SUMMARY

[0008] TECHNICAL PROBLEM

[0009] The present disclosure is designed to solve problems of the related art, and thus the present disclosure aims to provide a battery diagnostic device and a battery diagnostic method which can obtain relationship data representing a correspondence between a capacity and a voltage of a target cell by using a method of intermittently applying a high level of electrical stimulation to the target cell, and diagnose a negative electrode deterioration state (e.g., a negative electrode load amount, a negative electrode loss rate, etc. explained later) of the target cell based on the obtained relationship data.

[0010] These and other objects and advantages of the present disclosure can be understood from the following detailed description, and will become more fully apparent when the exemplary embodiments of the present disclosure are considered in conjunction with the accompanying drawings. Further, it will be readily understood that the objects and advantages of the present disclosure can be achieved by the structures shown in the claims and combinations thereof.

[0011] Technical Solution

[0012] In one aspect of the present disclosure, a battery diagnostic device is provided, including: a processor configured to control a stimulation application device to intermittently apply a second electrical stimulation greater than a first electrical stimulation to a target cell during a state change period until an electrical state of the target cell changes from an initial state to a target state, the target cell being a battery cell to be diagnosed; and a communication unit configured to obtain 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 a rest period of the second electrical stimulation in the state change period. The processor is configured to generate a measured full cell profile representing a correspondence between a capacity and the full cell voltage of the target cell based on the current time series data and the voltage time series data, and estimate a negative electrode load amount representing an amount of negative electrode active material per unit area of a negative electrode of the target cell by analyzing the measured full cell profile.

[0013] The first electrical stimulation can be an electrical stimulation that makes a difference between an OCV and a CCV in the target cell equal to or less than a reference value. The second electrical stimulation can be an electrical stimulation that makes the difference between the OCV and the CCV in the target cell greater than the reference value.

[0014] The first electrical stimulation can be charging using a first current rate, and the second electrical stimulation can be charging using a second current rate greater than the first current rate.

[0015] The first electrical stimulation can be discharging using a first current rate, and the second electrical stimulation can be discharging using a second current rate greater than the first current rate.

[0016] The voltage time series data can be measured values of the full cell voltage during the rest period of the second electrical stimulation, the measured values being arranged in chronological order as an OCV of the target cell.

[0017] The processor can be configured to control the stimulation application device to initiate the rest period of the second electrical stimulation whenever the current integral value of the current changes by a threshold integral value.

[0018] The processor can be configured to control the stimulation application device to resume the application of the second electrical stimulation when a reference time elapses from a start point of the rest period of the second electrical stimulation.

[0019] The processor can be configured to determine a negative electrode loss rate of the target cell based on the estimated value of the negative electrode loading amount.

[0020] The processor can be configured to limit at least one of an allowable voltage range and an allowable SOC range of the target cell based on the estimated value of the negative electrode loading amount.

[0021] In still another aspect of the present disclosure, there is also provided a charging station including the battery diagnostic device.

[0022] In yet another aspect of the present disclosure, there is also provided a cloud server including the battery diagnostic device.

[0023] In still another aspect of the present disclosure, there is also provided a battery diagnostic method including: controlling a stimulation application device to intermittently apply a second electrical stimulation greater than a first electrical stimulation to a target cell during a state change period until an electrical state of the target cell changes from an initial state to a target state, the target cell being a battery cell to be diagnosed; obtaining 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 a rest period of the second electrical stimulation applied in the state change period; generating a measured full cell profile representing a correspondence between a capacity of the target cell and the full cell voltage based on the current time series data and the voltage time series data; and estimating a negative electrode loading amount representing an amount of negative electrode active material per unit area of a negative electrode of the target cell by analyzing the measured full cell profile.

[0024] The voltage time series data can be measured values of the full cell voltage during the rest period of the second electrical stimulation, the measured values being arranged in chronological order as an OCV of the target cell.

[0025] The battery diagnostic method can further include determining a negative electrode loss rate of the target cell based on the estimated value of the negative electrode loading amount.

[0026] The battery diagnostic method can further include limiting at least one of an allowable voltage range and an allowable SOC range of the target cell based on the estimated value of the negative electrode loading amount.

[0027] Advantages

[0028] According to at least one embodiment of the present disclosure, the relationship data representing the correspondence between the capacity of the target monomer and the voltage can be obtained by using a method of intermittently applying a high level of electrical stimulation to the target monomer, and a negative electrode deterioration state (a negative electrode load amount, a negative electrode loss rate, etc. to be explained later) of the target monomer is diagnosed based on the obtained relationship data.

[0029] That is, by changing the electrical state of the target monomer using a high level of electrical stimulation, the time required to obtain the relationship data can be shortened, while also preventing a decrease in diagnostic accuracy caused by excessive polarization due to intermittent application of electrical stimulation.

[0030] Effects of the present disclosure are not limited to the above-mentioned effects, and those skilled in the art will clearly understand these and other effects from the attached claims. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings illustrate preferred embodiments of the present disclosure and are used in conjunction with the foregoing disclosure to provide a further understanding of the technical features of the present disclosure, and therefore, the present disclosure is not construed as being limited to the accompanying drawings.

[0032] Figure 1 FIG. 1 is a diagram exemplarily showing a configuration of an electric vehicle and a charging station including a battery diagnosis circuit according to the present disclosure.

[0033] Figure 2 FIG. 2 is a graph referred to in order to exemplarily describe an example of a reference positive electrode profile line and a reference negative electrode profile line.

[0034] Figure 3a and Figure 3b FIG. 3 is a graph referred to in order to exemplarily describe a process of obtaining a measured full monomer profile line of a target monomer.

[0035] Figures 4 to 6 FIG. 4 is a graph referred to in order to describe an example of a process of generating a comparative full monomer profile line for comparison with the measured full monomer profile line according to one embodiment of the present disclosure.

[0036] Figures 7 to 9 FIG. 5 is a graph referred to in order to describe another example of a process for generating a comparative full monomer profile line for comparison with the measured full monomer profile line according to one embodiment of the present disclosure.

[0037] Figure 10 FIG. 6 is a flowchart referred to in order to exemplarily describe a battery diagnosis method according to a first embodiment of the present disclosure.

[0038] Figure 11 FIG. 7 is a flowchart referred to in order to exemplarily describe a battery diagnosis method according to a second embodiment of the present disclosure.

[0039] Figure 12 FIG. 8 is a graph referred to in order to describe a process ofFigure 11 FIG. 1 is a diagram of a process of correcting voltage time series data performed in step S1122 . DETAILED DESCRIPTION

[0040] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be interpreted as limited to the general and dictionary meanings, but should be interpreted based on the meanings and concepts corresponding to the technical aspects of the present disclosure on the principle of allowing the inventor to appropriately define the terms for the best interpretation.

[0041] Therefore, the descriptions presented herein are merely preferred examples for illustrative purposes, and are not intended to limit the scope of the present disclosure, and it should be understood that other equivalents and modifications may be made thereto without departing from the scope of the present disclosure.

[0042] Terms including ordinal numbers such as “first,” “second,” etc. are used to distinguish one element from another among various elements, but are not intended to limit the elements by the terms.

[0043] Unless the context clearly indicates otherwise, the terms "comprise" and "include" when used in this specification specify the presence of the stated elements, but do not exclude the presence or addition of one or more other elements. In addition, the term "unit" as used herein refers to a processing unit of at least one function or operation, and can be implemented by hardware and software alone or in combination.

[0044] Furthermore, throughout the specification, it will be understood that when an element is referred to as being “connected to” another element, it can be directly connected to the other element or intervening elements may be present.

[0045] Figure 1 is a diagram exemplarily showing the configuration of an electric vehicle and a charging station including a battery diagnostic circuit according to the present disclosure.

[0046] refer to Figure 1 , the electric vehicle 1 includes a vehicle controller 2, a battery pack 10, an inverter 30, and a motor 40. The charging terminal P+ and the discharging terminal P- of the battery pack 10 can be electrically connected to the charging station 300 through a charging cable or the like.

[0047] The vehicle controller 2 (for example, ECU: Electronic Control Unit) is configured to send 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 switched to an on position by a user. The vehicle controller 2 is configured to send a key-off signal to the battery management system 100 in response to the start button being switched to an off position by the user. The charging station 300 can communicate with the vehicle controller 2 and supply charging power selected from constant power, constant current, and constant voltage through the charging terminal P+ and the discharging terminal P- of the battery pack 10.

[0048] The battery pack 10 includes a battery 11, a relay 20, and a battery management system 100.

[0049] The battery 11 includes at least one battery cell BC. In Figure 1 , the battery 11 is exemplarily shown to include a plurality of battery cells (BC1 to BC N , N is a natural number of 2 or more). The plurality of battery cells (BC1 to BC N ) can be provided to have the same electrochemical specifications. Hereinafter, when a feature common to the plurality of battery cells (BC1 to BC N ) is explained, the battery cell will be given a reference sign "BC". The charging station 300 can perform a charging and discharging cycle required for diagnosing the battery cell BC by cooperating with the inverter 30 having a discharging function.

[0050] The type of the battery cell BC is not particularly limited as long as it is an electrochemical element capable of being repeatedly charged and discharged. The battery cell BC is a diagnosis target of the charging station.

[0051] The relay 20 is connected in series to the battery 11 through a power path connecting the battery 11 and the inverter 30. In Figure 1 , the relay 20 is shown to be connected between the positive terminal of the battery 11 and the charging and discharging terminal P+. The relay 20 is controlled to be turned on and off in response to a switching signal from the battery management system 100. The relay 20 can be a mechanical contactor turned on and off by magnetic force of a coil, or a semiconductor switch such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

[0052] The inverter 30 is provided to convert a DC current from the battery 11 included in the battery pack 10 into an AC current in response to a command from the battery management system 100 or the vehicle controller 2. The AC current power from the inverter 30 is used to drive the motor 40. For example, as the motor 40, a three-phase AC current motor can be used. Components in the electric vehicle 1 that receive a discharging power from the battery 11, such as the inverter 30 and the motor 40, can be collectively referred to as an electrical load.

