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 positive participation endpoint.

Description

Technical Field

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

[0002] This application claims priority to Korean Patent Application No. 10-2023-0154876 filed on November 9, 2023, and Korean Patent Application No. 10-2023-0133644 filed on October 6, 2023, in Korea, the disclosures of which are incorporated herein by reference. Background Art

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

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

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

[0006] Accurately diagnosing a battery's internal state is crucial for its safety and longevity. To diagnose a battery's internal state without disassembling it, we primarily use relationship data (such as a full-cell profile) that shows the corresponding relationship between capacity and voltage.

[0007] Traditionally, full-cell profiles are obtained by repeatedly measuring a battery's voltage and capacity at short intervals while applying a constant electrical stimulus (e.g., constant-current charge or discharge) to the battery. However, to minimize polarization (or overpotential) that reduces diagnostic accuracy, the level of electrical stimulus applied to the target cell must be reduced, which has the limitation of requiring excessive time to obtain a full-cell profile. Furthermore, while higher levels of electrical stimulation are advantageous in terms of time reduction, they are accompanied by severe polarization, which cannot guarantee diagnostic accuracy. Summary of the Invention

[0008] Technical issues

[0009] The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure aims to provide a battery diagnostic device and a battery diagnostic method, which can obtain relationship data representing the corresponding relationship between the capacity and voltage of the target cell by using a method of intermittently applying high-level electrical stimulation to the target cell, and diagnose the positive electrode degradation state of the target cell (for example, the positive electrode participation endpoint explained later) based on the obtained relationship data.

[0010] These and other purposes and advantages of the present disclosure can be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of the present disclosure. Moreover, it will be readily understood that the purposes and advantages of the present disclosure can be achieved by the means shown in the appended claims and their combinations.

[0011] Technical Solution

[0012] In one aspect of the present disclosure, a battery diagnostic apparatus is provided, comprising: a processor configured to control a stimulus application device to intermittently apply a second electrical stimulus, greater than a first electrical stimulus, to a target cell during a state change period 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; and a communication unit configured to obtain current time-series data representing a history of changes in the current of the target cell during the state change period, and voltage time-series data representing a history of changes in the full-cell voltage of the target cell during a rest period of the second electrical stimulus applied during the state change period. The processor is configured to generate a measured full-cell profile representing a correspondence between the capacity and the full-cell voltage of the target cell based on the current time-series data and the voltage time-series data, and to estimate a positive electrode participation endpoint of the target cell by analyzing the measured full-cell profile.

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

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

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

[0016] The voltage time series data may be measured values ​​of the voltage of all cells during a rest period of the second electrical stimulation, the measured values ​​being arranged in time sequence as the OCV of the target cell.

[0017] The processor may be 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.

[0018] The processor may be 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.

[0019] The processor may be configured to determine whether a positive electrode capacity loss of the target cell occurs based on the estimated positive electrode participation endpoint.

[0020] The processor may 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 positive electrode participation endpoint.

[0021] In yet another aspect of the present disclosure, a charging station is provided, comprising the battery diagnostic device.

[0022] In yet another aspect of the present disclosure, a cloud server is provided, comprising a battery diagnosis device.

[0023] In another aspect of the present disclosure, a battery diagnosis method is also provided, including: controlling a 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 full-cell voltage of the target cell during a rest period of the second electrical stimulus applied in the state change period; generating a measured full-cell profile representing a correspondence between the capacity of the target cell and the full-cell voltage based on the current time series data and the voltage time series data; and estimating the positive electrode participation endpoint of the target cell by analyzing the measured full-cell profile.

[0024] The voltage time series data may be measured values ​​of the voltage of all cells during a rest period of the second electrical stimulation, the measured values ​​being arranged in time sequence as the OCV of the target cell.

[0025] The battery diagnosis method may further include determining whether a positive electrode capacity loss of the target cell occurs based on the estimated positive electrode participation endpoint.

[0026] The battery diagnosis method may further include limiting at least one of an allowable voltage range and an allowable SOC range of the target cell based on the estimated positive electrode participation endpoint.

[0027] Beneficial effects

[0028] According to at least one embodiment of the present disclosure, relational data representing the corresponding relationship between the capacity and voltage of the target cell can be obtained by using a method of intermittently applying high-level electrical stimulation to the target cell, and the positive electrode degradation state of the target cell (positive electrode participation endpoint explained later) can be diagnosed based on the obtained relational data.

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

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

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

[0032] 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.

[0033] Figure 2 are graphs referred to to describe examples of a reference positive electrode profile and a reference negative electrode profile, respectively.

[0034] Figure 3a and Figure 3b is a graph referred to to exemplarily describe a process of obtaining a measured whole-cell profile of a target cell.

[0035] Figures 4 to 6 is a diagram referred to to describe an example of a process of generating a comparative full-monobody profile line for comparison with a measured full-monobody profile line according to one embodiment of the present disclosure.

[0036] Figures 7 to 9 is a diagram referred to to describe another example of a process for generating a comparative full-monobody profile line for comparison with a measured full-monobody profile line according to one embodiment of the present disclosure.

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

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

[0039] Figure 12 is referred to in the description Figure 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 elements stated, but do not exclude the presence or addition of one or more other elements. In addition, the term "control 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 (e.g., an ECU: Electronic Control Unit) is configured to transmit a key-on signal to the battery management system 100 in response to a user switching a start button (not shown) provided in the electric vehicle 1 to the on position. The vehicle controller 2 is also configured to transmit a key-off signal to the battery management system 100 in response to a user switching the start button to the off position. The charging station 300 can communicate with the vehicle controller 2 and supply charging power selected from constant power, constant current, and constant voltage via the charge terminal P+ and discharge terminal P− of the battery pack 10.

