APARELHO DE DIAGNÓSTICO DE BATERIA, CONJUNTO DE BATERIAS, VEÍCULO ELÉTRICO E MÉTODO DE DIAGNÓSTICO DE BATERIA

Abstract

A battery diagnosis apparatus, a battery pack, an electric vehicle and a battery diagnosis method are provided. The battery diagnosis apparatus comprises: a sensing unit for acquiring capacity-voltage relationship data of a battery cell; and a control circuit for generating a Q-V profile, a normalized Q-V profile and a Q-dV / dQ profile on the basis of the capacity-voltage relationship data. The control circuit determines, on the basis of a cut-off reference point detected in the Q-dV / dQ profile, a characteristic parameter of the Q-V profile of interest, which is a high-capacity side portion of the normalized Q-V profile. The control circuit determines at least one degradation parameter on the basis of the characteristic parameter of the profile.

Description

1 / 31 Battery diagnostic device, battery pack, electric vehicle and battery diagnostic method. FIELD OF TECHNIQUE

[001] The present invention relates to the diagnosis of degradation in battery cells.

[002] The present application claims priority over the Application of Korean Patent Number 10-2023-0117255, filed on September 4, 2023 in the Republic of Korea, the description of which is incorporated herein by reference. BACKGROUND

[003] Recently, there has been a rapid increase in demand for portable electronic products, such as laptop computers, video cameras, and mobile phones, and with the extensive development of electric vehicles, energy storage accumulators, robots, and satellites, many studies are being conducted on high-performance batteries that can be repeatedly charged and discharged.

[004] Currently, commercially available batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, lithium batteries, and similar batteries, and among these, lithium batteries have little or no memory effect and are thus gaining more attention than nickel-based batteries due to their advantages: recharging can be done whenever convenient, the self-discharge rate is very low, and the energy density is high.

[005] There are many different degradation monitoring techniques for battery cells. Specifically, Differential Voltage Analysis (DVA) is based on time series data of at least one battery parameter (e.g., voltage, current) that can be observed outside the battery cells. Petition 870250083338, dated 09 / 16 / 2025, page 8 / 63 2 / 31

[006] In DVA, peaks in a differential voltage curve (also referred to as a 'Q-dV / dQ profile') are considered key factors, and some types of battery cells have a voltage plateau characteristic, where a change in voltage is maintained at almost 0 during charging or discharging. Since the differential voltage is also close to 0 in the capacity range where the voltage plateau characteristic is found, it is difficult to detect a peak in the Q-dV / dQ profile. Consequently, there is a need for an approach to diagnose degradation in battery cells precisely and easily, without extracting peak information that indicates degradation of the Q-dV / dQ profile. DESCRIPTION TECHNICAL PROBLEM

[007] The present description is designed to solve the problem described above and, therefore, the present description is directed to providing a battery diagnostic device and method to accurately estimate at least one degradation parameter for a degradation state of a battery cell that has a voltage plateau characteristic without disassembling the battery cell.

[008] These and other objectives and advantages of the present description can be understood from the following description and will become apparent from the exemplary embodiments of the present description. Also, it will be easily understood that the objectives and advantages of the present description can be achieved by the means presented in the appended claims and a combination thereof. TECHNICAL SOLUTION

[009] A battery diagnostic device, according to one aspect of the present description, includes a data acquisition unit configured to acquire capacity-voltage ratio data of a battery cell; and a control circuit configured Petition 870250083338, dated 09 / 16 / 2025, page 9 / 63 3 / 31 rado to generate a QV profile that indicates a matching relationship between a battery cell capacity and voltage, a normalized QV profile that indicates a matching relationship between a normalized capacity and battery cell voltage, and a Q-dV / dQ profile that indicates a matching relationship between the normalized capacity and a differential battery cell voltage based on capacity-voltage relationship data. The control circuit identifies a cutoff reference point located within a reference capacity range of the Q-dV / dQ profile. The control circuit determines a profile characteristic parameter associated with a QV profile of interest, where the QV profile of interest is a higher-capacity side portion of the normalized QV profile, based on a cutoff reference point capacity value.The control circuit determines at least one battery cell degradation parameter based on the profile characteristic parameter.

[0010] The control circuit can generate the normalized QV profile, normalizing the QV profile based on an entire capacity range of the QV profile. The control circuit can generate the Q-dV / dQ profile, differentiating the normalized QV profile.

[0011] The control circuit can be configured to define a local minimum point in the reference capability range as the Q-dV / dQ profile cutoff reference point.

[0012] The control circuit can be configured to generate a corrected QV profile of interest by performing a profile tuning procedure to match a start point and an end point of the QV profile of interest to a first reference point and a second reference point, respectively. The control circuit can be configured to determine an area of ​​a region of interest defined by the corrected QV profile of interest, the first reference point, and the second reference point as the parameter of Petition 870250083338, dated 09 / 16 / 2025, page 10 / 63 4 / 31 profile characteristic.

[0013] The control circuit can be configured to determine a first degradation parameter using the determined area as an input variable of a linear regression model. The linear regression model can be prepared beforehand as a relationship function between the profile characteristic parameter and a positive electrode degradation state.

[0014] The first degradation parameter may indicate a rate of capacity reduction due to degradation of the positive electrode of the battery cell.

[0015] The control circuit can determine a second degradation parameter based on a ratio of total battery cell capacity reduction and the first degradation parameter. The second degradation parameter can indicate a capacity reduction rate due to the loss of available lithium from the battery cell.

[0016] Capacity-voltage relationship data can indicate a history of capacity changes and a history of voltage changes of the battery while the battery cell is being charged or discharged.

[0017] A battery pack, according to another aspect of the present description, includes the battery diagnostic apparatus.

[0018] An electric vehicle, according to yet another aspect of the present description, includes the battery pack.

[0019] A battery diagnostic method, according to another aspect of the present description, includes acquiring capacity-voltage relationship data from a battery cell; generating a QV profile indicating a matching relationship between a battery cell capacity and voltage, a normalized QV profile indicating a matching relationship between a normalized capacity and battery cell voltage, and a Q-dV / dQ profile indicating Petition 870250083338, dated 09 / 16 / 2025, page 11 / 63 5 / 31 a correspondence relationship between the normalized capacity and a differential voltage of the battery cell based on capacity-voltage relationship data; identify a cutoff reference point located in a reference capacity range of the QdV / dQ profile; determine a profile characteristic parameter associated with a QV profile of interest, where the QV profile of interest is a higher capacity side portion of the normalized QV profile based on a cutoff reference point capacity value; and determine at least one battery cell degradation parameter based on the profile characteristic parameter.