[0053] The battery management system 100 includes a sensing unit 110 and a control circuit 130. The battery management system 100 can further include a communication circuit 150.

[0054] The sensing unit 110 includes a voltage sensor 111. The sensing unit 110 can further include a current sensor 112.

[0055] The voltage sensor 111 is connected to the positive and negative terminals of the battery cell BC and is configured to detect a voltage across both ends of the battery cell BC (also referred to as “full-cell voltage”) and generate a voltage signal representing a detected value of the detected voltage. The voltage sensor 111 can be implemented as one or a combination of two or more of known voltage detection elements such as a voltage measurement IC.

[0056] The current sensor 112 is connected to the battery 11 in series 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 (also referred to as “charging and discharging current”) and generate a current signal representing a detected value of the detected current. Since 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 as one or a combination of two or more of known current detection elements such as a shunt resistor, a Hall effect element, and the like.

[0057] The communication circuit 150 is configured to support wired or wireless communication between the control circuit 130 and the vehicle controller 2. The wired communication can be, for example, CAN (Controller Area Network) communication, and the wireless communication can be, for example, ZigBee or Bluetooth communication. The type of communication protocol is not particularly limited as long as it supports wired and wireless communication between the control circuit 130 and the vehicle controller 2. The communication circuit 150 can include an output device (e.g., a display, a speaker) that provides information received from the control circuit 130 and / or the vehicle controller 2 in a form recognizable by a user (driver).

[0058] The control circuit 130 is operatively coupled to the relay 20, the voltage sensor 111, and the communication circuit 150. The operative coupling of any two components means that the two components are directly or indirectly connected to enable sending and receiving signals in one direction or both directions.

[0059] The control circuit 130 can collect a voltage signal from the voltage sensor 111 and a current signal from the current sensor 112. In the present specification, a detection signal can be a term referring to only a voltage signal, or a term referring to both a voltage signal and a current signal. That is, the control circuit 130 can convert each analog signal collected from the sensors 111 and 112 into a digital value using an ADC (analog-to-digital converter) provided therein, and record the digital value. Alternatively, each of the voltage sensor 111 and the current sensor 112 can include an ADC therein and transmit a digital value to the control circuit 130.

[0060] The control circuit 130 can be referred to as a "battery controller", and can be implemented in hardware using at least one of an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a microprocessor, or an electrical unit for performing other functions.

[0061] The memory 131 can include at least one type of storage medium such as a flash memory type, a hard disk type, a solid state disk (SSD) type, a silicon disk driver (SDD) type, a multimedia card micro type, a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), or a programmable read-only memory (PROM). The memory 131 can store data and programs required for a computing operation of the control circuit 130. The memory 131 can store data representing a result of a computing operation performed by the control circuit 130.

[0062] When the relay 20 is turned on, the battery 11 enters a charging mode or a discharging mode. If the relay 20 is turned off while the battery 11 is being used in the charging mode or the discharging mode, the battery 11 switches to a rest mode.

[0063] The control circuit 130 can turn on the relay 20 in response to a key-on signal. The control circuit 130 can turn off the relay 20 in response to a key-off signal. The key-on signal is a signal requesting switching from the rest mode to the charging or discharging mode. The key-off signal is a signal requesting switching from the charging or discharging mode to the rest mode. Alternatively, the vehicle controller 2 can be responsible for turning on / off the relay 20 instead of the control circuit 130.

[0064] In the present specification, time-series data of a certain parameter indicates a history of a change in the parameter over time. In addition, a profile (or a curve) representing a correspondence relation of any two parameters obtained at the same timing in the same period can be a mapping of two time-series data of the two parameters, so that they can be represented in the form of a two-dimensional graph, or can be a polynomial equation obtained by applying predetermined curve fitting logic to a set of two mapped time-series data. Here, the number of the highest term of the polynomial equation can be predetermined.

[0065] The battery diagnosis device 302 includes a communication unit 310, a processor 320, and a memory unit 330.

[0066] The charging station 300 can include the stimulus application device 301 and the battery diagnosis device 302. Alternatively, the battery diagnosis device 302 can be configured independently of the charging station 300. For example, the battery diagnosis device 302 can be provided to be included in a cloud server (not shown). The cloud server can be placed remotely from the charging station 300. In this case, the communication unit 310 of the battery diagnosis device 302 can perform the diagnosis process of the target cell by remote communication with the stimulus application device 301 and / or the electric vehicle 1.

[0067] The battery diagnosis device 302 can be included in the battery pack 10, and in this case, the battery management system 100 can be omitted from the battery pack 10. In other words, the processor 320 can be responsible for all functions of the control circuit 130 of the battery management system 100. For example, the communication unit 310 can be included as a subcomponent of the processor 320, and can be responsible for all functions of the communication circuit 150 of the battery management system 100. Further, the communication unit 310 can collect voltage measurement information and current measurement information from the sensing unit 110.

[0068] The stimulus application device 301 can include a charger that provides charging power for normal charging of the battery pack 10. The stimulus application device 301 can apply various electrical stimuli to the battery cell BC for diagnosing the battery cell BC, either alone or in cooperation with the inverter 30.

[0069] 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 result of the diagnosis of the battery cell BC performed by the processor 320 to the electric vehicle 1.

[0070] In terms of hardware, the processor 320 can be implemented using at least one of an ASIC (Application-Specific Integrated Circuit), a DSP (Digital Signal Processor), a DSPD (Digital Signal Processing Device), a PLD (Programmable Logic Device), an FPGA (Field Programmable Gate Array), a microprocessor, and an electrical unit for performing other functions.

[0071] The memory unit 330 can include at least one type of storage medium, for example, a flash memory type, a hard disk type, a solid state disk (SSD) type, a silicon disk drive (SDD) type, a multimedia card micro type, a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), or a programmable read-only memory (PROM). The memory unit 330 can store data and programs required for a diagnostic process performed by the processor 320. The memory unit 330 can store data representing the results of the calculation operations of the processor 320. The memory unit 330 can store a data set and software for diagnosing the deterioration state of the battery cell BC.

[0072] Figure 2 is a graph referred to in order to describe an example of each of a reference positive electrode profile and a reference negative electrode profile. In In the graph of Figure 2 In the graph of

[0073] Referring to Figure 2 The memory unit 330 can store the reference positive electrode profile Rp and the reference negative electrode profile Rn. The reference cell can be a coin-type cell including a positive electrode half cell and a negative electrode half cell, or can be a 3-electrode cell. Hereinafter, the positive electrode of the reference cell and the positive electrode half cell will be described in equivalent terms, and the negative electrode of the reference cell and the negative electrode half cell will be described in equivalent terms.

[0074] The reference positive electrode profile Rp can be a profile representing a correspondence between a positive electrode voltage of a reference cell and a capacity. The positive electrode voltage of the reference cell refers to a potential difference between a potential of a reference electrode (not shown) and a potential of the positive electrode of the reference cell. The positive electrode profile can also be referred to as a positive electrode half cell profile.

[0075] The reference negative electrode profile Rn can be a profile representing a correspondence between a negative electrode voltage of a reference cell and a capacity. The negative electrode voltage of the reference cell refers to a potential difference between a potential of a reference electrode and a potential of the negative electrode of the reference cell. The negative electrode profile can also be referred to as a negative electrode half cell profile.

[0076] The potential of the reference electrode can be, for example, a redox potential of lithium. The positive electrode voltage can be simply referred to as a positive electrode potential, and the negative electrode voltage can be simply referred to as a negative electrode potential.

[0077] Each of the positive electrode voltage and the negative electrode voltage can be an open circuit voltage (OCV) or a closed circuit voltage (CCV).

[0078] The open-circuit voltage of each of the positive and negative electrodes of the reference cell can be obtained using a first charging protocol or a first discharging protocol. The first charging protocol can be an intermittent charging method, in which constant current charging at a first current rate and resting are performed alternately. The first discharging protocol can be an intermittent discharging method, in which constant current discharging at a first current rate and resting are performed alternately. The first current rate (e.g., 0.05C) can be predetermined to be greater than a second current rate (e.g., 3.0C), which will be explained later.

[0079] For example, whenever the charging time of constant current charging using the first charging protocol exceeds a set time or the charging capacity of the reference cell increases by a set capacity, charging of the reference cell may be stopped for a predetermined remaining time, and then constant current charging may be resumed. The charging capacity may be calculated by periodically or non-periodically accumulating sampled values ​​of the charging current.

[0080] As another example, whenever the discharge time of the constant current discharge of the first discharge protocol exceeds a set time or the discharge capacity of the reference cell decreases by a set capacity, the discharge of the reference cell may be stopped for a predetermined remaining time, and then the constant current discharge may be resumed. The discharge capacity may be calculated by periodically or non-periodically accumulating sampled values ​​of the discharge current (i.e., measured values ​​of the cell current).

[0081] At this time, multiple rest periods can 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 measured at specific timings within each rest period can be recorded as the positive electrode voltage and negative electrode voltage of the reference cell, respectively.

[0082] When compared to the open circuit voltage, the closed circuit voltage of each of the positive and negative electrodes of the reference cell can be obtained using a second charging protocol or a second discharging protocol. The second charging protocol can be 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, when the reference cell is continuously charged using the second charging protocol or continuously discharged using the second discharging protocol, the closed circuit voltages of the positive and negative electrodes of the reference cell, measured periodically or aperiodically, can be recorded as the positive electrode voltage and the negative electrode voltage of the reference cell.

