3084 results about "Voltage range" patented technology

The invention relates to the technical field of energy storage control, in particular to a grid-connected type light storage and charging energy storage control system which comprises a power bearing capacity monitoring module, a light storage power adjusting module, a grid-connected power feedback module, a power grid stability margin calculation module and an energy storage power dynamic control module. According to the method, the voltage and current data of the grid-connected point are acquired in real time, the power transmission capacity is calculated in combination with the rated voltage range and the safety power upper limit, the power adaptation precision of the grid-connected point is improved, the photovoltaic power generation grid-connected proportion is dynamically optimized on the basis of comparison between load growth rate calculation and the power adjustment range, and photovoltaic power output curve change rate analysis is combined. Power output fine control, calculation of the load change rate and combination of power grid power factor data are achieved, a charging and discharging mode adjustment strategy is optimized, the frequency change rate and fluctuation degree are monitored, the stability margin of the power grid is enhanced, frequency deviation of the power grid caused by load fluctuation is avoided, and the new energy consumption rate and the operation reliability of the power grid are improved.

The invention provides a server voltage monitoring system and method, electronic equipment and a storage medium, and relates to the technical field of computers, the system comprises a complex programmable logic device CPLD, and an initial timing module, a voltage acquisition module, an abnormal data storage module, a CPU processor and a baseboard management controller BMC module which are respectively in communication connection with the CPLD. The initial timing module activates the monitoring function of the CPLD through a startup signal; the voltage acquisition module acquires voltage data under the control of the CPLD so as to read the voltage data of the server mainboard; the CPLD obtains voltage data, compares the voltage data with a reference voltage range of the abnormal data storage module, triggers an interrupt signal after identifying abnormal fluctuation voltage, and feeds back the interrupt signal to the CPU and the BMC, so that the CPU and the BMC quickly output an alarm. The system covers full-cycle monitoring from startup to BMC startup, supports efficient acquisition, dynamic detection and low-delay response of multi-path voltage, relieves the voltage pressure of a BMC monitoring mainboard, and provides reliable guarantee for power supply safety of a server.

According to the power control method and system based on energy storage unit adjustment priority evaluation, an energy storage unit calibrates the charge state, the battery capacity and the health state of the energy storage unit and feeds back the charge state, the battery capacity and the health state to a battery management system; the battery management system verifies a built-in battery state estimation model of the battery management system by using the calibrated charge state and health state; based on the calibrated charge state and the battery capacity, calibrating the energy state range; calibrating the voltage standard deviation coefficient, the voltage range and the temperature range based on the measurement precision of the sensor; taking the weighted sum of each evaluation index score after calibration of the energy storage unit as a comprehensive evaluation score; determining the adjustment priority of the energy storage unit allowed to be adjusted by using the comprehensive evaluation score and the charge-discharge cycle times of the energy storage unit allowed to be adjusted; and selecting the adjustment-allowed energy storage unit with the highest adjustment priority as an execution unit for responding to the scheduling target power instruction, and ensuring the safe and stable operation of the energy storage system at the same time.

Systems and methods are disclosed for managing a tissue node potential of a neurostimulation system. The envisioned neurostimulation system can include an energy source, a housing or a housing portion, a stimulation node, a stimulation surface for contacting a tissue of a patient, and a control circuit. The control circuit can be configured to maintain at least one of the housing or housing portion, the stimulation node, or the stimulation surface at a predefined voltage or within a predefined voltage range.

The invention relates to a PFC-PWM (Pulse Width Modulation) dual-mode control method for a high-voltage direct-current power supply with a wide output voltage range. The output current of the high-voltage direct-current power supply is detected in real time, the critical threshold value of the load impedance is mapped into the hysteresis interval of the output current, the theoretical boundary of mode switching is obtained, and the control mode is dynamically adjusted. In order to further guarantee smooth switching of the two control modes, hysteresis control logic is designed, and undisturbed smooth switching of the PFM mode and the PWM mode is achieved. Based on an energy equivalence principle and a frequency consistency constraint of a critical load SWL working point, a current threshold criterion and a parameter pre-synchronization strategy are constructed, seamless connection of a mode switching process in a frequency domain and an energy domain is ensured, a transient oscillation risk is remarkably reduced, and a guarantee is provided for continuous and stable output of a full-range load working condition.