[0020] Q-dV / dQ profile generation can include generating the normalized QV profile, normalizing the QV profile based on an entire capacity range of the QV profile; and generating the Q-dV / dQ profile, differentiating the normalized QV profile.

[0021] Determining the profile characteristic parameter of the battery cell may involve generating a corrected QV profile of interest, performing a profile tuning procedure to match a start point and an end point of the QV profile of interest to a first reference point and a second reference point, respectively; and determining an area of ​​a region of interest defined by the corrected QV profile of interest, the first reference point and the second reference point as the profile characteristic parameter.

[0022] Determining at least one battery cell degradation parameter may involve determining a first degradation parameter by inserting the determined area into a linear regression model as an input variable. The linear regression model may be prepared beforehand as a relationship function between the profile characteristic parameter and a positive electrode degradation state. Petition 870250083338, dated 09 / 16 / 2025, page 12 / 63 6 / 31

[0023] Determining at least one battery cell degradation parameter may also include determining a second degradation parameter based on a ratio of total battery cell capacity reduction to the first degradation parameter. The second degradation parameter may indicate a capacity reduction rate due to the loss of available lithium from the battery cell. ADVANTAGEOUS EFFECTS

[0024] According to at least one embodiment of the present description, it may be possible to accurately estimate at least one degradation parameter for the degradation state of the battery cell without disassembling the battery cell. Specifically, the present description can diagnose the positive electrode degradation state of LFP battery cells with a voltage plateau characteristic in a non-destructive manner.

[0025] Furthermore, according to at least one embodiment of the present description, it may be possible to determine the positive electrode degradation state (e.g., the capacity degradation ratio derived from positive electrode degradation) of the battery cell more precisely by extracting and analyzing a portion (the 'QV profile of interest', as described below) of the voltage curve in which the degradation characteristics of the positive electrode material dominate the degradation characteristics of the negative electrode material in the entire voltage curve (the 'Q-V profile', as described below) of the battery cell for the predetermined voltage range.

[0026] Furthermore, according to at least one embodiment of the present description, it may be possible to easily calculate the lithium loss-derived capacity reduction ratio of the total capacity reduction ratio and the positive electrode degradation-derived capacity reduction ratio of the battery cell, using Petition 870250083338, dated 09 / 16 / 2025, page 13 / 63 7 / 31 establishing a relationship between the total capacity reduction ratio, the capacity reduction ratio derived from positive electrode degradation, and the capacity reduction ratio derived from lithium loss from the battery cell.

[0027] The effects of the present description are not limited to the effects mentioned above, and these and other effects will be clearly understood by those skilled in the art of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings illustrate exemplary embodiments of the present description and, together with the detailed description that follows, serve to provide a better understanding of the technical aspect of the present description and, therefore, the present description should not be interpreted as being limited to the drawings.

[0029] Figure 1 is a diagram that shows, exemplarily, an electric vehicle according to the present description.

[0030] Figure 2 is a graph showing an example of a profile. QV of a battery cell.

[0031] Figure 3 shows an example of a normalized QV profile acquired from the QV profile in Figure 2.

[0032] Figure 4 shows an example of a Q-dV / dQ profile in association with the normalized QV profile shown in Figure 3.

[0033] Figure 5 is a graph showing an example of a profile. QV of interest extracted from the normalized QV profile in Figure 4.

[0034] Figure 6 shows an example of a corrected QV profile of interest, acquired from the QV profile of interest in Figure 5.

[0035] Figure 7 is a referenced diagram in exemplarily describing a relationship between different levels of positive electrode degradation and corrected QV profiles of interest.

[0036] Figure 8 is a diagram referenced in describing examples Petition 870250083338, dated 09 / 16 / 2025, page 14 / 63 8 / 31 clearly a relationship between different levels of positive electrode degradation and an area of ​​a region of interest.

[0037] Figure 9 is a flowchart that schematically shows a battery diagnostic method according to an embodiment of the present description.

[0038] Figure 10 is a flowchart that shows, in an exemplary way, the subroutines that can be included in step S920 in Figure 9.

[0039] Figure 11 is a flowchart that shows, in an exemplary way, the subroutines that can be included in step S930 in Figure 9.

[0040] Figure 12 is a flowchart that exemplifies the subroutines that can be included in step S950 in Figure 9. BEST WAY

[0041] Hereafter, exemplary embodiments of the present description will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms or words used in the specification and appended claims should not be interpreted as being limited to general and dictionary meanings, but rather interpreted based on the meanings and concepts that correspond to the technical aspect of the present description, based on the principle that the inventor is permitted to define the terms appropriately for the best explanation.

[0042] Therefore, the embodiments described herein and the illustrations shown in the drawings are exemplary embodiments of the present description to describe the technical aspect of the present description and are not intended to be limiting, it should be understood that a variety of other equivalents and modifications could have been made at the time the application was filed.

[0043] Terms that include the ordinal number, such as first, second, and the like, are used to distinguish one element from another among several elements, but are not intended to limit the elements. Petition 870250083338, dated 09 / 16 / 2025, p. 15 / 63 9 / 31 ments by the terms.

[0044] Unless the context clearly indicates otherwise, the terms "comprise" and "include," when used in this specification, specify the presence of declared elements but do not preclude the presence or addition of one or more other elements. Furthermore, the term "control circuit 130," as used herein, refers to a processing unit of at least one function or operation and may be implemented by hardware and software, alone or in combination.

[0045] Furthermore, throughout the specification, it will also be understood that when an element is referred to as being connected to another element, it may be directly connected to the other element or intervening elements may be present.

[0046] Figure 1 is a diagram that shows, exemplarily, an electric vehicle according to the present description.

[0047] Referring to Figure 1, the electric vehicle 1 includes a system controller 2, a battery pack 10, an inverter 30, and an electric motor 40. The charge / discharge terminals P+, P- of the battery pack 10 can be electrically coupled to a charger 3 via a charging cable. The charger 3 may be included in the electric vehicle 1 or may be present at a charging station. The electric vehicle 1 is an example of a battery system that is a higher-level concept system, which includes the battery pack 10 for at least one energy storage or energy supply. Consequently, the following description can be commonly applied to the battery system that includes the electric vehicle 1.