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

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

[0051] The relay 20 is electrically connected in series to the battery 11 through a power path connecting the battery 11 and the inverter 30. Figure 1 , a relay 20 is shown connected between the positive terminal of the battery 11 and the charge and discharge terminal P+. The relay 20 is controlled to switch on and off in response to a switching signal from the battery management system 100. The relay 20 may be a mechanical contactor that switches on and off by the magnetic force of a coil, or a semiconductor switch such as a MOSFET (metal oxide semiconductor field effect transistor).

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

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

[0054] The sensing unit 110 includes a voltage sensor 111 . The sensing unit 110 may 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 the voltage across the battery cell BC (also referred to as the "full-cell voltage") and generate a voltage signal representing a detection value of the detected voltage. The voltage sensor 111 may be implemented as one or a combination of two or more known voltage detection elements, such as a voltage measurement IC.

[0056] The current sensor 112 is connected in series to the battery 11 through the current path between the battery 11 and the inverter 30. The current sensor 112 is configured to detect the current (also referred to as "charging and discharging current") flowing through the battery 11 and generate a current signal representing the detection value of the detected current. N ) are connected in series, so the current flowing in the battery 11 is the same as the current flowing in the battery cell BC. The current sensor 112 can be implemented as one or a combination of two or more known current detection elements such as a shunt resistor, a Hall effect element, etc.

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

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

[0059] Control circuit 130 can collect voltage signals from voltage sensor 111 and current signals from current sensor 112. In this specification, "detection signal" can refer to either the voltage signal alone or both. Specifically, control circuit 130 can use an ADC (analog-to-digital converter) built into it to convert each analog signal collected from sensors 111 and 112 into a digital value and record the digital value. Alternatively, each of voltage sensor 111 and current sensor 112 can include an ADC and transmit the digital value to control circuit 130.

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

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

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

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

[0064] In this specification, time series data for a particular parameter indicates the history of changes in that parameter over time. Furthermore, a profile (or curve) representing the corresponding relationship between any two parameters obtained at the same timing in the same period can be a mapping of the two time series data for the two parameters, such that they can be represented in the form of a two-dimensional graph, or can be a polynomial equation obtained by applying a predetermined curve fitting logic to a set of two mapped time series data. The degree of the highest term in the polynomial equation can be predetermined.

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

[0066] Charging station 300 may include a stimulus application device 301 and a battery diagnostic apparatus 302. Alternatively, battery diagnostic apparatus 302 may be configured independently of charging station 300. For example, battery diagnostic apparatus 302 may be configured to be included in a cloud server (not shown). The cloud server may be located remotely from charging station 300. In this case, communication unit 310 of battery diagnostic apparatus 302 may perform diagnostic procedures on target cells through remote communication with stimulus application device 301 and / or electric vehicle 1.

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

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

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

[0071] Memory unit 330 may include at least one type of storage medium, such as a flash memory type, a hard disk type, a solid-state drive (SSD) type, a silicon disk drive (SDD) type, a multimedia card micro type, a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), or a programmable read-only memory (PROM). Memory unit 330 may store data and programs required for diagnostic processes performed by processor 320. Memory unit 330 may also store data representing the results of computational operations performed by processor 320. Memory unit 330 may also store data sets and software used to diagnose the degradation state of battery cells BC.

[0072] Figure 2 is a graph referred to to describe an example of each of the reference positive electrode profile and the reference negative electrode profile. Figure 2 In the graph, the horizontal axis (X-axis) represents capacity (Ah), and the vertical axis (Y-axis) represents voltage.

[0073] refer to Figure 2 Memory unit 330 can store a reference positive electrode cross-sectional line Rp and a reference negative electrode cross-sectional line Rn. The reference cell can be a button-type cell including a positive electrode half cell and a negative electrode half cell, or can be a three-electrode cell. Hereinafter, the positive electrode and the positive electrode half cell of the reference cell will be described with equivalent terms, and the negative electrode and the negative electrode half cell of the reference cell will be described with equivalent terms.

[0074] The reference positive electrode profile Rp may be a profile that represents the relationship between the positive electrode voltage and capacity of a reference cell. The positive electrode voltage of a reference cell refers to the potential difference between the potential of a reference electrode (not shown) and the potential of the positive electrode of the reference cell. The positive electrode profile Rp may also be referred to as a positive electrode half-cell profile.

[0075] The reference negative electrode profile Rn may represent the relationship between the negative electrode voltage and capacity of a reference cell. The negative electrode voltage of a reference cell refers to the potential difference between the potential of the reference electrode and the potential of the negative electrode of the reference cell. The negative electrode profile Rn may also be referred to as a negative electrode half-cell profile.

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

[0077] Each of the positive electrode voltage and the negative electrode voltage may 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 stimulation may be discharge using a first current rate, and the second electrical stimulation may be discharge using a second current rate greater than the first current rate.

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

[0087] For the sake of explanation, assume Figures 2 to 9 The middle horizontal axis represents the charging capacity.

[0088] At least one of the reference positive electrode section line Rp and the reference negative electrode section line Rn may be aligned along the horizontal axis so that the common capacity range ( Figure 2 The synthesized results of a portion of the 5 to 50 Ah) match the reference full monomer profile R. Figure 2 An example is shown in which the reference negative electrode section line Rn is aligned to be shifted to the right based on the starting point (the point corresponding to the capacity 0) of the reference positive electrode section line Rp.

