Method and system for rapid testing of electrical performance and reliable release for lithium battery pack in / out warehouse

Abstract

The application provides a method and system for rapid testing of electrical performance and reliable release of lithium battery PACK in and out of a warehouse, and relates to the technical field of lithium battery PACK electrical performance testing. The method separates the polarization component and the ohmic component by analyzing the transient voltage response and the recovery voltage waveform of the lithium battery PACK in a static state, and constructs a performance characteristic space and performs topology mapping analysis in combination with the harmonic distortion rate and the phase delay under a high-frequency oscillation electric field. In this way, the health status of the lithium battery PACK can be quickly and accurately evaluated, and the reliable release of the lithium battery PACK can be realized. This method improves the efficiency and reliability of electrical performance testing, helps to discover potential problems in a timely manner, thereby avoiding safety hazards caused by abnormal battery performance, and meets the demand for rapid testing in large-scale industrial applications.

Description

Technical Field

[0001] This invention relates to the field of lithium battery PACK electrical performance testing technology, and more specifically, to a method and system for rapid electrical performance testing and reliable release of lithium battery PACKs for warehousing and outgoing. Background Technology

[0002] As a crucial energy carrier in the energy storage field, lithium batteries have seen significant improvements in application scope and technological level in recent years, driven by the rapid development of the new energy industry. Lithium-ion battery packs (PACKs), as the core unit of battery systems, are widely used in electric vehicles, energy storage systems, and consumer electronics. The performance of lithium-ion battery packs directly affects the safety, stability, and lifespan of the entire system, thus placing increasingly higher demands on the electrical performance testing technology of lithium-ion battery packs during the warehousing and distribution process. Traditional lithium-ion battery pack testing methods mainly rely on static parameter measurements (such as open-circuit voltage and internal resistance) and standardized charge-discharge cycle tests. However, these testing methods are typically time-consuming and cannot comprehensively analyze the complex dynamic processes and health status inside the battery. Especially in large-scale industrial production and application scenarios, traditional testing methods struggle to meet the requirements of speed, efficiency, and accuracy.

[0003] Existing technologies for testing the electrical performance of lithium-ion battery packs have gradually incorporated advanced techniques such as pulse testing, electrochemical impedance spectroscopy (EIS), and high-frequency oscillation signal testing. These methods can not only capture the dynamic response characteristics of the battery but also extract more characteristic parameters reflecting the electrochemical processes, thereby enabling a deeper performance evaluation of lithium-ion batteries. However, these technologies still have many shortcomings in practical applications. For example, pulse testing requires high precision in testing conditions, is susceptible to noise and external interference, and struggles to effectively separate the contributions of different electrochemical components; while electrochemical impedance spectroscopy, although possessing good resolution, has a long testing time and requires sophisticated equipment, making it unsuitable for large-scale industrial applications. Furthermore, existing health status assessment methods typically rely on single characteristic parameters, failing to fully utilize the correlation between multidimensional performance characteristics, resulting in a lack of globality and robustness in the health status analysis of lithium-ion battery packs. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention is proposed. This invention provides a method and system for rapid electrical performance testing and reliable release of lithium-ion battery packs upon entry and exit from warehouses.

[0005] According to one aspect of the present invention, a method for rapid electrical performance testing and reliable release of lithium battery packs for warehousing and outbound operations is provided, comprising:

[0006] In the static state of the lithium battery PACK, a bipolar alternating pulse current sequence is applied, and the transient voltage response and recovery voltage waveform of the lithium battery PACK are collected to separate the polarization component and the ohmic component.

[0007] An electrochemical fingerprint feature is constructed based on the polarization component and the ohmic component, and the discrete entropy value and time-domain symmetry parameter of the electrochemical fingerprint feature are calculated.

[0008] The lithium battery pack is placed in a high-frequency oscillating electric field, and the harmonic component distortion rate and phase delay of the lithium battery pack are measured. The performance characteristic space is generated by combining the discrete entropy value and the time-domain symmetry parameter.

[0009] A topological mapping transformation is performed on the performance feature space, and the health status of the lithium battery PACK is analyzed through the curvature and connectivity of the feature space. When the topological invariants of the feature space satisfy the homeomorphic condition, a release signal is output.

[0010] Furthermore, the electrochemical fingerprint features are obtained by extracting the ratio of the rising and falling rates of the polarization component as polarization feature values ​​and the decay trend of its peak-valley difference sequence as a stability indicator.