A circuit arrangement (10) for controlling an output voltage of the circuit arrangement (10). The circuit arrangement (10) comprises battery cells (121) forming a plurality of series-connectable cell modules (120, 120′). The cell modules (120, 120′) comprise: a first group of cell modules (150) comprising a first number of cell modules (150), Each cell module (120, 120′) of the first group has a first nominal cell module voltage in a range of 30-200 V, and at least one second group of cell modules (150′) comprising a second number of cell modules (150′). Each cell module (120, 120′) of said at least one second group has a second nominal cell module voltage that is less than the first nominal cell module voltage. The circuit arrangement (10) comprises a control unit (20) configured to: measure the output voltage of the circuit arrangement (10), and in order to control the measured output voltage towards the voltage target, control at least one respective electronic module (100, 100′) to adjust a respective contributing number of cell modules (120, 120′) of at least one of the first and second groups. Each cell module (120, 120′) of the respective contributing number of cell modules (120, 120′) is contributing, positively or negatively, to the output voltage of the circuit arrangement (10).

The invention belongs to the technical field of energy storage batteries, and discloses a deep learning prediction method and device for the voltage range of a battery system. The method comprises the following steps: collecting battery operation data of a battery cluster; the battery operation data comprises single battery range data, battery cluster charging and discharging power and battery cluster total voltage data; inputting the battery operation data into a pre-trained deep learning prediction model for prediction, and obtaining a voltage range prediction result of the battery cluster in future preset time; wherein the deep learning prediction model which is trained in advance is a BiGRU (BiGRU)-Transform-LSTM (Long Short Term Memory) model. According to the method, a mixed model of three different architectures of BiGRU-Transform-LSTM is adopted, the voltage range change of the battery can be effectively predicted, the voltage range change of a period of time in the future can be predicted according to current voltage and power information, and the method has a voltage consistency evaluation function; the method facilitates reasonable planning of a charging and discharging strategy of the battery pack, prolongs the service life of the battery, and improves the safety and reliability of the battery.

The invention relates to the technical field of power supply equipment power control. The load power track simulation control method comprises the steps of obtaining voltage information and current information of target power supply equipment, determining power deviation information and a dynamic target voltage range generated on the basis of a preset load behavior prediction model, constructing a combined regulation and control weight vector on the basis of the power deviation information, and obtaining a load power track simulation control result. According to the combined regulation and control weight vector and the dynamic target voltage range, constructing a target power evolution trajectory curve by using a physical response inversion mechanism, executing time discretization processing on the target regulation and control trajectory curve, extracting voltage change values and current change values corresponding to each time step, and calculating the target power evolution trajectory curve; and combining the voltage change value and the current change value according to a time sequence to form a control parameter sequence, and generating an analog control instruction matched with the target power evolution trajectory curve according to the control parameter sequence. The method has the effect of improving the real-time response capability of the power supply equipment under complex working conditions.

The invention discloses an electric energy bidirectional multipath AC / DC conversion circuit, and relates to the technical field of electric energy conversion, and the circuit comprises a power supply multipath power distribution module which is used for inversion filtering, multipath power distribution and electric energy complementary superposition processing; the intelligent control module is used for signal receiving and module control; the first adjusting module is used for constant-voltage adjustment, constant-current adjustment and residual electric energy superposition control and supplying power to the first output module; the second adjusting module is used for constant-voltage adjustment, constant-current adjustment and residual electric energy superposition control and supplying power to the second output module; the energy storage control module is used for storing residual electric energy and supplying power; and the compensation control module is used for boosting and providing electric energy for the first adjusting module or the second adjusting module. According to the electric energy bidirectional multipath AC / DC conversion circuit, multipath power distribution processing can be carried out, constant current or constant voltage adjustment processing can be carried out according to needs, the superposed residual electric energy is stored and is supplied to the first adjustment module or the second adjustment module, the utilization rate of the electric energy is improved, and a wider voltage range can be provided.

To provide a memory system and a memory device with high reliability.SOLUTION: A memory system of the embodiment includes a memory device and a memory controller. The memory device includes a plurality of memory cells. The memory controller is configured to determine a first voltage based on information regarding a gradient of a distribution of threshold voltages of each of the plurality of memory cells, and to perform tracking operations. The memory controller causes the memory device to perform a plurality of read operations using a plurality of read levels for the plurality of memory cells in the tracking operation. The memory controller acquires the number of ON cells in each of the plurality of read operations. The memory controller sets a first potential difference of the plurality of read levels in a voltage range lower than the first voltage and a second potential difference of the plurality of read levels in a voltage range higher than the first voltage to be different from each other.SELECTED DRAWING: Figure 12