[0048] System controller 2 (e.g., a Unit of The Electronic Control Unit (ECU) is configured to transmit a key-on signal to a 100-amp battery diagnostic device. Petition 870250083338, dated 09 / 16 / 2025, page 16 / 63 10 / 31 subject to the user changing a start button (not shown) of the electric vehicle 1 to an ON position. The system controller 2 is configured to transmit a key-off signal to the battery diagnostic device 100 in response to the user changing the start button to the OFF position. The charger 3 can supply a selected charging energy from constant energy, constant current, and constant voltage through the charge / discharge terminals P+, P- of the battery pack 10, via communication with the system controller 2.

[0049] Battery pack 10 includes a battery 11 and a relay 20. Battery set 10 may also include battery diagnostic device 100.

[0050] Battery 11 includes at least one BC battery cell. In Figure 1, battery 11, which includes a plurality of BC1~BCN battery cells (N is a natural number of 2 or greater) connected in series, is shown by way of illustration. The plurality of BC1~BCN battery cells may be provided with the same electrochemical specification. Hereafter, in the common description of the plurality of BC1~BCN battery cells, the symbol 'BC' is affixed to the battery cell. Charger 3 can perform the charge / discharge cycles necessary to diagnose the degradation state of the BC battery cell, through collaboration with inverter 30, which has a discharge function.

[0051] The BC battery cell must be diagnosed by the battery diagnostic device 100. The BC battery cell is not limited to a specific type and may include any electrochemical device that can be repeatedly charged and discharged. Preferably, the BC battery cell may be a lithium iron phosphate battery cell with a voltage plateau characteristic. The voltage plateau characteristic refers to a characteristic that a Petition 870250083338, dated 09 / 16 / 2025, page 17 / 63 11 / 31 The change in voltage is maintained below a predetermined limit in at least one capacity range (or SOC range). The lithium iron phosphate battery cell may also be referred to as a 'LiFePO4 battery cell', 'LFP battery cell', or 'LFP cell'. From now on, assume that the BC battery cell is an LFP battery cell, which includes LFP and graphite as the positive electrode material and the negative electrode material, respectively.

[0052] Relay 20 is electrically connected in series to battery 11 via a power path connecting battery 11 and inverter 30. Figure 1 shows relay 20 connected between a positive terminal of battery 11 and the charge / discharge terminal P+. Relay 20 is controlled to switch on / off in response to the switching signal from battery diagnostic device 100. Relay 20 may be a mechanical contactor that switches on or off by the magnetic force of a coil or a semiconductor switch, such as a Metal Oxide Semiconductor Field Effect Transistor (MOSFET).

[0053] The inverter 30 is provided to convert a direct current from the battery 11 included in the battery pack 10 to an alternating current in response to a command from the battery diagnostic device 100 or the system controller 2. The electric motor 40 operates using alternating current from the inverter 30. The electric motor 40 may include, for example, a three-phase alternating current motor. The components in the battery system supplied with the discharge energy from the battery 11, which includes the inverter 30 and the electric motor 40, may be collectively referred to as an electrical load.

[0054] The battery diagnostic device 100 can be implemented as a type of cloud server located in a remote location from the battery set 10. The battery diagnostic device 100 includes a control circuit 130. The battery diagnostic device 100 may also include at least one of a unit of Petition 870250083338, dated 09 / 16 / 2025, p. 18 / 63 12 / 31 detection 110 or a communication circuit 150. The 'data acquisition unit' described in the appended claims may refer to the detection unit 110 or the communication circuit 150, or both.

[0055] The 110 detection unit includes a voltage sensor 111. The detection unit may also include a current sensor. 112.

[0056] The voltage sensor 111 is connected to the positive and negative terminals of the BC battery cell and is configured to detect a voltage (referred to as 'total cell voltage') across the BC battery cell and generate a voltage signal indicating a detection value of the detected voltage. The voltage sensor 111 may include one of known voltage sensing devices, such as a voltage measurement IC or a combination thereof.

[0057] Current sensor 112 is connected in series to the battery via the current path between battery 11 and inverter 30. Current sensor 112 is configured to detect a current (referred to as 'charge / discharge current') flowing through battery 11 and generate a current signal indicating a detection value of the detected current. Because the plurality of battery cells BC1~BCN are connected in series, the current flowing in battery 11 is the same as the current flowing in battery cell BC. Current sensor 112 may include one of known current sensing devices, such as a shunt resistor or a Hall effect device, or a combination thereof.

[0058] Communication circuit 150 is configured to support wired or wireless communication between control circuit 130 and system controller 2. Wired communication can be, for example, controller area network (CAN) communication, and wireless communication can be, for example, Zigbee or Bluetooth communication. The communication protocol is not limited to a specific type. Petition 870250083338, dated 09 / 16 / 2025, page 19 / 63 13 / 31 and may include those that support wired / wireless communication between the control circuit 130 and the system controller 2. The communication circuit 150 may include an output device (e.g., a display, a speaker) to provide information received from the control circuit 130 and / or the system controller 2 in a format recognizable to the user (the driver).

[0059] Control circuit 130 is operatively coupled to relay 20, voltage sensor 111 and communication circuit 150. Operatively coupled refers to direct / indirect connection to allow signal transmission and reception in one or two directions.

[0060] Control circuit 130 can collect the voltage signal from voltage sensor 111 and the current signal from current sensor 112. In the specification, the detection signal, as used herein, may refer to the voltage signal only or to both the voltage and current signals. That is, control circuit 130 can convert and record each analog signal collected from sensors 111, 112 to a digital value, using an Analog-to-Digital Converter (ADC) fitted therein. Alternatively, each of the voltage sensor 111 and current sensor 112 may include the ADC therein, and transmit the digital value to control circuit 130.

[0061] The control circuit 130 may also be referred to as a 'battery controller' and be implemented in hardware using at least one of application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), microprocessors, or electrical units to perform other functions.

[0062] Memory 131 may include, for example, at least one type of instant memory storage medium, disPetition 870250083338, dated 09 / 16 / 2025, page 20 / 63 14 / 31 hard drive, Solid State Drive (SSD) type, Silicon Disk Drive (SDD) type, multimedia microcard type, random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM) or programmable read-only memory (PROM). Memory 131 may store data and programs required for the computation operation by control circuit 130. Memory 131 may store data indicating the results of the computation operation by control circuit 130. Memory 131 may store data sets and software used to diagnose the degradation state of battery cell BC. Memory 131 may be integrated into control circuit 130.