[0011] Simultaneously, the root mean square variance of the ohmic component is extracted as a volatility index, and its segmented slope change trend is used as a dynamic feature.

[0012] The polarization characteristic value, the stability index, the fluctuation index, and the dynamic characteristic are combined and normalized according to the electrochemical response time sequence to form a continuous electrochemical fingerprint characteristic.

[0013] Furthermore, the discrete entropy value of the electrochemical fingerprint feature is obtained by sampling the electrochemical fingerprint feature at equal intervals and dividing it into multiple continuous subsequences, calculating the mean and variance of each subsequence to construct a probability distribution function, obtaining the entropy value of each subsequence through the information entropy calculation formula, and then weighting and superimposing them to obtain the discrete entropy value.

[0014] The time-domain symmetry parameter is obtained by flipping the electrochemical fingerprint features along the time axis to obtain a mirror sequence, and by calculating and normalizing the main peak shift of its cross-correlation function.

[0015] Furthermore, the calculation of the time-domain symmetry parameter is shown in the following formula:

[0016]

[0017]

[0018] in, For time-domain symmetry parameters, This represents the i-th sample value of the original electrochemical fingerprint feature sequence. This represents the i-th sample value of the mirrored sequence after the time axis is flipped. The total length of the sequence. This is the cross-correlation function between the original sequence and the mirror sequence. This represents the offset of the main peak of the cross-correlation function. As the normalization factor, This represents the time delay.

[0019] Furthermore, the performance feature space is generated by obtaining the feature transformation matrix through principal component analysis, mapping the high-frequency response subspace and the time-domain feature subspace to the same coordinate system, and constructing the lithium battery PACK performance state feature space.

[0020] The high-frequency response subspace is composed of the harmonic distortion rate and the phase delay;

[0021] The time-domain feature subspace is composed of the discrete entropy value and the time-domain symmetry parameter.

[0022] Furthermore, the health status of the lithium battery PACK is analyzed by meshing the performance characteristic space to calculate the local curvature, extracting singular points in the curvature flow field and analyzing the characteristics of connected regions, and judging whether the spatial structure satisfies the homeomorphic condition based on topological invariants.

[0023] If a continuous deformation mapping relationship is found between the topology of the performance feature space and the standard topology, it indicates that the topological invariants of the performance feature space satisfy the homeomorphism condition, and the lithium battery PACK is in a stable configuration.

[0024] Further, calculating the local curvature includes the following steps:

[0025] The performance feature space is treated as a high-dimensional manifold. A local coordinate system is constructed in the neighborhood of the feature points, and the tangent space and normal space are calculated.

[0026] The Gaussian curvature and mean curvature of the point are calculated using the geodesic equation and the second fundamental form. A curvature change tensor is constructed based on the directional derivative of the curvature to obtain local curvature information.

[0027] According to another aspect of the present invention, a rapid electrical performance testing and reliable release system for lithium battery PACKs entering and leaving the warehouse is provided, comprising:

[0028] The pulse excitation module is used to apply a bipolar alternating pulse current sequence in the static state of the lithium battery PACK, acquire transient voltage response and recovery voltage waveform, and separate polarization component and ohmic component;

[0029] The feature extraction module is used to construct electrochemical fingerprint features based on polarization and ohmic components, and to calculate discrete entropy values ​​and time-domain symmetry parameters.

[0030] The high-frequency detection module is used to place the lithium battery PACK in a high-frequency oscillating electric field, measure the harmonic component distortion rate and phase delay, and generate a performance characteristic space by combining discrete entropy values ​​and time-domain symmetry parameters.

[0031] The topology analysis module is used to perform topological mapping transformation on the performance feature space. It analyzes the health status of the lithium battery PACK by the curvature and connectivity of the feature space. When the topological invariants of the feature space satisfy the homeomorphism condition, it outputs a release signal.

[0032] Compared with existing technologies, the present invention provides a rapid electrical performance testing and reliable release method and system for lithium battery packs entering and leaving the warehouse. It analyzes the transient voltage response and recovery voltage waveforms of lithium battery packs under static conditions to separate polarization and ohmic components. Combined with harmonic distortion rate and phase delay under a high-frequency oscillating electric field, a performance characteristic space is constructed and topological mapping analysis is performed. This allows for rapid and accurate assessment of the health status of lithium battery packs, enabling reliable release. This method improves the efficiency and reliability of electrical performance testing, helps to promptly identify potential problems, thereby avoiding safety hazards caused by abnormal battery performance, and meets the rapid testing requirements of large-scale industrial applications. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0034] Figure 1 This is a flowchart of a rapid electrical performance testing and reliable release method for lithium battery PACKs entering and leaving the warehouse, according to an embodiment of the present invention.