[0083] In this specification, the first electrical stimulation may refer to an electrical stimulation that makes the difference between OCV and CCV in the battery cell equal to or less than a reference value, and the second electrical stimulation refers to an electrical stimulation that makes the difference between OCV and CCV in the battery cell greater than a reference value.

[0084] 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 that is greater than the first current rate.

[0085] As another example, the first electrical stimulus can be discharging using a first current rate, and the second electrical stimulus can be discharging using a second current rate greater than the first current rate.

[0086] Implementing the first charging protocol or the first discharging protocol can mean continuously applying the first electrical stimulus to the battery cell. Implementing the second charging protocol or the second discharging protocol can mean intermittently applying the second electrical stimulus to the battery cell.

[0087] For ease of explanation, it is assumed that Figures 2 to 9 The horizontal axis in the middle represents the charging capacity.

[0088] At least one of the reference positive electrode profile Rp and the reference negative electrode profile Rn can be aligned along the horizontal axis such that the resultant of a part of the common capacity range of the two profiles (Rp, Rn) from 5 to 50 Ah in the middle matches the reference full cell profile R. Figure 2 Figure 2 An example in which the reference negative electrode profile Rn is aligned to be shifted right based on the starting point of the reference positive electrode profile Rp (point corresponding to the capacity 0) is shown.

[0089] From Figure 2 It can be found that the two ends of the reference positive electrode profile Rp and the reference negative electrode profile Rn are offset from each other. In other words, the capacity range of the reference positive electrode profile Rp and the capacity range of the reference negative electrode profile Rn do not match and only partially overlap. Therefore, the reference full cell profile R indicates the full cell voltage of the reference cell in a part of the capacity range common to the reference positive electrode profile Rp and the reference negative electrode profile Rn. In other words, the reference full cell profile R is an example of a full cell voltage profile obtained by directly subtracting a part of the reference negative electrode profile Rn from a part of the reference positive electrode profile Rp.

[0090] The reference full cell profile R can represent the correspondence between the capacity and the full cell voltage of a new battery cell verified as a good product. In other words, the reference cell has the same level of positive electrode performance and negative electrode performance as a new battery cell verified as a good product. The positive electrode performance and the negative electrode performance of any battery cell can be collectively referred to as "charging / discharging performance".

[0091] A new battery cell refers to a battery cell in a new state. The new state can be the same concept as BOL (beginning of life). For example, it can be referred to as BOL until the time when the cumulative charging / discharging capacity from the time of completion of manufacturing reaches a set capacity, and it can be referred to as MOL (middle of life) from the time when the cumulative charging / discharging capacity reaches the set capacity.

[0092] ​The reference full cell profile R can represent a correspondence between a voltage and a capacity of a reference cell within at least a voltage range of interest (e.g., 3.0 V to 4.0 V). The lower limit and the upper limit of the voltage range of interest can be a first set voltage (3.0 V in Figure 2 ) and a second set voltage (4.0 V in Figure 2 ).

[0093] If the full cell voltage of any battery cell, including the reference cell, is equal to the first set voltage, the SOC can be set to 0%. When the full cell voltage of any battery cell, including the reference cell, is equal to the second set voltage, the SOC can be set to 100%. According to Figure 2 , the reference cell can reach a fully charged state (SOC 100%) from a fully discharged state (SOC 0%) through a charge capacity of 45 Ah.

[0094] In the present specification, the positive participation start point on the positive profile of any battery cell indicates a positive voltage and a positive capacity (or a positive SOC) when the full cell voltage of the corresponding battery cell matches the first set voltage. Further, the negative participation start point on the negative profile of the corresponding battery cell indicates a negative voltage and a negative capacity (or a negative SOC) when the full cell voltage of the corresponding battery cell matches the first set voltage. Accordingly, the voltage difference between the positive participation start point and the negative participation start point can be equal to the first set voltage.

[0095] Further, the positive participation end point on the positive profile of any battery cell indicates a positive voltage and a positive capacity (or a positive SOC) when the full cell voltage of the corresponding battery cell matches the second set voltage. Further, the negative participation end point on the negative profile of the corresponding battery cell indicates a negative voltage and a negative capacity (or a negative SOC) when the full cell voltage of the corresponding battery cell matches the second set voltage. Accordingly, the voltage difference between the positive participation end point and the negative participation end point can be equal to the second set voltage.

[0096] In the present specification, the positive capacity (capacity value) at a specific point on the positive profile of any battery cell can mean a capacity difference between either one of two end points of the positive profile and the specific point. The positive SOC at a specific point on the positive profile of any battery cell can mean a ratio of a capacity difference between either one of two end points (e.g., a low capacity point) of the positive profile and the specific point to a capacity difference between the two end points of the positive profile. The capacity difference between the two end points of the positive profile can be referred to as a total positive capacity.

[0097] Likewise, the negative electrode capacity (capacity value) at a certain point on the negative electrode profile line of any battery cell can mean the capacity difference between either of the two end points of the negative electrode profile line (or the positive electrode profile line) and the certain point. The negative electrode SOC at a certain point on the negative electrode profile line of any battery cell can mean the ratio of the capacity difference between either of the two end points (e.g., the low capacity point) of the negative electrode profile line (or the positive electrode profile line) and the certain point to the capacity difference between the two end points of the negative electrode profile line. The capacity difference between the two end points of the negative electrode profile line can be referred to as the total negative electrode capacity.

[0098] In the memory unit 330, information indicating the voltage at each of the reference positive electrode participation start point (pi0), the reference positive electrode participation end point (pf0), the reference negative electrode participation start point (ni0), and the reference negative electrode participation end point (nf0) can be recorded in advance. 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 line 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 line Rn, respectively.

[0099] The voltage difference between the reference positive electrode participation start point (pi0) and the reference negative electrode participation start point (ni0) can be equal to a first set voltage (e.g., 3.0 V). The voltage difference between the reference positive electrode participation end point (pf0) and the reference negative electrode participation end point (nf0) can be equal to a second set voltage (e.g., 4.0 V).

[0100] Figure 3a and Figure 3b is a graph referred to to exemplarily describe a process of obtaining a measured full cell profile line of a target cell.

[0101] Figure 3a The graph depicted in FIG. 13 illustrates an example of a change in the full cell voltage of a target cell over time due to intermittent application of a second electrical stimulus. The target cell is a battery cell to be diagnosed by a battery diagnosis apparatus. The target cell can be a new battery cell that needs to be verified whether it is a good product, or a battery cell that is no longer a new product due to deterioration after being verified as a good product. Hereinafter, the target cell is also denoted by reference numeral BC.

[0102] Referring to Figure 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.

[0103] The process for controlling the stimulation applying device 301 to diagnose the target cell BC may be performed during a state change period until the electrical state of the target cell BC (e.g., full cell voltage) changes from an initial state (e.g., a first set voltage) to a target state (e.g., a second set voltage).

[0104] refer to Figure 3a In the graph, the voltage across all target cells BC shows an upward trend as it repeats a sawtooth pattern. Each rising sawtooth voltage segment is caused by the application of the second electrical stimulus, while the falling voltage segment is caused by the interruption of the second electrical stimulus. In other words, the falling voltage segment represents the change in the voltage across all target cells BC during each rest period.

[0105] During the state change period, the processor 320 may repeatedly record the current measurement value of the target cell BC to generate current time series data.

[0106] The processor 320 can control the stimulation application device 301 to initiate a rest period for the second electrical stimulation whenever a predetermined rest condition is met during the state change period. In other words, when the rest condition is met, the application of the second electrical stimulation can be temporarily stopped. For example, at least one of (i) a change in the current integrated value to a threshold integrated value, (ii) a change in the state of charge (SOC) to a threshold SOC, and (iii) the duration of the application of the second electrical stimulation reaching a threshold time can be preset as a rest condition. For example, if the total current integrated value during the state change period is 40Ah and the threshold integrated value is 2Ah, a total of 20 rest periods can be permitted during the state change period.

[0107] The processor 320 can determine at least one of a threshold integral value, a threshold SOC, and a threshold time based on the target cell BC's full charge capacity, SOH, or previous diagnostic results (e.g., the capacity value at the negative electrode end point, the negative electrode loss rate). At least one of the threshold integral value, SOC, and time can have a predetermined positive (or negative) correspondence with the full charge capacity, SOH, or previous diagnostic results, and relationship data defining this correspondence (a data table for controlling the rest period) can be pre-stored in the memory unit 330. Due to the predetermined positive (or negative) correspondence, as the full charge capacity, SOH, or previous diagnostic results decrease, at least one of the threshold integral value, SOC, and time also decreases. Therefore, as the target cell BC degrades over time, rest periods are applied at short intervals within the state change period, thereby preventing a decrease in the number of data points included in the voltage time series data. The voltage history data indicates the temporal history of all-cell voltage changes during the rest period of the state change period.

[0108] The processor 320 can obtain at least one of a threshold integration value, a threshold SOC, and a threshold time mapped to the full charge capacity, the SOH, or the previous diagnosis result from the data table for rest period control. The processor 320 can control the intermittent application process of the second electric stimulus in the state change period using at least one of the threshold integration value, the threshold SOC, and the threshold time obtained from the data table for rest period control.

[0109] When the reference time elapses from the starting time point of the rest period of the second electric stimulus, the processor 320 can control the stimulus application device 301 to resume the application of the second electric stimulus. The reference time can be determined in advance so that the polarization caused by the second electric stimulus can be sufficiently resolved. For example, the reference time, which is the length of time of the rest period, can be the time required for the polarization at the starting time point of the rest period to become 10% or less.

[0110] In each rest period of the second electric stimulus, the full cell voltage of the target monobloc BC is measured at least once. As an example, the processor 320 can record the measured value of the full cell voltage at the end time point of each rest period of the second electric stimulus as the OCV of the target monobloc BC. As another example, the full cell voltage can be measured at least three times in each rest period of the second electric stimulus, and the processor 320 can estimate the OCV of the target monobloc BC for each rest period based on the three full cell voltage measurement values for each rest period.

