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CN-122025874-A - Single-cell high-boost battery for low-speed electric vehicle and working method

CN122025874ACN 122025874 ACN122025874 ACN 122025874ACN-122025874-A

Abstract

The invention relates to the technical field of batteries, in particular to a single-cell high-boost battery for a low-speed electric vehicle and a working method thereof, wherein the battery comprises 1-4 strings of cells, a heat radiation plate, a boost module and a battery management system, the 1-4 strings of cells are connected in parallel, the cells are arranged in a battery shell, the upper part of the cells is electrically connected with the boost module, the heat radiation plate is arranged at the top of the battery shell, the battery management system is electrically connected with the boost module, and the battery management system comprises a parameter acquisition module, a characteristic tracking module, a frequency conversion modulation module, an impedance spectrum mapping module and a self-adaptive current limiting module. The battery management system provided by the invention can prevent the aged battery cells from being deeply overdriven or overheated due to overlarge current, and the service life of the battery system is obviously prolonged on the premise of ensuring the boosting output stability.

Inventors

  • LAI JIAN

Assignees

  • 广西亮见能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260224

Claims (10)

  1. 1. The single-cell high-boost battery for the low-speed electric vehicle is characterized by comprising 1-4 strings of cells, a heat dissipation plate, a boost module and a battery management system, wherein the 1-4 strings of cells are connected in parallel, the cells are arranged in a battery shell, the upper part of the cells is electrically connected with the boost module, the top of the battery shell is provided with the heat dissipation plate, and the battery management system is electrically connected with the boost module; the battery management system comprises a parameter acquisition module, a characteristic tracking module, a variable frequency modulation module, an impedance spectrum mapping module and an adaptive current limiting module; the parameter acquisition module synchronously acquires a boosting inductance current transient sequence, a single-cell terminal voltage transient value and a boosting output bus voltage value during the conducting action of the power switch tube of the DC-DC boost converter of the low-speed electric vehicle, and constructs a multidimensional operation data set; The characteristic tracking module is used for performing numerical differential operation on the boost inductor current transient sequence in the multidimensional operation data set to obtain an inductor current second-order curvature characteristic value; The variable frequency modulation module is used for comparing the second-order curvature characteristic value of the inductive current with a preset curvature deviation threshold value of a linear region, calculating a volt-second balance reset coefficient according to a voltage value of a boost output bus in the multidimensional operation data set and a voltage transient value of a single cell terminal, and generating a next period switching frequency set value by referring to the volt-second balance reset coefficient and a comparison result; The impedance spectrum mapping module is used for setting a stable time window for transient data sampling according to the set value of the next periodic switching frequency, monitoring the change of the boost inductor current transient sequence in the multidimensional operation data set in the stable time window and extracting a discrete impedance sequence; and the self-adaptive current limiting module analyzes the battery cell health state attenuation index according to the discrete impedance sequence, and corrects a preset maximum discharge current limiting value to obtain a self-adaptive current limiting protection instruction.
  2. 2. The single-cell high-boost battery for a low-speed electric vehicle according to claim 1, wherein the multi-dimensional operation data set comprises a boost inductor current transient sequence, a sampling time interval, a single-cell terminal voltage transient value and a boost output bus voltage value, the inductor current second-order curvature characteristic value is a value obtained by dividing a difference value of an inductor current first-order change rate value at adjacent moments by the sampling time interval, the next-period switching frequency set value is a reciprocal of a sum of an actual conduction time length of a power switch tube and an estimated inductor energy release reset time length, the discrete impedance sequence comprises a plurality of specified current interval dynamic impedance values obtained based on a ratio of a single-cell terminal voltage drop amplitude value to a current step abrupt change amplitude value, and the adaptive current limiting protection instruction is a signal generated by product correction of a maximum discharge current limit value by using a current derating coefficient matched according to a battery health state attenuation index.
  3. 3. The single-cell high-boost battery for a low-speed electric vehicle of claim 1, wherein said parameter acquisition module comprises: The inductive current sequence construction submodule starts the analog-to-digital converter to continuously sample the instantaneous current flowing through the boost energy storage inductor during the conducting action of the power switch tube of the DC-DC boost converter of the low-speed electric vehicle power system to obtain a boost inductor current transient sequence, and simultaneously records the time difference between two adjacent current acquisition actions to obtain a sampling time interval; The terminal voltage synchronous acquisition sub-module keeps synchronous with the time sequence during the conduction action of the power switch tube, and calls the voltage sensor to acquire terminal voltage data of a single cell of the low-speed electric vehicle, so as to generate a terminal voltage transient value of the single cell, and simultaneously monitors the voltage value of a boost output bus at the output end of the DC-DC boost converter in real time; And the multidimensional data integration sub-module is used for collecting the boost inductor current transient sequence and the sampling time interval, synchronously calling the single-cell terminal voltage transient value and the boost output bus voltage value, and carrying out alignment and encapsulation processing according to a uniform action cycle time stamp to construct a multidimensional operation data set.
  4. 4. The single cell high boost battery for a low speed electric vehicle of claim 1, wherein said feature tracking module comprises: The first-order difference quotient calculation sub-module extracts a boost inductor current transient sequence in the multidimensional operation data set, calculates a difference value of an instantaneous boost inductor current value at a current sampling time and a previous sampling time, calculates a ratio of the difference value to the sampling time interval to construct a first-order difference quotient, and obtains a first-order change rate of the inductor current; The change rate evolution analysis submodule calculates the difference value between the first-order change rate of the inductance current at the current moment and the first-order change rate of the inductance current at the previous moment to obtain the change rate increment; And the second-order curvature characteristic extraction submodule calculates the ratio of the change rate increment to the sampling time interval, and performs two-time value differential operation to obtain an inductance current second-order curvature characteristic value.