[0035] Figure 2 This is a battery pulse test response diagram in a rapid electrical performance testing and reliable release method for lithium battery PACK entry and exit from the warehouse according to an embodiment of the present invention.

[0036] Figure 3 This is a polarization characteristic analysis diagram in the rapid electrical performance testing and reliable release method for lithium battery PACK entry and exit from the warehouse according to an embodiment of the present invention. Detailed Implementation

[0037] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention; it should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0038] As mentioned in the background section, existing technologies for testing the electrical performance of lithium-ion battery packs include pulse testing, which requires high precision in test conditions, is susceptible to noise and external interference, and struggles to effectively separate the contributions of different electrochemical components. While electrochemical impedance spectroscopy (EIS) offers good resolution, it is time-consuming and requires sophisticated equipment, making it unsuitable for large-scale industrial applications. Furthermore, existing health status assessment methods typically rely on single characteristic parameters, failing to fully utilize the correlation between multidimensional performance characteristics, resulting in a lack of globality and robustness in the health status analysis of lithium-ion battery packs.

[0039] To address the aforementioned issues, we have invented a rapid electrical performance testing and reliable release method for lithium-ion battery packs (PACKs) during warehousing and outgoing. This invention applies a bipolar alternating pulse current sequence to the lithium-ion battery pack while it is in a static state, combined with harmonic analysis of a high-frequency oscillating electric field, to comprehensively extract core characteristic parameters such as transient voltage response, polarization composition, and ohmic composition, and construct an electrochemical fingerprint feature space. Furthermore, by calculating discrete entropy values, time-domain symmetry parameters, and the curvature and connectivity of topological features, the health status of the lithium-ion battery pack is comprehensively analyzed, ultimately achieving rapid and reliable release of the lithium-ion battery pack. This invention features high testing speed, strong robustness, and wide applicability, effectively solving the technical bottleneck of balancing speed and accuracy in existing technologies.

[0040] Figure 1 This is a flowchart illustrating a rapid electrical performance testing and reliable release method for lithium battery PACKs entering and leaving the warehouse, according to an embodiment of the present invention. Figure 1 As shown, the rapid electrical performance testing and reliable release method for lithium battery PACKs entering and leaving the warehouse includes:

[0041] S1: In the static state of the lithium battery PACK, a bipolar alternating pulse current sequence is applied, and the transient voltage response and recovery voltage waveform of the lithium battery PACK are collected to separate the polarization component and the ohmic component.

[0042] In the static state of the lithium battery pack, the lithium battery pack is first controlled to fully rest to eliminate residual effects from previous use. Then, an alternating sequence of forward pulse current with a large amplitude and a small duty cycle and a reverse pulse current with a small amplitude and a large duty cycle is applied to the lithium battery pack. The period ratio of the forward pulse current and the reverse pulse current is asymmetrically set and applied continuously for several cycles. During the application of the bipolar alternating pulse current sequence, a high-precision data acquisition module is used to record the transient voltage response of the lithium battery pack at a first sampling frequency, and the recovery voltage waveform is recorded at a second sampling frequency after each pulse. The first sampling frequency is greater than the second sampling frequency. Wavelet transform is used to perform time-frequency decomposition on the transient voltage response and the recovery voltage waveform to extract the high-frequency component to obtain the ohmic component and the low-frequency component to obtain the polarization component. The ohmic component characterizes the transient response characteristics of the lithium battery pack, and the polarization component characterizes the dynamic polarization characteristics of the lithium battery pack.

[0043] S2: Construct an electrochemical fingerprint feature based on the polarization component and the ohmic component, and calculate the discrete entropy value and time-domain symmetry parameter of the electrochemical fingerprint feature;

[0044] When the polarization component is acquired, an exponential fitting process is applied to it to extract the rate of change of the rising and falling segments of the polarization component. The ratio of the rate of change is used as the polarization feature value. At the same time, the peak-valley difference sequence of the polarization component is calculated. When the peak-valley difference sequence satisfies monotonicity, its decay trend is extracted as a polarization stability index. When the ohmic component is acquired, based on the fluctuation characteristics of the ohmic component, a sliding window method is used to extract waveform segments of multiple time windows. The root mean square value is calculated in each time window, and the variance of the root mean square value is extracted as an ohmic fluctuation index. At the same time, piecewise linear fitting is performed on the ohmic component, and the changing trend of the slope of each segment is calculated as an ohmic dynamic feature. After the polarization feature value, the polarization stability index, the ohmic fluctuation index, and the ohmic dynamic feature are all acquired, these features are combined according to the polarization and ohmic response time sequence to form an electrochemical fingerprint feature characterizing the performance characteristics of the lithium battery PACK.

