System and method for detecting electrochemical parameters of lithium battery cathode repair

Abstract

The application discloses a lithium battery positive electrode repair electrochemical parameter detection system and method, and belongs to the technical field of lithium battery detection. The method specifically comprises the following steps: applying a preset coupling electrochemical excitation to a repaired lithium battery positive electrode, collecting the potential change response and the current change response of the positive electrode in real time, obtaining electrochemical response data, performing open-circuit relaxation on the repaired lithium battery positive electrode after the coupling electrochemical excitation ends, performing decoupling analysis on the electrochemical response data based on the change relationship between the potential and time in the relaxation process, obtaining characteristic parameters corresponding to the lithium ion diffusion process and the interface polarization process, inversely obtaining an electrochemical parameter set for characterizing the positive electrode repair state, and determining the positive electrode repair effect according to the electrochemical parameter set. The application improves the integrity and consistency of the determination of the electrochemical state of the repaired positive electrode, and is suitable for the positive electrode state detection under different repair modes and repair degrees.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery testing technology, specifically a lithium battery positive electrode repair electrochemical parameter testing system and method. Background Technology

[0002] Lithium-ion batteries are prone to capacity decay, increased internal resistance, and intensified polarization under long-term cycling or abnormal operating conditions. Among these issues, the degradation of the cathode material structure and changes in interface state are considered important factors affecting battery performance. Repairing degraded cathodes has gradually become an important technical approach to extend battery life and improve resource utilization.

[0003] In existing technologies, the detection of the positive electrode state of lithium batteries mainly relies on methods such as capacity testing, DC internal resistance testing, electrochemical impedance spectroscopy, or open-circuit voltage testing. These methods typically focus on overall performance characterization and struggle to distinguish the different effects of repair behavior on the internal diffusion process and interfacial polarization process of the positive electrode. Furthermore, most detection methods are performed under steady-state or quasi-steady-state conditions, failing to fully consider the response differences of the repaired positive electrode during the stimulated relaxation process, resulting in limited indicative value of the detection results for the degree and effectiveness of repair. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a detection system and method for electrochemical parameters of lithium battery cathode repair. By performing correlation analysis on the cathode's stimulated response and relaxation behavior, electrochemical parameters corresponding to the lithium-ion diffusion process and interface polarization process are obtained, and the cathode repair status is determined accordingly.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] Methods for detecting electrochemical parameters in lithium-ion battery cathode repair include:

[0007] A preset coupled electrochemical excitation is applied to the repaired lithium battery cathode, the coupled electrochemical excitation being used to simultaneously trigger the lithium-ion migration process inside the cathode material and the reversible electrochemical response at the repair interface;

[0008] During the coupled electrochemical excitation process, the potential change response and current change response of the positive electrode are collected in real time to obtain electrochemical response data, which characterizes the dynamic behavior of the positive electrode after repair.

[0009] After the coupled electrochemical excitation is completed, the repaired lithium battery cathode is subjected to open-circuit relaxation, and based on the potential change relationship with time during the relaxation process, the electrochemical response data is decoupled and analyzed to obtain characteristic parameters corresponding to the lithium ion diffusion process and the interface polarization process.

[0010] Based on the electrochemical response data and the characteristic parameters, a set of electrochemical parameters characterizing the cathode repair state is obtained by inversion, and the cathode repair effect is determined according to the set of electrochemical parameters.

[0011] Specifically, the coupled electrochemical excitation includes one or more asymmetric bipolar excitation processes, causing the positive electrode to sequentially experience a repair activation state and a non-repair reference state in the same detection process. In the asymmetric bipolar excitation process, the positive excitation and the reverse excitation differ in one or more of the amplitude, duration, or energy input.

[0012] Specifically, during the coupled electrochemical excitation process, the potential change response and current change response of the positive electrode are acquired in real time to obtain electrochemical response data, including:

[0013] During the application of the coupled electrochemical excitation, the excitation process is continuously time-localized, and a time series identifier corresponding to the excitation process is generated;

[0014] Based on the time series identifier, the potential change response and current change response of the positive electrode are collected in pairs within each consecutive time interval of the excitation process to form original response pairs with time correspondence.

[0015] According to the time series identifier, the original response pair is segmented into segments, so that each response segment corresponds to a unique excitation process interval;

[0016] The response fragments are integrated according to the order of the excitation process to generate electrochemical response data.

[0017] Specifically, after the coupled electrochemical excitation is completed, the repaired lithium battery cathode is subjected to open-circuit relaxation. Based on the potential-time relationship during the relaxation process, the electrochemical response data is decoupled and analyzed to obtain characteristic parameters corresponding to the lithium-ion diffusion process and the interface polarization process, including:

[0018] After the coupled electrochemical excitation ends, the termination time of the coupled electrochemical excitation is determined as the start time point of open-circuit relaxation, and the relaxation time reference is established based on the start time point.

[0019] Based on the relaxation time reference, the repaired lithium battery cathode is subjected to open-circuit relaxation, and the potential changes are continuously recorded in the open-circuit state to form a complete relaxation time series.

[0020] According to a preset time progression rule, the relaxed time series is mapped into multiple mutually distinct time intervals;

[0021] The time intervals are respectively associated with electrochemical response data, and the relationship between potential changes and electrochemical response data in different time intervals is deconstructed.

[0022] Based on the deconstruction process, characteristic parameters corresponding to the lithium-ion diffusion process and the interface polarization process are generated.

[0023] Specifically, based on the aforementioned relaxation time reference, the repaired lithium battery positive electrode undergoes open-circuit relaxation, and the potential changes are continuously recorded in the open-circuit state to form a complete relaxation time series, including:

[0024] After the relaxation time reference is established, the positive electrode is switched from the excitation state to the open circuit state, and the time when the switch is completed is used as the starting mark for potential recording.

[0025] Based on the relaxation time reference, the recording rhythm of potential changes is determined so that each recording moment maintains a sequential relationship on the time axis;

[0026] According to the recording rhythm, the potential change of the repaired lithium battery positive electrode is continuously collected in the open circuit state to obtain potential data points arranged in chronological order.

[0027] The potential data points are encapsulated according to the starting marker and time sequence to form a relaxation time series corresponding to a single relaxation process.

[0028] Specifically, the time intervals are correlated with electrochemical response data, and the relationship between potential changes and electrochemical response data within different time intervals is deconstructed, including:

[0029] For each time interval, generate a set of interval anchor points including the start time and end time of the interval;

[0030] Based on the set of interval anchor points, data segments corresponding to each interval anchor point on the time axis are extracted from the electrochemical response data, and the data segments are time-aligned with the potential change segments in the corresponding time interval.

[0031] The time-aligned data pairs are split so that each split unit contains only a potential change segment within a time interval and its corresponding data segment, and each split unit is assigned an interval identifier.

[0032] The split units are grouped according to the interval identifiers to obtain a set of relational objects for different time intervals.

[0033] Specifically, based on the deconstruction processing results, characteristic parameters corresponding to the lithium-ion diffusion process and the interface polarization process are generated, including:

[0034] Based on the interval identifiers in the set of relational objects, the set of relational objects is divided into a first set of intervals and a second set of intervals.

[0035] Perform intra-group summarization processing on the relational objects contained in the first set of intervals and the second set of intervals to construct the first set of representation sequences and the second set of representation sequences;

[0036] The first set of characterization sequences is input into the first mapping rule to generate interface polarization feature parameters, and the second set of characterization sequences is input into the second mapping rule to generate lithium ion diffusion feature parameters.

[0037] The interface polarization characteristic parameters and the lithium-ion diffusion characteristic parameters are output in pairs using the same detection process identifier to form a characteristic parameter set.

[0038] Specifically, based on the electrochemical response data and the characteristic parameters, a set of electrochemical parameters characterizing the cathode repair state is obtained by inversion, and the cathode repair effect is determined according to the set of electrochemical parameters, including:

[0039] The electrochemical response data and characteristic parameters are paired according to the same detection process identifier to generate input data pairs for inversion processing;

[0040] Based on the input data, preset consistency constraints are extracted. The consistency constraints include time sequence constraints and segment correspondence constraints, forming an inversion constraint set.

[0041] Multiple candidate electrochemical parameter sets are constructed according to preset parameter dimensions, and each candidate electrochemical parameter set is assigned a candidate identifier.

[0042] Each candidate electrochemical parameter set is subjected to a screening process consistent with the inversion constraint set to obtain an electrochemical parameter set that matches the input data pair;

[0043] The electrochemical parameter set is used as input, and the result of the positive electrode repair status is output according to the preset judgment mapping rule.

[0044] Specifically, the electrochemical parameter set is used as input, and the determination result of the positive electrode repair state is output according to a preset determination mapping rule, including:

[0045] The parameters in the electrochemical parameter set are standardized in terms of dimensions and range to generate a standardized parameter vector.

[0046] A decision index identifier is generated based on the normalized parameter vector, and a target decision mapping rule is selected from a preset decision mapping rule library based on the decision index identifier;

[0047] The normalized parameter vector is input into the target determination mapping rule to obtain the determination label corresponding to the target determination mapping rule;

[0048] The determination label is bound to the detection process identifier and output as the determination result of the lithium battery positive electrode repair status.