  5. 5. The single-cell high-boost battery for a low-speed electric vehicle of claim 1, wherein the variable frequency modulation module comprises: The saturated turn-off time length measuring submodule compares the inductive current second-order curvature characteristic value with a preset linear area curvature deviation threshold value, if the inductive current second-order curvature characteristic value is recognized to exceed the linear area curvature deviation threshold value, the turn-on signal of the power switch tube is forcedly ended, the time length from the turn-on start to the forceful turn-off time is recorded, and the actual turn-on time length of the power switch tube is obtained; The reset balance time length estimation submodule calculates a boost voltage difference value between the voltage value of the boost output bus in the multidimensional operation data set and the voltage transient value of the single cell end, calculates a ratio of the voltage transient value of the single cell end to the boost voltage difference value, obtains a volt-second balance reset coefficient, and determines the inductor energy release reset time length according to the volt-second balance reset coefficient and the actual conduction time length of the power switch tube; And the variable frequency period generation submodule calculates the sum of the actual conduction time length of the power switch tube and the inductive energy release reset time length to obtain the total time length of the switch modulation period, performs reciprocal operation on the total time length of the switch modulation period and generates a next period switch frequency set value.
  6. 6. The single cell high boost battery for low speed electric vehicles of claim 1, wherein said impedance spectrum mapping module comprises: the interval window locking sub-module is used for determining a stable time window for transient data sampling according to the next periodic switching frequency set value, dividing the working current range of the boost energy storage inductor into a plurality of preset current discrete intervals, monitoring the distribution condition of the boost inductor current transient sequence in the multi-dimensional operation data set in the stable time window, and identifying the current interval transition state of the current value from a designated current discrete interval to an adjacent current discrete interval; The transition amplitude quantization submodule locks the time before and after the transition state of the current interval corresponds to the transition, calculates the difference value of the voltage transient value of the single cell terminal in the multidimensional operation data set before and after the transition to obtain the voltage drop amplitude value of the single cell terminal, synchronously calculates the difference value of the instantaneous boost inductance current value before and after the transition to obtain the current step abrupt change amplitude value; The discrete impedance construction submodule calculates the ratio of the voltage drop amplitude value of the single cell terminal to the current step mutation amplitude value, defines the dynamic impedance value of the corresponding current interval, gathers the impedance value calculation results of a plurality of current intervals, and constructs a discrete impedance sequence according to the distribution sequence of the current intervals.
  7. 7. The single cell high boost battery for a low speed electric vehicle of claim 1, wherein said adaptive current limiting module comprises: The sensitivity gradient calculation sub-module is used for sequentially arranging each current discrete interval in the discrete impedance sequence according to the current value by utilizing a piecewise linear approximation algorithm, calculating the difference value of the dynamic impedance values of the current intervals corresponding to two adjacent current discrete intervals to obtain an impedance change increment, simultaneously calculating the difference value of the central current values of the two corresponding current discrete intervals to obtain a current change increment, calculating the single-point impedance gradient values of the impedance change increment and the current change increment, integrating all the single-point impedance gradient values, and generating an internal resistance sensitivity gradient sequence; The attenuation index weighting submodule extracts the maximum value and the average value in the internal resistance sensitivity gradient sequence, calculates the deviation between the maximum value and the average value and a preset brand-new battery cell reference gradient respectively, calculates the weighted sum of the deviation by adopting a preset weight coefficient, and generates a battery cell health state attenuation index; And the current limiting instruction generation submodule is used for correcting a preset maximum discharge current limiting value according to the corresponding current derating coefficient matched with the difference amplitude exceeding the attenuation boundary threshold when the attenuation index of the health state of the battery cell exceeds the preset attenuation boundary threshold, so as to generate a battery cell aging self-adaptive current limiting protection instruction.
  8. 8. The single-cell high-boost battery for a low-speed electric vehicle of claim 7, wherein the weight coefficient includes setting the weight coefficient corresponding to the deviation of the maximum value to be numerically larger than the weight coefficient corresponding to the deviation of the average value, and dynamically increasing the preset weight coefficient assigned to the deviation of the maximum value when the proportion of the deviation value of the maximum value to the deviation value of the average value increases.
  9. 9. The single-cell high-boost battery for a low-speed electric vehicle of claim 7, wherein the current derating factor comprises constructing an inverse mapping relationship of the current derating factor and the difference amplitude, and matching the current derating factor with a smaller value for the difference amplitude with a larger value when the battery cell health state attenuation index exceeds a preset attenuation boundary threshold value so as to execute a reduction correction with a larger amplitude for a maximum discharge current limit value.
  10. 10. The working method of the single-cell high-boost battery for the low-speed electric vehicle is characterized by comprising the following steps of: S1, synchronously acquiring a boosting inductance current transient sequence, a single-cell end voltage transient value and a boosting output bus voltage value during the conducting action of a power switch tube of a DC-DC boost converter of a low-speed electric vehicle, and constructing a multidimensional operation data set; S2, performing numerical differential operation on the boost inductor current transient sequence in the multidimensional operation data set to obtain an inductor current second-order curvature characteristic value; S3, comparing the second-order curvature characteristic value of the inductance current with a preset curvature deviation threshold value of a linear region, calculating a volt-second balance reset coefficient according to a voltage value of a boost output bus in the multidimensional operation data set and a voltage transient value of a single cell terminal, and generating a next period switching frequency set value by referring to the volt-second balance reset coefficient and a comparison result; S4, setting a stable time window for transient data sampling according to the set value of the next periodic switching frequency, monitoring the change of the boost inductor current transient sequence in the multidimensional operation data set in the stable time window, and extracting a discrete impedance sequence; S5, analyzing the battery cell health state attenuation index according to the discrete impedance sequence, and correcting a preset maximum discharge current limit value to obtain the self-adaptive current limiting protection instruction.