[0045] Specifically, the polarization feature value and the ohmic fluctuation index are cross-combined according to the response time sequence. When a polarization response feature is detected, the polarization feature value is used as the feature point of the first part of the sequence; when an ohmic response feature is detected, the ohmic fluctuation index is used as the feature point of the second part of the sequence. After the initial sequence construction is completed, the polarization stability index is inserted into the corresponding polarization feature value position according to its time attribute, and the ohmic dynamic feature is inserted into the corresponding ohmic fluctuation index position according to its time attribute. After all features have been inserted in time sequence, the sequence is normalized to unify the dimensions of different features. If the normalization is completed, the sequence is rearranged in time order and smoothed by interpolation to form a continuous feature curve. This feature curve is the electrochemical fingerprint feature characterizing the performance characteristics of the lithium battery PACK.

[0046] It should be noted that the technical basis for using the ratio of the change rates as a polarization characteristic value is as follows: When a lithium-ion battery pack is charged and discharged, its polarization process reflects the electrochemical reaction kinetics. The rising segment of the polarization component reflects the charge accumulation process and the material migration process, while the falling segment reflects the charge release process and the material diffusion process. If the lithium-ion battery pack performs well, these two processes should exhibit a relatively stable dynamic equilibrium relationship. When measuring the polarization component, the rate of change in the rising segment characterizes the polarization formation rate of the lithium-ion battery pack, and the rate of change in the falling segment characterizes the polarization elimination rate. The ratio of the two directly reflects the dynamic equilibrium state of the electrochemical reaction inside the lithium-ion battery pack. When the performance of the lithium-ion battery pack deteriorates, changes in the internal structure or loss of active materials can lead to an imbalance in the polarization formation and elimination processes, causing the ratio of the change rates to deviate significantly. Therefore, by calculating the ratio of the change rates, the performance state of the lithium-ion battery pack can be effectively identified.

[0047] Furthermore, the electrochemical fingerprint features are sampled at equal intervals. After sampling, the electrochemical fingerprint features are divided into multiple continuous subsequences according to the time series. The mean and variance of each subsequence are calculated, and a probability distribution function is constructed based on the mean and variance. Once the probability distribution function is determined, the entropy value of each subsequence is obtained using the information entropy calculation formula. The weighted summation of the entropy values ​​of all subsequences yields the discrete entropy value. When calculating the time-domain symmetry parameter, the electrochemical fingerprint features are first flipped on the time axis to obtain a mirror sequence. After the mirror sequence is generated, the cross-correlation function between the original sequence and the mirror sequence is calculated, and the peak position offset is extracted within the main peak interval of the cross-correlation function. The closer the offset is to zero, the better the time-domain symmetry of the electrochemical fingerprint features. Based on this, the offset is normalized to obtain the time-domain symmetry parameter, which reflects the reversibility of the lithium battery PACK during the charging and discharging process, as shown in the following formula:

[0048]

[0049]

[0050] in, For time-domain symmetry parameters, This represents the i-th sample value of the original electrochemical fingerprint feature sequence. This represents the i-th sample value of the mirrored sequence after the time axis is flipped. The total length of the sequence. This is the cross-correlation function between the original sequence and the mirror sequence. This represents the offset of the main peak of the cross-correlation function. The normalization factor is the standard deviation of the cross-correlated sequences. This represents the time delay.

[0051] It should be noted that this parameter reveals the reversibility of the charging and discharging process from the perspective of the battery's dynamic response symmetry. However, a single parameter may have limitations in information dimensionality. Therefore, when it is combined with harmonic distortion characteristics and discrete entropy values ​​obtained under a high-frequency oscillating electric field to form a multi-dimensional feature, a more comprehensive performance feature space can be constructed. Among them, the time-domain symmetry parameter mainly characterizes the macroscopic dynamic balance of the battery, harmonic distortion reflects the high-frequency response characteristics of the battery, and discrete entropy values ​​describe the complexity of the battery response. This combination of multi-dimensional features enables the subsequent topological mapping analysis to more accurately evaluate the battery state from the perspective of geometric structure. In particular, during the topological mapping process, the change of the time-domain symmetry parameter will directly affect the geometric characteristics of the feature space. When the battery performance deteriorates, the asymmetric charging and discharging behavior will cause significant changes in the topological structure of the feature space, thereby causing the topological invariants to deviate from the homeomorphic condition.