[0049] A lithium battery cathode repair electrochemical parameter detection system is used to implement the lithium battery cathode repair electrochemical parameter detection method, including: an excitation module, a data acquisition module, a decoupling analysis module, and a repair judgment module;

[0050] The excitation module is used to apply a preset coupled electrochemical excitation to the repaired lithium battery cathode. The coupled electrochemical excitation is used to simultaneously trigger the lithium-ion migration process inside the cathode material and the reversible electrochemical response of the repair interface.

[0051] The data acquisition module is used to acquire the potential change response and current change response of the positive electrode in real time during the coupled electrochemical excitation process to obtain electrochemical response data, which characterizes the dynamic behavior of the positive electrode after repair.

[0052] The decoupling analysis module is used to perform open-circuit relaxation on the repaired lithium battery cathode after the coupled electrochemical excitation ends, and to perform decoupling analysis on the electrochemical response data based on the potential change relationship with time during the relaxation process, so as to obtain characteristic parameters corresponding to the lithium ion diffusion process and the interface polarization process.

[0053] The repair determination module is used to invert the electrochemical response data and the characteristic parameters to obtain a set of electrochemical parameters characterizing the cathode repair state, and to determine the cathode repair effect based on the set of electrochemical parameters.

[0054] Compared with the prior art, the beneficial effects of the present invention are:

[0055] This invention proposes a system and method for detecting electrochemical parameters in lithium-ion battery cathode repair. By correlating and deconstructing the electrochemical response data obtained during the excitation phase with the time series formed during the relaxation phase, characteristic parameters corresponding to the lithium-ion diffusion process and the interface polarization process are generated. Based on these characteristic parameters, a set of electrochemical parameters characterizing the cathode repair state is obtained, enabling the determination of the cathode repair state. This method avoids the problem of data fragmentation between different detection methods, ensuring that repair-related information can be consistently expressed between dynamic response and relaxation behavior. This improves the completeness and consistency of the determination of the electrochemical state of the repaired cathode, and is applicable to cathode state detection under different repair methods and repair levels. Attached Figure Description

[0056] Figure 1The flowchart of the method for detecting electrochemical parameters for lithium battery cathode repair provided by the present invention;

[0057] Figure 2 A schematic diagram of coupled electrochemical excitation provided by the present invention;

[0058] Figure 3 This is a schematic diagram of interval mapping and relation object construction provided by the present invention;

[0059] Figure 4 A schematic diagram illustrating the output repair status determination result provided by the present invention;

[0060] Figure 5 The diagram shows the architecture of the lithium battery cathode repair electrochemical parameter detection system provided by this invention. Detailed Implementation

[0061] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application. These all fall within the protection scope of the present application.

[0062] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0063] It should be noted that, unless there is a conflict, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. In addition, the terms "first," "second," and "third" used in this application do not limit the data or execution order, but only distinguish identical or similar items with essentially the same function and effect.

[0064] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0065] Example 1:

[0066] Please see Figures 1-4This invention provides an embodiment of a method for detecting electrochemical parameters of a lithium battery cathode repair. The method employs an electrochemical testing device to test the cathode under test. The electrochemical testing device includes an electrochemical workstation, a constant temperature chamber, a data acquisition unit, and a data processing unit. The repaired cathode is used as the working electrode and forms a test circuit with the counter electrode and a reference electrode. During the testing process, the ambient temperature is controlled at 25±1℃. Before testing, the cathode under test is allowed to stand for 30 minutes. At the end of the standing period, the cathode potential is measured to be 3.3200V, and the potential change rate within 5 consecutive minutes is less than 0.1mV / min.

[0067] The specific steps include the following:

[0068] Step S1: Apply a preset coupled electrochemical excitation to the repaired lithium battery cathode. The coupled electrochemical excitation is used to simultaneously trigger the lithium-ion migration process inside the cathode material and the reversible electrochemical response of the repair interface. The coupled electrochemical excitation includes one or more asymmetric bipolar excitation processes, so that the cathode sequentially experiences a repair activation state and a non-repair baseline state in the same detection process. In the asymmetric bipolar excitation process, the forward excitation and the reverse excitation differ in one or more of the amplitude, duration or energy input.

[0069] In this embodiment, one or more sets of asymmetric bipolar excitation sequences are applied to the repaired lithium battery positive electrode within a preset voltage window. Each set of excitation sequences includes a forward excitation segment, a transition phase, a reverse excitation segment, and a reference holding segment in chronological order. The forward excitation segment and the reverse excitation segment are intentionally set to be different in at least one of amplitude, duration, or energy input. For example, the forward excitation segment uses a higher amplitude and a shorter duration to form a sudden migration drive; the reverse excitation segment uses a lower amplitude and a longer duration to form a slow-release recovery drive; or the energy inputs of the two segments are unequal to form a net The bias is applied, and a reference hold segment is introduced at the end of each set of excitation sequences to bring the positive electrode back to a reproducible non-repair reference state within the same detection process. The principle is that the asymmetric bipolar excitation simultaneously introduces a fast perturbation and a slow recovery electrochemical driving mode on the same time axis. The unequal input of the positive and reverse excitations causes the reversible response of the repair interface to be superimposed on the overall response of the electrode with distinguishable temporal characteristics. The reference hold segment provides a unified reference to suppress the incomparability caused by drift, thereby forming a continuous excitation trajectory that includes both the repair activation state and the non-repair reference state within a single process.

[0070] It should be noted that the coupled electrochemical excitation is not an arbitrary form of excitation signal, but a pre-set excitation sequence based on the electrochemical response characteristics of the cathode material. Its core lies in introducing different energy injection paths in the same detection process through asymmetric bipolar excitation, thereby simultaneously stimulating the diffusion behavior inside the cathode material and the reversible response of the repair interface.

[0071] like Figure 2 As shown, when applying coupled electrochemical excitation to the repaired lithium battery cathode, excitation stages 1, 2, 3, and 4 are sequentially set along the time axis. Each excitation stage is executed continuously in a predetermined order, forming a complete coupled electrochemical excitation process. At the boundary of each excitation stage, time positioning points T1, T2, T3, and T4 are set respectively, and each time positioning point is associated with the corresponding excitation stage. Based on this, a unique time sequence identifier is generated for each time positioning point, which is denoted as time identifier sequence 1, time identifier sequence 2, time identifier sequence 3, and time identifier sequence 4 respectively. Through the above settings, the key moments in the excitation process are clearly marked, and a set of time sequence identifiers with sequential relationships is formed on the time axis. During the excitation execution process, a forward excitation current and a reverse excitation current are applied simultaneously. The forward excitation current and the reverse excitation current differ in amplitude, duration, or input order, thereby forming an asymmetric bipolar excitation trajectory on the time axis. Based on the time span between time positioning points T1 and T4, the entire excitation process is further divided into time interval 1, time interval 2 and time interval 3. Each time interval is defined by adjacent time positioning points and is associated with the corresponding time sequence identifier.

[0072] The following excitations are applied sequentially to the positive electrode under test: Excitation stage 1 is the forward excitation stage, with an excitation current I_pos of +0.20A and a duration t_pos of 5s; Excitation stage 2 is the transition stage, with an output current of 0A and a duration of 0.5s; Excitation stage 3 is the reverse excitation stage, with an excitation current I_neg of -0.10A and a duration t_neg of 10s; Excitation stage 4 is the reference holding stage, where the output current is switched to 0A, causing the positive electrode under test to enter an open-circuit relaxation state.

[0073] The forward excitation charge is: Q_pos = I_pos × t_pos = 0.20 × 5 = 1.00C; the absolute value of the reverse excitation charge is: Q_neg = |I_neg| × t_neg = 0.10 × 10 = 1.00C; the forward and reverse excitation charges are equal, but the current amplitude and duration of the forward and reverse excitations are different; the current amplitude asymmetry coefficient is: K_I = |I_pos| / |I_neg| = 0.20 / 0.10 = 2.00, and the duration asymmetry coefficient is: K_t = t_pos / t_neg = 5 / 10 = 0.50, where |∙| represents the absolute value sign; the excitation process belongs to asymmetric bipolar excitation with different amplitudes and durations.

[0074] Set the time positioning points according to the moment when the excitation state changes: T0=0s, which is the start time of positive excitation; T1=5.0s, which is the end time of positive excitation; T2=5.5s, which is the start time of reverse excitation; T3=15.5s, which is the end time of reverse excitation and the start time of open-circuit relaxation.

[0075] This creates three consecutive excitation process intervals: P1 is 0 to 5.0s, corresponding to the positive excitation stage; P2 is 5.0 to 5.5s, corresponding to the transition stage; and P3 is 5.5 to 15.5s, corresponding to the negative excitation stage.

[0076] Step S2: During the coupled electrochemical excitation process, the potential change response and current change response of the positive electrode are collected in real time to obtain electrochemical response data. The electrochemical response data characterizes the dynamic behavior of the positive electrode after repair.

[0077] The specific steps of step S2 are as follows:

[0078] Step S201: During the application of the coupled electrochemical excitation, the excitation process is continuously time-localized, and a time series identifier corresponding to the excitation process is generated.