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

[0090] The reference full-cell profile R represents the relationship between the capacity and full-cell voltage of a new, verified good battery cell. In other words, the reference cell has the same positive and negative electrode performance as a new, verified good battery cell. The positive and negative electrode performance of any battery cell can be collectively referred to as "charge / discharge performance."

[0091] A new battery cell refers to a battery cell in a new state. This new state can be the same concept as BOL (Beginning of Life). For example, the period from the time the cumulative charge / discharge capacity reaches the set capacity after manufacturing completion is called BOL, and from the time the cumulative charge / discharge capacity reaches the set capacity, it is called MOL (Middle of Life).

[0092] The reference full cell profile R may represent the corresponding relationship between the voltage and capacity of the reference cell within at least the voltage range of interest (eg, 3.0 V to 4.0 V). The lower limit and upper limit of the voltage range of interest may be the first set voltage ( Figure 2 3.0V) and the second set voltage ( Figure 2 4.0V in the CMOS).

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

[0094] In this specification, the positive electrode participation starting point on the positive electrode section line of any battery cell indicates the positive electrode voltage and positive electrode capacity (or positive electrode SOC) when the total cell voltage of the corresponding battery cell matches the first set voltage. Furthermore, the negative electrode participation starting point on the negative electrode section line of the corresponding battery cell indicates the negative electrode voltage and negative electrode capacity (or negative electrode SOC) when the total cell voltage of the corresponding battery cell matches the first set voltage. Therefore, the voltage difference between the positive electrode participation starting point and the negative electrode participation starting point can be equal to the first set voltage.

[0095] Furthermore, the positive electrode participation endpoint on the positive electrode section line of any battery cell indicates the positive electrode voltage and positive electrode capacity (or positive electrode SOC) when the full cell voltage of the corresponding battery cell matches the second set voltage. Furthermore, the negative electrode participation endpoint on the negative electrode section line of the corresponding battery cell indicates the negative electrode voltage and negative electrode capacity (or negative electrode SOC) when the full cell voltage of the corresponding battery cell matches the second set voltage. Therefore, the voltage difference between the positive electrode participation endpoint and the negative electrode participation endpoint can be equal to the second set voltage.

[0096] In this specification, the positive electrode capacity (capacity value) at a specific point on the positive electrode section line of any battery cell may refer to the capacity difference between either of the two endpoints of the positive electrode section line and the specific point. The positive electrode SOC at a specific point on the positive electrode section line of any battery cell may refer to the ratio of the capacity difference between either of the two endpoints of the positive electrode section line (e.g., the low-capacity point) and the specific point to the capacity difference between the two endpoints of the positive electrode section line. The capacity difference between the two endpoints of the positive electrode section line may be referred to as the total positive electrode capacity.

[0097] Similarly, the negative electrode capacity (capacity value) at a specific point on the negative electrode section line of any battery cell can refer to the capacity difference between either of the two endpoints of the negative electrode section line (or the positive electrode section line) and the specific point. The negative electrode SOC at a specific point on the negative electrode section line of any battery cell can refer to the ratio of the capacity difference between either of the two endpoints (e.g., the low-capacity point) of the negative electrode section line (or the positive electrode section line) and the specific point to the capacity difference between the two endpoints of the negative electrode section line. The capacity difference between the two endpoints of the negative electrode section line can be referred to as the total negative electrode capacity.

[0098] In memory unit 330, information indicating the voltage at each of the reference positive electrode participation starting point (pi0), the reference positive electrode participation end point (pf0), the reference negative electrode participation starting point (ni0), and the reference negative electrode participation end point (nf0) may be pre-recorded. The reference positive electrode participation starting point (pi0) and the reference positive electrode participation end point (pf0) are the positive electrode participation starting point and the positive electrode participation end point, respectively, on reference positive electrode profile line Rp. The reference negative electrode participation starting point (ni0) and the reference negative electrode participation end point (nf0) are the negative electrode participation starting point and the negative electrode participation end point, respectively, on reference negative electrode profile line Rn.

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

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

[0101] Figure 3a The graph depicted in FIG shows an example of the change in the full-cell voltage of a target cell over time due to the intermittent application of the second electrical stimulus. The target cell is a battery cell to be diagnosed by the battery diagnostic device. The target cell may be a new battery cell that needs to be verified as a good product, or a battery cell that has been verified as a good product and is no longer a new product due to deterioration. Hereinafter, the target cell is also denoted by the reference symbol BC.

[0102] refer to Figure 3a , the processor 320 can control the stimulation applying device 301 to intermittently apply a second electrical stimulation greater than the first electrical stimulation 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] Processor 320 may determine at least one of a threshold integral value, a threshold SOC, and a threshold time based on the target cell's full charge capacity, SOH, or previous diagnostic results (e.g., the potential and / or capacity value at the positive electrode participation endpoint). At least one of the threshold integral value, SOC, and time may have a predetermined negative correlation with the full charge capacity, SOH, or previous diagnostic results, and relationship data defining this correlation (a data table for controlling the rest period) may be pre-stored in memory unit 330. Due to the predetermined negative correlation, 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 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 changes in the full-cell voltage during the rest period of the state change period.

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

[0109] When a reference time has passed since the start time of the rest period of the second electrical stimulation, the processor 320 may control the stimulation application device 301 to resume application of the second electrical stimulation. The reference time may be predetermined so that the polarization caused by the second electrical stimulation can be sufficiently resolved. For example, the reference time, which serves as the length of the rest period, may be the time required for the polarization at the start time of the rest period to become 10% or less.

