19454 results about "Short circuit" patented technology

The invention provides a mining circuit fault self-diagnosis method and system. According to the method, current and voltage waveforms and three-dimensional vibration signals of a cable are collected, and anti-interference data are generated through self-adaptive noise reduction and time sequence synchronization; a waveform interception window is dynamically adjusted based on the correlation between the mechanical vibration intensity and the current transient rate, the wave crest slope variable quantity is extracted from the current transient segment, high-frequency harmonic energy is separated from the voltage transient segment, time-frequency analysis is carried out on the vibration signal to extract an energy sudden increase frequency point, and a mechanical damage spectrum feature set is constructed; inputting the features into a space-time correlation model, and verifying space-time consistency of current distortion and voltage abnormity to generate composite features; dynamically correcting a fault threshold based on the environmental interference factor; and finally, a short-circuit peak or open-circuit oscillation diagnosis result is output according to the association strength of the electrical and mechanical characteristics. According to the invention, accurate fault self-diagnosis of the mining cable under a complex working condition is realized.

A DC relay for anti-short circuit current and arc extinction includes two static contact leading-out ends, a movable contact piece in a straight sheet type, a pushing rod assembly, a fixed upper yoke, a follow-up yoke and a lower armature. The fixed upper yoke is fixed above the movable contact piece, corresponding to a position between the two movable contacts. The follow-up upper yoke is fixed on the pushing rod assembly, above the movable contact piece, corresponding to a position between the two movable contacts. The lower armature is fixed on a bottom end face of the movable contact piece. The fixed upper yoke, the follow-up upper yoke and the lower armature are respectively arranged in a width direction of the movable contact piece, and two magnetic conductive loops are formed in the width direction of the movable contact piece.

The invention discloses a distributed power supply access-oriented power distribution network fault distance measurement method and system, and relates to the technical field of power systems, and the method comprises the steps: collecting the electrical parameters and operation states of distributed power supply access nodes in a power distribution network in real time, building a dynamic manifold model based on an ecological niche theory, and carrying out the calculation of the dynamic manifold model; adaptively adjusting manifold learning neighborhood parameters according to power fluctuation data included in the electrical parameters, and updating node ecological niches to reconstruct a dynamic manifold model; based on the reconstructed dynamic manifold model, fault features are extracted from three scales of a current harmonic component, a feed line inter-harmonic propagation path and whole network voltage influence, and a three-dimensional feature vector is generated through fusion of a graph correlation algorithm; based on the expanded fault sample library and the power fluctuation data, constructing a fault transfer relation model to predict a ground fault and a short circuit risk area; a fault source is modeled by adopting a topological neural network, and a fault point distance measurement value is output through state prediction and strategy deduction.

The invention relates to a follow-up network type control smooth switching method based on a generalized operation short-circuit ratio index. The follow-up network type control smooth switching method comprises the following steps of 1, introducing a generalized operation short-circuit ratio (GOSCR) as a switching index, and proposing a GOSCR-based hysteresis control mode switching judgment index under different power grid strength and power output working conditions; step 2, establishing a unified new energy grid-connected control unit model: constructing a unified grid-connected control model in two modes of network following control and network construction control, systematically analyzing oscillation characteristics of a grid-connected unit in the two modes, and defining boundary conditions of mode switching; 3, proposing an LADRC-based undisturbed switching control strategy: observing and estimating system current disturbance parameters online by utilizing LESO, realizing real-time compensation of disturbance quantity, and reducing dynamic sudden change in the switching process; the method has the advantages that GOSCR switching indexes are introduced to comprehensively evaluate the strength, a unified grid-connected control model is established, and an undisturbed switching control strategy is provided.