[0063] When relay 20 is switched on during the operation of electrical load 30, 40 and / or charger 3, battery 11 is in charging mode or a discharging mode. When relay 20 is switched off while battery 11 is in use in charging mode or discharging mode, battery 11 is switched to a standby mode.

[0064] Control circuit 130 can turn relay 20 on in response to the switch-on signal. Control circuit 130 can turn relay 20 off in response to the switch-off signal. The switch-on signal is a signal that requests a change from rest to load or discharge. The switch-off signal is a signal that requests a change from load or discharge to rest. Alternatively, instead of control circuit 130, system controller 2 can assume responsibility for the on-off control of relay 20.

[0065] In the specification, time series data for a parameter indicate a history of time-dependent changes in the parameter. Furthermore, a profile (or curve) indicating a correspondence relationship between two parameters acquired simultaneously over a period of time can be a polynomial equation acquired Petition 870250083338, dated 09 / 16 / 2025, page 21 / 63 15 / 31 is achieved by mapping time series data from the two parameters to represent them in the form of a two-dimensional graph, or by applying a predetermined curve fitting logic to a set of two mapped time series data. Here, the maximum degree of the polynomial equation can be predefined.

[0066] Figure 2 is a graph showing an example of a battery cell QV profile, Figure 3 shows an example of a normalized QV profile acquired from the QV profile in Figure 2, and Figure 4 shows an example of a Q-dV / dQ profile in association with the normalized QV profile shown in Figure 3.

[0067] Graph 200 shown in Figure 2 is a QV profile that indicates a correspondence relationship between the capacity and voltage of battery cell BC, according to the capacity-voltage relationship data described below. In graph 200, the vertical geometric axis indicates the voltage of battery cell BC and the horizontal geometric axis indicates the capacity (unit mAh).

[0068] The QV 200 profile may also be referred to as a 'capacity-voltage profile', a 'capacity-voltage curve' or a 'total cell profile'. As described above, the BC battery cell has a voltage plateau characteristic, and the QV 200 profile shows that the voltage is maintained almost uniformly across the capacity range between approximately 20 mAh and 40 mAh.

[0069] Assume that the QV 200 profile is acquired through the charging cycle of the BC battery cell. In the charging cycle, constant energy or constant current can be used.

[0070] In the constant power charging cycle, as the battery voltage increases, the charging current gradually decreases. Consequently, not only voltage time series data indicate the time-dependent history of changes in battery voltage, but also current time series data. Petition 870250083338, dated 09 / 16 / 2025, page 22 / 63 16 / 31 te which indicate the time-dependent history of changes in the current flowing through the battery are essentially required.

[0071] In the constant current charging cycle, the charging current, which has a predetermined current rate, is controlled to flow through the BC battery cell. Consequently, it can be assumed that the capacity at a specific time is equal to a value obtained by multiplying the elapsed time from the start time of the constant current charging cycle to the specific time (i.e., a time difference between the start time and the specific time) by the predetermined current rate.Even in the constant current charging cycle, the actual charging current may be temporarily lower than or higher than the intended charging current, so the control circuit 130 can calculate the capacity during real-time charging or discharging by repeatedly and periodically accumulating a current measurement value acquired by directly measuring the current flowing in the battery cell BC using the current sensor 112, to generate current time series data.

[0072] The charging cycle can last until the voltage of the BC battery cell changes at least within a predetermined voltage range. The QV 200 profile indicates the matching relationship between the capacity and voltage of the BC battery cell, acquired over a period of time until the BC battery cell voltage reaches the upper voltage limit of the predetermined voltage range, or the lower voltage limit, through the constant current charging cycle.

[0073] The QV 200 profile shown in Figure 2 shows that the voltage of battery cell BC increases from 2.6 V (lower voltage limit) to 3.6 V (upper voltage limit), while the capacity of battery cell BC changes from 0 mAh to 52 mAh. Here, the range between 0 mAh and 52 mAh can be the entire capacity range of the Petition 870250083338, dated 09 / 16 / 2025, page 23 / 63 17 / 31 QV 200 profile, and this corresponds to the predetermined voltage range.

[0074] In relation, the entire capacity range, which at least corresponds to the predetermined voltage range, may change depending on the degradation state of the BC battery cell. Furthermore, although the degradation state of two different BC battery cells is the same, the capacity range of the two BC battery cells may be different due to process deviation in manufacturing. To improve the ease and suitability of data processing required to diagnose the degradation state of the BC battery cell and ensure the accuracy of the diagnostic result, it is necessary to apply a normalization procedure to the entire capacity range.

[0075] Graph 300 shown in Figure 3 is an example of a normalized QV profile obtained by applying the normalization procedure to the QV 200 profile. In graph 300, the vertical geometric axis indicates the voltage of battery cell BC in the same way as Figure 2, and the horizontal geometric axis indicates the normalized capacity (% in units). Normalized capacity can be the equivalent term for State of Charge (SOC).

[0076] When voltage and capacitance according to the QV 200 profile have a mathematical relationship according to the following Equation 1, voltage and normalized capacitance according to the QV 300 profile have a mathematical relationship according to the following Equation 2. Equation 1 = ÂWs). Equation 2 x 100 Qtotal Q B_normal . 1ÕÕ

[0077] In Equation 1, Qb denotes an arbitrary capacity value. Petition 870250083338, dated 09 / 16 / 2025, page 24 / 63 18 / 31 within the entire capacity range, and Vb denotes a voltage value mapped to Qb in the QV 200 profile. In Equation 2, QB_normal denotes a normalized capacity value that corresponds to Qb, and Qtotal denotes the size of the entire capacity range (i.e., the upper capacity limit of the entire capacity range). For reference, Figure 3 shows the normalization result of each data point of the entire capacity range from Figure 2 as a percentage (a range between 0% and 100%), but this should be understood as an example. For example, instead of the range between 0% and 100%, this could be normalized to a different range between 0 and 1.

[0078] Graph 400 shown in Figure 4 is an example of a Q-dV / dQ profile. The Q-dV / dQ 400 profile may also be referred to as a 'capacity differential voltage profile' or a 'capacity differential voltage curve'.