[0110] During each rest period of the second electrical stimulation, the full-cell voltage of the target cell BC is measured at least once. As an example, the processor 320 may record the measured full-cell voltage at the end of each rest period of the second electrical stimulation as the OCV of the target cell BC. As another example, the full-cell voltage may be measured at least three times during each rest period of the second electrical stimulation, and the processor 320 may estimate the OCV of the target cell BC for each rest period based on the three full-cell voltage measurements during each rest period.

[0111] Therefore, voltage time series data can be generated by recording OCV a plurality of times with a time difference during the state change period. Figure 3a Each OCV point marked in OCV ) are data points representing voltage time series data.

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

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

[0114] The conditions related to the diagnosis of target monosomic BC are assumed to be as follows.

[0115] (i) First electrical stimulation = charging at 0.05 C

[0116] (ii) Second electrical stimulation = charging at 3.0 C

[0117] (iii) Length of rest period of second electrical stimulation = 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] Specifically, each data point of the current time series data and the voltage time series data is indexed in chronological order. Therefore, the processor 320 can generate the capacity time series data by sequentially integrating the data points of the current time series data. Furthermore, the processor 320 can generate a measured full-cell profile M by applying a curve fitting algorithm to a set of multiple Q-OCV pairs obtained by mapping the capacity time series data to 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 polynomial equations 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 may represent the corresponding relationship between the capacity and OCV of the target cell BC within at least a voltage range of interest (eg, 3.0 V to 4.0 V).

[0129] Since there are inevitably some differences in the charge / discharge performance between the reference cell and the target cell BC, there are also some differences between the measured full-cell profile M and the reference full-cell profile R, such as Figure 3b As shown in .

[0130] For example, at the same capacity value, the voltage of the measured full-cell profile M is higher than the voltage of the reference full-cell profile R, which is caused by manufacturing defects of the target cell BC, loss of positive electrode capacity, loss of negative electrode capacity and / or loss of available lithium. Obviously, as the target cell BC deteriorates through repeated charge / discharge, the difference between the measured full-cell profile M and the reference full-cell profile R will gradually increase. Figure 3b , and reference Figure 2 Unlike the reference cell described, the full cell voltage of the target cell BC requires a charging capacity of 40 Ah to reach the second set voltage from the first set voltage, which is 5 Ah less than the charging capacity of 50 Ah of the reference cell under the same conditions.

[0131] At the same time, Figure 2 and Figure 3b In the graph of , Ah is used as the unit on the horizontal axis, but the unit can be expressed in other forms. For example, the unit on the horizontal axis can be percentage %, which represents SOC (state of charge) instead of Ah.

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

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

[0134] Processor 320 can generate at least one comparative full-cell profile by directly adjusting reference positive electrode profile Rp and reference negative electrode profile Rn. Alternatively, at least one comparative full-cell profile can be pre-determined based on reference positive electrode profile Rp and reference negative electrode profile Rn and stored in memory unit 330. In this case, processor 320 can also obtain the comparative full-cell profile by accessing memory unit 330 and reading the comparative full-cell profile.

[0135] The processor 320 can generate multiple comparative full-cell profiles based on the reference positive profile Rp and the reference negative profile Rp by repeatedly adjusting each of the reference positive profile Rp and the reference negative profile Rp to several levels and then synthesizing them. The comparative full-cell profiles can also be referred to as "adjusted reference full-cell profiles."

[0136] The processor 320 may designate any one of the plurality of comparative full-cell profiles that has the smallest error relative to the measured full-cell profile M. The processor 320 may then determine that the adjusted positive and negative electrode profiles mapped to the designated comparative full-cell profiles are the positive and negative electrode profiles of the target cell BC.

[0137] In this regard, various methods known at the time of filing this application can be used to determine the error between two section lines, each of which can be represented in a two-dimensional coordinate system. For example, the integral of the absolute value of the area between the two section lines or the RMSE (root mean square error) can be used as the error between the two section lines.

[0138] According to this configuration of the present disclosure, various state information regarding the target cell BC can be obtained based on the finalized adjusted positive and negative electrode profiles. The finalized adjusted positive and negative electrode profiles can be mapped to a comparison full-cell profile with minimal error. In particular, the comparison full-cell profile obtained using the finalized adjusted positive and negative electrode profiles can be nearly identical in shape to the measured full-cell profile M.

[0139] Therefore, according to the present disclosure, even without disassembling the target cell BC or manufacturing the target cell BC in the form of a three-electrode battery, the positive electrode cross-sectional line and the negative electrode cross-sectional line of the target cell BC can be obtained.

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

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

[0142] Furthermore, according to one embodiment of the present disclosure, the positive and negative electrode profiles of the target cell BC can be obtained in a simple manner. This disclosure can be implemented even if only one reference positive electrode profile Rp and one reference negative electrode profile Rn are stored in the memory unit 330. In other words, there is no need to store multiple reference positive electrode profiles Rp and / or multiple reference negative electrode profiles Rn in the memory unit 330. Therefore, the storage capacity of the memory unit 330 does not need to be high, and the extensive preliminary testing required to ensure the availability of multiple reference positive electrode profiles Rp and / or multiple reference negative electrode profiles Rn is not necessary.