The invention relates to the technical field of industrial safety, and discloses an electrolytic aluminum short circuit port operation safety early warning system based on multi-parameter collaborative awareness and intelligent diagnosis, and the system comprises a parameter collaborative awareness module, a dynamic diagnosis module, an early warning decision module, and an execution feedback module. By constructing a multi-dimensional parameter collaborative sensing mechanism, fusing temperature field distribution, current balance degree and insulation state multi-source data in real time and dynamically capturing early abnormal symptoms of a short circuit port, the hysteresis problem of traditional single-parameter threshold monitoring is solved, conversion from passive response to active defense is achieved, and the comprehensiveness and timeliness of operation state monitoring are improved; and meanwhile, based on a historical fault database and a real-time evolution model, a health index is generated and a fault path is predicted, so that maintenance personnel can pre-judge a development trend and a time window of potential risks in advance, and sudden equipment accidents are avoided.

The invention relates to the technical field of power grid energy storage systems, in particular to a battery intelligent fault diagnosis method and system suitable for a power grid energy storage system. According to the method, multi-source monitoring data including battery electrical parameters, power grid features, environmental conditions and historical operation records are obtained, unified time step alignment and feature extraction processing are carried out on the data, and statistical features, time sequence features and frequency domain features are obtained. A double-layer diagnosis model structure is adopted, a random forest model is used for diagnosing main fault modes such as over-charging and over-discharging, and a convolutional neural network model is used for diagnosing complex fault modes such as short circuit and temperature out-of-control. The system has a dynamic updating mechanism, and online optimization is realized by calculating incremental updating values of model parameters; meanwhile, a model evaluation mechanism is established, and when an evaluation index is lower than a preset standard, a retraining process is triggered. According to the invention, high-precision and real-time identification and early warning of the battery fault are realized, and the operation reliability and safety of the energy storage system are significantly improved.

The invention discloses a printed circuit board defect detection system. The image acquisition module is used for acquiring a multispectral image of a printed circuit board to be detected, and the image preprocessing module is used for denoising, enhancing and normalizing the acquired image. The feature extraction module extracts geometric and spectral information from the preprocessed image, including the shape and layout structure of the circuit. The deep learning module processes the extracted preliminary geometric and spectral information, and the basic network sub-module performs feature extraction through a pre-trained convolutional neural network to generate high-level features. And the self-adaptive adjustment sub-module carries out fine adjustment on the high-level features through defect sample data with labels, and generates specific features for identifying and classifying various defects of the printed circuit board. The defect identification and classification sub-module combines high-level features and specific features to realize accurate detection of short circuit, open circuit, insufficient etching, welding defects and the like. And the visualization module is used for marking the position and the type of the defect and generating a detection report.

The invention relates to a solar cell and a manufacturing method thereof. The solar cell comprises a substrate, a first electrode and a second electrode, the front surface of the substrate comprises a first metallization region and a first non-metallization region, the first metallization region is provided with a first pyramid structure, the first non-metallization region is provided with a second pyramid structure, the spire of the first pyramid structure is higher than that of the second pyramid structure, and the first metallization region is provided with a first diffusion doping region; the back surface of the substrate comprises a second metallization region and a second non-metallization region, a tunneling layer and a semiconductor doping layer are sequentially laminated on one side, far away from the substrate, of the second metallization region, and the second non-metallization region is provided with a third pyramid structure; the first electrode is arranged in the first metallization region, and the first electrode is electrically connected with the first diffusion doping region; and the second electrode is arranged in the second metallization region and is electrically connected with the semiconductor doping layer. The short-circuit current output and the overall photoelectric conversion efficiency of the cell are improved, and the double-sided rate of the cell is improved.

The invention relates to the technical field of energy storage batteries, and discloses a yacht energy storage battery internal short circuit detection method, device and equipment and a medium, and the method comprises the steps: sampling the voltage and current of a yacht energy storage battery pack, and obtaining original sampling data; performing parameter identification to obtain RC network dynamic response data; performing sliding window Fourier transform and wavelet packet decomposition to obtain a target feature vector; performing voltage abrupt change feature judgment, current abrupt change feature judgment and impedance spectrum feature judgment based on the target feature vector to obtain a multi-stage fault judgment result; starting the three-ring nested control structure and inputting the three-ring nested control structure into a PWM modulation unit to obtain a control compensation signal; the control compensation signal is input into the current sharing controller, the PWM duty ratio of the parallel branches is adjusted, and a current sharing control signal is obtained, the reliability of fault detection is improved, cooperative control of state protection, power balance and current tracking is achieved, and the current distribution problem of the parallel branches is effectively solved.

