CN-122025888-A - Battery pack electrolysis double-closed-loop cooperative control method and device considering abnormal working conditions

CN122025888ACN 122025888 ACN122025888 ACN 122025888ACN-122025888-A

Abstract

The application discloses a battery pack electrolysis double-closed-loop cooperative control method and system considering abnormal working conditions, and relates to the technical field of waste battery management, wherein the method comprises the steps of obtaining electric characteristic response parameters of each single battery, comparing the electric characteristic response parameters with a preset new battery parameter library, and identifying failure mode types; the method comprises the steps of obtaining monitoring parameters of each single battery, judging abnormal working conditions and triggering a single-level closed loop when abnormal characteristics appear, executing a differential control strategy by the single-level closed loop according to the type of failure modes, responding to the monitoring parameters not to be recovered to be normal, judging that control fails and triggering a group-level cooperative closed loop, isolating or transferring the failed single battery to a limited operation branch, recombining the electrical topology of the residual single battery to form a recombined battery pack and adjusting a serial-parallel connection relation, feeding back a state to the single-level closed loop when the operation of the recombined battery pack is stable, and iteratively completing the available capacity assessment.

Inventors

LI JIE
YUAN YA
MA ZHONGRUI
Ma Chaorong
HU BIN

Assignees

聚创(广东)智能装备有限公司

Dates

Publication Date: 20260512
Application Date: 20260128

Claims (10)