[0079] In this embodiment, the excitation start time is predetermined as the zero point before the start of coupled electrochemical excitation, and the time axis is continuously advanced throughout the entire excitation process. Each change node of the excitation state during the excitation process is recorded as a time positioning point. The change nodes of the excitation state include process boundaries that can be clearly distinguished on the time axis, such as excitation direction switching, excitation amplitude change, and the start or end of the excitation holding period. Each time positioning point is bound to the corresponding excitation state to form a time sequence identifier. The principle is that by discretizing the continuous excitation process into a sequence structure of multiple time positioning points connected end to end, the excitation application process, which originally only has instantaneous meaning, is transformed into a time object with clear stage division and sequential relationship. This allows the subsequently acquired potential change response and current change response to be accurately located under the same time reference and correspond to the specific excitation stage. Through the above continuous time positioning processing, a time sequence identifier set covering the entire coupled electrochemical excitation process is obtained.

[0080] It should be noted that the time series identifier is used to impose a unified time constraint on the excitation process and the acquisition process. Its generation method does not depend on a specific clock precision or sampling frequency, but is determined based on the nodes of excitation state change.

[0081] Step S202: Based on the time series identifier, the potential change response and current change response of the positive electrode are collected in pairs within each continuous time interval of the excitation process to form original response pairs with time correspondence.

[0082] In this embodiment, under the constraint of the time sequence identifier generated in step S201, the entire coupled electrochemical excitation process is divided into several continuous time intervals. Within each time interval, the potential and current changes of the positive electrode are synchronously recorded using the same time reference, so that each recording moment corresponds to a unique time sequence identifier. In specific implementation, the adjacent time positioning points in the time sequence identifier are used as the interval boundaries. Potential recording and current recording are started simultaneously at the beginning of the interval and the corresponding recording is stopped simultaneously at the end of the interval, thereby ensuring a one-to-one correspondence between the potential change response and the current change response on the time axis. The principle is that by using the time sequence identifier as a unique reference, the potential and current records, which may originally have time offsets, are forcibly bound to the same excitation process interval, so that the two types of response data no longer exist as their own independent acquisition sequences, but are organized into paired data units with a clear time correspondence. Through the above paired acquisition method, a set of original response pairs covering the entire excitation process is formed, where each original response pair can be traced back to a specific excitation stage and time interval.

[0083] Step S203: Divide the original response pair into segments according to the time series identifier, so that each response segment corresponds to a unique excitation process interval.

[0084] In this embodiment, based on the time sequence identifiers formed in step S201, the original response pairs obtained in step S202 are segmented along the time axis. Specifically, the time positioning points corresponding to adjacent time sequence identifiers are used as the segmentation boundaries. The continuously recorded original response pairs are sequentially scanned. When any time positioning point is scanned, the encapsulation of the previous segment is completed and the recording of the next segment begins. Each segmented response segment completely contains the paired data of the potential change response and the current change response within the excitation process interval and is bound to the corresponding time sequence identifier. The principle is that by using the time positioning point of the excitation process instead of a fixed time length as the segment division basis, each response segment naturally inherits the process attributes of the corresponding excitation interval, thereby avoiding the mixing of data under different excitation states in the same segment. Through the above segment division process, multiple sets of response segments that are connected end to end on the time axis and are independent of each other in excitation logic are obtained, so that each response segment has a unique and clear excitation process interval affiliation.

[0085] Step S204: Integrate the response fragments according to the order of the excitation process to generate electrochemical response data.

[0086] In this embodiment, based on the multiple response fragments obtained in step S203, the chronological order of the response fragments on the time axis is confirmed according to the time sequence identifiers bound to each response fragment, and they are arranged and integrated sequentially according to the chronological order. Specifically, the starting time sequence identifier of the excitation process is used as the integration starting point, and the corresponding response fragment is used as the first data unit. Subsequently, subsequent response fragments are introduced one by one in ascending order of time sequence identifiers, maintaining the temporal continuity within each response fragment during the integration process. The principle is that by using the order of the excitation process rather than the order of fragment generation as the integration basis, the discrete response fragments obtained from different excitation intervals are reassembled into a complete response trajectory in the time dimension, thereby restoring the data evolution relationship that corresponds one-to-one with the coupled electrochemical excitation process. Through the above integration process, electrochemical response data covering the entire excitation process is generated. This data retains the independent boundary information of each excitation interval and has a continuous temporal sequence structure.

[0087] During the excitation process, the positive electrode potential and current are synchronously acquired at a sampling frequency of 100Hz. For each sampling point, the sampling time, excitation process interval, potential value, and current value are recorded. The obtained partial data are as follows: Before the start of forward excitation, i.e., at t=0, the current is 0A and the potential is 3.3200V; 20ms after the start of forward excitation, i.e., at t=0.02s, the current is +0.20A and the potential is 3.3260V; before the end of forward excitation, i.e., at t=5.0s, the current is +0.20A and the potential is 3.3440V; at the end of the transition phase, i.e., at t=5.5s, the current is 0A and the potential is 3.3390V; 20ms after the start of reverse excitation, i.e., at t=5.52s, the current is -0.10A and the potential is 3.3360V; before the end of reverse excitation, i.e., at t=15.5s, the current is -0.10A and the potential is 3.3060V; after the reverse excitation ends and switches to the open-circuit relaxation state, the potential experiences a momentary rebound of 3mV, and the open-circuit initial potential is 3.3090V.

[0088] Calculate the forward instantaneous response resistance. The instantaneous potential change caused by the forward excitation is: d_E_pos = 3.3260 - 3.3200 = 0.0060V, and the forward instantaneous response resistance is: R0_pos = |d_E_pos| / |I_pos| = 0.0060 / 0.20 = 0.030Ω; Calculate the reverse instantaneous response resistance. The instantaneous potential change at the start of the reverse excitation is: d_E_neg = 3.3 360-3.3390=-0.0030V, the reverse instantaneous response resistance is: R0_neg=|d_E_neg| / |I_neg|=0.0030 / 0.10=0.030Ω. Taking the average of the forward and reverse instantaneous response resistances, we get the instantaneous response resistance: R0=(R0_pos+R0_neg) / 2=(0.030+0.030) / 2=0.030Ω.

[0089] Electrochemical response data is generated by dividing the potential and current data in P1, P2, and P3 into time segments T0, T1, T2, and T3. The P1 data segment contains the potential and current responses during the forward excitation phase; the P2 data segment contains the potential recovery response during the transition phase; and the P3 data segment contains the potential and current responses during the reverse excitation phase. These data segments are then integrated in the order of P1, P2, and P3 to obtain electrochemical response data D_K001. Electrochemical response data D_K001 includes the following response quantities: instantaneous response resistance R0 is 0.030Ω; total potential change during forward excitation is 0.0240V; total potential change during reverse excitation is -0.0330V; average potential change rate during forward excitation is 0.0240 / 5 = 0.0048V / s; and the absolute value of the average potential change rate during reverse excitation is 0.0330 / 10 = 0.0033V / s.

[0090] Step S3: After the coupled electrochemical excitation is completed, the repaired lithium battery cathode is subjected to open-circuit relaxation, and based on the potential change relationship with time during the relaxation process, the electrochemical response data is decoupled and analyzed to obtain characteristic parameters corresponding to the lithium ion diffusion process and the interface polarization process.

[0091] The specific steps of step S3 are as follows:

[0092] Step S301: After the coupled electrochemical excitation ends, determine the termination time of the coupled electrochemical excitation as the starting time point of the open-circuit relaxation, and establish the relaxation time reference based on this starting time point.

[0093] In this embodiment, after the coupled electrochemical excitation is applied, the moment when the last excitation state change ends is determined as the electrochemical excitation termination moment, and this termination moment is recorded as the starting time point of open-circuit relaxation. Based on this, the time axis is redefined with the starting time point as the zero point of time, so that all subsequent potential changes are recorded with reference to this zero point of time. The principle is that by fixing the physically clear and repeatable moment of the excitation end as the unique time starting point of the relaxation process, the time offset introduced by the difference in excitation duration or data acquisition delay between different detection processes can be eliminated, so that the relaxation process can be carried out under the same reference conditions.

[0094] Step S302: Based on the relaxation time reference, perform open-circuit relaxation on the repaired lithium battery positive electrode, and continuously record the potential changes in the open-circuit state to form a complete relaxation time series.

[0095] The specific steps of step S302 are as follows:

[0096] Step S3021: After the relaxation time reference is established, the positive electrode is switched from the excitation state to the open circuit state, and the time of completion of the switch is used as the starting mark for potential recording.