The invention provides a test method and device for a motor active short-circuit relay, and a storage medium. The method includes the steps: performing the zero speed detection of a motor after a motor controller completes a low-voltage power-on operation, wherein when the motor controller is powered down, a first relay and a second relay are both switched on; controlling the second relay to be turned on if the motor passes the zero speed detection, and injecting a first excitation signal at the control ends of a first phase winding and a third phase winding through the motor controller; performing injection detection of the first excitation signal to determine whether the first excitation signal is successfully injected or not; controlling the first relay to be turned on if the first excitation signal is successfully injected, and obtaining a voltage across two ends of the first relay; and judging whether the power-on test of the first relay is successful or not according to the voltage across two ends of the first relay. The method can realize the turn-on test of the short-circuit relay, and ensures the reliability of the active short-circuit function of the vehicle motor duringdriving.

The invention discloses a vehicle stopping electrical safety monitoring system, and relates to the technical field of new energy vehicle control, the vehicle stopping electrical safety monitoring system comprises an intelligent sensing layer, a digital twin decision-making layer, a hierarchical execution layer and a safety escape layer, and the intelligent sensing layer comprises a multi-mode sensor array and is used for collecting physical parameters, chemical parameters and environmental parameters of a vehicle electrical system in real time. According to the method, a high-precision three-dimensional model, an embedded electrolyte leakage model and a wire harness aging model are constructed, the high-precision three-dimensional model comprises a battery compartment geometric structure and a wire harness layout, the former simulates a diffusion path and predicts a short-circuit risk based on fluid dynamics, and the latter realizes fault evolution prediction based on a physical mechanism by combining vibration fatigue and insulation material aging analysis. The hysteresis of traditional threshold value alarm is broken through, a dynamic threshold value table is generated in combination with environment temperature, the charge state and historical fault data, the problem that a traditional fixed threshold value cannot adapt to complex working conditions is solved, and the false alarm rate and the missing alarm rate are reduced.

The invention discloses a photovoltaic cell string, a photovoltaic module and a photovoltaic module preparation method, and relates to the technical field of photovoltaic power generation. According to one specific embodiment, the photovoltaic cell string comprises a cell piece, a welding strip and a first insulating strip, the battery pieces are connected in series through the welding strip to form a battery string; the first insulating strip is adhered to the back surface of the first end of the battery string; and the front welding strip of the first end of the battery string extends out of the edge of the first end of the battery string, is folded to the back surface of the first end of the battery string and is adhered to the first insulating strip. According to the embodiment, the battery piece cracking risk and the assembly short circuit risk can be reduced, the assembly yield is improved, and the new equipment development cost is reduced.

The utility model is suitable for the technical field of solar cells, and provides a back contact cell assembly and a photovoltaic system.The back contact cell assembly comprises a cell string, an insulating strip and a bus bar, the cell string comprises a plurality of cell pieces connected in series, the cell pieces are distributed in the first direction, the insulating strip is arranged on the backlight face of the cell pieces in the second direction, the first direction and the second direction intersect, the bus bars are arranged on the sides, away from the battery pieces, of the insulating strips in the second direction, and the insulating strips cover the bus bars. Therefore, the bus bar is hidden in the backlight surfaces of the plurality of battery pieces, and the bus bar cannot be observed from one side of the light receiving surface, so that the overall color of the front surface of the back contact battery assembly is uniform and beautiful. And meanwhile, the insulating strip can be arranged between the bus bar and the battery piece, so that the short circuit problem is avoided.