[0143] In the following, reference Figures 4 to 9 , a process of analyzing and measuring the full-cell profile M to estimate one of the parameters involved in the current charge / discharge performance of the target cell BC (eg, the positive electrode participation termination point) will be described.

[0144] Figures 4 to 6 is a diagram referred to to describe an example of a process of generating a comparative full-monobody profile line for comparison with a measured full-monobody profile line according to one embodiment of the present disclosure.

[0145] Will refer to Figures 4 to 6 The described process for generating comparative full-cell profiles proceeds in the following order: a first routine (see Figure 4 ), a second routine for performing the section line shift (see Figure 5 ) and a third routine for performing capacity scaling (see Figure 6 ). That is, the process for generating a comparative full-body section line according to one embodiment of the present disclosure includes first to third routines.

[0146] First, refer to Figure 4 , reference positive electrode section line Rp and reference negative electrode section line Rn and Figure 2 The same as those shown in .

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

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

[0149] As an example, processor 320 may divide the positive electrode voltage range from the starting point to the end point (or the second set voltage) of reference positive electrode profile Rp into multiple small voltage segments and then set the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the positive electrode participation starting point (pi). Each small voltage segment may have a predetermined size (e.g., 0.01V). Next, processor 320 may set a point on reference negative electrode profile Rn that is lower than the positive electrode participation starting point (pi) by a first set voltage (e.g., 3V) as the negative electrode participation starting point (ni).

[0150] As another example, the processor 320 may divide the negative electrode voltage range from the start point to the end point of the reference negative electrode profile Rn into multiple small voltage segments of predetermined sizes, and then set the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the negative electrode participation starting point (ni). Next, the processor 320 may search for a point on the reference positive electrode profile Rp that is greater than the negative electrode participation starting point (ni) by a first set voltage, and set the searched point as the positive electrode participation starting point (pi).

[0151] Either the positive electrode participation endpoint (pf) or the negative electrode participation endpoint (nf) depends on the other.

[0152] As an example, the processor 320 may divide the voltage range from the second set voltage to the end point of the reference positive electrode profile Rp into multiple small voltage segments of predetermined sizes, and then set the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the positive electrode participation end point (pf). Next, the processor 320 may set a point on the reference negative electrode profile Rn that is lower than the positive electrode participation end point (pf) by a second set voltage (e.g., 4V) as the negative electrode participation end point (nf).

[0153] As another example, the processor 320 may divide the negative electrode voltage range from the start point to the end point of the reference negative electrode profile Rn into multiple small voltage segments of predetermined sizes, and then set the boundary point between two adjacent small voltage segments among the multiple small voltage segments as the negative electrode participation end point (nf). Next, the processor 320 may search for a point on the reference positive electrode profile Rp that is a second set voltage greater than the negative electrode participation end point (nf), and set the searched point as the positive electrode participation end point (pf).

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

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

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

[0157] Figure 5 The diagram shows a case where only the reference positive electrode profile Rp is shifted leftward to generate an adjusted reference positive electrode profile (Rp'). Consequently, the capacity value at the positive electrode participation starting point (pi') matches the capacity value at the negative electrode participation starting point (ni). The adjusted reference positive electrode profile (Rp') is the result of applying the voltage adjustment process between the left-shifted positive electrode participation starting point (pi) and the negative electrode participation starting point (ni) to the reference positive electrode profile Rp. As a result, the two points (pi, pi') differ only in capacity value and have the same voltage. The two points (pf, pf') also differ only in capacity value and have the same voltage.

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

[0159] according to Figure 5 In the example shown in , the processor 320 performs an additional adjustment process to shrink or expand at least one of the adjusted reference positive profile line (Rp′) and the reference negative profile line Rn along the horizontal axis.

[0160] refer to Figure 6, processor 320 can generate an adjusted reference positive electrode profile (Rp') by contracting or expanding the adjusted reference positive electrode profile (Rp') so that the capacity range between the two points (pi', pf') of the adjusted reference positive electrode profile (Rp') matches the capacity range of the full-cell profile M. In this case, any one of the two points (pi', pf') can be fixed. Therefore, the capacity difference between the two points (pi', pf') of the adjusted reference positive electrode profile (Rp') can match the capacity range of the full-cell profile M.

[0161] Furthermore, processor 320 can generate an adjusted reference negative electrode profile (Rn') by shrinking or expanding reference negative electrode profile Rn, such that the capacity range between two points (ni, nf) on reference positive electrode profile Rn matches the capacity range of full-cell profile M. In this case, any one of the two points (ni, nf) can be fixed. Therefore, the capacity difference between the two points (ni, nf') on the adjusted reference negative electrode profile (Rn') can match the capacity range of full-cell profile M.

[0162] exist Figure 6 The adjusted reference positive electrode profile (Rp'') is the contraction Figure 5 The results of the adjusted reference positive profile (Rp') shown in the figure and the adjusted reference negative profile (Rn') are the expansion Figure 5 The results for the reference negative electrode profile Rn are shown in FIG.

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

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

[0165] In addition, the capacity range of the two points (pi', pf') of the adjusted reference positive electrode profile (Rp') matches the capacity range of the two points (ni, nf') of the adjusted reference negative electrode profile (Rn'). Processor 320 can generate a comparative full-cell profile S by subtracting the profile between the two points (pi, pf') of the adjusted reference positive electrode profile (Rp') from the profile between the two points (ni, nf') of the adjusted reference negative electrode profile (Rn').

[0166] The processor 320 may calculate an error (section line error) between comparison values ​​between the comparison full-unit section line S and the reference full-unit section line R.