[0097] In this embodiment, after establishing the relaxation time reference in step S301, an excitation removal operation is performed to prevent the positive electrode from receiving external electrochemical excitation. After the excitation removal is completed, an open-circuit state confirmation operation is performed, and the moment of confirmation is defined as the switching completion moment. Subsequently, the switching completion moment is written into the start mark under the relaxation time reference to trigger the starting point location of the potential recording process. The principle is that there is usually an observable state transition interval between excitation removal and the formation of the open circuit state. If the excitation termination moment is directly used as the starting point of potential recording, it is easy to incorporate the non-open circuit data in the transition interval into the relaxation trajectory, resulting in the starting point semantics of the relaxation sequence being non-unique. By using the open circuit confirmation completion as the starting mark, the starting point of potential recording is consistent with the physical conditions of open circuit relaxation and a clear correspondence is established with the relaxation time reference, thereby obtaining a potential recording starting mark that is traceable on the time axis with the switching completion moment as the starting point.

[0098] Step S3022: Based on the relaxation time reference, determine the recording rhythm of potential changes so that each recording moment maintains a sequential relationship on the time axis.

[0099] In this embodiment, after determining the starting mark of potential recording, the time progression method for subsequent potential recording is pre-set based on the relaxation time reference established in step S301. Specifically, this includes dividing consecutive recording time points according to the relaxation time reference and numbering each recording time point sequentially to form an ordered recording sequence. The interval between the recording time points can adopt different time progression strategies in the early and late stages of relaxation. For example, a denser number of recording time points can be set in the time range close to the starting mark, while a sparser number of recording time points can be set in the time range far from the starting mark, so that the entire recording process maintains continuous progress on the time axis and has a clear sequence. The principle is that by using the relaxation time reference as the sole reference, the potential recording rhythm is uniformly planned to avoid the time sequence disorder caused by random or irregular recording, so that each potential recording point naturally carries its relative positional relationship in the relaxation process. Through the above recording rhythm setting, a set of recording time sequences with a clear order and traceability on the time axis is obtained.

[0100] Step S3023: According to the recording rhythm, continuously collect the potential changes of the repaired lithium battery positive electrode in the open circuit state to obtain potential data points arranged in chronological order.

[0101] In this embodiment, after setting the recording rhythm in step S3022, starting from the potential recording start mark determined in step S3021, the repaired lithium battery positive electrode potential is recorded point by point in the open circuit state strictly according to the recording rhythm. Each recording corresponds to a unique recording time under the relaxation time reference, and the order of recording times is kept from being skipped or rearranged during the recording process. When the recording progresses to the preset relaxation end time, the potential acquisition is stopped and all recording results are sealed. The principle is that by completely constraining the potential acquisition action within the predetermined recording rhythm and relaxation time reference, each potential data point has a clear time assignment, thereby avoiding the time mismatch problem caused by irregular sampling. Through the above continuous acquisition method, a set of potential data points arranged sequentially on the time axis is obtained, and the sequence of data points completely covers the open circuit relaxation process.

[0102] Step S3024: Encapsulate the potential data points according to the starting mark and time sequence to form a relaxation time series corresponding to a single relaxation process.

[0103] In this embodiment, after obtaining the potential data points arranged in chronological order in step S3023, the starting marker determined in step S3021 is used as the sequence head identifier to uniformly collect all potential data points. Specifically, each potential data point is bound to its corresponding recording time under the relaxation time reference and arranged in chronological order. After the arrangement is completed, the starting marker is associated with the arranged potential data points as a whole to form a sequence object with a clear starting point and continuous time progression relationship. The principle is that the encapsulation operation elevates the originally scattered individual potential data points into a time sequence with overall semantics, so that the sequence not only contains potential change information, but also embeds its temporal position relationship in the complete relaxation process, thereby avoiding the problem of unclear sequence starting point or ambiguous data attribution in the subsequent analysis process. Through the above encapsulation process, a relaxation time sequence corresponding only to a single open-circuit relaxation process is formed.

[0104] It should be noted that the analysis of the open-circuit relaxation process is based on a unified relaxation time reference, which takes the open-circuit confirmation time after the coupled electrochemical excitation ends as the starting point, thereby ensuring the comparability of relaxation data between different detection procedures. After forming a complete relaxation time series, the entire series is not analyzed directly. Instead, the relaxation time series is processed by interval mapping according to a preset time progression rule. The time progression rule divides the relaxation process into segments according to the time progression order, so that the time interval near the beginning of relaxation is relatively short, while the time interval near the later stage of relaxation is relatively long, in order to adapt to the characteristic that the potential change rate gradually slows down during the relaxation process. Through the above interval mapping process, a single continuous relaxation time series is transformed into multiple time intervals with clear start and end boundaries, so that different time intervals structurally correspond to different stages of change in the relaxation process.

[0105] The moment T3, when the reverse excitation ends and the open-circuit switching is completed, is determined as the relaxation start time. Using T3 as the zero point of the relaxation time, the relative relaxation time t_r is defined as: t_r = t - T3, where t represents the actual sampling time corresponding to a certain potential sampling point during the relaxation process. The total recording time for open-circuit relaxation is 600s. Potentials are sampled at 100Hz within 0–10s; at 10Hz within 10–100s; and at 1Hz within 100–600s. The obtained partial relaxation potential data are as follows: 3.309000V at t_r=0s; 3.309235V at t_r=0.1s; 3.310088V at t_r=0.5s; 3.310978V at t_r=1s; 3.312304V at t_r=2s; and 3.3141V at t_r=5s. 88V; when t_r=10s, the potential is 3.314890V; when t_r=30s, the potential is 3.315368V; when t_r=60s, the potential is 3.315950V; when t_r=100s, the potential is 3.316531V; when t_r=300s, the potential is 3.317723V; when t_r=600s, the potential is 3.317977V.

[0106] Step S303: According to the preset time progression rule, the relaxation time series is mapped into multiple mutually distinct time intervals, so that different time intervals correspond to different stages of change in the relaxation process.

[0107] In this embodiment, after obtaining the complete relaxation time series, the relaxation time series is subjected to interval mapping processing according to a pre-set time progression rule. The time progression rule takes the relaxation time reference as the starting point and divides multiple consecutive time periods according to the chronological order of time progression, and assigns an independent interval identifier to each time period. In specific implementation, a step-by-step progression method can be adopted, setting a shorter time interval in the initial stage of relaxation and gradually extending the length of the time interval in the subsequent stages of relaxation, so that the division of time intervals matches the natural evolution of the potential change rhythm during the relaxation process. The principle is that by using the time progression rule rather than a fixed number of sampling points as the basis for interval division, the relaxation time series is reconstructed into multiple interval units with chronological order and independent boundaries in the time dimension, thereby avoiding the mixing of changes in different relaxation stages in the same time period. Through the above mapping processing, a single relaxation time series is transformed into multiple mutually distinguishable time intervals, so that each time interval clearly corresponds to a different change stage in the relaxation process.

[0108] Step S304: Correlate the time intervals with the electrochemical response data respectively, and deconstruct the relationship between the potential changes in different time intervals and the electrochemical response data.

[0109] like Figure 3 As shown, the specific steps of step S304 are as follows:

[0110] Step S3041: For each time interval, generate a set of interval anchor points including the start time and end time of the interval.

[0111] In this embodiment, after completing the interval mapping of the relaxed time series in step S303, for each obtained time interval, the start time and end time of the time interval under the relaxed time reference are read and recorded as a set of boundary information. In specific implementation, the corresponding start time and end time are written into the interval anchor point record in pairs using the time interval identifier as an index, thereby forming a set of independent and complete interval anchor points for each time interval. The principle is that by explicitly extracting and solidifying the boundaries of each time interval in the continuous time series into interval anchor points, the time interval is transformed from an abstract time range into a time object with clear start and end boundaries, avoiding overlap or mismatch caused by fuzzy interval boundaries in the subsequent data association process. Through the above interval anchor point generation process, an interval anchor point set covering all relaxed time intervals is obtained.

[0112] The relaxation time series is divided into three time intervals: Interval A1 (0–10 s), labeled A1, characterizes the rapid polarization recovery process in the initial open-circuit phase; Interval A2 (10–100 s), labeled A2 (with 10 s belonging to interval A2), characterizes the mid-term relaxation process; and Interval A3 (100–600 s), labeled A3 (with 100 s belonging to interval A3), characterizes the slow recovery process in the later stage. The corresponding interval anchor points are: {0 s, 10 s} for A1; {10 s, 100 s} for A2; and {100 s, 600 s} for A3.

[0113] Step S3042: Based on the set of interval anchor points, extract the data segments corresponding to each interval anchor point on the time axis from the electrochemical response data, and time-align the data segments with the potential change segments in the corresponding time interval.

[0114] In this embodiment, after obtaining the set of interval anchor points, the start and end times corresponding to each time interval are read sequentially. Using this time range as a filtering condition, the electrochemical response data generated in step S204 is scanned along the time axis, and continuous data falling between the start and end times is extracted as corresponding data segments. Subsequently, the data segments are compared with the potential change segments already obtained in the same time interval to ensure that their starting positions and progression order remain consistent under the relaxation time reference. The principle is that by using the interval anchor points as the only time constraint, the electrochemical response data that originally spanned the entire excitation and relaxation process is extracted in a directional manner according to the time window and aligned with the potential change segments formed in the relaxation stage within the same time frame, thereby establishing a one-to-one correspondence between data from different sources and different stages in the time dimension. Through the above extraction and alignment processing, a combination of data segments that strictly correspond to each time interval is obtained, so that the potential changes in each time interval and the response data in the excitation stage form directly related paired data units on the time axis.