Description

Single-cell high-boost battery for low-speed electric vehicle and working method Technical Field The invention relates to the technical field of batteries, in particular to a single-cell high-boost battery for a low-speed electric vehicle and a working method thereof. Background The traditional electric bicycle generally adopts a 16-24 series lithium battery scheme, and secondly, the BMS management complexity, the processing cost, the assembly efficiency and the after-sales fault risk are high due to the fact that the series connection quantity is large, the cost of the small-capacity power battery core is high, the assembly efficiency is low, the overall heat dissipation performance is insufficient, and the service life of a battery system is further influenced. The technical field of electric energy management mainly relates to acquisition, storage, conversion, distribution, monitoring and the like of electric energy, covers the design of a battery system structure, voltage and current regulation energy conversion path management and the matching relation between electric equipment and a power supply, generally surrounds a battery as a main energy source in application scenes of low-speed electric vehicles and the like, and realizes basic support of the whole vehicle power by a battery management circuit voltage boosting or reducing circuit and protection and control logic in a battery cell combination mode so as to ensure that different power loads operate under rated voltage and current conditions. The single-cell high-boost battery system for the low-speed electric vehicle is a battery system which takes a single cell as an energy source in the low-speed electric vehicle, and boosts the low voltage of the single cell to the voltage level required by a vehicle driving system and vehicle-mounted electric equipment by arranging a boost circuit, and generally comprises a connection mode of a single cell input end and a boost conversion unit, forms a boost topology structure by an inductance switch device diode and an energy storage capacitor, is connected with a detection element in series or in parallel at a cell output end to acquire voltage and current information, and controls the boosting process according to preset parameters, thereby providing stable electric energy input for a motor controller lighting system and auxiliary electric appliances of the low-speed electric vehicle. The existing single-cell high-boost battery system of the low-speed electric vehicle generally adopts a fixed parameter or simple instantaneous value feedback control strategy, ignores the nonlinear change of the magnetic characteristic of the boost energy storage inductor under the high-load working condition, cannot identify the precursor of magnetic saturation by analyzing the microcosmic shape characteristic of the current waveform, leads a power switch tube to maintain a conducting state after the inductor enters a saturation region, causes rapid current rising and increases the heat loss and breakdown risk of a power device, and meanwhile, the system lacks the dynamic sensing capability of the evolution characteristic of the internal impedance of the battery, still maintains a fixed maximum discharge limit preset by a factory under the conditions that the battery ages and the internal resistance is obviously increased, so that the terminal voltage excessively drops during load operation, the irreversible attenuation of the capacity of the battery is aggravated, and the serious consequences of overheat and even damage of the battery are caused by overload operation. Disclosure of Invention In order to solve the technical problems in the prior art, the embodiment of the invention provides a single-cell high-boost battery for a low-speed electric vehicle and a working method. The technical scheme is as follows: On the one hand, the battery comprises 1-4 strings of electric cores, a heat dissipation plate, a boosting module and a battery management system, wherein the electric cores of the 1-4 strings are connected in parallel, the electric cores are arranged in a battery shell, the upper parts of the electric cores are electrically connected with the boosting module, the top of the battery shell is provided with the heat dissipation plate, and the battery management system is electrically connected with the boosting module; the battery management system comprises a parameter acquisition module, a characteristic tracking module, a variable frequency modulation module, an impedance spectrum mapping module and an adaptive current limiting module; the parameter acquisition module synchronously acquires a boosting inductance current transient sequence, a single-cell terminal voltage transient value and a boosting output bus voltage value during the conducting action of the power switch tube of the DC-DC boost converter of the low-speed electric vehicle, and constructs a multidimensional operation data set; The characteristic tr