1. The battery pack electrolysis double-closed-loop cooperative control method considering abnormal working conditions is characterized by comprising the following steps of: Acquiring electrical characteristic response parameters of each single battery, comparing the electrical characteristic response parameters with a preset new battery parameter library, and identifying the type of failure mode; Acquiring monitoring parameters of each single battery, and judging that abnormal working conditions occur and triggering a single-level closed loop when abnormal characteristics appear in response to the monitoring parameters; the monomer-level closed loop executes a differential control strategy according to the failure mode type, and determines that control fails and triggers a group-level cooperative closed loop in response to the monitoring parameter not returning to normal; and the group-level cooperative closed loop isolates or transfers the invalid single battery to a limited operation branch according to the type of the invalid mode, the electric topology of the recombined residual single battery forms a recombined battery group and adjusts the serial-parallel connection relation, and when the recombined battery group operates stably, the state is fed back to the single-level closed loop, and the available capacity assessment is completed iteratively.
2. The method for collaborative control of battery electrolysis double closed loops considering abnormal conditions according to claim 1, wherein the obtaining of the electrical characteristic response parameters of each single battery comprises sequentially applying a step current excitation signal, a sinusoidal sweep frequency excitation signal and a pulse voltage excitation signal, extracting a voltage recovery time constant, a steady-state polarization voltage, a real part minimum value of impedance in an intermediate frequency region, a phase angle in a low frequency region and a current decay time constant; The identifying the failure mode type includes: the relative deviation of the current decay time constant is negative, the absolute value exceeds a first deviation threshold value, and meanwhile, when the real part minimum value of the impedance of the intermediate frequency region is lower than a preset impedance threshold value, the internal micro short circuit is identified; The relative deviation of the voltage recovery time constant is positive and exceeds a second deviation threshold value, and the electrolyte is identified as dry when the phase angle of the low-frequency area is lower than a preset phase angle threshold value; The relative deviation of the steady-state polarized voltage is positive and exceeds a third deviation threshold value, and the phase angle of a low-frequency area is lower than a preset phase angle threshold value, and lithium dendrite puncture is identified; the abnormal characteristic of the monitoring parameter comprises that the temperature rise rate exceeds a preset temperature rise rate threshold value, the sum of absolute values of negative differences of two continuous adjacent sampling points of the terminal voltage exceeds a preset voltage drop threshold value or the response delay time of the terminal voltage exceeds a preset delay time threshold value, and abnormal working conditions are judged to occur when any condition is met.
3. The battery electrolysis double closed loop cooperative control method considering abnormal conditions according to claim 1, wherein the differential control strategy comprises: For a single battery with the failure mode type of internal micro short circuit, cutting off a charge-discharge loop when the single battery is positioned in the central area of the battery pack, and cutting off the charge-discharge loop or limiting current to a safety lower limit when the single battery is positioned in the edge area of the battery pack; for a single battery with a failure mode type of electrolyte drying, setting a charging cut-off voltage to a first safe voltage value and injecting pulse current; Setting a charging cut-off voltage to a second safety voltage value for a single battery with a failure mode type of lithium dendrite piercing; the central area of the battery pack is an area, surrounding the periphery of each single battery by other single batteries, and the edge area of the battery pack is an area, at least one side of each single battery is directly contacted with an air heat dissipation medium.
4. The battery electrolysis double closed loop cooperative control method considering abnormal conditions according to claim 3, wherein the differential control strategy further comprises: the single-level closed loop synchronously collects a target single battery temperature sampling value and an adjacent single battery temperature sampling value in a fixed period during the execution of a control action; Calculating a temperature change slope of the target single battery through linear fitting according to the continuous temperature sampling values of the target single battery, and calculating a temperature change slope of the adjacent single battery through linear fitting according to the continuous temperature sampling values of the adjacent single battery; When the temperature change slope of the target single battery is greater than zero and the temperature change slope of the adjacent single battery is greater than zero, judging that the thermal diffusion risk exists, outputting a runaway failure mark by the single-level closed loop and triggering the group-level cooperative closed loop; And after the group-level cooperative closed loop receives the out-of-control failure mark, electric isolation is carried out on the target single battery and the adjacent single batteries, and the isolation range is expanded to all single batteries in direct physical contact with the adjacent single batteries.
5. The battery electrolysis double closed loop cooperative control method considering abnormal conditions according to claim 3, wherein the differential control strategy further comprises: The single-level closed loop calculates a temperature change slope sign based on a temperature sampling value sequence, and calculates a standard deviation of an absolute value of a voltage difference between continuous sampling points based on a terminal voltage sampling value sequence; When the temperature change slope sign is changed from positive to negative and the standard deviation is continuously reduced for more than the preset duration, judging that the recovery trend is established, and continuously executing three-stage recovery verification after the recovery trend is established; And when the temperature change slope sign is continuously positive or the standard deviation is not continuously reduced, judging that the recovery trend is not established, and continuing to count down the recovery monitoring timer until the recovery monitoring timer is reset to zero.
6. The battery electrolysis double closed loop cooperative control method considering abnormal conditions according to claim 5, wherein the judgment that the monitoring parameter is not recovered to normal is realized by three-stage recovery verification, wherein the three-stage recovery verification comprises temperature safety verification, voltage stability verification and thermal isolation verification; The temperature safety verification is carried out on a temperature sampling value sequence acquired during the execution of the control action by exponential function fitting, and verification is passed when a fitting determination coefficient exceeds a preset fitting degree threshold value and a damping time constant obtained by fitting is in a preset damping time constant range; The voltage stability verification divides a terminal voltage sampling value sequence acquired during the execution of the control action into an initial recovery section, a platform stabilizing section and a final stabilizing section according to time sequence, and the verification is passed when the voltage rising rate of the initial recovery section exceeds a preset rising rate threshold value, the difference value between the maximum value and the minimum value of the voltage of the platform stabilizing section is smaller than a preset fluctuation amplitude threshold value, and the absolute value of the voltage change slope of the final stabilizing section is smaller than a preset slope threshold value; The thermal isolation verification is carried out based on a temperature sampling value acquired during the execution of the control action to calculate the temperature change slope of the target single battery and the temperature change slope of the adjacent single battery, wherein the temperature change slope of the target single battery is negative, the temperature change slope of the adjacent single battery is greater than or equal to zero, and the verification is carried out when the current temperature difference value of the target single battery and the adjacent single battery exceeds a preset temperature difference threshold; and after the three-stage verification passes sequentially, judging that the monitoring parameters are recovered to be normal.
7. The battery electrolysis double-closed-loop cooperative control method considering abnormal conditions according to claim 1, wherein the triggering group level cooperative closed-loop is realized based on four-level control ending judgment: The termination condition of the group-level cooperative closed loop comprises the restoration of the monitoring parameters to normal or the return of the monitoring timer to zero; when the monitoring parameters are recovered to be normal, calculating the absolute deviation between the temperature sampling value of the target single battery and the health reference temperature and the absolute deviation between the terminal voltage sampling value and the health reference voltage; The control outcome is marked as fully recovered when both absolute deviations are less than the first deviation threshold; the control outcome is marked as partially recovered when both absolute deviations are less than the second deviation threshold but greater than the first deviation threshold; The countdown of the recovery monitoring timer returns to zero, the temperature rise rate of the target single battery is calculated when the monitoring parameters are not recovered to be normal, and the control result is marked as controllable failure when the temperature rise rate is smaller than a preset deterioration rate threshold; The temperature rise rate is greater than or equal to a preset deterioration rate threshold, and the control outcome is marked as out-of-control failure; The complete recovery and partial recovery trigger cascade utilization process, the controllable failure trigger group level cooperates with the conventional isolation process, and the uncontrolled failure trigger group level cooperates with the emergency shutdown process.
8. The method for collaborative control of battery electrolysis double closed loops considering abnormal conditions according to claim 3, further comprising calculating a failure evolution slope by a single-level closed loop based on a sequence of temperature samples and a sequence of terminal voltage samples of a target single battery during execution of a control action; And when the failure evolution slope is towards zero or a negative value, judging that the failure mode is towards stable, and when the failure evolution slope is continuously a positive value, judging that the failure mode is still developing.
9. The battery electrolysis double-closed-loop cooperative control method considering abnormal working conditions according to claim 1, wherein the electrical topology of the group-level cooperative closed-loop recombined residual single battery comprises: when the internal micro-short circuit is performed, the single battery performs electrical isolation; when the electrolyte is dried or lithium dendrite is pierced, the single battery is transferred to a limited operation branch; Dividing healthy single batteries with continuous column numbers and same row numbers in row-column coordinates into candidate strings, marking the candidate strings as high-capacity strings or medium-capacity strings according to control ending grades, and connecting the candidate strings with the marked candidate strings in parallel to form a recombinant battery pack; Monitoring the total voltage fluctuation amplitude, the branch current unbalance and the single temperature difference value of the recombinant battery pack, adjusting the serial-parallel connection relation when any parameter exceeds a preset threshold value, and judging that the operation is stable when all parameters meet the threshold value; And calculating the available capacity of the stabilized recombinant battery pack and feeding back to the single-stage closed loop.
10. The battery pack electrolysis double closed-loop cooperative control system considering the abnormal working condition adopts the battery pack electrolysis double closed-loop cooperative control method considering the abnormal working condition according to any one of claims 1-9, and is characterized by comprising a diagnosis module, a control module and a control module, wherein the diagnosis module acquires the electric characteristic response parameters of each single battery, compares the electric characteristic response parameters with a preset new battery parameter library and identifies the type of failure mode; the monitoring module is used for acquiring monitoring parameters of each single battery, judging that abnormal working conditions occur and triggering a single-level closed loop when abnormal characteristics appear in response to the monitoring parameters; the single control module is used for executing a differential control strategy according to the failure mode type, judging that the control fails and triggering a group-level cooperative closed loop in response to the monitoring parameter not returning to normal; And the group-level cooperative closed loop isolates or transfers the invalid single battery to a limited operation branch according to the type of the invalid mode, the electric topology of the rest single battery is recombined to form a recombined battery group, the serial-parallel connection relation is regulated, and when the operation of the recombined battery group is stable, the state is fed back to the single-level closed loop, and the available capacity assessment is completed in an iterative mode.