[0115] Step S3043: Split the time-aligned data pairs so that each split unit contains only a potential change segment within a time interval and its corresponding data segment, and assign an interval identifier to each split unit.

[0116] In this embodiment, after aligning the data segments and potential change segments in step S3042, the time range corresponding to the interval anchor point is used as the splitting boundary. The paired data units are scanned interval by interval. When the scan enters the time range defined by a certain interval anchor point, the potential change segment and its corresponding data segment within that time range are extracted as a complete data unit. The data unit is encapsulated when the scan reaches the end of the interval. Subsequently, the data unit is bound to the corresponding time interval identifier to form an information carrier with a clear interval affiliation. The principle is that by using the interval anchor point as the splitting basis, the splitting operation strictly follows the time interval division logic, ensuring that each splitting unit contains only relevant data within a single interval, thereby avoiding the mixing of data from different time intervals in the same unit. Through the above splitting and identifier assignment process, multiple independent splitting units are formed, and each splitting unit clearly corresponds to a time interval.

[0117] Step S3044: Group each splitting unit according to the interval identifier to obtain a set of relational objects for different time intervals.

[0118] In this embodiment, after obtaining multiple splitting units with interval identifiers in step S3043, the splitting units are retrieved by interval identifiers, and the splitting units are assigned to corresponding interval sets according to the values ​​of the interval identifiers. Specifically, the interval identifiers are used as unique settling indexes to sequentially traverse the splitting units. When the interval identifier of a splitting unit is found to be consistent with a certain interval identifier, the splitting unit is included in the corresponding settling container, and multiple distinct settling results are formed after the traversal is completed. The principle is that by using interval identifiers as the core for settling, the originally discretely distributed splitting units are reorganized according to the unified dimension of time interval, thereby integrating potential change segments and corresponding electrochemical response segments within the same time interval into a data set with intrinsic correlation. Through the above settling process, a set of relational objects for different time intervals is obtained, and each set of relational objects corresponds to a specific relaxation time interval.

[0119] like Figure 3 As shown, after the coupled electrochemical excitation process ends, the excitation termination time is determined as the relaxation start time T0, and a relaxation time reference is established based on this time. This ensures that subsequent potential changes are recorded under a unified time reference. Along the time reference direction, open-circuit relaxation is performed on the repaired lithium battery cathode, and the potential change response of the cathode during the relaxation process is continuously acquired, forming a complete relaxation time series. Based on this relaxation time series, the relaxation process is divided into multiple continuous and mutually distinct time intervals according to a preset time progression rule, such as... Figure 3 The time intervals 1, 2, 3, and 4 shown are arranged sequentially on the time axis and correspond to different stages in the relaxation process, transforming the relaxation time series from a single continuous sequence into a segmented structure with clear boundaries. After dividing the time intervals, potential change segments corresponding to each time interval are extracted from the relaxation time series to form potential change segment 1, potential change segment 2, and potential change segment 3. Simultaneously, based on the boundary information of the time intervals, data segments corresponding to the time intervals on the time axis are extracted from the electrochemical response data obtained during the excitation stage, and these data segments are aligned with the potential change segments in the time dimension. Subsequently, the aligned data is split, ensuring that each split unit contains only the potential change segment within a single time interval and its corresponding data segment. Further, the split units are grouped according to the time interval identifier, aggregating split units belonging to the same time interval into a corresponding set of relational objects, such as... Figure 3 The relation object set 1, relation object set 2, and relation object set 3 are shown in the figure.

[0120] A correspondence is established between the data segments of the excitation phase and the data segments of the relaxation phase. The reverse excitation data segment P3 is associated with the early relaxation interval A1 to form the first relational object J1; the excitation response data D_K001 is associated with the mid-term relaxation interval A2 to form the second relational object J2; and the excitation response data D_K001 is associated with the late relaxation interval A3 to form the third relational object J3. J1 is assigned to the first set of intervals for calculating interface polarization characteristic parameters; J2 and J3 are assigned to the second set of intervals for calculating lithium-ion diffusion characteristic parameters.

[0121] Step S305: Based on the deconstruction processing results, generate characteristic parameters corresponding to the lithium-ion diffusion process and the interface polarization process, respectively.

[0122] The specific steps of step S305 are as follows:

[0123] Step S3051: Based on the interval identifiers in the set of relational objects, divide the set of relational objects into a first set of intervals and a second set of intervals, wherein the first set of intervals corresponds to an earlier time interval and the second set of intervals corresponds to a later time interval.

[0124] In this embodiment, after obtaining the set of relational objects formed in step S3044, the interval identifier bound to each relational object is read, and the relational objects are sorted according to the time sequence corresponding to the interval identifier. After sorting, the time progression direction under the relaxation time base is used as the dividing criterion, and the relational objects in the earlier part of the sorting result are assigned to the first set of intervals, and the relational objects in the later part of the sorting result are assigned to the second set of intervals. The first set of intervals covers the earlier time intervals after the relaxation process begins, and the second set of intervals covers the later time intervals after the relaxation process. The principle is that by using the time sequence implied by the interval identifier as the sole criterion, the set of relational objects is segmented and reorganized along the relaxation time axis, so that relational objects that are originally in the same set but have different time attributes are clearly distinguished, thereby introducing early and late time layering at the data structure level. Through the above grouping process, two interval sets that are continuous and do not overlap in the time dimension are formed.

[0125] Step S3052: Perform intra-group summary processing on the relational objects contained in the first set of intervals and the second set of intervals to construct the first set of representation sequences and the second set of representation sequences.

[0126] In this embodiment, after completing step S3051 of grouping the relational object set by time, intra-group summarization processing is performed on the first group of interval sets and the second group of interval sets respectively. Specifically, the relational objects contained in each group of interval sets are read sequentially according to the time order of the interval identifiers, and the potential change segments contained in each relational object are connected and integrated with the corresponding data segments in the direction of time progression. During the integration process, the data order within each relational object is not disrupted, and a continuous time connection is established between adjacent relational objects, thereby forming a continuous data sequence covering the corresponding time range. The principle is that by summarizing multiple relational objects in the same group of intervals with time order as the main line, the data originally scattered in multiple intervals is reorganized into a sequence structure with overall continuity in the time dimension, thereby elevating the interval-level data to a group-level representation. Through the above intra-group summarization processing, the first group of representation sequences corresponding to the first group of interval sets and the second group of representation sequences corresponding to the second group of interval sets are constructed respectively.

[0127] Step S3053: Input the first set of characterization sequences into the first mapping rule to generate interface polarization feature parameters, and input the second set of characterization sequences into the second mapping rule to generate lithium ion diffusion feature parameters.

[0128] In this embodiment, based on the first and second sets of characterization sequences constructed in step S3052, different mapping rules are selected for the two sets of characterization sequences and mapping processing is performed. Specifically, the first set of characterization sequences is input into a preset first mapping rule according to its time coverage and data organization method, and the second set of characterization sequences is input into a preset second mapping rule according to its time progression characteristics. The first mapping rule focuses on converting the change amplitude, change rate, and relative stability relationship in the first characterization sequence within a short time scale to extract feature information that can characterize interface polarization behavior. The second mapping rule focuses on converting the trend relationship, change decay characteristics, and overall evolution morphology of the second characterization sequence that evolves gradually over time to extract feature information that can characterize the lithium-ion diffusion process. The principle is that by using different mapping paths for the characterization sequences obtained by different time groups, data from the same detection process are given different physical orientations in the conversion stage, thereby converting time-layered information into parameter-layered information. Through the above mapping processing, interface polarization feature parameters corresponding to the interface polarization process and lithium-ion diffusion feature parameters corresponding to the lithium-ion diffusion process are generated respectively.

[0129] Step S3054: Output the interface polarization characteristic parameters and the lithium-ion diffusion characteristic parameters in pairs using the same detection process identifier to form a characteristic parameter set.

[0130] In this embodiment, after obtaining the interface polarization feature parameters and lithium-ion diffusion feature parameters respectively, the detection process identifier associated with both types of feature parameters is read, and the two types of feature parameters are paired and bound using the detection process identifier as a unified index. In specific implementation, the interface polarization feature parameters and lithium-ion diffusion feature parameters generated under the same detection process identifier are simultaneously written into the same parameter recording unit, and the source differentiation information of the two types of parameters is maintained in the parameter recording unit. The principle is that by using the detection process identifier as the unique association link, feature parameters generated from different time intervals and through different mapping rules are re-aggregated into the same process context, and through the above-mentioned paired output processing, a feature parameter set corresponding one-to-one with a single detection process is formed.

[0131] The relaxation potential within the A1 interval from 0 to 10 s is fitted using a single exponential recovery model (corresponding to the first mapping rule): E_p(t_r) = E_p_inf - A_p × exp(-t_r / tau_p), where E_p(t_r) represents the fitted potential in the early relaxation stage; E_p_inf represents the potential after recovery of the early polarization process; A_p represents the amplitude of the interface polarization potential; tau_p represents the interface polarization relaxation time constant; and exp(∙) represents the exponential function. The measured potential data in the A1 interval were fitted with nonlinear least squares to obtain E_p_inf=3.3150V; A_p=0.0060V; tau_p=2.50s; that is, the early relaxation potential model is: E_p(t_r)=3.3150-0.0060×exp(-t_r / 2.50), when t_r=0: E_p(0)=3.3150-0.0060=3.3090V, which is consistent with the actual measured open circuit initiation potential of 3.3090V.