[0111] Therefore, the voltage time series data can be generated by recording the OCV multiple times with a time difference during the state change period. Figure 3a Each OCV point (D OCV ) marked in the graph is an example of a data point representing the voltage time series data.

[0112] The inventors of the present disclosure have recognized through multiple experiments that the voltage time series data generated in the above-described manner using the second electric stimulus has high consistency with the voltage time series data generated when the first electric stimulus is actually applied to the target monobloc BC.

[0113] From now on, the advantages of the diagnosis method based on the intermittent application of the second electric stimulus rather than the continuous application of the first electric stimulus will be described.

[0114] Assume that the conditions related to the diagnosis of the target monobloc BC are as follows.

[0115] (i) First electric stimulus = charging at 0.05 C

[0116] (ii) Second electric stimulus = charging at 3.0 C

[0117] (iii) Length of the rest period of the second electric stimulus = 12 minutes

[0118] (iv) Total capacity change during the state change period = 80% of the full charge capacity (FCC) of the target cell BC

[0119] (v) Threshold integral value = 3% of the fully charged capacity of the target cell BC

[0120] Then, the time taken for the target cell BC to change from the initial state to the target state by continuously applying the first electrical stimulation is 1 / 0.05*80%=16 hours.

[0121] In contrast, the time required for the target cell BC's charge capacity to increase by the threshold integral value through the second electrical stimulation is 0.03 / 3 * 80% = 0.008 hours. Furthermore, since a rest period is granted every time the charge capacity increases by 3%, a total of 26 rest periods are permitted during the state change period. Therefore, the time required for the target cell BC to change from its initial state to its target state through the intermittent application of the second electrical stimulation is (0.008 hours + 0.2 hours) * 26 = 5.4 hours.

[0122] In other words, compared with the method of continuously applying the first electrical stimulation, the method of intermittently applying the second electrical stimulation is advantageous in shortening the time for obtaining the entire monomer section line.

[0123] exist Figure 3b In the graph, the horizontal axis (X-axis) represents capacity (Ah), and the vertical axis (Y-axis) represents voltage.

[0124] refer to Figure 3b The processor 320 may generate a measured full-cell profile M representing a corresponding relationship between the capacity and voltage (also referred to as “full-cell voltage”) of the target cell BC. The measured full-cell profile may also be referred to as a QV profile or a Q-OCV profile.

[0125] Here, the full cell voltage is the voltage across the target cell BC and is distinguished from the positive and negative voltages described above. In other words, the full cell voltage of the target cell BC can be regarded as the difference between the positive and negative voltages of the target cell BC.

[0126] In order to generate the measured full-cell profile M, current time series data and voltage time series data mapped to the state change period may be used.

[0127] In detail, each data point of the current time series data and the voltage time series data is indexed in time sequence. Accordingly, the processor 320 can generate the capacity time series data by sequentially integrating the data points of the current time series data. Also, the processor 320 can generate the measured full cell profile M by applying a curve fitting algorithm to a set of a plurality of Q-OCV pairs obtained through a 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 can be a polynomial equation in which the order of the highest term is predetermined.

[0128] Similar to the reference full cell profile R, the measured full cell profile M can represent a correspondence between the capacity and the OCV of the target cell BC within at least a voltage range of interest (e.g., 3.0 V to 4.0 V).

[0129] Since there are some differences in the charging / discharging performance between the reference cell and the target cell BC inevitably, there are also some differences between the measured full cell profile M and the reference full cell profile R, as shown in Figure 3b

[0130] 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 the manufacturing defect of the target cell BC, the loss of the positive electrode capacity, the loss of the negative electrode capacity, and / or the loss of the available lithium. Obviously, as the target cell BC deteriorates through repeated charging / discharging, the difference between the measured full cell profile M and the reference full cell profile R will gradually increase. According to Figure 3b , the reference Figure 2 Unlike the reference cell described above, the full cell voltage of the target cell BC requires a charge capacity of 40 Ah 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.

[0131] Meanwhile, in the graph of Figure 2 and Figure 3b , Ah is used as a unit on the horizontal axis, but the unit can be expressed in other forms. For example, the unit on the horizontal axis can be a percentage %, which represents the SOC (State of Charge), rather than Ah.

[0132] When generating the measured full cell profile M, the processor 320 can be configured to compare the measured full cell profile M with at least one comparative full cell profile. Here, the comparative full cell profile can be a result of generating an adjusted positive electrode profile and an adjusted negative electrode profile by adjusting each of the reference positive electrode profile Rp and the reference negative electrode profile Rn stored in the memory unit 330 and then synthesizing (combining) the adjusted positive electrode profile and the adjusted negative electrode profile. ​

[0133] In other words, when the reference full cell profile R is a result of subtracting a portion of the reference negative electrode profile Rn from a portion of the reference positive electrode profile Rp, the comparative full cell profile can be regarded as a result of subtracting a portion of the adjusted negative electrode profile from a portion of the adjusted positive electrode profile.

[0134] The processor 320 can generate at least one comparative full cell profile by directly adjusting the reference positive electrode profile Rp and the reference negative electrode profile Rn. Alternatively, at least one comparative full cell profile can be pre-ensured 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 comparative full cell profile by accessing the memory unit 330 and reading the comparative full cell profile.

[0135] The processor 320 can generate a plurality of comparative full cell profiles from the reference positive electrode profile Rp and the reference negative electrode profile Rp by repeatedly adjusting each of the reference positive electrode profile Rp and the reference negative electrode profile Rp to a number of levels and then synthesizing their adjustment processes. The comparative full cell profile can also be referred to as an "adjusted reference full cell profile".

[0136] The processor 320 can designate any one of the plurality of comparative full cell profiles, which has the smallest error with respect to the measured full cell profile M. Then, the processor 320 can determine that the adjusted positive electrode profile and the adjusted negative electrode profile mapped to the designated comparative full cell profile are the positive electrode profile and the negative electrode profile of the target cell BC.

[0137] In this regard, various methods known at the time of filing the present application can be employed to determine the error between two profiles, each of which can be expressed in a two-dimensional coordinate system. For example, the integral of the absolute value of the area between two profiles or the RMSE (Root Mean Square Error) can be used as the error between two profiles.

[0138] According to this configuration of the present disclosure, various state information about the target cell BC can be obtained based on the finally determined adjusted positive electrode profile and the adjusted negative electrode profile. The finally determined adjusted positive electrode profile and the adjusted negative electrode profile can be mapped to the comparative full cell profile mapped with the smallest error. In particular, the comparative full cell profile resulting from the finally determined adjusted positive electrode profile and the adjusted negative electrode profile can be almost identical in shape to the measured full cell profile M, etc.

[0139] Accordingly, according to the present disclosure, even if the target cell BC is not disassembled or manufactured in the form of a 3-electrode battery, the positive electrode profile and the negative electrode profile of the target cell BC can be obtained.

[0140] If the target monomer BC is a new battery monomer, the adjusted positive electrode profile and the adjusted negative electrode profile can be more easily analyzed and utilized to diagnose whether a defect occurs in the target monomer BC, and if a defect occurs, what type of defect it is.

[0141] If the battery monomer is used after the target monomer BC is verified as a good product, how much the target monomer BC is deteriorated can be determined for each deterioration item through the adjusted positive electrode profile and the adjusted negative electrode profile.

[0142] In addition, according to one embodiment of the disclosure, the positive electrode profile and the negative electrode profile of the target monomer BC can be obtained in a simple manner. The disclosure can be implemented even if only one reference positive electrode profile Rp and one reference negative electrode profile Rn are stored in the memory unit 330. That is, it is not necessary to store a plurality of reference positive electrode profiles Rp and / or a plurality of reference negative electrode profiles Rn in the memory unit 330. Accordingly, the storage capacity of the memory unit 330 does not need to be high, and a large amount of preliminary tests required to secure a plurality of reference positive electrode profiles Rp and / or a plurality of reference negative electrode profiles Rn need not be performed.

[0143] Hereinafter, with reference to Figures 4 to 9 , a process of analyzing the measured full monomer profile M to estimate the negative electrode loading, which is one of parameters involved in the current charge / discharge performance of the target monomer BC, will be described. The negative electrode loading of any battery monomer is a term indicating the amount of negative electrode active material per unit area of the negative electrode of the battery monomer, and its unit can be mAh / cm 2 or mg / cm 2 .

[0144] Figures 4 to 6 is a graph referred to in order to describe an example of a process of generating a comparison full monomer profile for comparison with the measured full monomer profile according to one embodiment of the disclosure.

[0145] With reference to Figures 4 to 6 the process for generating the comparison full monomer profile will be explained in the following order: a first routine for setting four points (positive electrode participation start point, positive electrode participation end point, negative electrode participation start point, negative electrode participation end point) corresponding to a voltage range of interest (see Figure 4 ), a second routine for performing profile shifting (see Figure 5 ), and a third routine for performing capacity scaling (see Figure 6 ). That is, the process for generating the comparison full monomer profile according to one embodiment of the disclosure includes the first to third routines.

[0146] First, with reference to Figure 4 , the reference positive electrode profile Rp and the reference negative electrode profile Rn are compared with Figure 2those shown in FIG. 3.

[0147] The processor 320 determines a positive electrode participation start point (pi), a positive electrode participation end point (pf), a negative electrode participation start point (ni), and a negative electrode participation end point (nf) on the reference positive electrode profile line Rp and the reference negative electrode profile line Rn.

[0148] Either of the positive electrode participation start point (pi) and the negative electrode participation start point (ni) depends on the other.