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

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

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

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

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

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

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

[0174] Figures 7 to 9 is a diagram referred to to describe another example of a process of generating a comparative full-monobody profile for comparison with a measured full-monobody profile according to one embodiment of the present disclosure. For reference, Figures 7 to 9 The embodiment shown in Figures 4 to 6 Therefore, it is usually used to describe Figures 4 to 6 The embodiments shown in Figures 7 to 9 The terms or reference numerals of the embodiments shown in FIG should be understood as being limited to each embodiment.

[0175] To refer to Figures 7 to 9 The explained process of generating comparative full-cell profiles proceeds in the following order: The fourth routine of capacity scaling is executed (see Figure 7 ), set the fourth point (positive electrode participation start point, positive electrode participation end point, negative electrode participation start point and negative electrode participation end point) of the fifth routine (see Figure 8 ) and a sixth routine that performs section line shifting (see Figure 9 ). That is, the process of generating a comparative full-body cross-section line according to another embodiment of the present disclosure includes fourth to sixth routines.

[0176] refer to Figure 7, the processor 320 generates an adjusted reference positive profile line (Rp′) and an adjusted reference negative profile line (Rn′) by applying a positive scaling factor and a negative scaling factor selected from the scaling value range to the reference positive profile line Rp and the reference negative profile line (Rn), respectively.

[0177] The scaling value range can be predetermined or can vary based on the ratio of the size of the capacity range of the measured full-cell profile M to the size of the capacity range of the reference full-cell profile (R). As an example, assuming that the positive and negative scaling factors can be selected from values ​​with intervals of 0.1% in the scaling value range (e.g., 90 to 99%) (i.e., 90%, 90.1%, 90.2%, ... 98.9%, 99%), 91 values ​​can be selected as the positive and negative scaling factors, respectively. In this case, based on 91×91=8281 adjustment levels (combinations of positive and negative scaling factors), a maximum of 8281 adjusted profile pairs can be generated. An adjusted profile pair refers to a combination of an adjusted positive profile and an adjusted negative profile.

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

[0179] Since the positive and negative scaling factors are less than 100%, the reference positive cross-sectional line Rp is contracted along the horizontal axis to obtain an adjusted reference positive cross-sectional line (Rp'), and the reference negative cross-sectional line Rn is contracted along the horizontal axis to obtain an adjusted reference negative cross-sectional line (Rn'). For ease of understanding, the reference positive cross-sectional line Rp and the reference negative cross-sectional line Rn are shown with their starting points fixed and their remaining portions contracted to the left along the horizontal axis.

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

[0181] Either the positive electrode participation starting point (pi') or the negative electrode participation starting point (ni') may depend on the other. Furthermore, either the positive electrode participation end point (pf') or the negative electrode participation end point (nf') may depend on the other. Furthermore, either the positive electrode participation starting point (pi') or the positive electrode participation end point (pf') may be set based on the other.

[0182] That is, if any one of the positive electrode participation starting point (pi'), the positive electrode participation end point (pf'), the negative electrode participation starting point (ni') and the negative electrode participation end point (nf') is set, the remaining three points can be automatically set by the first set voltage, the second set voltage and / or measuring the size of the capacity range of the full-cell profile M (for example, the charging capacity of 0% to 100% SOC).

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

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

[0185] As another example, the processor 320 may divide the voltage range from the second set voltage to the endpoint of the adjusted reference positive electrode profile (Rp') into multiple small voltage segments of predetermined sizes, and then set the boundary points of two adjacent small voltage segments among the multiple small voltage segments as the positive electrode participation endpoint (pf'). Next, the processor 320 may search for a point on the adjusted reference negative electrode profile (Rn') that is lower than the positive electrode participation endpoint (pf') by a second set voltage (e.g., 4V), and set the searched point as the negative electrode participation endpoint (nf').

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

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

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

[0189] As another example, when the positive electrode participation endpoint (pf') is first determined, the processor 320 can 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'). In addition, the processor 320 can search for a point on the adjusted reference negative electrode profile (Rn') that is lower than the positive electrode participation endpoint (pf') by a second set voltage and set the searched point as the negative electrode participation endpoint (nf'). In addition, the processor 320 can 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').

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

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

[0197] As described above, processor 320 can generate a comparative full-cell cross-section corresponding to each pair of a positive and negative scale factor selected from the scale value range. Since there are multiple pairs of positive and negative scale factors, it is obvious that multiple comparative cross-sections will also be generated. Processor 320 can identify the minimum cross-section error among the multiple comparative full-cell cross-sections and then obtain information mapped to the minimum cross-section error from memory unit 330.

[0198] The processor 320 can extract the positive electrode participation endpoint ( Figure 6 pf'' or Figure 9 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 may have been recorded in the memory unit 330 by performing the above-mentioned analysis process when the target cell BC is in the new state.

[0199] The processor 320 may determine at least one degradation parameter (eg, positive electrode participation endpoint) based on the information mapped to the minimum profile error. Table 1 below summarizes the degradation parameters and formulas that may be used to determine each degradation parameter.