The invention discloses a distributed electrochemical energy storage fire alarm system based on an intelligent algorithm, and relates to the technical field of energy storage battery safety monitoring. Technical processes of multi-source data acquisition and preprocessing, key health factor extraction, multi-modal feature fusion, depth model detection, cross-system intervention and adaptive strategy optimization are provided; a high-quality data stream is generated through real-time synchronous sampling and noise filtering, weak fault symptoms such as internal short circuit or material deterioration are highlighted by applying a multi-dimensional feature structure, a deep learning model is utilized to accurately recognize and output early warning, and then load reduction, isolation and temperature control measures are carried out in cooperation with a BMS, an EMS and a fire fighting system. An evolutionary algorithm or a reinforcement learning continuous iteration intervention strategy is introduced in a simulation environment, high-sensitivity capture and rapid suppression of latent risks under multi-scene complex working conditions are achieved, the rate of missing report and false report can be remarkably reduced, and the overall safety of the system is remarkably enhanced.

The invention discloses a series lithium battery pack power supply equalization management method. The method comprises the following steps: acquiring an original data set of a series lithium battery pack; calculating a voltage change rate, a temperature sudden rise rate and an internal resistance fluctuation amplitude, and obtaining a dynamic feature set of battery operation; when the dynamic feature set exceeds a corresponding preset threshold value, obtaining a short-circuit risk assessment result; matching a pre-established battery pack topological structure diagram with the short-circuit risk assessment result, determining a target battery identifier needing to be isolated, generating an isolation instruction by adopting a relay control algorithm, and completing the isolation of the short-circuit battery; adjusting the charging current distribution of the updated battery pack through an equalization management algorithm to obtain equalized battery operation parameters; and if the voltage, temperature and internal resistance data of the residual single batteries are all in a normal range, determining that the system stability is recovered, and obtaining a final running state of the battery pack. The short-circuit risk of the lithium battery pack can be effectively prevented, and intelligent management and safety improvement of the battery pack are realized.

The invention relates to the technical field of circuit control, in particular to a control method and system of a bidirectional charging and discharging circuit. The method comprises the following steps: collecting current monitoring data and voltage monitoring data of a bidirectional charging and discharging circuit in real time; performing arc characteristic analysis on the current monitoring data and the voltage monitoring data to obtain arc characteristic data; analyzing a high-frequency harmonic component and a current ripple fluctuation amplitude of the bidirectional charging and discharging circuit based on the arc characteristic data; performing direct-current arc detection on the bidirectional charging and discharging circuit according to the high-frequency harmonic component and the current ripple fluctuation amplitude to generate a direct-current arc fault judgment result; and calculating the instantaneous current change rate of the current monitoring data, and carrying out short-circuit detection on the bidirectional charging and discharging circuit through the instantaneous current change rate. By monitoring current and voltage data in real time, arc and short circuit characteristics are accurately analyzed, relay control is optimized, an accurate control instruction is generated, and the safety and reliability of the two-way charging and discharging circuit are improved.

The invention relates to the field of data processing, in particular to an operation state monitoring method and system for battery automatic short circuit antipole detection equipment, and the method comprises the steps: obtaining the current, voltage and temperature historical data of the battery detection equipment, calculating the data fluctuation degree through employing an HWKS algorithm, setting an initial k'value, and calculating the initial k 'value; clustering the historical operation data of different levels, analyzing the aggregation degree and local density of a cluster, correcting an initial k'value to obtain a corrected significant k value, taking the significant k value as a parameter value in an HWKS algorithm, obtaining the abnormal degree of the data of each level, performing weighted summation on the abnormal degree of the data of each level, and obtaining the abnormal degree of the data of each level. And the data processing module is used for acquiring the comprehensive abnormal degree of the data of each level, judging whether the data point is abnormal data based on the comprehensive abnormal degree, and monitoring the detection equipment. According to the method, the k value is adjusted in a self-adaptive mode, abnormal points in the data are accurately recognized, and therefore the accuracy of operation monitoring is improved.