[0149] As an example, the processor 320 can divide a positive electrode voltage range from a start point to an end point (or a second set voltage) of the reference positive electrode profile line Rp into a plurality of small voltage sections, and then set a boundary point of two adjacent small voltage sections among the plurality of small voltage sections as the positive electrode participation start point (pi). Each small voltage section can have a predetermined size (e.g., 0.01 V). Next, the processor 320 can set a point on the reference negative electrode profile line Rn which is smaller than the positive electrode participation start point (pi) by a first set voltage (e.g., 3 V) as the negative electrode participation start point (ni).

[0150] As another example, the processor 320 can divide a negative electrode voltage range from a start point to an end point of the reference negative electrode profile line Rn into a plurality of small voltage sections of a predetermined size, and then set a boundary point between two adjacent small voltage sections among the plurality of small voltage sections as the negative electrode participation start point (ni). Next, the processor 320 can search for a point from the reference positive electrode profile line Rp which is greater than the negative electrode participation start point (ni) by a first set voltage, and set the searched point as the positive electrode participation start point (pi).

[0151] Either of the positive electrode participation end point (pf) and the negative electrode participation end point (nf) depends on the other.

[0152] As an example, the processor 320 can divide a voltage range from a second set voltage to an end point of the reference positive electrode profile line Rp into a plurality of small voltage sections of a predetermined size, and then set a boundary point of two adjacent small voltage sections among the plurality of small voltage sections as the positive electrode participation end point (pf). Next, the processor 320 can set a point on the reference negative electrode profile line Rn which is smaller than the positive electrode participation end point (pf) by a second set voltage (e.g., 4 V) as the negative electrode participation end point (nf).

[0153] As another example, the processor 320 can divide a negative electrode voltage range from a start point to an end point of the reference negative electrode profile line Rn into a plurality of small voltage sections of a predetermined size, and then set a boundary point between two adjacent small voltage sections among the plurality of small voltage sections as the negative electrode participation end point (nf). Next, the processor 320 can search for a point from the reference positive electrode profile line Rp which is greater than the negative electrode participation end point (nf) by a second set voltage, and set the searched point as the positive electrode participation end point (pf).

[0154] If the positive electrode participation start point (pi), the positive electrode participation end point (pf), the negative electrode participation start point (ni), and the negative electrode participation end point (nf) are completely determined, the processor 320 shifts at least one of the reference positive electrode profile Rp and the reference negative electrode profile Rn left or right along the horizontal axis.

[0155] Referring to Figure 5 , the processor 320 can shift the reference positive electrode profile Rp left (toward low capacity) or the reference negative electrode profile Rn right (toward high capacity) or both of them so that the capacity values of the positive electrode participation start point (pi) and the negative electrode participation start point (ni) match.

[0156] Alternatively, the processor 320 shifts the reference positive electrode profile Rp left or the reference negative electrode profile Rn right or both of them so that the capacity values of the positive electrode participation end point (pf) and the negative electrode participation end point (nf) match.

[0157] Figure 5 A case where only the reference positive electrode profile Rp is shifted left to generate an adjusted reference positive electrode profile (Rp') and thus the capacity value of the positive electrode participation start point (pi') matches that of the negative electrode participation start point (ni) is illustrated. The adjusted reference positive electrode profile (Rp') is a result of applying an adjustment process that shifts the voltage difference between the positive electrode participation start point (pi) and the negative electrode participation start point (ni) left to the reference positive electrode profile Rp. Thus, 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.

[0158] If the adjusted result profile (Rp', Rn) in which at least one of the reference positive electrode profile Rp and the reference negative electrode profile Rn is shifted is secured, the processor 320 scales the capacity range of at least one of the adjusted result profile (Rp', Rn).

[0159] According to Figure 5 , the processor 320 performs an additional adjustment process to contract or expand at least one of the adjusted reference positive electrode profile (Rp') and the reference negative electrode profile Rn along the horizontal axis.

[0160] Referring to Figure 6The processor 320 can generate an adjusted reference positive electrode profile (Rp'') by contracting or expanding the adjusted reference positive electrode profile (Rp') such that the size of the capacity range between the two points (pi', pf') of the adjusted reference positive electrode profile (Rp') matches the size of the capacity range of the measured full cell profile M. At this time, any one point (pi') of the two points (pi', pf') can be fixed. Accordingly, the capacity difference between the two points (pi', pf'') of the adjusted reference positive electrode profile (Rp'') can match the capacity range of the measured full cell profile M.

[0161] Further, the processor 320 can generate an adjusted reference negative electrode profile (Rn') by contracting or expanding the reference negative electrode profile Rn such that the size of the capacity range between the two points (ni, nf) of the reference positive electrode profile Rn matches the size of the capacity range of the measured full cell profile M. At this time, any one point (ni) of the two points (ni, nf) can be fixed. Accordingly, the capacity difference between the two points (ni, nf') of the adjusted reference negative electrode profile (Rn') can match the capacity range of the measured full cell profile M.

[0162] In Figure 6 , the adjusted reference positive electrode profile (Rp'') is a result of contracting the adjusted reference positive electrode profile (Rp') shown in Figure 5 , and the adjusted reference negative electrode profile (Rn') is a result of expanding the reference negative electrode profile Rn shown in Figure 5 .

[0163] The positive electrode participation end point (pf'') on the adjusted reference positive electrode profile (Rp'') corresponds to the positive electrode participation end point (pf) on the adjusted reference positive electrode profile (Rp'). The negative electrode participation end point (nf') on the adjusted reference negative electrode profile (Rn') corresponds to the negative electrode participation end point (nf) on the reference negative electrode profile Rn.

[0164] The capacity difference between the positive electrode participation start point (pi') and the positive electrode participation end point (pf'') of the adjusted reference positive electrode profile (Rp'') corresponds to the size of the capacity range of the measured full cell profile M. Likewise, the capacity difference between the negative electrode participation start point (ni) and the negative electrode participation end point (nf') of the adjusted reference negative electrode profile (Rn') corresponds to the size of the capacity range of the measured full cell profile M.

[0165] In addition, the capacity range of the two points (pi', pf'') of the adjusted reference positive electrode profile line (Rp'') is matched with the capacity range of the two points (ni, nf') of the adjusted reference negative electrode profile line (Rn'). The processor 320 can generate the comparison full cell profile line S by subtracting the profile line between the two points (pi, pf') of the adjusted reference positive electrode profile line (Rp'') from the profile line between the two points (ni, nf') of the adjusted reference negative electrode profile line (Rn').

[0166] The processor 320 can calculate an error (profile line error) between the comparison value between the comparison full cell profile line S and the reference full cell profile line R.

[0167] The processor 320 can map at least two of the adjusted reference positive electrode profile line (Rp''), the adjusted reference negative electrode profile line (Rn'), the positive electrode participation start point (pi'), the positive electrode participation end point (pf''), the negative electrode participation start point (ni), the negative electrode participation end point (nf'), the positive electrode scaling factor, the negative electrode scaling factor, the comparison full cell profile line S, and the profile line error to each other and record in the memory unit 330.

[0168] The positive electrode scaling factor can represent a ratio of a capacity difference between both ends of the adjusted reference positive electrode profile line (Rp'') to a capacity difference between both ends of the reference positive electrode profile line Rp. Alternatively, the positive electrode scaling factor can represent a ratio of a capacity difference between the two points (pi', pf'') to a capacity difference between the two points (pi0, pf0). Alternatively, the positive electrode scaling factor can represent a ratio of a positive electrode capacity difference between the two points (pi', pf'') to a positive electrode capacity difference between the two points (pi0, pf0). Alternatively, the positive electrode scaling factor can represent a ratio of a positive electrode SOC difference between the two points (pi', pf'') to a positive electrode SOC difference between the two points (pi0, pf0).

[0169] The negative electrode scaling factor can represent a ratio of a capacity difference between both ends of the adjusted reference negative electrode profile line (Rn') to a capacity difference between both ends of the reference negative electrode profile line Rn. Alternatively, the negative electrode scaling factor can represent a ratio of a capacity difference between the two points (ni, nf') to a capacity difference between the two points (ni0, nf0). Alternatively, the negative electrode scaling factor can represent a ratio of a negative electrode capacity difference between the two points (ni, nf') to a negative electrode capacity difference between the two points (ni0, nf0). Alternatively, the negative electrode scaling factor can represent a ratio of a negative electrode SOC difference between the two points (ni, nf') to a negative electrode SOC difference between the two points (ni0, nf0).

[0170] Meanwhile, as described above, when the positive electrode voltage range of the reference positive electrode profile Rp is divided into a plurality of small voltage sections, a boundary point of two adjacent small voltage sections among the plurality of small voltage sections can be set as the positive electrode participation start point (pi).

[0171] For example, if the positive electrode voltage range of the reference positive electrode profile Rp is divided into 100 small voltage ranges, there can be 100 boundary points that can be set as the positive electrode participation start point (pi). Also, if the voltage range of the reference positive electrode profile Rp that is greater than or equal to the second set voltage is divided into 40 small voltage ranges, there can be 40 boundary points that can be set as the positive electrode participation end point (pf). In this case, at least 4000 different comparative full cell profiles can be generated.

[0172] Of course, those skilled in the art will readily understand that, as the size of the small voltage section decreases, the maximum number of comparative full cell profiles that can be generated increases, and, conversely, as the size of the small voltage section increases, the maximum number of comparative full cell profiles that can be generated decreases.

[0173] The processor 320 can identify a minimum value among profile errors of the plurality of comparative full cell profiles generated as described above, and then obtain information (for example, at least one of the positive electrode participation start point, the positive electrode participation end point, the negative electrode participation start point, the negative electrode participation end point, the positive electrode scaling factor, and the negative electrode scaling factor) mapped to the minimum profile error from the memory unit 330.