Description

Battery pack electrolysis double-closed-loop cooperative control method and device considering abnormal working conditions Technical Field The application relates to the technical field of waste battery management, in particular to a battery pack electrolysis double-closed-loop cooperative control method and system considering abnormal working conditions. Background The power battery packs of the abandoned heavy vehicles are often disassembled for gradient utilization in scenes such as energy storage stations, street lamps and the like after the abandoned heavy vehicles are retired, the battery packs undergo frequent high-rate charge and discharge, high-temperature environment operation and vibration impact in the long-distance transportation process during the service period of the vehicles, and the disassembled single batteries show obvious individual differences. The current method commonly adopted in the industry is to set uniform fixed protection thresholds such as an upper temperature limit and a lower voltage limit for all single batteries, and trigger protection action when monitoring parameters cross the thresholds, and the method has insufficient adaptability when facing to waste batteries with complex sources. The fixed threshold protection scheme takes all the single batteries as objects with consistent parameter characteristics, and ignores the significant differences of capacity attenuation degree, internal resistance increase amplitude and failure modes of the single batteries in the abandoned heavy vehicle battery pack, which are generated by different service histories. The battery cells with better health status may be interrupted due to frequent false alarm of the conservative threshold value in the normal charge and discharge process, while the battery cells with internal micro-short circuit are not reported because the initial parameter is still within the threshold value range, and the battery cells often enter the rapid development stage of thermal runaway when the parameter crosses the threshold value. The isolation protection mechanism based on the unified threshold value does not consider the influence of the physical position of the single battery in the battery pack on the heat dissipation condition, and does not design a differentiated control strategy aiming at the physical mechanism of different failure modes. The lack of an effective group-level cooperative isolation mechanism after the control failure of a single battery cell in the abandoned heavy vehicle battery pack leads to the rapid conduction of local thermal runaway risks to adjacent battery cells through a metal busbar, and finally causes the interlocking failure of the whole battery pack. Disclosure of Invention The present application has been made in view of the above-described problems. Therefore, the application provides a battery pack electrolysis double-closed-loop cooperative control method and system considering abnormal working conditions, which can solve the problems in the background technology. In order to solve the technical problems, the application provides the following technical scheme: In a first aspect, the application provides a battery pack electrolysis double-closed loop cooperative control method considering abnormal working conditions, which comprises the steps of obtaining electric characteristic response parameters of each single battery, comparing the electric characteristic response parameters with a preset new battery parameter library, and identifying a failure mode type; Acquiring monitoring parameters of each single battery, and judging that abnormal working conditions occur and triggering a single-level closed loop when abnormal characteristics appear in response to the monitoring parameters; the monomer-level closed loop executes a differential control strategy according to the failure mode type, and determines that control fails and triggers a group-level cooperative closed loop in response to the monitoring parameter not returning to normal; and the group-level cooperative closed loop isolates or transfers the invalid single battery to a limited operation branch according to the type of the invalid mode, the electric topology of the recombined residual single battery forms a recombined battery group and adjusts the serial-parallel connection relation, and when the recombined battery group operates stably, the state is fed back to the single-level closed loop, and the available capacity assessment is completed iteratively. Preferably, the step current excitation signal, the sinusoidal sweep frequency excitation signal and the pulse voltage excitation signal are sequentially applied, and the voltage recovery time constant, the steady-state polarization voltage, the real part minimum value of the impedance of the intermediate frequency region, the phase angle of the low frequency region and the current decay time constant are extracted; The identifying the failure mode type includes: