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CN-121978569-A - BMS battery health monitoring method and system

CN121978569ACN 121978569 ACN121978569 ACN 121978569ACN-121978569-A

Abstract

The invention relates to the technical field of battery health monitoring, and discloses a BMS battery health monitoring method and system. The method comprises the steps of counting the switching event times and the total cycle duration of a battery in a complete charge-discharge cycle, determining a sampling period according to the switching event times and the total cycle duration, synchronously acquiring a current value and a temperature value at each sampling time of the sampling period, calculating the temperature variation between adjacent sampling times, calculating capacity increment based on the temperature variation and the current value, accumulating and summing the capacity increment to obtain the initial cycle capacity of an ith round, calculating a temperature peak value deviation ratio and a temperature integration area deviation ratio, obtaining the correction cycle capacity of the ith round through iterative correction, calculating an evaluation capacity, and calculating a battery health state index according to the evaluation capacity and the rated capacity, wherein i is more than or equal to 5. The invention effectively eliminates accidental errors of single measurement, so that the final estimated capacity integrates the temperature response characteristics and capacity attenuation rules of multiple cycles.

Inventors

  • TAO WEI
  • Xiang Mufeng
  • XIONG LICHUN

Assignees

  • 深圳市百千成电子有限公司

Dates

Publication Date
20260505
Application Date
20260206

Claims (10)