[0174] Figures 7 to 9 is a diagram referred to describe another example of a process of generating a comparative full cell profile for comparison with a measured full cell profile according to one embodiment of the disclosure. As a reference, Figures 7 to 9 the embodiment shown in Figures 4 to 6 the embodiment shown in Figures 4 to 6 the terms or reference numerals commonly used to describe Figures 7 to 9 the embodiment shown in

[0175] Reference should be made to Figures 7 to 9 the process of generating a comparative full cell profile explained in the following order: a fourth routine of performing capacity scaling (see Figure 7 ), a fifth routine of setting four points (a positive electrode participation start point, a positive electrode participation end point, a negative electrode participation start point, and a negative electrode participation end point) (see Figure 8 ), and a sixth routine of performing profile shifting (see Figure 9 ). That is, the process of generating a comparative full cell profile according to another embodiment of the disclosure includes the fourth to sixth routines.

[0176] Reference should be made to Figure 7The processor 320 generates an adjusted reference positive profile line (Rp') and an adjusted reference negative profile line (Rn') by applying the positive scaling factor and the negative scaling factor selected from the scaling value range to the reference positive profile line Rp and the reference negative profile line (Rn), respectively.

[0177] The scaling value range can be predetermined or can vary according to a ratio of a size of a capacity range of the measured full cell profile line M to a size of a capacity range of the reference full cell profile line (R). As an example, assuming that the positive scaling factor and the negative scaling factor can be selected among values spaced by 0.1% in the scaling value range (e.g., 90 to 99%), i.e., 90%, 90.1%, 90.2%, …, 98.9%, 99%, 91 values can be selected as the positive scaling factor and the negative scaling factor, respectively. In this case, according to 91 x 91 = 8281 adjustment levels (combinations of the positive scaling factor and the negative scaling factor), up to 8281 adjusted profile line pairs can be generated. The adjusted profile line pair refers to a combination of the adjusted positive profile line and the adjusted negative profile line.

[0178] Referring to Figure 7 The adjusted reference positive profile line (Rp') and the adjusted reference negative profile line (Rn') respectively show results of applying the positive scaling factor and the negative scaling factor to the reference positive profile line Rp and the reference negative profile line Rn.

[0179] Since the positive scaling factor and the negative scaling factor are less than 100%, the adjusted reference positive profile line (Rp') is obtained by contracting the reference positive profile line Rp along the horizontal axis, and the adjusted reference negative profile line (Rn') is also obtained by contracting the reference negative profile line Rn along the horizontal axis. For ease of understanding, the reference positive profile line Rp and the reference negative profile line Rn are shown in a form in which their starting points are fixed and the remaining portions are contracted to the left along the horizontal axis, respectively.

[0180] Referring to Figure 8 The processor 320 determines the positive participation starting point (pi'), the positive participation ending point (pf'), the negative participation starting point (ni'), and the negative participation ending point (nf') on the adjusted reference positive profile line (Rp') and the adjusted reference negative profile line (Rp').

[0181] Either one of the positive participation starting point (pi') and the negative participation starting point (ni') can depend on the other. Also, either one of the positive participation ending point (pf') and the negative participation ending point (nf') can depend on the other. In addition, either one of the positive participation starting point (pi') and the positive participation ending point (pf') can be set based on the other.

[0182] That is, if any one of the positive electrode participation start point (pi'), the positive electrode participation end point (pf'), the negative electrode participation start point (ni'), and the negative electrode participation end point (nf') is set, the remaining three points can be automatically set by the first set voltage, the second set voltage, and / or the size of the capacity range of the measured full-cell profile M (for example, 45 Ah - 5 Ah = 40 Ah in FIG. 45). Figure 3b

[0183] As an example, the processor 320 can divide the positive electrode voltage range from the start point to the end point of the adjusted reference positive electrode profile (Rp') (or the second set voltage) into a plurality of small voltage sections, and then set the boundary point of two adjacent small voltage sections among the plurality of small voltage sections as the positive electrode participation start point (pi'). Next, the processor 320 can set a point on the adjusted reference negative electrode profile (Rn) that is smaller than the positive electrode participation start point (pi') by the first set voltage (for example, 3 V) as the negative electrode participation start point (ni').

[0184] As another example, the processor 320 can divide the negative electrode voltage range from the start point to the end point of the adjusted reference negative electrode profile (Rn') into a plurality of small voltage sections of a predetermined size, and then set the boundary point of two adjacent small voltage sections among the plurality of small voltage sections as the negative electrode participation start point (ni'). Next, the processor 320 can search for a point from the reference positive electrode profile (Rp) that is greater than the negative electrode participation start point (ni') by the first set voltage, and set the searched point as the positive electrode participation start point (pi').

[0185] As yet another example, the processor 320 can divide the voltage range from the second set voltage to the end point of the adjusted reference positive electrode profile (Rp') into a plurality of small voltage sections of a predetermined size, and then set the boundary point of two adjacent small voltage sections among the plurality of small voltage sections as the positive electrode participation end point (pf'). Next, the processor 320 can search for a point from the adjusted reference negative electrode profile (Rn') that is smaller than the positive electrode participation end point (pf') by the second set voltage (for example, 4 V), and set the searched point as the negative electrode participation end point (nf').

[0186] As yet another example, the processor 320 can divide the negative electrode voltage range from the start point to the end point of the adjusted reference negative electrode profile (Rn') into a plurality of small voltage sections of a predetermined size, and then set the boundary point of two adjacent small voltage sections among the plurality of small voltage sections as the negative electrode participation end point (nf'). Next, the processor 320 can search for a point from the adjusted reference positive electrode profile (Rp') that is greater than the negative electrode participation end point (nf') by the second set voltage, and set the searched point as the positive electrode participation end point (pf').

[0187] ​If any one of the positive electrode participation start point (pi'), the positive electrode participation end point (pf'), the negative electrode participation start point (ni'), and the negative electrode participation end point (nf') is determined, the processor 320 can additionally determine the remaining three points based on the determined point.

[0188] For example, if the positive electrode participation start point (pi') is first determined, the processor 320 can set a point on the adjusted reference positive electrode profile line (Rp') having a capacity value greater than the capacity range of the measured full cell profile line M by the size of the capacity value of the positive electrode participation start point (pi') as the positive electrode participation end point (pf'). Also, the processor 320 can search for a point lower than the positive electrode participation start point (pi') by the first set voltage from the adjusted reference negative electrode profile line (Rn'), and set the searched point as the negative electrode participation start point (ni'). Also, the processor 320 can set a point on the adjusted reference negative electrode profile line (Rn') having a capacity value greater than the capacity range of the measured full cell profile line M by the size of the capacity value of the negative electrode participation start point (ni') as the negative electrode participation end point (nf').

[0189] As another example, when the positive electrode participation end point (pf') is first determined, the processor 320 can set a point on the adjusted reference positive electrode profile line (Rp') having a capacity value smaller than the capacity range of the measured full cell profile line M by the size of the capacity value of the positive electrode participation end point (pf') as the positive electrode participation start point (pi'). Also, the processor 320 can search for a point lower than the positive electrode participation end point (pf') by the second set voltage from the adjusted reference negative electrode profile line (Rn'), and set the searched point as the negative electrode participation end point (nf'). Also, the processor 320 can set a point on the adjusted reference negative electrode profile line (Rn') having a capacity value smaller than the capacity range of the measured full cell profile line M by the size of the capacity value of the negative electrode participation end point (nf') as the negative electrode participation start point (ni').

[0190] As still another example, when the negative electrode participation start point (ni') is determined, the processor 320 can set a point on the adjusted reference negative electrode profile line (Rn') having a capacity value greater than the capacity range of the measured full cell profile line M by the size of the capacity value of the negative electrode participation start point (ni') as the negative electrode participation end point (nf'). Also, the processor 320 can search for a point higher than the negative electrode participation start point (ni') by the first set voltage from the adjusted reference positive electrode profile line (Rp'), and set the searched point as the positive electrode participation start point (pi'). Also, the processor 320 can set a point on the adjusted reference positive electrode profile line (Rp') having a capacity value greater than the capacity range of the measured full cell profile line M by the size of the capacity value of the positive electrode participation start point (pi') as the positive electrode participation end point (pf').

[0191] As another example, when the negative electrode participation endpoint (nf') is determined, the processor 320 may set a point on the adjusted reference negative electrode profile (Rn') having a capacity value that is smaller than the capacity value of the negative electrode participation endpoint (nf') by the size of the capacity range of the measured full-cell profile M as the negative electrode participation starting point (ni'). Furthermore, the processor 320 may search the adjusted reference positive electrode profile (Rp') for a point that is higher than the negative electrode participation endpoint (nf') by a second set voltage, and set the searched point as the positive electrode participation endpoint (pf'). Furthermore, the processor 320 may set a point on the adjusted reference positive electrode profile (Rp') having a capacity value that is smaller than the capacity value of the positive electrode participation endpoint (pf') by the size of the capacity range of the measured full-cell profile M as the positive electrode participation starting point (pi').

[0192] If the positive electrode participation starting point (pi'), the positive electrode participation end point (pf'), the negative electrode participation starting point (ni') and the negative electrode participation end point (nf') are completely determined based on the positive electrode scaling factor and the negative electrode scaling factor, the processor 320 can shift at least one of the adjusted reference positive electrode profile (Rp') and the adjusted reference negative electrode profile (Rn') to the left or right along the horizontal axis so that the capacity values ​​of the positive electrode participation starting point (pi') and the negative electrode participation starting point (ni') match or the capacity values ​​of the positive electrode participation starting point (pf') and the negative electrode participation starting point (nf') match.