The invention relates to the technical field of mode control, and discloses a metro operation dual-mode control method and system based on pulse width modulation coding. The method comprises the following steps: defining an initialization voltage range through a power supply measurement module, and adopting a dual redundancy measurement module to realize manual control and automatic operation channel voltage dual-path calibration; the signal collector collects a real-time current signal, and the signal comparator performs anomaly detection to generate a mode selection control signal; the pulse width modulation encoder calculates a duty ratio parameter and generates a current-limiting pulse width modulation signal; the multiple protectors judge the fault state, and the delay controller adjusts the disconnection time sequence of the relay; the time sequence controller establishes a mode switching rule, and the relay linkage controller optimizes an output state; the data collector extracts operation parameters, and the communication interface completes data electrical isolation transmission. Seamless switching between the manual control mode and the automatic operation mode is achieved through the pulse width modulation coding technology, and the stability and reliability of the system in the mode switching process are ensured.

Disclosed in the present invention are a current lookup table-based permanent magnet synchronous motor wide voltage range control method and a medium. The method comprises: by means of a full-speed domain current calibration method, obtaining a rotating speed-torque two-dimensional lookup table under a rated bus voltage; on the basis of the lookup table, multiplying a given rotating speed with a front-and-rear amplitude limiting voltage ratio to achieve wide voltage range control; and performing friction torque compensation and sampling delay compensation of a three-phase current at different rotating speeds. The present invention takes into account bus voltage fluctuation under the complex working condition of an electric vehicle, and multiplies the given rotating speed with a variable voltage coefficient ku to obtain an input rotating speed of an input current lookup table, such that precise current control of the permanent magnet synchronous motor under different bus voltage working conditions can be achieved, thereby avoiding the complex and tedious process of re-calibration of the current lookup table under different bus voltages; the present invention also takes into account friction torque compensation and phase current sampling delay compensation at different rotating speeds, wherein the friction torque compensation can be achieved by directly adding a friction torque error into a given torque signal in real time.

The invention relates to the technical field of power electronic transformers, and discloses an all-condition DAB inductance parameter optimization selection method based on three-phase-shift modulation, which aims at DAB wide-voltage and full-power-range operation conditions, adopts a three-phase-shift modulation strategy, establishes a stress model and a loss model of each part of the DAB, performs per-unit processing on evaluation indexes under different working conditions, and obtains a DAB inductance parameter optimization selection result. And obtaining an evaluation function for inductance parameter optimization selection, determining evaluation function weight coefficients under different working conditions according to a DAB working scene, and obtaining an optimal inductance parameter value in all working conditions after obtaining an all-working-condition comprehensive evaluation function through weighting. According to the full-working-condition DAB inductance parameter optimization selection method based on three-phase-shift modulation, the current stress and the loss index of the DAB can be optimized within the wide output voltage and output power range, comprehensive high-efficiency operation of the DAB within the wide voltage range and the full working condition is achieved, and device stress is effectively reduced.

The invention discloses a hybrid rectifier bridge LLC resonant converter with a wide output voltage range and a control method thereof, and belongs to the technical field of power generation, power transformation or power distribution. The converter comprises a primary-side inversion network, a resonance network, a high-frequency transformer bank and a secondary-side hybrid rectification network with a bidirectional switch, and ultra-wide output voltage gain is achieved. According to the control method, the primary side adopts phase shift control, and the secondary side adaptively switches the working modes of the full-bridge rectification network and the voltage doubling rectification network through a superposition type asymmetric PWM (Pulse Width Modulation) and phase shift control mode, so that a half-cycle soft switching is provided for the bidirectional switch while the voltage regulation range is greatly widened, and the voltage regulation efficiency is improved. And meanwhile, the loss of the diode is greatly reduced, and the optimization between low switching loss and low conduction loss is realized. According to the invention, free switching between a high-voltage mode and a low-voltage mode can be realized under the condition that the original advantages of LLC are kept, the control method is simple and effective, and improvement of conversion efficiency can be ensured while an ultra-wide output voltage range is realized.

The present disclosure provides a receiver front-end circuit including: first and second input units that alternately operate according to a common mode voltage of a differential input signal and output a differential output signal; a variable resistance unit that adjusts a differential load resistance supplied to the differential output signal according to the variable resistance control signal; and a control unit generating a variable resistance control signal according to a common mode voltage of the differential input signal. According to the receiver front-end circuit disclosed by the invention, the receiving of the differential input signal with a wider common-mode voltage range can be realized under low power supply voltage, and the output amplitude of the generated differential output signal does not change greatly along with the change of the common-mode voltage of the differential input signal; therefore, the compatibility of the receiver is improved, and the power consumption is reduced.