[0079] Control circuit 130 differentiates the voltage of the normalized QV profile 300 with respect to the normalized capacity to generate the Q-dV / dQ profile 400. Specifically, control circuit 130 can determine a differential voltage dV / dQ or a ratio between a dV change in voltage V to a dQ change in normalized capacity Q[%], and register the Q-dV / dQ profile 400 as ratio data, which indicate a matching relationship between the normalized capacity Q and the differential voltage dV / dQ in memory.

[0080] Control circuit 130 can define a cutoff reference point located in a predetermined reference capability range of the Q-dV / dQ 400 profile. The reference capability range may partially overlap with the capability range in which the voltage plateau characteristic of the BC battery cell is found.

[0081] Specifically, control circuit 130 can identify a local maximum point Pmax that has the maximum differential voltage in the reference capability range of the Q-dV / dQ 400 profile. Subse Petition 870250083338, dated 09 / 16 / 2025, page 25 / 63 19 / 31 Currently, control circuit 130 can identify (detect) the cut-off reference point Pcut-off located on the side with greater capacity than the local maximum point Pmax of the Q-dV / dQ 400 profile. The cut-off reference point Pcut-off can be a local minimum point that has the capacity value Qcut-off in the reference capacity range.

[0082] When there are two or more local minimum points in the reference capacity range, the local minimum point that has the greatest capacity difference from the local maximum point Pmax can be identified as the cut-off reference point Pcut-off. The cut-off reference point Pcut-off can be the last local minimum point in the Q-dV / dQ 400 profile, originating from the voltage characteristics of the negative electrode material of the BC battery cell.That is, the side with the higher capacity than the Pcut-off reference point can be the capacity range in which the voltage characteristics of the positive electrode material of the BC battery cell dominate the voltage characteristics of the negative electrode material. Consequently, those skilled in the art will readily understand that when only the higher capacity side of the normalized QV 300 profile is analyzed, the degradation state of the positive electrode of the BC battery cell can be accurately estimated.

[0083] It has been confirmed through many experiments that the voltage characteristics of the negative electrode material are reflected on the higher capacity side of the normalized QV 300 profile to a relatively small extent compared to the other side. Consequently, the inventors recognized that, among many different degradation parameters associated with the degradation state of the BC battery cell, a parameter for positive electrode degradation can be precisely diagnosed through analysis of the higher capacity side of the normalized QV 300 profile. Petition 870250083338, dated 09 / 16 / 2025, page 26 / 63 20 / 31 In the specification, when the normalized QV profile 300 is divided into a lower capacity side portion and a higher capacity side portion based on the Pcut-off reference point, as shown in Figure 3, the higher capacity side portion of the normalized QV profile 300 can be referred to as a 'QV profile of interest' (see 500 in Figure 5). As shown in Figure 4, a range between 50% and 99% is defined as the reference capacity range.

[0084] Figure 5 is a graph showing an example of the QV profile of interest extracted from the normalized QV profile of Figure 4, and Figure 6 shows an example of a corrected QV profile of interest, acquired from the QV profile of interest of Figure 5.

[0085] Referring to Figure 5, the QV profile of interest 500 is an enlarged form of a portion of the normalized QV profile 300 that corresponds to a capacity range of interest (e.g., 92% to 99%) using the capacity value (e.g., 92%) of the Pcut-off reference point and the upper capacity limit (e.g., 99%) of the reference capacity range as the lower capacity limit and the upper capacity limit, respectively.

[0086] In relation, even if the positive electrode degradation state of the BC battery cell is the same, when other degradation factors of the BC battery cell, such as the negative electrode degradation state or the amount of usable lithium, are different, the starting point, the ending point, and / or the shape (e.g., the curvature) of the QV profile of interest 500 extracted from the QV profile of interest 500 may change.Consequently, in a manner similar to the normalization procedure applied to the QV 200 profile, it is necessary to apply the normalization procedure to the QV profile of interest 500.

[0087] Referring to Figure 6, it shows the corrected QV profile of interest 600, acquired through the normalization procedure (a profile tuning procedure) performed on the QV profile of in. Petition 870250083338, dated 09 / 16 / 2025, p. 27 / 63 21 / 31 interest 500.

[0088] Specifically, control circuit 130 can generate the corrected QV profile of interest 600 by performing at least one shift or scaling of the QV profile of interest 500 to match the initial point Ps and the final point Pe of the QV profile of interest 500 to a first predetermined reference point Pri and a second predetermined reference point Pr2, respectively. The initial point Ps of the QV profile of interest 500 can be a point that has the minimum capacity value of the QV profile of interest 500. The final point Pe of the QV profile of interest 500 can be a point that has the maximum capacity value of the QV profile of interest 500.

[0089] The capacitance value of the first reference point Pri is less than the capacitance value of the initial point Ps, and the voltage value of the first reference point Pri is less than the voltage value of the initial point Ps. Furthermore, the capacitance value of the second reference point Pr2 is greater than the capacitance value of the final point Pe, and the voltage value of the second reference point Pr2 is greater than the voltage value of the final point Pe.

[0090] Control circuit 130 can perform a first operation of shifting the QV profile of interest 500 along at least one of the geometric capacitance axis or the geometric voltage axis and a second operation of scaling the QV profile of interest 500 along at least one of the geometric capacitance axis or the geometric voltage axis to match the initial point Ps to the first reference point Pri or the final point Pe to the second reference point Pr2. The first operation can include at least horizontal movement (movement to the left or right with respect to the horizontal geometric axis) or vertical movement (movement up or down with respect to the vertical geometric axis). The second operation can include at least one Petition 870250083338, dated 09 / 16 / 2025, page 28 / 63 22 / 31 reduction or enlargement based on at least one of the horizontal geometric axis or the vertical geometric axis.

[0091] Assume that the two-dimensional coordinates of the initial point Ps, the final point Pe, the first reference point Pri, and the second reference point Pr2 are (Qs, Vs), (Qe, Ve), (Qri, Vri), (Qr2, Vr2), respectively. In Figure 6, the two-dimensional coordinates of the first reference point Pri are (90%, 3.25 V) and the two-dimensional coordinates of the second reference point PR2 are (100%, 3.55 V). The control circuit 130 can shift the QV profile of interest 500 to the side of lower capacitance by Qs - Qri and to the side of lower voltage by Vs - Vri. Consequently, since the initial point Ps corresponds to the first reference point Pri, it is now necessary to correspond the final point Pe to the second reference point Pr2. Consequently, the control circuit 130 can scale the QV profile of interest 500 at a ratio of (Qr2 - Qri) / (Qe - Qs) along the geometric capacity axis and at a ratio of (Vr2 - Vri) / (Ve - Vs) along the geometric capacity axis.Consequently, the operation of generating the corrected QV profile of interest 600 from the QV profile of interest 500 is completed. As a result, the two points Ps and Pe in the QV profile of interest 600 may deviate from the corrected QV profile of interest 600, as shown in Figure 6.

[0092] Control circuit 130 can determine a profile characteristic parameter based on the corrected QV profile of interest 600. Control circuit 130 can determine the area of ​​a region of interest A defined by the corrected QV profile of interest 600, the first reference point Pri, and the second reference point Pr2 as the profile characteristic parameter. That is, the region of interest A can be a closed region surrounded by the corrected QV profile of interest 600, a first reference line, and a second reference line. The first reference line can be a Petition 870250083338, dated 09 / 16 / 2025, page 29 / 63 23 / 31 horizontal line (parallel to the geometric axis of capacitance) that passes through the first reference point Pri. The second reference line can be a vertical line (parallel to the geometric axis of voltage) that passes through the second reference point PR2.

[0093] Control circuit 130 can determine a first degradation parameter associated with the degradation state of battery cell BC by inserting the area of ​​the region of interest A, determined as the profile characteristic parameter, into a linear regression model as an input variable. The first degradation parameter can indicate a capacity reduction ratio due to positive electrode degradation of the battery cell. The capacity reduction ratio caused by positive electrode degradation can be referred to as a 'positive electrode degradation level' or 'capacity reduction ratio derived from positive electrode degradation'. Hereafter, the linear regression model will be described in more detail with reference to Figures 8 and 9.

[0094] Relationship data were created that can be used to generate the linear regression model by a process of forcibly degrading a plurality of BC battery cells prepared for an experiment to different levels of positive electrode degradation, a process of calculating the area of ​​a region of interest for each of the forcibly degraded BC battery cells, a process of disassembling each of the forcibly degraded BC battery cells to fabricate a positive electrode half-cell, and a process for measuring and recording the usable capacity of each positive electrode half-cell in that order.

[0095] Figure 7 is a referenced diagram used to exemplarily describe a relationship between different levels of positive electrode degradation and the corrected QV profiles of interest, and Figure 8 is a referenced diagram used to exemplarily describe a relationship Petition 870250083338, dated 09 / 16 / 2025, page 30 / 63 24 / 31 between different levels of positive electrode degradation and the area of ​​the region of interest.

[0096] Figure 7 shows a pattern in which the corrected QV profile of interest changes with increasing positive electrode degradation level. The positive electrode degradation level may refer to a capacity reduction ratio derived from positive electrode degradation.

[0097] Referring to Figure 7, a curve 710 indicates the corrected QV profile of interest acquired at a positive electrode degradation level of 0%, that is, when the positive electrode is new, a curve 720 indicates the corrected QV profile of interest acquired at a positive electrode degradation level of 1.75%, and a curve 730 indicates the corrected QV profile of interest acquired at a positive electrode degradation level of 9.40%.

[0098] That is, as the level of positive electrode degradation is greater, the corrected QV profile of interest gradually changes to a shape close to a straight line connecting the first reference point PR1 to the second reference point PR2, and consequently the area of ​​the region of interest increases, as can be seen in Figure 7.

[0099] Referring to Figure 8, the linear regression model 800 can be prepared beforehand as a function of the relationship between the profile characteristic parameter (the area of ​​the region of interest) and the state of positive electrode degradation. Point 810 is associated with curve 710 in Figure 7, point 820 is associated with curve 720 in Figure 7, and point 830 is associated with curve 730 in Figure 7. Although not fully shown, in addition to points 810, 820, and 830, additional points were acquired from the experiment described above and then used to acquire the linear regression model 800 through linear regression analysis.The linear regression model 800 can be pre-stored in memory 131. The following Equation 3 is... Petition 870250083338, dated 09 / 16 / 2025, page 31 / 63 25 / 31 an example of the linear regression model 800. Equation 3 y = Ax + B

[00100] In Equation 3, A and B are two coefficients that indicate the slope of the straight line and the y-intercept, respectively, according to the linear regression model 800, x denotes the area of ​​the region of interest as the input variable, and y denotes the positive electrode degradation level as the output variable. A and B can change depending on the type and composition ratio of each of the positive electrode and negative electrode materials. Consequently, A and B can be appropriately tuned according to the type and manufacturing information (e.g., the type and composition ratio of each of the positive electrode and negative electrode materials) of the BC battery cell provided for diagnosis. For example, A and B of the linear regression model 800 shown in Figure 8 are 5.63 and -8.76, respectively.

[00101] Control circuit 130 can input the area of ​​the region of interest (A in Figure 6) acquired from battery cell BC having an unknown positive electrode degradation state in linear regression model 800 as the input variable x, and acquire the positive electrode degradation level as the output variable y. Point 840 is a point in linear regression model 800 that corresponds to the area of ​​the region of interest (A in Figure 6).

[00102] TABLE 1 below summarizes the relationship between the number of constant power charge cycles described above (number of cycles), the total capacity reduction ratio, the area of ​​the region of interest, the first degradation parameter (capacity reduction ratio derived from positive electrode degradation) and the second degradation parameter (capacity reduction ratio derived from available lithium loss). Here, available lithium may refer to a Petition 870250083338, dated 09 / 16 / 2025, page 32 / 63 26 / 31 quantity of lithium ions that can participate in the charge / discharge reaction of the BC battery cell. TABLE 1 Classification Total Capacity Reduction Ratio (%) Area of ​​Interest Region of Capacity Reduction Ratio Derived from Positive Electrode Degradation (%) Capacity Reduction Ratio Derived from Available Lithium Loss (%) Number of Cycles = 0 0 1.51 0 0 Number of Cycles = 100 3.40 1.63 0.87 2.53 Number of Cycles = 200 6.70 1.75 1.75 4.95 Number of Cycles = 600 16.50 3.22 9.40 7.10

[00103] According to TABLE 1, it can be seen that as the number of cycles increases, each of the total capacity reduction ratio, the area of ​​the region of interest, the capacity reduction ratio derived from positive electrode degradation, and the capacity reduction ratio derived from loss of available lithium also increases. For reference, the number of cycles can be counted as one each time a charge (or discharge) cycle with constant energy (or constant current) is completed.