The invention relates to the technical field of batteries, and discloses a single battery and a battery pack, the single battery comprises a shell, a first cover plate, a battery cell and a first pole, along a first direction, one end of the shell is provided with a first opening, the battery cell is arranged in the shell, a first tab of the battery cell extends out from one end part of a battery cell body of the battery cell, and a second tab of the battery cell extends out from the other end part of the battery cell body; the first electrode lug is bent towards the first cover plate and forms a first bending point and a second bending point, the first electrode column and the first electrode lug are welded to form a first welding printing area, the first welding printing area is located between the second bending point and the end part of the first electrode lug, the length of the first electrode lug between the first bending point and the second bending point is L, in a second direction perpendicular to the first direction, a first spacing distance between the edge of the first welding printing area and the edge of the first cover plate is d, in the first direction, a second spacing distance between the inner side of the first cover plate and the root of the first tab is c, and L is larger than or equal to 0.6 mm and smaller than or equal to 20 mm. And the risks of tab tearing and battery monomer short circuit are reduced.

The invention discloses a solid-state battery cell manufacturing method and device based on single-sided rubber frame forming, and relates to the technical field of solid-state battery manufacturing. The method comprises the following steps: manufacturing a rubber frame on one surface of a first pole piece positioned at a forming station; the second pole pieces and the first pole pieces with the rubber frames are sequentially and alternately conveyed to a lamination station, and the first pole pieces and the second pole pieces are sequentially and alternately laminated, so that the second pole pieces are embedded into the rubber frames of the first pole pieces; wherein the electrodes of the first pole piece and the second pole piece are opposite, and the thickness of the rubber frame is greater than or equal to that of the second pole piece. According to the invention, two times of rubber frame forming on one pole piece are not needed, so that the connectivity between the pole pieces is improved, and the conditions that the solid electrolyte layer and the pole pieces deviate relatively and the two adjacent pole pieces are short-circuited are avoided.

The invention provides an all-solid-state battery, a preparation method thereof and electric equipment. The all-solid-state battery comprises a positive plate, a negative plate and an electrolyte layer positioned between the positive plate and the negative plate, the positive plate comprises a positive current collector layer and a positive active material layer, one side of the positive active material layer is coated with an insulating layer at an interval, and the circumferential edge of the negative plate is in lap joint with the insulating layer. The all-solid-state battery can improve the insulation performance in the using process, and the effect of reducing the risk of short circuit is achieved.

The present disclosure provides a method and device for calculating fault measurement impedance of a hybrid-connected grid-following and grid-forming wind power system. The method includes: obtaining characteristics of the grid-following and grid-forming converters and a corresponding low voltage ride-through control strategy; establishing an equivalent circuit under a corresponding fault state; conducting a simplified analysis on the wind power system to obtain an equivalent network diagram; obtaining a sub-circuit diagram of each power source excitation acting alone; obtaining short-circuit currents on both sides of the corresponding system and a grid connection point voltage; superimposing to obtain total short-circuit current on both sides of the wind power system and total grid connection point voltage; and obtaining a measurement impedance at a protection installation location on the new energy source side. The method can accurately calculate the measurement impedance value at the protection installation location after the wind power system has fault.

The invention relates to the technical field of power battery safety, in particular to a safety early warning method and device for a power battery, and the method specifically comprises the following steps: S1, marking a sample, and obtaining the basic information and operation data of the carried battery; s2, screening discharge condition data and cleaning the data; s3, setting a sliding window; s4, calculating an entropy value of voltage ranking of each monomer in each group; s5, calculating the entropy slope of the entropy of the voltage ranking of each monomer in each group along with the change of mileage, and preliminarily positioning the risk battery cell; s6, feature parameters of all samples are extracted and calculated; s7, training the model by adopting a random forest algorithm; and S8, collecting the data set marked as the to-be-evaluated vehicle data set, extracting the entropy slope of each battery cell of the to-be-analyzed battery, and judging an abnormal battery cell. According to the safety early warning method of the power battery provided by the invention, the abnormal single battery cell possibly having an internal short circuit risk can be identified in time, and the accuracy and reliability of safety early warning are improved.