A power converter includes a transformer, a resonant circuit, a first switch and a second switch, a resonant adjustment circuit, and a controller. The transformer includes a primary-side winding and a secondary-side winding coupled to the primary-side winding. The resonant circuit is coupled to the primary-side winding, and the resonant circuit includes a resonant capacitor and a resonant inductor provided by at least the primary-side winding. The first switch and the second switch are commonly connected to a node, and the node is coupled to the resonant circuit. The resonant adjustment circuit is coupled to the resonant circuit. The controller is used to control an enabled time of the resonant adjustment circuit according to an output voltage of the power converter so as to maintain the efficiency of transmitting the energy from the primary-side winding to the secondary-side winding under a full output voltage range.

The invention relates to the technical field of electrochemistry, and particularly discloses a secondary battery and an electric device. The secondary battery comprises a positive pole piece, a negative pole piece, a diaphragm and an electrolyte, and a positive active material in the positive pole piece comprises a lithium-containing material with an olivine structure; carrying out a charge-discharge test on the secondary battery at 25 DEG C at 0.33 C in a voltage range of 2.5-4.25 V to obtain a discharge curve; the discharge curve comprises three discharge platforms with different potentials, and the three discharge platforms are sequentially marked as a first discharge platform, a second discharge platform and a third discharge platform according to the sequence of the potentials from high to low; the potential difference value between the second discharge platform and the third discharge platform is 23-192 mV; and the discharge capacity of the third discharge platform accounts for 3.5-88% of the total discharge capacity of the secondary battery. The secondary battery provided by the invention has relatively high low-temperature and low-SOC discharge power and good energy density.

The embodiment of the invention provides a charging method and device, electronic equipment and a storage medium, and belongs to the technical field of lithium ion batteries, and the method comprises the steps: detecting whether a charging voltage value is smaller than a first preset threshold voltage value or not; if the charging voltage value is smaller than the first preset threshold voltage value, pre-charging the to-be-charged battery based on the first preset current until the charging voltage value reaches the first preset threshold voltage value, and controlling the to-be-charged battery to enter a constant-current charging stage; charging the to-be-charged battery based on a second preset current until the capacity value of the to-be-charged battery reaches a preset capacity threshold value, and entering a multi-stage constant-voltage charging stage; according to each charging voltage determined in the preset charging voltage range, performing stage charging on the to-be-charged battery until the charging voltage value reaches a second preset threshold voltage value, and controlling the to-be-charged battery to enter a final constant voltage charging stage; and when the charging current value is reduced to the charging current threshold value, charging is stopped. Through the provided scheme, the charging efficiency is improved, and the risk of battery damage is reduced.

The invention provides a preparation method and application of a corrosion-resistant micro-arc oxidation film layer. The method comprises the following steps: pretreating valve metal and / or an alloy matrix thereof; and the pretreated valve metal and / or an alloy matrix of the valve metal are / is immersed in electrolyte of a bipolar superaudio frequency pulse micro-arc oxidation system, micro-arc oxidation parameters are set as follows: the voltage ranges from-50 V to 600 V, the power output pulse frequency ranges from 1 kHz to 150 kHz, the duty ratio ranges from 0.1 to 0.5, micro-arc oxidation is conducted for a preset duration, and the metal matrix with the corrosion-resistant micro-arc oxidation film layer is obtained. According to the method, the high-corrosion-resistance micro-arc oxidation film layer can be obtained.

The invention provides an energy storage system fault diagnosis method, an energy storage system and electric equipment, and relates to the field of energy storage systems.The method comprises the steps that a fault preliminary screening result sent by a cloud server is received, and the fault preliminary screening result comprises information of an abnormal battery cluster; battery cell data of target battery cells are obtained based on the information of the abnormal battery cluster, the target battery cells are all battery cells in the abnormal battery cluster, and the battery cell data comprise voltage data and current data; the battery cell data of the target battery cell is input to a correlation model for fault diagnosis, the correlation model is used for representing the correlation between the short circuit in the battery and the capacity increment, and the method comprises the steps that the corresponding relation between the capacity increment and the voltage is determined based on the voltage data and the current data; calculating the electric leakage amount of the target battery cell in the preset voltage interval based on the corresponding relation between the capacity increment and the voltage; and determining a fault cell in the target cell based on the electric leakage amount. The method provided by the invention is helpful for improving the fault diagnosis precision of the energy storage system.