[00104] The total capacity reduction ratio can be a ratio of a total load capacity reduction due to degradation and the total load capacity when the battery cell BC is new. When assuming that the total load capacity in the new battery = P, the total load capacity in the degraded battery = U, the total load capacity reduction = W, W = PU, the total capacity reduction ratio = (W / P) X 100%.

[00105] It was acknowledged that the sum of the reduction ratio Petition 870250083338, dated 09 / 16 / 2025, page 33 / 63 27 / 31 of the capacity derived from positive electrode degradation and the rate of capacity reduction derived from available lithium loss is substantially equal to the rate of total capacity reduction. Consequently, control circuit 130 can determine the rate of capacity reduction derived from available lithium loss as the second degradation parameter, subtracting the positive electrode degradation level determined through Equation 3 described above from the rate of total capacity reduction.

[00106] Figure 9 is a flowchart that schematically shows a battery diagnostic method according to an embodiment of the present description. The method according to Figure 9 includes steps S910 to S960. The method according to Figure 9 may also include step S970.

[00107] Referring to Figures 1 to 9, in step S910, the control circuit 130 acquires capacity-voltage ratio data from the BC battery cell using the data acquisition unit. In the specification, data or information acquisition may refer to generation through software processing, input via a user or input device, and / or reception via a communication channel.

[00108] For example, when the data acquisition unit includes the sensing unit 110, the control circuit 130 can generate voltage time series and capacitance time series based on the sensing signal generated by the sensing unit 110. The capacitance-voltage relationship data can include the voltage time series and the capacitance time series. The voltage time series data points and the current time series data points can be mapped in a one-to-one relationship.

[00109] The voltage time series can indicate the time-dependent history of changes in the voltage of the BC battery cell. Petition 870250083338, dated 09 / 16 / 2025, page 34 / 63 28 / 31 while the BC battery cell is charged (or discharged) with constant energy (or constant current) within the predetermined voltage range. The current time series can indicate the time-dependent history of changes in the current flowing through the BC battery cell for the same time period as the time period during which the voltage time series is acquired.

[00110] As another example, when the data acquisition unit includes communication circuit 150, control circuit 130 can receive capacitance-voltage ratio data from an external device using communication circuit 150.

[00111] In stage S920, control circuit 130 generates QV profile 200, normalized QV profile 300, and Q-dV / dQ profile 400 of battery cell BC based on capacity-voltage ratio data.

[00112] In step S930, control circuit 130 identifies the cut-off reference point Pcut-off of the Q-dV / dQ 400 profile.

[00113] In step S940, control circuit 130 extracts the QV profile of interest 500, which is the higher capacity side portion of the normalized QV profile 300, based on the Qcut-off capacity value of the Pcut-off cutoff reference point.

[00114] In step S950, control circuit 130 determines the profile characteristic parameter associated with the QV profile of interest 500.

[00115] In stage S960, control circuit 130 determines at least one degradation parameter associated with the degradation state of the BC battery cell based on the profile characteristic parameter. Consequently, at least one of the first degradation parameter or the second degradation parameter can be determined.

[00116] In stage S970, control circuit 130 can determine at least one protection parameter for battery cell BC. Petition 870250083338, dated 09 / 16 / 2025, page 35 / 63 29 / 31 based on at least one degradation parameter determined in step S960. For example, at least one of the maximum load voltage, minimum discharge voltage, maximum permissible current, or maximum permissible energy can be determined as a protection parameter.

[00117] When (i) the voltage of battery cell BC is equal to or greater than the maximum charging voltage or equal to or less than the minimum discharging voltage, (ii) the current flowing through battery cell BC is equal to or greater than the maximum permissible current, and / or (iii) the charging or discharging energy of battery cell BC is equal to or greater than the maximum permissible energy, control circuit 130 may change relay 20 to the OFF state or transmit a shutdown request to inverter 30 and / or charger 3.

[00118] Figure 10 is a flowchart that exemplifies the subroutines that can be included in step S920 of Figure 9.

[00119] In step S1010, control circuit 130 generates QV profile 200 from the voltage time series data generated in step S910.

[00120] In step S1020, control circuit 130 normalizes QV profile 200 based on the entire capacity range of QV profile 200 to generate normalized QV profile 300.

[00121] In step S1030, control circuit 130 can differentiate the normalized QV profile 300 to generate the Q-dV / dQ profile 400, which indicates the matching relationship between the normalized capacitance and the differential voltage of the BC battery cell.

[00122] Figure 11 is a flowchart that exemplifies the subroutines that can be included in step S930 of Figure 9.

[00123] Referring to Figure 11, in step S1110, control circuit 130 identifies the local maximum point Pmax that has the maximum differential voltage in the reference capability range of the Q-dV / dQ 400 profile. Petition 870250083338, dated 09 / 16 / 2025, page 36 / 63 30 / 31

[00124] In stage S1120, control circuit 130 defines the local minimum point located on the side with greater capacity than the local maximum point Pmax as the cut-off reference point Pcut-off, of the Q-dV / dQ 400 profile.

[00125] Figure 12 is a flowchart that exemplifies the subroutines that can be included in step S950 of Figure 9.

[00126] Referring to Figure 12, in step S1210, control circuit 130 generates the corrected QV profile of interest 600, performing the shift operation and the scaling operation of the QV profile of interest 500 to match the initial point Ps and the final point Pe of the QV profile of interest 500 to the first predetermined reference point Pri and the second predetermined reference point Pr2, respectively.

[00127] In step S1220, control circuit 130 calculates the area of ​​the region of interest A defined by the corrected QV profile of interest 600, the first reference point Pri, and the second reference point Pr2. The region of interest A can be a region surrounded by the corrected QV profile of interest 600, the first reference line L1, and the second reference line L2. The first reference line L1 can be a horizontal line passing through the first reference point Pri. The second reference line L2 can be a vertical line passing through the second reference point Pr2.