The invention discloses a network-following flexible switching prediction control method and system for a grid-connected converter, and the method comprises the steps: calculating a short-circuit ratio according to obtained power grid impedance data, and if the short-circuit ratio is smaller than a switching threshold value, indicating that the power grid strength is reduced, and otherwise, indicating that the power grid strength is not reduced. At the moment, a prediction control reference current in the switching process is calculated through an adaptive switching function in a first switching function form and a current reference value in a grid following mode and a grid construction mode, and the grid-connected converter is switched from the grid following mode to the grid construction mode; and otherwise, indicating that the power grid intensity is increased, calculating a prediction control reference current in a switching process through an adaptive switching function in a second switching function form and a current reference value in a grid following mode and a grid construction mode, and switching the grid-connected converter from the grid construction mode to the grid following mode. Therefore, according to the adaptive switching function-based network-following flexible switching prediction control method, rapid and flexible switching of the grid-connected converter module is ensured, and the stability and the grid-connected output efficiency of the converter in the new energy grid-connected power generation system can be effectively improved.

The invention provides a distributed photovoltaic access distribution network voltage fluctuation evaluation method, medium and system, and belongs to the technical field of distributed photovoltaic, and the method comprises the steps: firstly collecting the parameters of a photovoltaic system and a distribution network, and building a power grid response equation set considering the parameters; more parameter samples are obtained through data augmentation and expansion, and indexes such as voltage, power and harmonic waves of each node are calculated according to the response equation set. Constructing a voltage fluctuation evaluation index matrix including voltage deviation, fluctuation, harmonic waves, short-circuit capacity change and the like; and decomposing the matrix by adopting singular value decomposition to obtain a voltage stability and fluctuation evaluation matrix, and finally calculating a voltage stability index and a fluctuation index. If the voltage fluctuation evaluation index exceeds a preset threshold value, an alarm is triggered, and decision support is provided for distribution network planning and operation. According to the invention, the technical problems of short evaluation time scale and difficulty in capturing the dynamic characteristics of voltage fluctuation in the evaluation of the distributed photovoltaic access distribution network in the prior art are solved.

The invention relates to the technical field of power system short circuit detection, and discloses a short circuit parameter measurement algorithm development method and system, and the method comprises the steps: carrying out the short circuit parameter measurement background analysis, and collecting a non-fault disturbance signal; non-fault disturbance signals are preprocessed, and key features are extracted; and establishing a short-circuit parameter prediction algorithm model, and performing classified early warning according to a prediction result. According to the invention, the reliability of short-circuit parameter prediction is improved. The response speed and accuracy to current and voltage changes are improved, and the problems of delay and false alarm in a traditional method can be effectively avoided. The model can retain key features when processing multi-source signals, and the accuracy and robustness of short-circuit parameter prediction are improved. According to the invention, accurate measurement of short-circuit current and voltage is realized, rapid identification and response can be ensured when a fault occurs in a power system, the fault recovery time of the system is reduced, and the safety and reliability of power grid operation are improved.

The invention discloses a CPLD-driven IGBT short-circuit current dynamic monitoring method and system, and relates to the technical field of power electronics, and the method comprises the specific steps of S100 real-time data acquisition, S200 dynamic threshold calculation, S300 short-circuit state judgment, S400 rapid protection execution, and S500 fault data recording and uploading. Accurate and prospective judgment of the short circuit state of the IGBT is achieved, two stress parameters including the direct-current bus voltage and the junction temperature serve as independent variables, when the bus voltage rises, the voltage stress borne by the IGBT in the turn-off period is increased, meanwhile, the current peak at the short circuit moment is more remarkable, early warning is conducted in advance by dynamically lowering the threshold value, and therefore the short circuit state of the IGBT is accurately judged. According to the mechanism, the monitoring system does not simply respond to the occurred overcurrent, but can pre-judge the safety boundary of the device under the current working condition, so that intervention is implemented before the current really reaches a dangerous peak value, and a protection blind area under a severe working condition is effectively avoided.