[0132] The apparent interfacial polarization resistance is calculated based on the reverse excitation current: R_int = A_p / |I_neg| = 0.0060 / 0.10 = 0.060Ω. The interfacial polarization characteristic parameters are obtained as: P_pol = {R0, R_int, A_p, tau_p}, that is, P_pol = {0.030Ω, 0.060Ω, 0.0060V, 2.50s}.

[0133] The intervals A2 and A3 are grouped together to form a late-stage relaxation characterization sequence from 10 to 600 seconds. This characterization sequence is then fitted using an exponential recovery model (corresponding to the second mapping rule): E_d(t_r) = E_eq - A_d × exp[-(t_r-10) / tau_d], where: E_eq represents the equilibrium potential after sufficient relaxation; A_d represents the amplitude of the diffusion-related potential that has not yet recovered at 10 seconds; and tau_d represents the diffusion-related relaxation time. The constants and fitting results are: E_eq = 3.3180V; A_d = 0.003110V; tau_d = 120s; that is, the later relaxation potential model is: E_d(t_r) = 3.3180 - 0.003110 × exp[-(t_r - 10) / 120]. Based on the diffusion-related relaxation time constant, the diffusion recovery rate coefficient K_diff is calculated as: K_diff = 1 / tau_d = 1 / 120 = 0.00833s -1 The obtained lithium-ion diffusion characteristic parameters are: P_diff={A_d, tau_d, K_diff}, i.e.: P_diff={0.003110V, 120s, 0.00833s}. -1}

[0134] Step S4: Based on the electrochemical response data and the characteristic parameters, an electrochemical parameter set characterizing the cathode repair state is obtained by inversion, and the cathode repair effect is determined according to the electrochemical parameter set.

[0135] like Figure 4 As shown, the specific steps of step S4 are as follows:

[0136] Step S401: Pair the electrochemical response data with the characteristic parameters according to the same detection process identifier to generate input data pairs for inversion processing.

[0137] In this embodiment, after obtaining the electrochemical response data generated in step S204 and the feature parameter set formed in step S3054, the detection process identifier bound to both is read, and the detection process identifier is used as the unique matching condition for pairing. Specifically, the data set corresponding to a certain detection process identifier is retrieved in the electrochemical response data, and the feature parameter record with the same detection process identifier is retrieved in the feature parameter set. The two are then merged to form a data pairing unit. The principle is that by using the detection process identifier, a unified marker that runs through the entire process of excitation, acquisition, relaxation, deconstruction, and parameter generation, as the pairing basis, the dynamic response data and the staticized feature parameters are logically re-merged, avoiding the cross-use of data between different detection processes. Through the above pairing process, one or more sets of one-to-one corresponding input data pairs are generated. Each input data pair completely contains the electrochemical response evolution information and its corresponding feature parameter information under the same detection process.

[0138] Step S402: Extract preset consistency constraints based on the input data. The consistency constraints include time sequence constraints and segment correspondence constraints, and form an inversion constraint set.

[0139] In this embodiment, after obtaining the input data pair formed in step S401, the electrochemical response data and feature parameters contained in the input data pair are subjected to structured analysis. The time sequence information and fragment correspondence information of the two during the generation process are extracted respectively, and consistency constraints are constructed accordingly. Among them, the time sequence constraint is limited by reading the time identifier of each response fragment in the electrochemical response data to ensure that the order of the response fragments in the inversion process is not disrupted. The fragment correspondence constraint is limited by reading the interval identifier or generation source identifier retained in the feature parameters to ensure that the feature parameters can only be associated with response fragments with the same source. The principle is that by explicitly extracting the time relationship and source relationship originally implicit in the data structure as constraint conditions, the inversion process is no longer a free combination of parameters, but is restricted to a feasible range that conforms to the internal logic of the detection process. Through the above consistency constraint extraction process, an inversion constraint set containing time sequence constraints and fragment correspondence constraints is formed.

[0140] The following inversion constraints are set: the instantaneous response resistance R0 must originate from the current step response in excitation phase P1 or P3; the interface polarization potential amplitude A_p and the interface polarization relaxation time constant tau_p must originate from the early relaxation interval A1; the diffusion-dependent relaxation time constant tau_d must originate from the middle and late relaxation intervals A2 and A3; the data segments corresponding to the parameters must maintain the time sequence of P1, P2, P3, A1, A2, and A3.

[0141] Based on the measurement error, further numerical constraints are set: the allowable range of R0 is 0.027~0.033Ω; the allowable range of R_int is 0.055~0.065Ω; the allowable range of tau_p is 2.20~2.80s; and the allowable range of tau_d is 105~135s. It should be noted that the ranges with the symbol ~ include the maximum and minimum values, that is, they are closed intervals, as indicated in special cases.

[0142] Step S403: Construct multiple candidate electrochemical parameter sets according to preset parameter dimensions, and assign a candidate identifier to each candidate electrochemical parameter set.

[0143] In this embodiment, after forming the inversion constraint set in step S402, the electrochemical parameters to be inverted are combined and constructed according to the preset parameter dimensions. The preset parameter dimensions include parameter dimensions for characterizing interface behavior and parameter dimensions for characterizing diffusion behavior. In specific implementation, the parameter value range is discretely divided according to the parameter dimensions, and multiple parameter combination units are generated based on different value combinations. Each parameter combination unit constitutes a candidate electrochemical parameter set. Subsequently, a unique candidate identifier is assigned to each candidate electrochemical parameter set for differentiation and indexing in the subsequent screening and matching process. The principle is that by systematically enumerating possible parameter combinations at the parameter dimension level, the inversion process has a clear candidate space structure, while the introduction of candidate identifiers ensures that each parameter combination is logically traceable and distinguishable. Through the above construction and identifier assignment process, a set of candidate electrochemical parameters with a clear structure and clear origin is formed.

[0144] Three candidate electrochemical parameter sets were constructed based on four parameter dimensions: R0, R_int, tau_p, and tau_d. The candidate electrochemical parameter set C01 is {0.030Ω, 0.060Ω, 2.50s, 120s}; the candidate electrochemical parameter set C02 is {0.030Ω, 0.060Ω, 120s, 2.50s}; and the candidate electrochemical parameter set C03 is {0.030Ω, 0.060Ω, 2.50s, 180s}.

[0145] Step S404: Perform a screening process on each of the candidate electrochemical parameter sets that is consistent with the inversion constraint set to obtain an electrochemical parameter set that matches the input data pair.

[0146] In this embodiment, after obtaining the multiple candidate electrochemical parameter sets constructed in step S403, the candidate identifier corresponding to each candidate electrochemical parameter set is read sequentially, and it is compared item by item with the inversion constraint set formed in step S402. Specifically, each candidate electrochemical parameter set is checked to see if it meets the constraint conditions defined in the inversion constraint set in both the time sequence dimension and the segment correspondence dimension. When a candidate electrochemical parameter set is found to be inconsistent with any constraint condition, the candidate electrochemical parameter set is excluded from the selection range. The principle is that by using the inversion constraint set as the screening criterion, the candidate electrochemical parameter sets are constrained and verified one by one, so that the inversion process is changed from parameter probing to constraint matching, thereby ensuring that the parameter set finally retained is consistent with the input data pair in terms of generation logic. Through the above screening process, an electrochemical parameter set that matches the input data pair in both time sequence and segment source is obtained from multiple candidate electrochemical parameter sets.

[0147] Constraint verification was performed on each candidate electrochemical parameter set. The parameters in C01 were of correct origin, correct time sequence, and consistent detection process identification, and all parameters were within the allowable range, so C01 was retained. In C02, the time intervals corresponding to tau_p and tau_d were interchanged, which did not meet the segment correspondence constraint, so C02 was excluded. In C03, the value of tau_d exceeded the allowable range, so C03 was excluded. The electrochemical parameter set {0.030Ω, 0.060Ω, 2.50s, 120s} that matched the input data pair was obtained.

[0148] Step S405: Using the set of electrochemical parameters as input, output the determination result of the positive electrode repair state according to the preset determination mapping rule.

[0149] The specific steps of step S405 are as follows:

[0150] Step S4051: Standardize the parameters in the electrochemical parameter set by unifying their dimensions and ranges to generate a standardized parameter vector.

[0151] In this embodiment, after obtaining the electrochemical parameter set screened in step S404, each electrochemical parameter contained in the parameter set is read sequentially, and each parameter is processed according to a predetermined parameter standardization rule. The parameter standardization rule includes specifying a unified dimensional benchmark for different types of parameters and limiting their corresponding value range. In specific implementation, parameters that originally had different dimensions or different value ranges are recalibrated so that their values ​​are mapped to the same comparable scale, while maintaining the relative order of each parameter in the parameter set. The principle is that by unifying the parameter dimensions and value ranges, the problem of incomparability caused by differences in dimensions or different value ranges between different parameters is eliminated, and the parameter set is transformed from a discrete multidimensional parameter group into a parameter expression form with a consistent structure. Through the above standardization process, a standardized parameter vector is generated, which is formed by multiple standardized parameters arranged in a predetermined order. This standardized parameter vector serves as the standardized input carrier for subsequent determination mapping steps and has a clear dimensional structure and consistent data semantics.