[00128] In step S1230, control circuit 130 determines that the profile characteristic parameter is equal to the area of ​​the region of interest A. In step S970, control circuit 130 can determine the first degradation parameter y associated with the degradation state of battery cell BC, using the profile characteristic parameter determined in step S1130 as the input variable x of the linear regression model 800 (see Equation 3). The linear regression model 800 can be prepared beforehand as a function of Petition 870250083338, dated 09 / 16 / 2025, page 37 / 63 31 / 31 ratio, which indicates the correspondence between the profile characteristic parameter and the positive electrode degradation state.

[00129] The embodiments of the present description, as described above, are not incorporated solely through the apparatus and the method, and can be implemented through programs that perform the functions corresponding to the exemplary configurations of the present description or through recording media that have the programs recorded therein, and such implementation can be easily achieved by those skilled in the art of describing the embodiments described above.

[00130] Although the present description has been described above with respect to a limited number of embodiments and designs, the present description is not limited to this and it is obvious to those skilled in the art that various modifications and alterations may be made to it within the technical aspect of the present description and the scope of the appended claims and their equivalents.

[00131] Furthermore, as many substitutions, modifications, and alterations may be made to the present description, as described above by those skilled in the art, without departing from the technical aspect of the present description, the present description is not limited by the embodiments described above and the accompanying drawings, and some or all embodiments may be selectively combined to permit various modifications. Petition 870250083338, dated 09 / 16 / 2025, pp. 38 / 63

Claims

1 / 5 CLAIMS 1. Battery diagnostic apparatus, characterized in that it comprises: a data acquisition unit configured to acquire capacity-voltage ratio data from a battery cell; and a control circuit configured to generate a QV profile indicating a matching relationship between a capacity and a voltage of the battery cell, a normalized QV profile indicating a matching relationship between a normalized capacity and the voltage of the battery cell, and a Q-dV / dQ profile indicating a matching relationship between the normalized capacity and a differential voltage of the battery cell based on the capacity-voltage ratio data, wherein the control circuit is configured to: identify a cutoff reference point located within a reference capacity range of the Q-dV / dQ profile, determine a profile characteristic parameter associated with a QV profile of interest,where the QV profile of interest is a larger capacity side portion of the normalized QV profile based on a cutoff reference point capacity value, and determine at least one battery cell degradation parameter based on the profile characteristic parameter.

2. Battery diagnostic device according to claim 1, characterized in that the control circuit is configured to: generate the normalized QV profile, normalizing the QV profile based on an entire capacity range of the QV profile, and generate the Q-dV / dQ profile, differentiating the normalized QV profile. Petition 870250083338, dated 09 / 16 / 2025, p. 39 / 63 2 / 5 3. Battery diagnostic device according to claim 1, characterized in that the control circuit is configured to define a local minimum point in the reference capacitance range as the cutoff reference point of the Q-dV / dQ profile.

4. Battery diagnostic device according to claim 1, characterized in that the control circuit is configured to: generate a corrected QV profile of interest, performing a profile tuning procedure to match a start point and an end point of the QV profile of interest to a first reference point and a second reference point, respectively, and determine an area of ​​a region of interest defined by the corrected QV profile of interest, the first reference point and the second reference point as the profile characteristic parameter.

5. Battery diagnostic device according to claim 4, characterized in that the control circuit is configured to determine a first degradation parameter using the determined area as an input variable of a linear regression model, and wherein the linear regression model is prepared beforehand as a relationship function between the profile characteristic parameter and a positive electrode degradation state.

6. Battery diagnostic device according to claim 5, characterized in that the first degradation parameter indicates a rate of capacity reduction due to degradation of the positive electrode of the battery cell.

7. Battery diagnostic device according to claim 5, characterized in that the control circuit is configured to determine a second degradation parameter based on a ratio of total battery cell capacity reduction and the first degradation parameter, and wherein the second degradation parameter indicates a capacity reduction ratio due to loss of available lithium from the battery cell.

8. Battery diagnostic device according to claim 1, characterized in that the capacity-voltage relationship data indicate a history of capacity changes and a history of voltage changes of the battery while the battery cell is being charged or discharged.

9. Battery pack, characterized in that it comprises the battery diagnostic apparatus, as defined in any one of claims 1 to 8.

10. Electric vehicle, characterized in that it comprises the battery pack as defined in claim 9.

11. Battery diagnostic method, characterized in that it comprises: acquiring capacity-voltage ratio data from a battery cell; generating a QV profile indicating a correspondence relationship between a capacity and a voltage of the battery cell, a normalized QV profile indicating a correspondence relationship between a normalized capacity and the voltage of the battery cell, and a Q-dV / dQ profile indicating a correspondence relationship between the normalized capacity and a differential voltage of the battery cell based on the capacity-voltage ratio data; identifying a cutoff reference point located within a reference capacity range of the Q-dV / dQ profile; determining a profile characteristic parameter associated with a QV profile of interest, wherein the QV profile of interest is Petition 870250083338, dated 09 / 16 / 2025, p.41 / 63 4 / 5 a larger capacity side portion of the normalized QV profile based on a cutoff reference point capacity value; and determine at least one battery cell degradation parameter based on the profile characteristic parameter.

12. Battery diagnostic method according to claim 11, characterized in that the generation of the QdV / dQ profile comprises: generating the normalized QV profile, normalizing the QV profile based on an entire capacity range of the QV profile; and generating the Q-dV / dQ profile, differentiating the normalized QV profile.

13. Battery diagnostic method according to claim 11, characterized in that the determination of the battery cell profile characteristic parameter comprises: generating a corrected QV profile of interest by performing a profile tuning procedure to match a start point and an end point of the QV profile of interest to a first reference point and a second reference point, respectively; and determining an area of ​​a region of interest defined by the corrected QV profile of interest, the first reference point and the second reference point as the profile characteristic parameter.

14. Battery diagnostic method according to claim 13, characterized in that the determination of at least one battery cell degradation parameter comprises determining a first degradation parameter, inserting the determined area into a linear regression model as an input variable, and wherein the linear regression model is previously prepared as a relationship function between the profile characteristic parameter and a positive electrode degradation state.

15. Battery diagnostic method according to claim 14, characterized in that the determination of at least one battery cell degradation parameter further comprises: determining a second degradation parameter based on the ratio of total capacity reduction of the battery cell to the first degradation parameter, wherein the second degradation parameter indicates a capacity reduction ratio per available lithium loss from the battery cell. Petition 870250083338, dated 09 / 16 / 2025, pp. 43 / 63

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