The invention discloses a new energy bearing capacity evaluation method considering transient overvoltage constraint, and belongs to the technical field of energy safety. The invention discloses a new energy bearing capacity evaluation method considering transient overvoltage constraint. The method comprises the following steps: S1, calculating a short-circuit ratio of a multi-new energy station sending end system; s2, calculating the transient overvoltage of a new energy station node in the sending end system; and S3, constructing a power grid new energy bearing capacity evaluation model considering the transient overvoltage constraint. According to the new energy bearing capacity evaluation method considering the transient overvoltage constraint, the mathematical relation among the transient overvoltage amplitude, the system short-circuit ratio and the active power of the new energy station is used as a main line, and the system short-circuit ratio is used as an intermediate quantity; a mathematical expression of a new energy station node transient overvoltage amplitude and new energy station active power is established, and a power grid new energy bearing capacity evaluation model considering multiple new energy station transient overvoltage constraints is constructed, so that it is ensured that an optimal new energy station output value can be obtained, and safe operation of a power grid is ensured.

The invention discloses a lithium battery internal short circuit diagnosis method and system based on impedance spectroscopy analysis, and relates to the technical field of lithium battery short circuit diagnosis, and the method comprises the steps: building a standard impedance spectroscopy library based on the identification identity information of a target battery; performing an electrochemical impedance spectrum test on the target battery to obtain a monitoring impedance spectrum; mapping the monitoring impedance spectrum to the standard impedance spectrum library, and judging a spectrum interval of the monitoring impedance spectrum; calculating the offset of the upper adjacent impedance spectrum and the lower adjacent impedance spectrum; calculating to obtain a virtual impedance spectrum; and fusing the virtual impedance spectrum and the monitoring impedance spectrum, extracting an impedance feature set, and carrying out short circuit judgment to obtain a short circuit diagnosis result. The lithium battery internal short circuit diagnosis method solves the technical problem that in the prior art, lithium battery internal short circuit diagnosis is affected by temperature and SOC, and accurate judgment is difficult, and the technical effects of achieving accurate judgment of lithium battery internal short circuit and improving the accuracy and reliability of lithium battery internal short circuit diagnosis are achieved.

The invention relates to the field of photovoltaic technology, in particular to a solar cell, a photovoltaic module and a preparation method of the solar cell, the solar cell comprises a substrate, the substrate comprises a first surface and a second surface, the first surface comprises a first area and a second area, and the second surface comprises a third area and a fourth area, the first diffusion layer is located on the first area or located in the substrate corresponding to the first area, the first diffusion layer is opposite to the substrate in conductive type, the second diffusion layer is located in the substrate corresponding to the third area, the second diffusion layer is opposite to the first diffusion layer in conductive type, and the first passivation layer is located on the third area and the fourth area. The first passivation layer covers the second diffusion layer and is in contact with the substrate, the first electrode electrically connected with the first diffusion layer is arranged on the first area, the second electrode electrically connected with the second diffusion layer is arranged on the third area, and the open-circuit voltage and the short-circuit current of the solar cell are improved through the design, and the photoelectric conversion efficiency is improved.

The invention relates to a quantitative evaluation method for robust stability of a hybrid multi-infeed system constructed with a network. The quantitative evaluation method comprises the following steps: S1, constructing a hybrid multi-infeed system model; s2, enabling the series-parallel multi-infeed system to be equivalent to an equivalent network construction subsystem and an equivalent network following subsystem, and respectively calculating a generalized short-circuit ratio as a power grid strength quantitative index; s3, selecting a nominal system model, and determining a critical value of small interference stability of a nominal system through the dominant feature root locus; s4, drawing a frequency domain characteristic curve of the uncertainty perturbation singular value, and determining an uncertainty perturbation upper bound; and S5, drawing a complementary sensitivity peak curve when the decoupled nominal system is connected to alternating current networks with different power grid intensities, and quantifying a critical value and a margin of robust stability under a power grid intensity perspective by combining an uncertainty perturbation upper bound. Compared with the prior art, the robust small-interference stability quantitative evaluation method is creatively provided, and technical support can be provided for coordinated optimization configuration and safe and stable operation of the high-proportion new energy grid-connected system.