[0152] By establishing parameter reference ranges through repairing qualified reference samples and unrepaired reference samples, a normalized parameter vector {0.833, 0.667, 0.875, 0.800} is generated. The normalization calculation is performed using existing technology, and the specific calculation process will not be elaborated here.

[0153] Step S4052: Generate a decision index identifier based on the normalized parameter vector, and select a target decision mapping rule from the preset decision mapping rule library according to the decision index identifier.

[0154] In this embodiment, after obtaining the normalized parameter vector, the normalized parameter vector is first read as a whole, and its structural feature information is extracted according to a pre-set parameter arrangement order. The structural feature information includes the number of parameter dimensions, the order of parameter combinations, and the distribution position of each parameter in the value domain. A unique decision index identifier is generated based on the structural feature information, and this decision index identifier is input as a query condition into a preset decision mapping rule base. Subsequently, the mapping rule matching the decision index identifier is retrieved in the decision mapping rule base, and the retrieved mapping rule is determined as the target decision mapping rule. The principle is that by abstracting the overall structural information of the normalized parameter vector into a decision index identifier, different parameter combinations can be quickly mapped to the corresponding decision path, thereby avoiding indiscriminate matching in all rules. Through the above index generation and rule selection processing, the target decision mapping rule corresponding to the current normalized parameter vector is determined while maintaining the consistency of the decision logic.

[0155] It should be noted that the decision mapping rule base contains multiple decision mapping rules, each corresponding to a parameter structure type and associated with one or more positive electrode repair state determination logics. The parameter structure type is limited by at least the following information: the number of parameter dimensions, the parameter arrangement order, and the interval distribution characteristics of each parameter in the normalized value domain. The decision mapping rules can be implemented using threshold comparison rules, interval mapping rules, weight combination rules, or combinations thereof. Their specific forms are not uniquely limited, but all take a normalized parameter vector as input and output a determination label representing the positive electrode repair state as the result. Through the above methods, normalized parameter vectors under different parameter structures can be automatically matched to the corresponding decision mapping rules, thereby avoiding indiscriminate matching in all rules and improving the certainty and consistency of the determination process.

[0156] Step S4053: Input the normalized parameter vector into the target determination mapping rule to obtain the determination label corresponding to the target determination mapping rule.

[0157] In this embodiment, after selecting the target determination mapping rule in step S4052, the normalized parameter vector obtained in step S4051 is loaded into the target determination mapping rule as input, and the normalized parameter vector is parsed item by item according to the parameter reading order specified by the mapping rule. During the parsing process, each parameter in the normalized parameter vector participates in the determination process with its position order and value range in the vector, so that the mapping rule can perform discrimination processing on the normalized parameter vector based on the combination relationship between the parameters. The principle is that by directly introducing the parameter vector that has completed the unification of dimensions and the normalization of structure into the matching determination mapping rule, the determination process only focuses on the intrinsic relationship between the parameters, and is no longer affected by the original data source or parameter scale differences. Through the above mapping process, a determination label corresponding to the target determination mapping rule is obtained.

[0158] Based on the four parameters contained in the normalized parameter vector, and considering that smaller values ​​indicate better repair results, a judgment index identifier is generated: Index_K001=4L. Here, the number 4 indicates that the normalized parameter vector contains four parameters, and the letter L indicates that all four parameters use a low-value-optimized normalization method. Based on the judgment index identifier 4L, a weighted judgment rule for the four parameters is selected from the judgment mapping rule base. Let the weights of each parameter be: instantaneous response resistance weight w1 = 0.20; apparent interface polarization resistance weight w2 = 0.30; interface polarization relaxation time constant weight w3 = 0.20; diffusion-related relaxation time constant weight w4 = 0.30. The sum of all weights is: w1 + w2 + w3 + w4 = 1.00. The comprehensive evaluation value Q of the repair state is calculated according to the following formula: Q = w1 × z_R0 + w2 × z_Rint + w3 × z_taup + w4 × z_taud = 0.20 × 0.833 + 0 0.30×0.667+0.20×0.875+0.30×0.800=0.1666+0.2001+0.1750+0.2400=0.7817, z_R0 represents the normalized result of the instantaneous response resistance, z_Rint represents the normalized result of the apparent interface polarization resistance, z_taup represents the normalized result of the interface polarization relaxation time constant, and z_taud represents the normalized result of the diffusion-related relaxation time constant. Keeping Q to three decimal places, we get Q=0.782.

[0159] Step S4054: Bind the determination label to the detection process identifier and output it as the determination result of the lithium battery positive electrode repair status.

[0160] In this embodiment, after obtaining the judgment tag generated in step S4053, the detection process identifier corresponding to the judgment tag is read, and the two are bound one by one to form a judgment result record with a clear process belonging relationship. In specific implementation, the detection process identifier is used as the main index, the judgment tag is written into the corresponding judgment result entry, and the consistency of the identifier between the judgment result entry and the electrochemical response data, characteristic parameters and electrochemical parameter set generated in the previous steps is maintained. The principle is that by binding the judgment tag with the detection process identifier, the abstract judgment result can be fixed to a specific and unique detection process, thereby avoiding confusion or misuse of judgment results between different detection processes. Through the above binding and output processing, a lithium battery positive electrode repair status judgment result is formed with the detection process identifier as the index. This judgment result is clearly recorded as the final output of the complete detection process and can be directly used for subsequent storage, comparison or traceability analysis.

[0161] like Figure 4As shown, after completing the relaxation time interval mapping and obtaining the set of relational objects, the set of relational objects is first divided into a first set of intervals and a second set of intervals based on the time interval identifiers corresponding to each relational object. The first set of intervals corresponds to the earlier time intervals in the relaxation process, and the second set of intervals corresponds to the later time intervals, thus structurally distinguishing the data at different time levels. After dividing the interval sets, the first and second sets of intervals are summarized within each set to construct characterization sequence 1 and characterization sequence 2. Characterization sequence 1 is formed by integrating relational objects within each time interval of the first set of intervals in chronological order, and characterization sequence 2 is formed by integrating relational objects within each time interval of the second set of intervals in chronological order, thereby allowing the two types of characterization sequences to reflect the electrochemical behavior characteristics at different time stages. Subsequently, the characterization sequences are mapped according to mapping rules. Characterization sequence 1 is input into the first mapping rule to generate interface polarization characteristic parameters, and characterization sequence 2 is input into the second mapping rule to generate lithium-ion diffusion characteristic parameters. Through the above mapping steps, representation information from different time intervals is converted into feature parameters with clear physical orientation, while maintaining the independence of the two types of feature parameters in the generation path.

[0162] After obtaining the interface polarization characteristic parameters and lithium-ion diffusion characteristic parameters, the two types of characteristic parameters are paired and aggregated to form a characteristic parameter set. This set, along with the electrochemical response data obtained in the same detection process, is used as the inversion input. Simultaneously, an inversion constraint set is introduced to constrain the correspondence between the characteristic parameter set and the electrochemical response data, and an electrochemical parameter set consistent with the detection process is obtained. Further, the electrochemical parameter set is input into the judgment mapping rule, and the judgment result of the positive electrode repair state is generated according to the preset judgment logic. Through the above implementation method, a complete logical closed loop from time interval grouping, characterization sequence construction, characteristic parameter generation, parameter inversion to repair state judgment is realized, so that the judgment result of the positive electrode repair state has a clear data source and process correlation.

[0163] The preset judgment rules are as follows: when Q is greater than or equal to 0.750, the judgment label is "repair qualified"; when Q is greater than or equal to 0.450 and less than 0.750, the judgment label is "partially repaired"; when Q is less than 0.450, the judgment label is "insufficiently repaired". In this test, Q = 0.782, which is greater than 0.750. Therefore, the repair status of the cathode under test is judged as "repair qualified". The final output results are: Electrochemical parameter set: {0.030Ω, 0.060Ω, 2.50s, 120s}; Normalized parameter vector: {0.833, 0.667, 0.875, 0.800}; Comprehensive evaluation value of repair status: 0.782; Repair status judgment label: Repair qualified.

[0164] Example 2:

[0165] Please see Figure 5 Another embodiment of the present invention provides a lithium battery cathode repair electrochemical parameter detection system, comprising: an excitation module, a data acquisition module, a decoupling analysis module, and a repair determination module;

[0166] The excitation module is used to apply a preset coupled electrochemical excitation to the repaired lithium battery cathode. The coupled electrochemical excitation is used to simultaneously trigger the lithium-ion migration process inside the cathode material and the reversible electrochemical response of the repair interface.

[0167] The data acquisition module is used to acquire the potential change response and current change response of the positive electrode in real time during the coupled electrochemical excitation process to obtain electrochemical response data, which characterizes the dynamic behavior of the positive electrode after repair.