The invention provides a clock input buffer and electronic equipment. The clock input buffer comprises a multi-protocol input circuit, a level conversion circuit, a step-down circuit and a clock buffer circuit. The multi-protocol input circuit is adjusted to different working modes through a control signal transmitted by the control unit so as to be compatible with various input protocols, the multi-protocol input circuit processes an input signal based on a target working mode, and the level conversion circuit performs level shifting on an output signal of the multi-protocol input circuit so as to realize multi-protocol conversion. The voltage reduction circuit is used for converting the output signal into a low-voltage domain signal so as to meet the working voltage requirement of the clock buffer circuit, and meanwhile, the voltage reduction circuit is used for reducing the power supply voltage so as to provide low-voltage power supply voltage for the clock buffer circuit; therefore, the clock buffer circuit can buffer high-speed signals in different input protocols and voltage ranges by using a low-voltage domain device, and the application scenarios of the clock input buffer are greatly expanded.

The invention provides a power battery health state assessment method. The method comprises the following steps: calculating SOH of a battery monomer based on battery monomer parameters, battery monomer capacity variation in a charging process and a battery initial temperature-capacity coefficient relation curve; intervals are divided according to the average SOC value of the battery at the charging end moment, and battery consistency parameters are obtained through calculation according to the SOC of the single batteries in different intervals and the voltage range threshold value; and obtaining the health state of the power battery based on the SOH of the single battery and the battery consistency parameter. The method can be widely applied to power battery health state evaluation of the new energy electric vehicle, and is beneficial to finding battery performance degradation in time, optimizing battery management and maintenance strategies, prolonging the service life of the battery and improving the reliability and safety of the electric vehicle.

The invention relates to the technical field of battery management, and discloses a hybrid battery module equalization method and system based on battery cell health state identification, and the method comprises the steps: carrying out the multi-dimensional state fusion evaluation of a battery cell based on the voltage, temperature and total loop current of the battery cell in a battery module, and obtaining the charge state and health state of the battery cell; based on a preset voltage difference threshold value, performing threshold value judgment on the voltage range of the battery cell to obtain a diagnosis trigger signal of the battery cell; carrying out capacity cross validation on the charge state and the health state to obtain a determination result of capacity inconsistency of the battery cell; carrying out abnormal fluctuation analysis on the voltage change characteristics of the battery cells to obtain an internal resistance inconsistency judgment result of the battery cells; carrying out equalization strategy decision on the battery cell to obtain an equalization mode instruction of the battery cell; performing equalization operation on the battery cell according to the equalization mode instruction; according to the invention, the equalization rate of the hybrid battery module based on cell health state identification can be improved.

The invention belongs to the technical field of display, and provides a pixel driving circuit and a display panel, data voltage is accessed through a compensation circuit, the data voltage is compared with at least one reference voltage, a target voltage interval where the data voltage is located is judged according to a comparison result, and compensation direct current is output according to the target voltage interval; the pixel driving circuit responds to access of a selection signal and outputs a driving current according to the data voltage and the compensation direct current so as to lighten a light-emitting element; wherein the current of the compensation direct current is in negative correlation with a value in the target voltage interval; therefore, the driving capability of the line scanning driving circuit is enhanced, the possibility of influence of parasitic parameters RC on signals is reduced, and the accuracy of data voltage transmission is improved.

The invention discloses a wide-voltage bidirectional charging and discharging device and a control method thereof, the wide-voltage bidirectional charging and discharging device comprises a first bidirectional inversion module, a first transformer, a second bidirectional inversion module, a first voltage conversion module and a control module, the first voltage conversion module is controlled to be switched to a boost conversion state or a buck conversion state according to the charging and discharging state, the voltage of the first direct current port, the voltage of the fourth direct current port and the turn ratio of the first transformer; according to the technical scheme, the voltage is monitored in real time, the step-up state or the step-down state is intelligently switched according to the turn ratio of the first transformer, bidirectional charging and discharging control in a wide voltage range is achieved, the problems that an existing device is single in function and limited in adaptation range are solved, and the service life of the device is prolonged. And moreover, the compatibility of batteries and loads with different voltage levels is greatly improved, the efficient and flexible charging and discharging requirements in multiple scenes are met, and good applicability and popularization value are achieved.