[0200] Table 1

[0201]

[0202] Each variable listed in Table 1 is a diagnostic factor that can be determined through the above analysis process. The definitions of the degradation parameters and variables in Table 1 can be as follows. <Degradation Parameters>

[0203] P SOH : Cathode SOH (healthy state) of target cell BC

[0204] N SOH : Negative electrode SOH of target monomer BC

[0205] L SOH : Available lithium SOH of target monomer BC

[0206] F SOH : All monomer SOH of target monomer 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] As any battery cell degrades, at least one of the total positive electrode capacity, total negative electrode capacity, available lithium content, and total full cell capacity of the corresponding battery cell may gradually decrease from the value in the BOL state. The total full cell capacity may represent the capacity difference between the two end points of the full cell profile. For example, the total full cell capacity may represent the fully charged capacity (FCC). The available lithium content may represent the total amount of lithium that can contribute to charging and discharging of the battery cell. SOH It can express the maintenance rate of the total positive electrode capacity. SOH It can express the maintenance rate of the total negative electrode capacity. SOH It can indicate the maintenance rate of available lithium. SOH It can express the maintenance rate of the total monomer capacity.

[0214] P SOH With P LOSS sum, N SOH With N LOSS The sum of L SOH With L LOSS The sum of F SOH With F LOSS The sum of can be equal to 1. LOSS Can be equal to P LOSS With L LOSS sum.

[0215] 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_refrepresents 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.

[0216] <variable>

[0217] 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

[0218] 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

[0219] pf BOL : The positive electrode capacity (positive electrode SOC) at the end point when the target monomer BC is in the BOL state

[0220] 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

[0221] 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

[0222] 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

[0223] 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)

[0224] nf MOL : The current negative electrode participation endpoint of the target monomer BC (e.g., Figure 6The negative electrode capacity (negative electrode SOC) of nf') is shown in

[0225] ps BOL : positive electrode scaling factor when the target monomer BC is in the BOL state

[0226] ps MOL : Current positive scaling factor of the target monomer BC

[0227] ns BOL : Negative scaling factor when the target monomer BC is in the BOL state

[0228] ns MOL : Current negative scaling factor of target cell BC

[0229] 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.

[0230] The processor 320 may diagnose that a capacity loss occurs in the positive electrode of the target cell BC in response to a decrease in the positive electrode capacity (or positive electrode SOC) at the positive electrode participation endpoint relative to a value in a new product state.

[0231] Processor 320 can limit at least one of the permissible voltage range and the permissible SOC range of the target cell BC based on the positive electrode participation endpoint. Relationship data indicating a predetermined positive correlation between the change (e.g., decrease) in the positive electrode capacity (or positive electrode SOC) at the positive electrode participation endpoint relative to a new product state and a limit level can be pre-stored in memory unit 330. In other words, according to the relationship data, a decrease in the capacity value (positive electrode capacity or positive electrode SOC) at the positive electrode participation endpoint can cause a decrease in at least one of the permissible voltage range and the permissible SOC range. Decreasing the range means at least one of increasing the lower limit of the range or decreasing the upper limit of the range.

[0232] For example, assuming that the allowable voltage range and the allowable SOC range are 2.5 V to 4.5 V and 5% to 95%, respectively, if the positive electrode capacity at the positive electrode participation endpoint is estimated to be 90% of the value in the BOL state, the allowable voltage range can be reduced to 2.75 V to 4.05 V, and the allowable SOC range can be reduced to 5.5% to 85.5%.

[0233] Figure 10 is a flowchart exemplarily describing a battery diagnosis method according to a first embodiment of the present disclosure. Figure 10 The method may be executed by a battery diagnosis device.

[0234] At step S1010 , the processor 320 controls the stimulation applying device 301 to intermittently apply a second electrical stimulation greater than the first electrical stimulation to the target cell BC during a state change period until the electrical state of the target cell BC changes from the initial state to the target state.

[0235] In step S1020, the processor 320 uses the communication unit 310 to obtain current time series data indicating a change history of the current of the target cell BC during the state change period and voltage time series data indicating a change history of the overall cell voltage of the target cell BC during the rest period of the second electrical stimulation applied in the state change period. The voltage time series data may include a measured value of the overall cell voltage at the end time point of each rest period (see Figure 3a D OCV ).

[0236] The communication unit 310 may collect, from the electric vehicle 1 , current time series data and voltage time series data generated by the electric vehicle 1 after the state change period ends.

[0237] Alternatively, the communication unit 310 may periodically collect measurement data representing at least one of the current of the target cell BC and the voltage of all cells from the electric vehicle 1 during the state change period. In this case, each measurement value collected multiple times during the state change period may be recorded in chronological order in the memory unit 330. The processor 320 may generate current time series data and voltage time series data based on the collection of measurement values ​​collected during the state change period.

[0238] In step S1030, the processor 320 generates a measured full-cell profile indicating a corresponding relationship between the capacity of the target cell BC and the full-cell voltage based on the current time series data and the voltage time series data (see Figure 3b in the text).

[0239] In step S1040 , the processor 320 analyzes and measures the entire cell profile to estimate the cathode participation endpoint of the target cell BC.

[0240] In step S1050 , the processor 320 determines whether the positive electrode capacity loss of the target cell BC occurs based on the estimated positive electrode participation endpoint.

[0241] In step S1060 , the processor 320 limits at least one of the permissible voltage range and the permissible SOC range of the target cell BC based on the estimated positive electrode participation endpoint. Alternatively or instead, the permissible current of the target cell BC may be limited (adjusted downward).

[0242] In accordance with Figure 10In the method, at least one of steps S1050 and S1060 may be omitted.

[0243] In step S1070, the processor 320 may transmit the diagnosis result of the target cell BC to the electric vehicle 1 using the communication unit 310. The diagnosis result includes at least one of positive electrode participation end point, positive electrode capacity loss, restricted allowable voltage range, and restricted allowable SOC range.