[0193] Figure 9 The adjusted reference negative profile (Rn'') shown in Figure 8 This is achieved by shifting the adjusted reference negative electrode profile (Rn') shown in the figure to the right. Therefore, the capacity values ​​at the positive electrode participation starting point (pi') and the negative electrode participation starting point (ni'') match each other on the horizontal axis. Relatedly, the capacity difference between the positive electrode participation starting point (pi') and the positive electrode participation end point (pf') is equal to the capacity difference between the negative electrode participation starting point (ni') and the negative electrode participation end point (nf'). Therefore, if the capacity values ​​at the positive electrode participation starting point (pi') and the negative electrode participation starting point (ni'') match each other, then the capacity values ​​at the positive electrode participation end point (pf') and the negative electrode participation end point (nf') also match each other on the horizontal axis.

[0194] refer to Figure 9 , the processor 320 may generate a comparative full-cell profile U by subtracting a partial profile between two points (pi', pf') of the adjusted reference positive profile (Rp') from a partial profile between two points (ni'', nf'') of the adjusted reference negative profile (Rn'').

[0195] The processor 320 may calculate an error (section line error) between the comparison full-unit section line U and the reference full-unit section line R.

[0196] The processor 320 can map at least two of the adjusted reference positive electrode profile (Rp'), the adjusted reference negative electrode profile (Rn"), the positive electrode participation start point (pi'), the positive electrode participation end point (pf'), the negative electrode participation start point (ni"), the negative electrode participation end point (nf"), the positive electrode scaling factor, the negative electrode scaling factor, the comparison full cell profile U, and the profile error to each other and record in the memory unit 330.

[0197] As described above, the processor 320 can generate the comparison full cell profile corresponding to each pair of the positive electrode scaling factor and the negative electrode scaling factor selected from the scaling value range. Since the pairs of the positive electrode scaling factor and the negative electrode scaling factor are plural, it is obvious that the comparison profiles will also be generated in a plural number. The processor 320 can identify the minimum value among the profile errors of the plural comparison full cell profiles, and then obtain information mapped to the minimum profile error from the memory unit 330.

[0198] The processor 320 can determine the negative electrode load amount of the target cell BC according to the information mapped to the minimum profile error. The processor 320 can estimate the negative electrode load amount of the target cell BC based on the extracted negative electrode scaling factor. For reference, at least one of the positive electrode participation start point, the positive electrode participation end point, the negative electrode participation start point, the negative electrode participation end point, the positive electrode scaling factor, and the negative electrode scaling factor when the target cell BC is in the new state can have been recorded in the memory unit 330 by performing the above-described analysis process when the target cell BC is in the new state.

[0199] The processor 320 can determine at least one deterioration parameter (for example, the positive electrode participation end point) based on the information mapped to the minimum profile error. Table 1 below summarizes the deterioration parameters and the formulas that can be used to determine each of the deterioration parameters.

[0200] Table 1

[0201]

[0202] Each of the variables listed in Table 1 is a diagnostic factor that can be determined through the above-described analysis process. The definitions of the deterioration parameters and the variables in Table 1 can be as follows.

[0203] P SOH : Positive SOH (State of Health) of the target cell BC

[0204] N SOH : Negative SOH of the target cell BC

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

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

[0207] P LOSS : Positive electrode loss rate of target monomer BC

[0208] N LOSS : Negative electrode loss rate of target monomer BC

[0209] L LOSS : Available lithium loss rate of target monomer BC

[0210] F LOSS : Total monomer loss rate of target monomer BC

[0211] P loading_MOL : Target monomer BC cathode loading

[0212] N loading_MOL : Negative electrode loading of target monomer BC

[0213] The positive electrode loading of any battery cell represents the amount of positive electrode active material (or available capacity) per unit area of ​​the positive electrode of the battery cell. The negative electrode loading of any battery cell represents the amount of negative electrode active material (or available capacity) per unit area of ​​the negative electrode of the battery cell. The unit of loading can be mAh / cm 2 or mg / cm 2 In Table 1, P loading_ref represents the reference positive electrode loading, and N loading_ref Represents a reference negative electrode loading amount. The reference positive electrode loading amount is a predetermined value representing the amount of positive electrode active material (or available capacity) per unit area of ​​the positive electrode of a reference cell. The reference positive electrode loading amount may be a value obtained by dividing the reference positive electrode capacity by the reference positive electrode area. Here, the reference positive electrode capacity may be a value preset to the total positive electrode capacity of the reference cell. The reference positive electrode area may be a value preset to the area of ​​the positive electrode of the reference cell. The reference negative electrode loading amount is a predetermined value representing the amount of negative electrode active material (or available capacity) per unit area of ​​the negative electrode of the reference cell. The reference negative electrode loading amount may be a value obtained by dividing the reference negative electrode capacity by the reference negative electrode area. Here, the reference negative electrode capacity may be a value preset to the total negative electrode capacity of the reference cell. The reference negative electrode area may be a value preset to the negative electrode area of ​​the reference cell.

[0214] <variable>

[0215] pi BOL : The positive electrode capacity (positive electrode SOC) at the starting point of positive electrode participation when the target monomer BC is in the BOL state

[0216] pi MOL : The current cathode participation starting point of the target monomer BC (e.g., Figure 6 The positive electrode capacity (positive electrode SOC) of pi') shown in

[0217] pf BOL : The positive electrode capacity (positive electrode SOC) at the end point when the target monomer BC is in the BOL state

[0218] pf MOL : The current cathode participation endpoint of the target monomer BC (e.g., Figure 6 The positive electrode capacity (positive electrode SOC) of the pf') shown in

[0219] ni BOL : Negative electrode capacity (negative electrode SOC) at the starting point of negative electrode participation when the target monomer BC is in the BOL state

[0220] ni MOL : The current negative electrode participation starting point of the target monomer BC (e.g., Figure 6 The negative electrode capacity (negative electrode SOC) of ni) is shown in

[0221] nf BOL : When the target monomer BC is in the BOL state, the negative electrode capacity of the negative electrode at the end point (negative electrode SOC)

[0222] nf MOL : The current negative electrode participation endpoint of the target monomer BC (e.g., Figure 6 The negative electrode capacity (negative electrode SOC) of nf') is shown in

[0223] ps BOL : positive electrode scaling factor when the target monomer BC is in the BOL state

[0224] ps MOL : Current positive scaling factor of the target monomer BC

[0225] ns BOL : Negative scaling factor when the target monomer BC is in the BOL state

[0226] ns MOL : Current negative scaling factor of target cell BC

[0227] The process of determining diagnostic factors for a target monomer BC may be repeated periodically or aperiodically throughout the life of the target monomer BC.

[0228] The processor 320 can limit at least one of the allowable voltage range and the allowable SOC range of the target unit BC based on the estimated value of the negative electrode load amount of the target unit BC. Relationship data indicating a predetermined positive correlation between the amount of decrease in the negative electrode load amount with respect to the BOL state and the limit level can be pre-stored in the memory unit 330. That is, according to the relationship data, a decrease in the negative electrode load amount causes a decrease in at least one of the allowable voltage range and the allowable SOC range. The decrease in the range means an increase in at least one of the lower limit of the range and the upper limit of the range.

[0229] For example, assume that the allowable voltage range and the allowable SOC range are 2.5 V to 4.5 V and 5% to 95%, respectively. If the current negative electrode load amount N loading_MOL is estimated to be 90% of the value N loading_BOL at the BOL state, the allowable voltage range can be decreased to 2.75 V to 4.05 V, and the allowable SOC range can be decreased to 5.5% to 85.5%.

[0230] Figure 10 is a flowchart exemplarily describing a battery diagnosis method according to the first embodiment of the present disclosure. The method according to Figure 10 may be executed by the battery diagnosis device.

[0231] At step S1010, the processor 320 controls the stimulus application device 301 to intermittently apply a second electric stimulus greater than the first electric stimulus to the target unit BC during a state change period until the electrical state of the target unit BC changes from an initial state to a target state.

[0232] At step S1020, the processor 320 obtains, using the communication unit 310, current time series data representing a change history of the electric current of the target unit BC during the state change period and voltage time series data representing a change history of the full-cell voltage of the target unit BC during the rest period of the second electric stimulus applied in the state change period. The voltage time series data can include a measured value of the full-cell voltage at an end time point of each rest period (see Figure 3a D OCV ).

[0233] The communication unit 310 can collect, from the electric vehicle 1 after the end of the state change period, the current time series data and the voltage time series data generated by the electric vehicle 1.

[0234] Alternatively, the communication unit 310 can periodically collect, from the electric vehicle 1 during the state change period, measurement data representing at least one of a measurement value of the current of the target cell BC and a measurement value of the full-cell voltage. In this case, each measurement value collected multiple times during the state change period can be recorded in the memory unit 330 in chronological order. The processor 320 can generate the current time series data and the voltage time series data from the set of measurement values collected during the state change period.

[0235] In step S1030, the processor 320 generates a measured full-cell profile 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 (see Figure 3b in M).

[0236] In step S1040, the processor 320 analyzes the measured full-cell profile to estimate the negative electrode load amount of the target cell BC. The negative electrode load amount represents the amount of negative electrode active material per unit area of the negative electrode of the target cell.

[0237] In step S1050, the processor 320 determines the negative electrode loss rate of the target cell BC based on the estimated value of the negative electrode load amount (which can also be referred to as the “negative electrode capacity loss rate”).

[0238] In step S1060, the processor 320 limits at least one of the allowable voltage range and the allowable SOC range of the target cell BC based on the estimated value of the negative electrode load amount. Alternatively or in addition, the allowable current of the target cell BC can be limited (down-regulated).

[0239] In the method according to Figure 10 , only one of steps S1050 and S1060 can be performed.

[0240] In step S1070, the processor 320 can transmit, using the communication unit 310, a diagnosis result of the target cell BC to the electric vehicle 1. The diagnosis result includes at least one of the negative electrode load amount, the negative electrode loss rate, the limited allowable voltage range, and the limited allowable SOC range.

[0241] Figure 11 is a flowchart exemplarily describing a battery diagnosis method according to a second embodiment of the present disclosure. The method according to Figure 11 may be performed by a battery diagnosis apparatus.