[0052] S3: Place the lithium battery PACK in a high-frequency oscillating electric field, measure the harmonic component distortion rate and phase delay of the lithium battery PACK, and generate a performance characteristic space by combining the discrete entropy value and the time-domain symmetry parameter;

[0053] First, a high-frequency excitation source is constructed to generate an oscillating electric field sequence with progressively increasing frequency. When the oscillating electric field sequence is applied to the lithium-ion battery pack, a high-speed sampling system is used to synchronously acquire the voltage and current response waveforms of the lithium-ion battery pack. Real-time Fourier analysis is performed on the response waveforms to extract the amplitude of each harmonic component. After acquiring the harmonic components, the ratio of the fundamental component to the higher harmonic components is calculated to obtain the harmonic component distortion rate. Simultaneously, the voltage and current phase differences at each frequency point are extracted to obtain the phase delay. Once the harmonic component distortion rate and the phase delay are determined, they are fused with the discrete entropy value and the time-domain symmetry parameter obtained in the previous steps. The performance feature space is constructed through multi-dimensional feature mapping, where each dimension of the performance feature space corresponds to the harmonic component distortion rate, the phase delay, the discrete entropy value, and the time-domain symmetry parameter, respectively. Each point in the performance feature space represents a working state of the lithium-ion battery pack.

[0054] Furthermore, the harmonic component distortion rate, the phase delay, the discrete entropy value, and the time-domain symmetry parameter are normalized. After normalization, the correlation matrix between each feature is calculated based on the principal component analysis method, and the main feature direction is determined according to the eigenvalues ​​of the correlation matrix. After determining the main feature direction, a feature transformation matrix is ​​constructed. When the feature transformation matrix is ​​applied to the original features, orthogonal feature basis vectors are generated, and a coordinate system of the performance feature space is established according to the direction of the feature basis vectors. If the coordinate system is established, the harmonic component distortion rate and the phase delay constitute a high-frequency response subspace, and the discrete entropy value and the time-domain symmetry parameter constitute a time-domain feature subspace. When the two subspaces are mapped to the same coordinate system through the feature transformation matrix, a complete feature space characterizing the performance state of the lithium battery PACK is formed.

[0055] The process of calculating the correlation matrix between features based on principal component analysis is as follows: First, the harmonic component distortion rate, the phase delay, the discrete entropy value, and the time-domain symmetry parameter are arranged in time sequence to form a feature sample matrix. After the feature sample matrix is ​​formed, each feature is centered, i.e., its mean is subtracted. After the centering process is completed, the covariance between any two features is calculated, and the covariance values ​​of all feature pairs are filled into the symmetric matrix. After the symmetric matrix is ​​formed, the covariance is converted into the correlation coefficient through standardization, thereby obtaining the correlation matrix.

[0056] S4: Perform a topological mapping transformation on the performance feature space, analyze the health status of the lithium battery PACK through the curvature and connectivity of the feature space, and output a release signal when the topological invariants of the feature space satisfy the homeomorphic condition.

[0057] First, a mesh partitioning structure for the performance characteristic space is established. After mesh partitioning, the local curvature at each mesh node is calculated, and a curvature flow field is constructed based on the distribution characteristics of the local curvature. After obtaining the curvature flow field, singularities are extracted, and the types and distributions of these singularities are analyzed. Simultaneously, connected regions in the performance characteristic space are examined, and the number and shape of connected branches are determined by tracing characteristic trajectories. After completing singularity analysis and connectivity analysis, the Betti number and Euler characteristic number of the performance characteristic space are calculated, and the homotopy group characteristics of the performance characteristic space at different scales are examined. If a continuous deformation mapping relationship is found between the topology of the performance characteristic space and the standard topology, it indicates that the topological invariants of the performance characteristic space satisfy the homeomorphism condition. At this time, the performance characteristics of the lithium battery PACK are in a stable configuration, and a release signal is generated accordingly. Conversely, if the topology of the performance characteristic space undergoes abrupt changes or a singular configuration appears, it indicates that the lithium battery PACK may have performance anomalies, requiring in-depth analysis.