[0168] The decoupling analysis module is used to perform open-circuit relaxation on the repaired lithium battery cathode after the coupled electrochemical excitation ends, and to perform decoupling analysis on the electrochemical response data based on the potential change relationship with time during the relaxation process, so as to obtain characteristic parameters corresponding to the lithium ion diffusion process and the interface polarization process.

[0169] The repair determination module is used to invert the electrochemical response data and the characteristic parameters to obtain a set of electrochemical parameters characterizing the cathode repair state, and to determine the cathode repair effect based on the set of electrochemical parameters.

[0170] In addition, the parts of the technical solutions provided in the embodiments of this application that are consistent with the implementation principles of the corresponding technical solutions in the prior art have not been described in detail, so as to avoid excessive elaboration.

[0171] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting electrochemical parameters during the repair of a lithium battery cathode, characterized in that, include: A preset coupled electrochemical excitation is applied to the repaired lithium battery cathode, the coupled electrochemical excitation being used to simultaneously trigger the lithium-ion migration process inside the cathode material and the reversible electrochemical response at the repair interface; During the coupled electrochemical excitation process, the potential change response and current change response of the positive electrode are collected in real time to obtain electrochemical response data, which characterizes the dynamic behavior of the positive electrode after repair. After the coupled electrochemical excitation is completed, the repaired lithium battery cathode is subjected to open-circuit relaxation, and based on the potential change relationship with time during the relaxation process, the electrochemical response data is decoupled and analyzed to obtain characteristic parameters corresponding to the lithium ion diffusion process and the interface polarization process. Based on the electrochemical response data and the characteristic parameters, a set of electrochemical parameters characterizing the cathode repair state is obtained by inversion, and the cathode repair effect is judged according to the set of electrochemical parameters. After the coupled electrochemical excitation is completed, the repaired lithium battery cathode is subjected to open-circuit relaxation. Based on the potential-time relationship during the relaxation process, the electrochemical response data is decoupled and analyzed to obtain characteristic parameters corresponding to the lithium-ion diffusion process and the interface polarization process, including: After the coupled electrochemical excitation ends, the termination time of the coupled electrochemical excitation is determined as the start time point of open-circuit relaxation, and the relaxation time reference is established based on the start time point. Based on the relaxation time reference, the repaired lithium battery cathode is subjected to open-circuit relaxation, and the potential changes are continuously recorded in the open-circuit state to form a complete relaxation time series. According to a preset time progression rule, the relaxed time series is mapped into multiple mutually distinct time intervals; The time intervals are respectively associated with electrochemical response data, and the relationship between potential changes and electrochemical response data in different time intervals is deconstructed. Based on the deconstruction process, characteristic parameters corresponding to the lithium-ion diffusion process and the interface polarization process are generated.

2. The method for detecting electrochemical parameters for lithium battery cathode repair as described in claim 1, characterized in that, The coupled electrochemical excitation includes one or more asymmetric bipolar excitation processes, which cause the positive electrode to sequentially experience a repair activation state and a non-repair reference state in the same detection process. In the asymmetric bipolar excitation process, the positive excitation and the reverse excitation differ in one or more of the amplitude, duration or energy input.

3. The method for detecting electrochemical parameters for lithium battery cathode repair as described in claim 1, characterized in that, During the coupled electrochemical excitation process, the potential change response and current change response of the positive electrode are acquired in real time to obtain electrochemical response data, including: During the application of the coupled electrochemical excitation, the excitation process is continuously time-localized, and a time series identifier corresponding to the excitation process is generated; Based on the time series identifier, the potential change response and current change response of the positive electrode are collected in pairs within each consecutive time interval of the excitation process to form original response pairs with time correspondence. According to the time series identifier, the original response is divided into segments, so that each response segment corresponds to a unique excitation process interval; The response fragments are integrated according to the order of the excitation process to generate electrochemical response data.

4. The method for detecting electrochemical parameters for lithium battery cathode repair as described in claim 1, characterized in that, Based on the aforementioned relaxation time reference, the repaired lithium battery cathode is subjected to open-circuit relaxation, and the potential changes are continuously recorded in the open-circuit state to form a complete relaxation time series, including: After the relaxation time reference is established, the positive electrode is switched from the excitation state to the open circuit state, and the time when the switch is completed is used as the starting mark for potential recording. Based on the relaxation time reference, the recording rhythm of potential changes is determined so that each recording moment maintains a sequential relationship on the time axis; According to the recording rhythm, the potential change of the repaired lithium battery positive electrode is continuously collected in the open circuit state to obtain potential data points arranged in chronological order. The potential data points are encapsulated according to the starting marker and time sequence to form a relaxation time series corresponding to a single relaxation process.

5. The method for detecting electrochemical parameters for lithium battery cathode repair as described in claim 4, characterized in that, The time intervals are respectively correlated with electrochemical response data, and the relationship between potential changes and electrochemical response data in different time intervals is deconstructed, including: For each time interval, generate a set of interval anchor points including the start time and end time of the interval; Based on the set of interval anchor points, data segments corresponding to each interval anchor point on the time axis are extracted from the electrochemical response data, and the data segments are time-aligned with the potential change segments in the corresponding time interval. The time-aligned data pairs are split so that each split unit contains only a potential change segment within a time interval and its corresponding data segment, and each split unit is assigned an interval identifier. The split units are grouped according to the interval identifiers to obtain a set of relational objects for different time intervals.

6. The method for detecting electrochemical parameters for lithium battery cathode repair as described in claim 5, characterized in that, Based on the deconstruction process results, characteristic parameters corresponding to the lithium-ion diffusion process and the interface polarization process are generated, including: Based on the interval identifiers in the set of relational objects, the set of relational objects is divided into a first set of intervals and a second set of intervals. Perform intra-group summarization processing on the relational objects contained in the first set of intervals and the second set of intervals to construct the first set of representation sequences and the second set of representation sequences; The first set of characterization sequences is input into the first mapping rule to generate interface polarization feature parameters, and the second set of characterization sequences is input into the second mapping rule to generate lithium ion diffusion feature parameters. The interface polarization characteristic parameters and the lithium-ion diffusion characteristic parameters are output in pairs using the same detection process identifier to form a characteristic parameter set.

7. The method for detecting electrochemical parameters for lithium battery cathode repair as described in claim 1, characterized in that, Based on the electrochemical response data and the characteristic parameters, a set of electrochemical parameters characterizing the cathode repair state is obtained by inversion, and the cathode repair effect is determined according to the set of electrochemical parameters, including: The electrochemical response data and characteristic parameters are paired according to the same detection process identifier to generate input data pairs for inversion processing; Based on the input data, preset consistency constraints are extracted. The consistency constraints include time sequence constraints and segment correspondence constraints, forming an inversion constraint set. Multiple candidate electrochemical parameter sets are constructed according to preset parameter dimensions, and each candidate electrochemical parameter set is assigned a candidate identifier. Each candidate electrochemical parameter set is subjected to a screening process consistent with the inversion constraint set to obtain an electrochemical parameter set that matches the input data pair; The electrochemical parameter set is used as input, and the result of the positive electrode repair status is output according to the preset judgment mapping rule.

8. The method for detecting electrochemical parameters for lithium battery cathode repair as described in claim 7, characterized in that, Using the set of electrochemical parameters as input, the determination result of the positive electrode repair state is output according to a preset determination mapping rule, including: The parameters in the electrochemical parameter set are standardized in terms of dimensions and range to generate a standardized parameter vector. A decision index identifier is generated based on the normalized parameter vector, and a target decision mapping rule is selected from a preset decision mapping rule library based on the decision index identifier; The normalized parameter vector is input into the target determination mapping rule to obtain the determination label corresponding to the target determination mapping rule; The determination label is bound to the detection process identifier and output as the determination result of the lithium battery positive electrode repair status.

9. A lithium battery cathode repair electrochemical parameter detection system, used to implement the lithium battery cathode repair electrochemical parameter detection method according to any one of claims 1-8, characterized in that, include: The module consists of an incentive module, a data acquisition module, a decoupling analysis module, and a repair judgment module. The excitation module is used to apply a preset coupled electrochemical excitation to the repaired lithium battery cathode. The coupled electrochemical excitation is used to simultaneously trigger the lithium-ion migration process inside the cathode material and the reversible electrochemical response of the repair interface. The data acquisition module is used to acquire the potential change response and current change response of the positive electrode in real time during the coupled electrochemical excitation process to obtain electrochemical response data, which characterizes the dynamic behavior of the positive electrode after repair. The decoupling analysis module is used to perform open-circuit relaxation on the repaired lithium battery cathode after the coupled electrochemical excitation ends, and to perform decoupling analysis on the electrochemical response data based on the potential change relationship with time during the relaxation process, so as to obtain characteristic parameters corresponding to the lithium ion diffusion process and the interface polarization process. The repair determination module is used to invert the electrochemical response data and the characteristic parameters to obtain a set of electrochemical parameters characterizing the cathode repair state, and to determine the cathode repair effect based on the set of electrochemical parameters.

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