  1. 1. A BMS battery health monitoring method, comprising: Counting the switching event times and the total cycle duration of the battery in a complete charge-discharge cycle, and determining a sampling period according to the switching event times and the total cycle duration; synchronously acquiring a current value and a temperature value at each sampling time of the sampling period, calculating the temperature variation between adjacent sampling times, and calculating a capacity increment based on the temperature variation and the current value; The capacity increment is accumulated and summed in the ith cycle to obtain the initial cycle capacity of the ith cycle, the temperature peak value deviation ratio and the temperature integral area deviation ratio of the ith cycle and the ith-1 cycle are calculated, and the corrected cycle capacity of the ith cycle is obtained through iterative correction; calculating an arithmetic average value according to the i-th round of correction circulation capacity to obtain an estimated capacity, and calculating a battery health state index according to the estimated capacity and the rated capacity, wherein i is more than or equal to 5.
  2. 2. The BMS battery health monitoring method according to claim 1, wherein counting the number of switching events and the total cycle duration of the battery in a complete charge-discharge cycle, and determining a sampling period according to the number of switching events and the total cycle duration, comprises: Monitoring the charge and discharge state of the battery, marking the moment when the charge state is switched to the discharge state or the discharge state is switched to the charge state as a switching event, and counting the switching event times in the complete charge and discharge cycle; And obtaining the total cycle time length, dividing the switching event times by the total cycle time length to obtain the switching frequency, and dividing the total cycle time length by the switching event times to obtain the sampling period.
  3. 3. The BMS battery health monitoring method according to claim 2, wherein the monitoring of the charge and discharge state of the battery, the moment when the charge state is switched to the discharge state or the discharge state is switched to the charge state is marked as a switching event, counting the number of switching events in the complete charge and discharge cycle, comprises: collecting the current direction of the battery in real time, and judging whether the battery is in a charging state or a discharging state according to the current direction; And comparing the charge and discharge states at adjacent moments, and accumulating the switching event counter to obtain the switching event times when detecting that the charge state is changed into the discharge state or the discharge state is changed into the charge state.
  4. 4. The BMS battery health monitoring method according to claim 1, wherein synchronously sampling a current value and a temperature value at each sampling time of the sampling period, calculating a temperature variation between adjacent sampling times, and calculating a capacity increment based on the temperature variation and the current value, comprising: Synchronously collecting a current value and a temperature value of the battery at each sampling time of the sampling period, and calculating the difference between the temperature values of adjacent sampling times to obtain a temperature variation; And adding 1 to the ratio of the temperature variation to the normalized reference temperature difference to obtain a temperature correction coefficient, and multiplying the current value, the sampling period and the temperature correction coefficient to obtain a capacity increment.
  5. 5. The BMS battery health monitoring method according to claim 4, wherein adding 1 to the ratio of the temperature variation to the normalized reference temperature difference to obtain a temperature correction coefficient, and multiplying the current value, the sampling period, and the temperature correction coefficient to obtain a capacity increment, comprises: Dividing the temperature variation by a normalized reference temperature difference to obtain a temperature deviation ratio, and adding 1 to the temperature deviation ratio to obtain a temperature correction coefficient; Multiplying the current value by the sampling period to obtain a preliminary capacity value, and multiplying the preliminary capacity value by the temperature correction coefficient to obtain a capacity increment.
  6. 6. The BMS battery health monitoring method according to claim 1, wherein the adding and summing the capacity increment in the ith cycle to obtain an ith initial cycle capacity, calculating a temperature peak deviation ratio and a temperature integral area deviation ratio of the ith cycle and the i-1 th cycle, and obtaining an ith corrected cycle capacity through iterative correction, comprising: Accumulating and summing capacity increment in the ith cycle to obtain the initial cycle capacity of the ith cycle, extracting a maximum temperature value from a temperature value sequence of the ith cycle to serve as an ith cycle temperature peak value, multiplying each temperature value by the sampling period, and accumulating to obtain an ith cycle temperature integration area; Dividing the difference between the ith round of temperature peak value and the ith-1 round of temperature peak value by the ith-1 round of temperature peak value to obtain a temperature peak value deviation ratio, and dividing the difference between the ith round of temperature integration area and the ith-1 round of temperature integration area by the ith-1 round of temperature integration area to obtain a temperature integration area deviation ratio; carrying out average value operation on the temperature peak value deviation ratio and the temperature integral area deviation ratio to obtain a comprehensive deviation ratio; Determining a decreasing weight coefficient according to the round distance between each historical round and the ith round, multiplying the cycle capacity of each historical round by the difference value obtained by subtracting the product of the decreasing weight coefficient and the comprehensive deviation ratio from 1, correcting, and multiplying the initial cycle capacity of the ith round by the difference value obtained by subtracting the comprehensive deviation ratio from 1, thus obtaining the corrected cycle capacity of the ith round.
  7. 7. The BMS battery health monitoring method according to claim 6, wherein dividing a difference between the i-th and i-1-th wheel temperature peaks by the i-1-th wheel temperature peak to obtain a temperature peak deviation ratio, dividing a difference between the i-th and i-1-th wheel temperature integration areas by the i-1-th wheel temperature integration area to obtain a temperature integration area deviation ratio, comprising: The temperature peak value of the ith round is subjected to difference with the temperature peak value of the ith round to obtain a temperature peak value difference value, and the temperature peak value difference value is divided by the temperature peak value of the ith round to obtain a temperature peak value deviation ratio; The temperature integral area of the ith wheel is subjected to difference with the temperature integral area of the ith-1 wheel to obtain a temperature integral area difference value, and the temperature integral area difference value is divided by the temperature integral area of the ith-1 wheel to obtain a temperature integral area deviation ratio; and adding the temperature peak deviation ratio and the temperature integration area deviation ratio, and dividing the sum by 2 to obtain a comprehensive deviation ratio.
  8. 8. The BMS battery health monitoring method of claim 6, wherein determining a decreasing weight coefficient according to a round distance between each historical round and an i-th round, correcting a cycle capacity of each historical round by multiplying 1 by a difference of subtracting a product of the decreasing weight coefficient and the integrated deviation ratio, and multiplying the i-th round initial cycle capacity by 1 by a difference of subtracting the integrated deviation ratio to obtain an i-th round corrected cycle capacity, comprising: calculating a round sequence number difference value between an ith round and each historical round to obtain a round distance, and calculating a decremental weight coefficient corresponding to each historical round according to the round distance and a preset attenuation coefficient; multiplying the decreasing weight coefficient by the comprehensive deviation ratio, subtracting from 1 to obtain a history correction factor, and multiplying the circulation capacity of each history round by the corresponding history correction factor to obtain a correction circulation capacity of each history round; And subtracting the integrated deviation ratio from 1 to obtain a current correction factor, and multiplying the i-th round of initial circulation capacity by the current correction factor to obtain the i-th round of correction circulation capacity.
  9. 9. The BMS battery health monitoring method according to claim 1, wherein the calculating an arithmetic mean value according to the i-th round of correction cycle capacity to obtain an estimated capacity, and calculating a battery health state index according to the estimated capacity and a rated capacity, wherein i is equal to or greater than 5, comprises: Accumulating and summing the correction circulation capacity of the 1 st round to the correction circulation capacity of the i th round to obtain a correction capacity sum, dividing the correction capacity sum by i to obtain an evaluation capacity, wherein i is more than or equal to 5; And reading rated capacity from a battery parameter database, dividing the rated capacity by the rated capacity to obtain a capacity ratio, and multiplying the capacity ratio by 100 to obtain a battery health state index.
  10. 10. A BMS battery health monitoring system, characterized by steps for implementing the BMS battery health monitoring method of any one of claims 1 to 7, comprising: the statistics module is used for counting the switching event times and the total cycle duration of the battery in the complete charge-discharge cycle, and determining a sampling period according to the switching event times and the total cycle duration; The calculation module is used for synchronously acquiring a current value and a temperature value at each sampling time of the sampling period, calculating the temperature variation between adjacent sampling times and calculating the capacity increment based on the temperature variation and the current value; the iteration correction module is used for carrying out accumulation summation on the capacity increment in the ith round of circulation to obtain the initial circulation capacity of the ith round, calculating the temperature peak value deviation ratio and the temperature integral area deviation ratio of the ith round and the ith-1 round, and obtaining the correction circulation capacity of the ith round through iteration correction; The evaluation module is used for calculating an arithmetic average value according to the ith round of correction circulation capacity to obtain an evaluation capacity, and calculating a battery health state index according to the evaluation capacity and the rated capacity, wherein i is more than or equal to 5.