[0058] The process of calculating the local curvature of the performance feature space is as follows: First, the performance feature space is considered as a high-dimensional manifold. A local coordinate system is constructed in the neighborhood of each feature point. After determining the local coordinate system, the tangent space and normal space at that point are calculated. After obtaining the tangent space and normal space, geodesics in different directions originating from the feature point are calculated using the geodesic equation, and the deviation of the geodesics at that point is extracted. Once the deviation of the geodesics in all directions is determined, the second fundamental form of the point is constructed. If the construction of the second fundamental form is completed, the Gaussian curvature and mean curvature of the point are calculated using the eigenvalues ​​of the second fundamental form. At the same time, the principal curvature distribution in the neighborhood of the point is analyzed. The Gaussian curvature reflects the intrinsic geometric characteristics of the local space at that point, and the mean curvature reflects the extrinsic geometric characteristics of the local space at that point. After obtaining the local curvature information, a curvature change tensor is constructed based on the directional derivative of the curvature. As shown in the following equation:

[0059]

[0060]

[0061]

[0062] in, Let curvature change tensor, For Gaussian curvature, For the mean curvature, Let be the principal curvature in the i-th direction. The direction vector in the local coordinate system. For the Kronecker function, For measuring geodesic deviation, Let be the trajectory of the geodesic in the i-th direction. To measure the components of a tensor, For gradient operators, These are geodesic parameters.

[0063] Furthermore, the process of extracting singularities from the curvature flow field is as follows: Gradient calculation is performed on the curvature flow field. After the gradient calculation is completed, locations where gradient values ​​abruptly change are searched within the curvature flow field; these locations may correspond to singularities. After determining the possible singularity locations, an index field is calculated near each candidate point. When the index field is integrated around the candidate point, if the integral value is not zero, the point is confirmed as a singularity. Once a singularity is confirmed, the flow field morphology within the neighborhood of each singularity is analyzed. The type of singularity is determined by examining the rotation direction and divergence degree of streamlines. If the streamlines exhibit rotational characteristics, it is a vortex-type singularity; if the streamlines exhibit convergence or divergence characteristics, it is a source-sink type singularity. After completing the singularity classification, the spatial distribution of different types of singularities is statistically analyzed. When a dense concentration of singularities is found in certain regions, these regions are marked as characteristic abrupt change regions. Simultaneously, the topological relationships between singularities are examined, and the dynamic changes in the performance characteristics of the lithium-ion battery pack are revealed by analyzing the evolution of singularities.

[0064] Furthermore, the process of calculating the topological invariants of the performance feature space and examining the homotopy group characteristics is as follows: The performance feature space is partitioned using simplexes. After partitioning, the number of simplexes in different dimensions is counted, and a boundary operator matrix is ​​constructed. The Betti numbers of each dimension are obtained by calculating the kernel space and image space dimensions of the boundary operator matrix. After obtaining the Betti numbers, the Euler characteristic number of the performance feature space is calculated based on the number of simplexes and the Betti numbers. After completing the calculation of topological invariants, the performance feature space is decomposed into multiple scales. Simplex chain complexes are constructed at each scale, and the homology group mapping relationship between adjacent scales is analyzed. If the homology group is found to remain stable during scale changes, the characteristics of the persistent homology group are calculated. Once the birth-death spectrum of the persistent homology group is determined, its characteristic structure is extracted as the homotopy group characteristics of the performance feature space. Simultaneously, the evolution process of the homotopy group characteristics with scale is examined. By analyzing the persistence and stability of the homotopy group, the essential topological structure of the performance feature space is revealed, providing a basis for judging homeomorphism conditions.

[0065] In summary, the rapid electrical performance testing and reliable release method for lithium-ion battery packs in and out of storage based on embodiments of the present invention has been clarified. This method analyzes the transient voltage response and recovery voltage waveforms of lithium-ion battery packs under static conditions to separate polarization and ohmic components. Furthermore, it combines the harmonic distortion rate and phase delay under a high-frequency oscillating electric field to construct a performance characteristic space and perform topological mapping analysis. This allows for rapid and accurate assessment of the health status of lithium-ion battery packs, enabling reliable release. This method improves the efficiency and reliability of electrical performance testing, helps to promptly identify potential problems, thereby avoiding safety hazards caused by abnormal battery performance and meeting the rapid testing requirements of large-scale industrial applications.