The invention relates to the technical field of energy storage battery performance detection, and discloses a performance detection device and method for an energy storage battery, and the method comprises the steps: calculating a thermal safety coefficient based on the internal temperature of the battery, the temperature gradient, the Joule heat generation rate and the environment temperature; calculating a voltage safety coefficient based on the battery end voltage, the voltage change rate and the voltage range; according to the thermal safety coefficient, the voltage safety coefficient, the battery expansion strain and the internal pressure, calculating the collaboration reflecting the multi-physical field state coordination; calculating an aging coefficient based on the accumulated current stress, the accumulated cycle index and the high stress duration of the battery; and finally, based on the collaboration, the aging coefficient and the rated current, calculating the target charging and discharging current and performing real-time adjustment. The device comprises a memory and a processor and is used for executing the method. According to the invention, multi-dimensional fusion evaluation and self-adaptive management of thermal, electrical and mechanical states and aging processes of the energy storage battery are realized, and the operation safety and service life of the battery are remarkably improved.

The invention discloses a bidirectional CLLC resonant converter with a wide input and output voltage range, and relates to the technical field of bidirectional DC / DC converters in the field of switching power supplies. According to the bidirectional CLLC resonant converter, bidirectional switching bridge arms are added to a primary circuit and a secondary circuit in a conversion main circuit respectively; the control circuit performs pulse frequency control on a switching tube in the LLC resonant network and also performs duty ratio control on the bidirectional switching bridge arm circuit, so that the gain range of the resonant converter can be further widened on the basis of performing pulse frequency control on the LLC resonant network, and meanwhile, the whole-process soft switching can be realized, and the reliability of the resonant converter is improved. And the efficiency of the converter is improved.

The invention discloses a lithium battery module multi-working-condition multi-fault diagnosis method and system, and belongs to the field of battery pack fault diagnosis. Comprising the steps that under different working conditions, voltage data of each single battery in a battery pack under different faults are collected and preprocessed; calculating the voltage range of a single battery in the battery pack, and extracting the voltage range with a fixed length as an input feature data set through a moving window method; dividing the input feature data set into a training set and a test set, and training an LSTM model by using the training set; inputting the test set into the trained LSTM model, and determining a fault and a fault type according to a model output result; and according to the fault type and the change rule of the maximum voltage battery number and the minimum voltage battery number in the feature window, positioning the fault battery. According to the method, accurate classification diagnosis of multiple faults of the battery pack is realized through the voltage range in combination with the LSTM model, the position of the fault battery is determined, and the safety and reliability of operation of the battery pack are improved.

The invention discloses a soft switching modulation method and system for minimum current stress in a full power range. The system comprises an expansion phase shift optimization unit, an in-loop direct power control unit and a cooperative control unit. The in-loop direct power control unit is used for obtaining dynamic correction power, the expansion phase shift optimization unit is used for generating a phase shift ratio combination [D1, D2] which simultaneously meets the minimum current stress and the ZVS condition, and the cooperative control unit generates a PWM driving signal according to the generated phase shift ratio combination [D1, D2] to achieve soft switching control. According to the invention, the problem of current stress minimization in a wide voltage range can be effectively solved, the problem of ZVS loss in a light-load working condition can be prevented, and a load / voltage sudden change condition can be coped with in time; through the design of the ZVS boundary guarantee, the method is especially suitable for scenes needing wide voltage range efficient energy transmission, such as new energy grid connection and electric vehicle charging.

The embodiment of the invention provides a silicon-carbon negative electrode material and a preparation method thereof, a negative electrode plate and a battery, the silicon-carbon negative electrode material comprises a silicon-carbon inner core and a coating layer coating the silicon-carbon inner core, and the silicon-carbon inner core comprises a porous carbon substrate and nanometer silicon arranged on the porous carbon substrate. The test result of the first cyclic volt-ampere test of the silicon carbon negative electrode material meets at least one of the following conditions: (a) the value of dQ / (dV * C) of a discharge differential capacity curve in a voltage interval of 0.45 V + / -0.05 V is less than or equal to 1.7, dQ / dV represents differential capacity, the unit is mAh / V, C represents charge capacity, and the unit is mAh; (b) no sharp peak exists in a discharge differential capacity curve in a voltage interval of 0.45 V + / -0.05 V, the battery can present a smooth and stable discharge process, the capacity retention ratio and the stability of the battery after circulation are improved, and the preparation method is simple, convenient and feasible, and is suitable for industrial production.