Description

BMS battery health monitoring method and system Technical Field The invention relates to the technical field of battery health monitoring, in particular to a BMS battery health monitoring method and system. Background The health state monitoring of the battery management system is a core technology for guaranteeing the safe operation of the power battery. The conventional BMS evaluates the battery capacity using a coulometric method, integrates and accumulates charge and discharge currents at regular time intervals, but this method has significant drawbacks. In practical application, the battery frequently undergoes charge-discharge state switching, the sampling points at the switching transient moment are distributed unreasonably due to fixed sampling step length, and the influence of state transition on the battery performance cannot be accurately captured. Meanwhile, the existing method only uses the temperature as a static compensation parameter, and the temperature dynamic change process is not coupled to capacity calculation, so that the evaluation accuracy is reduced when the temperature is rapidly changed under the high-magnification working condition. In addition, the single cycle measurement result is easily affected by transient working condition fluctuation, has larger accidental errors, cannot reflect the attenuation trend of the battery in multiple cycles, and causes insufficient reliability of the state of health assessment. Disclosure of Invention The invention aims to provide a BMS battery health monitoring method and system, which effectively eliminate accidental errors of single measurement, and integrate final estimated capacity with temperature response characteristics and capacity decay rules of multiple cycles. In order to achieve the above object, the present invention provides a method for monitoring health of a BMS battery, comprising the steps of: Counting the switching event times and the total cycle duration of the battery in a complete charge-discharge cycle, and determining a sampling period according to the switching event times and the total cycle duration; synchronously acquiring a current value and a temperature value at each sampling time of the sampling period, calculating the temperature variation between adjacent sampling times, and calculating a capacity increment based on the temperature variation and the current value; The capacity increment is accumulated and summed in the ith cycle to obtain the initial cycle capacity of the ith cycle, the temperature peak value deviation ratio and the temperature integral area deviation ratio of the ith cycle and the ith-1 cycle are calculated, and the corrected cycle capacity of the ith cycle is obtained through iterative correction; calculating an arithmetic average value according to the i-th round of correction circulation capacity to obtain an estimated capacity, and calculating a battery health state index according to the estimated capacity and the rated capacity, wherein i is more than or equal to 5. Optionally, in a first implementation manner of the first aspect of the present invention, counting a switching event number and a total cycle duration of the battery in a complete charge-discharge cycle, and determining a sampling period according to the switching event number and the total cycle duration includes: Monitoring the charge and discharge state of the battery, marking the moment when the charge state is switched to the discharge state or the discharge state is switched to the charge state as a switching event, and counting the switching event times in the complete charge and discharge cycle; And obtaining the total cycle time length, dividing the switching event times by the total cycle time length to obtain the switching frequency, and dividing the total cycle time length by the switching event times to obtain the sampling period. Optionally, in a second implementation manner of the first aspect of the present invention, the monitoring the charge-discharge state of the battery, marking the moment when the charge state is switched to the discharge state or the discharge state is switched to the charge state as a switching event, counting the number of switching events in the complete charge-discharge cycle includes: collecting the current direction of the battery in real time, and judging whether the battery is in a charging state or a discharging state according to the current direction; And comparing the charge and discharge states at adjacent moments, and accumulating the switching event counter to obtain the switching event times when detecting that the charge state is changed into the discharge state or the discharge state is changed into the charge state. Optionally, in a third implementation manner of the first aspect of the present invention, the sampling a current value and a temperature value at each sampling time of the sampling period synchronously, calculating a temperature variation between adjacent