[0066] Here, those skilled in the art will understand that the specific operations of each step in the above-described rapid electrical performance testing and reliable release system for lithium battery PACK warehousing have been referenced above. Figures 1 to 3 The description of the rapid electrical performance testing and reliable release method for lithium battery PACKs entering and leaving the warehouse is detailed here, and therefore, its repeated description will be omitted.

[0067] It needs to be explained that, Figure 2 This is a battery pulse test response graph, consisting of: an upper part showing the pulse current, displaying the applied charge / discharge current pulse; and a lower part showing the voltage response, displaying the battery voltage change curve under the pulse current. In the graph, "PulseCurrent" represents the pulse current, "Current (C-rate)" represents the current (C-rate), "Voltage Response" represents the voltage response, "Smoothed Response" represents the smoothed response, "Voltage (V)" represents the voltage (volts), and "Time (s)" represents the time (seconds).

[0068] Figure 3 This is a polarization characteristic analysis diagram, specifically showing the voltage response change of the battery after a pulse, highlighting the battery's polarization recovery characteristics. In the diagram, "Polarization Response" represents the polarization response, "Polarization Analysis" represents the polarization analysis, "Voltage (V)" represents the voltage (volts), and "Time (s)" represents the time (seconds).

[0069] According to another aspect of the present invention, a rapid electrical performance testing and reliable release system for lithium battery PACKs entering and leaving the warehouse is provided, comprising:

[0070] The pulse excitation module is used to apply a bipolar alternating pulse current sequence in the static state of the lithium battery PACK, acquire transient voltage response and recovery voltage waveform, and separate polarization component and ohmic component;

[0071] The feature extraction module is used to construct electrochemical fingerprint features based on polarization and ohmic components, and to calculate discrete entropy values ​​and time-domain symmetry parameters.

[0072] The high-frequency detection module is used to place the lithium battery PACK in a high-frequency oscillating electric field, measure the harmonic component distortion rate and phase delay, and generate a performance characteristic space by combining discrete entropy values ​​and time-domain symmetry parameters.

[0073] The topology analysis module is used to perform topological mapping transformation on the performance feature space. It analyzes the health status of the lithium battery PACK by the curvature and connectivity of the feature space. When the topological invariants of the feature space satisfy the homeomorphism condition, it outputs a release signal.

[0074] In summary, the rapid electrical performance testing and reliable release system for lithium-ion battery packs in and out of storage, based on embodiments of the present invention, is explained. It analyzes the transient voltage response and recovery voltage waveforms of lithium-ion battery packs in a static state to separate polarization and ohmic components. Combined with harmonic distortion rate and phase delay under a high-frequency oscillating electric field, a performance characteristic space is constructed and topological mapping analysis is performed. This allows for rapid and accurate assessment of the health status of lithium-ion battery packs, enabling reliable release. This method improves the efficiency and reliability of electrical performance testing, helps to promptly identify potential problems, thereby avoiding safety hazards caused by abnormal battery performance, and meets the rapid testing requirements of large-scale industrial applications.

Claims

1. A rapid electrical performance testing and reliable release method for lithium battery PACKs entering and leaving the warehouse, characterized in that, include: In the static state of the lithium battery PACK, a bipolar alternating pulse current sequence is applied, and the transient voltage response and recovery voltage waveform of the lithium battery PACK are collected to separate the polarization component and the ohmic component. An electrochemical fingerprint feature is constructed based on the polarization component and the ohmic component, and the discrete entropy value and time-domain symmetry parameter of the electrochemical fingerprint feature are calculated. The lithium battery pack is placed in a high-frequency oscillating electric field, and the harmonic component distortion rate and phase delay of the lithium battery pack are measured. The performance characteristic space is generated by combining the discrete entropy value and the time-domain symmetry parameter. A topological mapping transformation is performed on the performance feature space, and the health status of the lithium battery PACK is analyzed through the curvature and connectivity of the feature space. When the topological invariants of the feature space satisfy the homeomorphic condition, a release signal is output.

2. The method for rapid electrical performance testing and reliable release of lithium battery PACKs for warehousing and outgoing operations according to claim 1, characterized in that, The electrochemical fingerprint features are obtained by extracting the ratio of the rising and falling rates of the polarization components as polarization feature values ​​and the decay trend of the peak-valley difference sequence as a stability indicator. Simultaneously, the root mean square variance of the ohmic component is extracted as a volatility index, and its segmented slope change trend is used as a dynamic feature. The polarization characteristic value, the stability index, the fluctuation index, and the dynamic characteristic are combined and normalized according to the electrochemical response time sequence to form a continuous electrochemical fingerprint characteristic.