[0242] At step S1110, the processor 320 controls the stimulus application device 301 to intermittently apply, to the target cell BC, a second electric stimulus greater than the first electric stimulus during a state change period until the electrical state of the target cell BC changes from an initial state to a target state.

[0243] In step S1120, the processor 320 obtains, using the communication unit 310, current time series data representing a history of changes in the current of the target cell BC during the state change period and voltage time series data representing a history of changes in the full-cell voltage of the target cell BC during the rest period of the second electric stimulus applied during the state change period.

[0244] Unlike the above according to the first embodiment, the voltage time series data obtained in step S1120 includes a measurement value of the full-cell voltage measured three or more times for each rest period.

[0245] 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 can be provided to replace a set of three measurement values of the full-cell voltage for each rest period included in the voltage time series data obtained in step S1120 with a single OCV value. Thus, if a total of X rest periods are permitted during the state change period and the full-cell voltage is measured three times for each rest period, it will be readily understood by those skilled in the art that the voltage time series data obtained in step S1120 will include 3X full-cell voltage measurement values, and the corrected voltage time series data will include X OCV values.

[0246] In step S1130, the processor 320 generates a measured full-cell profile 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 (see M in FIG. 12). Figure 3b

[0247] In step S1140, the processor 320 analyzes the measured full-cell profile to estimate the negative electrode load amount of the target cell BC.

[0248] In step S1150, the processor 320 determines the negative electrode loss rate of the target cell BC based on the estimated value of the negative electrode load amount.

[0249] In step S1160, the processor 320 limits at least one of the allowable voltage range and the allowable SOC range of the target cell BC based on the estimated value of the negative electrode load amount. Alternatively or additionally, the allowable current of the target cell BC can be limited (down-regulated).

[0250] In the method according to Figure 11 , only one of steps S1150 and S1160 can be performed.

[0251] ​In step S1170, the processor 320 can transmit the diagnosis result of the target monobloc BC to the electric vehicle 1 through the communication unit 310. The diagnosis result includes at least one of the negative electrode load amount, the negative electrode loss rate, the limited allowable voltage range, and the limited allowable SOC range.

[0252] Figure 12 is referred to in describing the process of correcting the voltage time series data performed in step S1122 of Figure 11 of the process of correcting the voltage time series data performed in step S1122 of

[0253] Figure 12 the symbol 1200 in Figure 3a one of the voltage drop segments shown in R indicates a point in time at which the reference time has elapsed from a start point in time of the rest period. Until t R the portion of t R is depicted as a solid line, and the portion after t

[0254] Referring to Figure 12 , during each rest period, the target monobloc BC is placed in a no-load state in which neither charging nor discharging is performed.

[0255] During the no-load state, the full monobloc voltage of the target monobloc BC gradually converges toward the OCV corresponding to the SOC of the target monobloc BC. The behavior of the full monobloc voltage of the target monobloc BC in a certain rest period can be equivalent to the voltage response of a primary RC circuit, such as the following Equation 1.

[0256] < Equation 1 >

[0257]

[0258] In Equation 1, t is the time elapsed from a start point in time of a certain rest period, V full (t) is the full monobloc voltage at t, V OCV is the actual OCV, V S is the full monobloc voltage at the start point in time of the certain rest period, and τ is a time constant determined by the internal resistance and the capacity of the target monobloc BC.

[0259] In Equation 1, V full (t) is measurable, and V OCV , V S , and τ are unknown. Since there are three unknown values, the OCV of the certain rest period can be estimated based on V full (t) measured at three different timings in the certain rest period. The following Equation 2 can be used to estimate the OCV of each rest period.

[0260] <Formula 2>

[0261] In Equation 1, t is the time elapsed from the starting time point of the specific rest period, Vfull(t) is the full cell voltage at t, VOCV is the actual OCV, VS is the full cell voltage at the starting time point of the specific rest period, and τ is a time constant determined by the internal resistance and the capacity of the target cell BC.

[0262] In Equation 1, Vfull(t) is measurable, and VOCV, VS, and τ are unknown. Since there are three unknown values, the OCV of the specific rest period can be estimated based on Vfull(t) measured at three different timings in the specific rest period. Equation 2 below can be used to estimate the OCV of each rest period.

[0263] <Formula 2>

[0264]

[0265] In Equation 2, t1, t2, and t3 are sequential measurement timings of the full cell voltage. The time difference between t1 and t2 can be the same as the time difference between t2 and t3. Meanwhile, in Figure 12 , t R and t3 are shown to be different, but t R = t3 is also possible. In this case, V full (t3) = D OCV .

[0266] The processor 320 can determine D OCV in the same manner as V OCV_C calculated by Equation 2.

[0267] The processor 320 can convert the voltage time series data obtained in step S1120 into the corrected voltage time series data of step S1130 by repeating the process of replacing the three full cell voltage measurement values (V OCV_C (t1), V full (t2), V full (t3)) of each rest period with a single OCV value (D full ) for all rest periods. The corrected voltage time series data contains X OCV values. The processor 320 can apply curve fitting logic to the corrected voltage time series data to generate the measured full cell profile M.

[0268] For reference, D OCV is a measured value of the full cell voltage at the end time point of the rest period (before the polarization is completely resolved), and D OCV_C is the full cell voltage in a state where the polarization is completely resolved (i.e., VOCV ) of the target monomer BC. Thus, it can be considered that D OCV_C is closer to the actual OCV of the target monomer BC. OCV is closer to the actual OCV of the target monomer BC.

[0269] The embodiments of the disclosure described above are not only realized by the apparatus and the method, and can be realized by a program or a recording medium having a program recorded thereon which performs a function corresponding to the configuration of the embodiments of the disclosure, and according to the disclosure of the previously described embodiments, a person skilled in the art can easily realize such a realization.

[0270] Although the disclosure has been described above with respect to a limited number of embodiments and drawings, the disclosure is not limited thereto, and it is obvious to those skilled in the art that various modifications and changes can be made to the technical aspects of the disclosure and the scope of the appended claims.

[0271] In addition, since a person skilled in the art can make many substitutions, modifications, and changes to the disclosure without departing from the technical aspects of the disclosure, the disclosure is not limited by the above-described embodiments and drawings, and some or all of the embodiments can be selectively combined to allow various modifications.

Claims

1. A battery diagnostic device comprising: a processor configured to control the stimulus applying device to intermittently apply a second electrical stimulus greater than the first electrical stimulus to a target cell during a state change period until the electrical state of the target cell changes from an initial state to a target state, the target cell being a battery cell to be diagnosed; as well as 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 a rest period of the second electrical stimulation applied in the state change period, Wherein, the processor is configured to: generating a measured full-cell profile indicating a corresponding relationship 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 The negative electrode loading amount is estimated by analyzing the measured whole cell profile, where the negative electrode loading amount represents the amount of negative electrode active material per unit area of ​​the negative electrode of the target cell.

2. The battery diagnostic device according to claim 1, wherein: The first electrical stimulation is an electrical stimulation that makes the difference between the OCV and the CCV in the target cell equal to or less than a reference value; and The second electrical stimulation is an electrical stimulation that makes the difference between the OCV and the CCV in the target cell greater than the reference value.

3. The battery diagnostic device according to claim 1, wherein: The first electrical stimulation is charging using a first current rate, and The second electrical stimulation is charging using a second current rate that is greater than the first current rate.

4. The battery diagnostic device according to claim 1, wherein: The first electrical stimulation is a discharge using a first current rate, and The second electrical stimulation is performed by discharging at a second current rate that is greater than the first current rate.

5. The battery diagnostic device according to claim 1, wherein: The voltage time series data are measured values ​​of the whole-cell voltage during the rest period of the second electrical stimulation, and the measured values ​​are arranged in time sequence as the OCV of the target cell.

6. The battery diagnostic device according to claim 1, wherein: The processor is configured to control the stimulation applying device to initiate a rest period of the second electrical stimulation each time a current integrated value of the current changes by a threshold integrated value.

7. The battery diagnostic device according to claim 6, wherein: The processor is configured to control the stimulation applying device to resume application of the second electrical stimulation when a reference time has elapsed from a start time point of the rest period of the second electrical stimulation.

8. The battery diagnostic device according to claim 1, wherein: The processor is configured to determine a negative electrode loss rate of the target cell based on the estimated value of the negative electrode loading amount.

9. The battery diagnostic device according to claim 1, wherein: The processor is configured to limit at least one of an allowable voltage range and an allowable SOC range of the target cell based on the estimated value of the negative electrode load amount. 10 . A charging station comprising the battery diagnostic device according to claim 1 . 11 . A cloud server comprising the battery diagnosis device according to claim 1 .

12. A battery diagnosis method comprising: controlling the stimulus applying device to intermittently apply a second electrical stimulus greater than the first electrical stimulus to a target cell during a state change period until the electrical state of the target cell changes from an initial state to a target state, the target cell being a battery cell to be diagnosed; 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 entire cell voltage of the target cell during a rest period of the second electrical stimulation applied in the state change period; generating a measured full-cell profile indicating a corresponding relationship 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; as well as The negative electrode loading amount is estimated by analyzing the measured whole cell profile, where the negative electrode loading amount represents the amount of negative electrode active material per unit area of ​​the negative electrode of the target cell.

13. The battery diagnosis method according to claim 12, wherein: The voltage time series data are measured values ​​of the whole-cell voltage during the rest period of the second electrical stimulation, and the measured values ​​are arranged in time sequence as the OCV of the target cell.

14. The battery diagnosis method according to claim 12, further comprising: The negative electrode loss rate of the target monomer is determined based on the estimated value of the negative electrode loading amount.

15. The battery diagnosis method according to claim 12, further comprising: At least one of an allowable voltage range and an allowable SOC range of the target cell is restricted based on the estimated value of the negative electrode load amount.

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