[0244] Figure 11 is a flowchart exemplarily describing a battery diagnosis method according to a second embodiment of the present disclosure. Figure 11 The method may be executed by a battery diagnosis device.

[0245] At step S1110 , the processor 320 controls the stimulation applying device 301 to intermittently apply a second electrical stimulation greater than the first electrical stimulation to the target cell BC during a state change period until the electrical state of the target cell BC changes from the initial state to the target state.

[0246] In step S1120, the processor 320 uses the communication unit 310 to obtain current time series data representing the change history of the current of the target cell BC during the state change period and voltage time series data representing the change history of the full-cell voltage of the target cell BC during the rest period of the second electrical stimulation applied during the state change period.

[0247] Unlike the above-described first embodiment, the voltage time series data obtained in step S1120 includes measurement values ​​of the entire cell voltage measured three or more times per rest period.

[0248] 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 the set of three full-cell voltage measurements for each rest period included in the voltage time-series data acquired in step S1120 with a single OCV value. Therefore, if a total of X rest periods are permitted during the state change period and the full-cell voltage is measured three times during each rest period, those skilled in the art will readily appreciate that the voltage time-series data acquired in step S1120 will include 3X full-cell voltage measurements, and the corrected voltage time-series data will include X OCV values.

[0249] In step S1130, the processor 320 generates a measured full-cell profile indicating a corresponding relationship between the capacity of the target cell BC and the full-cell voltage based on the current time series data and the corrected voltage time series data (see Figure 3b in the text).

[0250] In step S1140 , the processor 320 analyzes and measures the entire cell profile M to estimate the cathode participation endpoint of the target cell BC.

[0251] In step S1150 , the processor 320 determines whether the positive electrode capacity loss of the target cell BC occurs based on the estimated positive electrode participation endpoint.

[0252] In step S1160 , the processor 320 limits at least one of the permissible voltage range and the permissible SOC range of the target cell BC based on the estimated positive electrode participation endpoint. Alternatively or instead, the permissible current of the target cell BC may be limited (adjusted downward).

[0253] In accordance with Figure 11 In the method, at least one of steps S1150 and S1160 may be omitted.

[0254] In step S1170, the processor 320 may transmit the diagnosis result of the target cell BC to the electric vehicle 1 through the communication unit 310. The diagnosis result includes at least one of positive electrode participation end point, positive electrode capacity loss, restricted allowable voltage range, and restricted allowable SOC range.

[0255] Figure 12 is referred to in the description Figure 11 FIG. 1 is a diagram of a process of correcting voltage time series data performed in step S1122 .

[0256] Figure 12 The symbol 1200 indicates Figure 3a One of the voltage drop segments shown in t R Indicates the time point at which the reference time has passed since the start time point of the rest period. R The part is depicted as a solid line, and at t R The subsequent portion is depicted as a dotted line.

[0257] refer to Figure 12 , during each rest period, the target cell BC is placed in a no-load state in which it is neither charged nor discharged.

[0258] During the no-load state, the full-cell voltage of the target cell BC gradually converges toward the OCV corresponding to the SOC of the target cell BC. The behavior of the full-cell voltage of the target cell BC in a specific rest period can be equivalent to the voltage response of the primary RC circuit, such as the following formula 1.

[0259] <Formula 1>

[0260]

[0261] In formula 1, t is the time elapsed from the start time of a specific rest period, V full (t) is the total cell voltage at t, V OCV is the actual OCV, V S is the full-cell voltage at the starting time point of a specific rest period, and τ is a time constant determined by the internal resistance and capacity of the target cell BC.

[0262] In Formula 1, V full (t) is measurable, so V OCV 、V S and τ are unknown. Since there are three unknown values, we can use V full (t) to estimate the OCV of a specific rest period. The following formula 2 can be used to estimate the OCV of each rest period.

[0263] <Formula 2>

[0264]

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

[0266] The processor 320 can calculate V OCV The same method is used to determine D OCV_C .

[0267] The processor 320 may perform the above operations by repeatedly using a single OCV value (D OCV_C ) replaces the three full-cell voltage measurements (V full (t1), V full (t2), V full The voltage time series data obtained in step S1120 is converted into corrected voltage time series data in step S1130 by a process (t3). The corrected voltage time series data includes X OCV values. The processor 320 may apply curve fitting logic to the corrected voltage time series data to generate a measured full-cell profile M.

[0268] For reference, D OCVis the measured value of the full-cell voltage at the end of the rest period (before the polarization is fully resolved), and D OCV_C is the full cell voltage in a state where polarization is completely resolved (i.e., V OCV ). Therefore, it can be considered that D OCV_C than D OCV Closer to the actual OCV of the target monomer BC.

[0269] The embodiments of the present disclosure described above are not only implemented by the device and method, but can also be implemented by a program that executes functions corresponding to the configuration of the embodiments of the present disclosure or a recording medium having the program recorded thereon, and based on the disclosure content of the previously described embodiments, those skilled in the art can easily implement such an implementation.

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

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

Claims

1. A battery diagnostic 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 cathode participation endpoint of the target monomer is estimated by analyzing the measured full monomer profile.

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 using 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 whether a positive electrode capacity loss of the target cell occurs based on the estimated positive electrode participation endpoint.

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 positive electrode participation endpoint. 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 cathode participation endpoint of the target monomer is estimated by analyzing the measured full monomer profile.

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: Whether the cathode capacity loss of the target cell occurs is determined based on the estimated cathode participation endpoint.

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 limited based on the estimated positive electrode participation endpoint.

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