3. The method for rapid electrical performance testing and reliable release of lithium battery PACKs for warehousing and outgoing operations according to claim 2, characterized in that, The discrete entropy value of the electrochemical fingerprint feature is obtained by sampling the electrochemical fingerprint feature at equal intervals and dividing it into multiple continuous subsequences, calculating the mean and variance of each subsequence to construct a probability distribution function, obtaining the entropy value of each subsequence through the information entropy calculation formula, and then weighting and superimposing them to obtain the discrete entropy value. The time-domain symmetry parameter is obtained by flipping the electrochemical fingerprint features along the time axis to obtain a mirror sequence, and by calculating and normalizing the main peak shift of its cross-correlation function.

4. The method for rapid electrical performance testing and reliable release of lithium battery PACKs for warehousing and outgoing operations according to claim 3, characterized in that, The time-domain symmetry parameter is calculated as follows: in, For time-domain symmetry parameters, This represents the i-th sample value of the original electrochemical fingerprint feature sequence. This represents the i-th sample value of the mirrored sequence after the time axis is flipped. The total length of the sequence. This is the cross-correlation function between the original sequence and the mirror sequence. This represents the offset of the main peak of the cross-correlation function. As the normalization factor, This represents the time delay.

5. The method for rapid electrical performance testing and reliable release of lithium battery PACKs for warehousing and outgoing operations according to claim 4, characterized in that, The performance feature space is generated by obtaining the feature transformation matrix through principal component analysis, mapping the high-frequency response subspace and the time-domain feature subspace to the same coordinate system, and constructing the lithium battery PACK performance state feature space. The high-frequency response subspace is composed of the harmonic distortion rate and the phase delay; The time-domain feature subspace is composed of the discrete entropy value and the time-domain symmetry parameter.

6. The method for rapid electrical performance testing and reliable release of lithium battery PACKs for warehousing and outgoing operations according to claim 5, characterized in that, The health status of the lithium battery PACK is analyzed by meshing the performance characteristic space, calculating the local curvature, extracting singular points of the curvature flow field and analyzing the characteristics of the connected regions, and judging whether the spatial structure satisfies the homeomorphic condition based on topological invariants. If a continuous deformation mapping relationship is found between the topology of the performance feature space and the standard topology, it indicates that the topological invariants of the performance feature space satisfy the homeomorphism condition, and the lithium battery PACK is in a stable configuration.

7. The method for rapid electrical performance testing and reliable release of lithium battery PACKs for warehousing and outgoing operations according to claim 6, characterized in that, Calculating the local curvature includes the following steps: The performance feature space is treated as a high-dimensional manifold. A local coordinate system is constructed in the neighborhood of the feature points, and the tangent space and normal space are calculated. The Gaussian curvature and mean curvature of the point are calculated using the geodesic equation and the second fundamental form. A curvature change tensor is constructed based on the directional derivative of the curvature to obtain local curvature information.

8. A rapid electrical performance testing and reliable release system for lithium battery PACK warehousing, based on the rapid electrical performance testing and reliable release method for lithium battery PACK warehousing as described in any one of claims 1 to 7, characterized in that... include: The pulse excitation module is used to apply a bipolar alternating pulse current sequence in the static state of the lithium battery PACK, acquire transient voltage response and recovery voltage waveform, and separate polarization component and ohmic component; The feature extraction module is used to construct electrochemical fingerprint features based on polarization and ohmic components, and to calculate discrete entropy values ​​and time-domain symmetry parameters. The high-frequency detection module is used to place the lithium battery PACK in a high-frequency oscillating electric field, measure the harmonic component distortion rate and phase delay, and generate a performance characteristic space by combining discrete entropy values ​​and time-domain symmetry parameters. The topology analysis module is used to perform topological mapping transformation on the performance feature space. It analyzes the health status of the lithium battery PACK by the curvature and connectivity of the feature space. When the topological invariants of the feature space satisfy the homeomorphism condition, it outputs a release signal.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the rapid electrical performance testing and reliable release method for lithium battery PACK entry and exit from warehouses as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the rapid electrical performance testing and reliable release method for lithium battery PACK entry and exit from the warehouse as described in any one of claims 1 to 7.

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