Method, apparatus, device and medium for estimating performance parameters of a battery

Patent metadata

Field	Value
Publication number	US-11573273-B2
Application number	US-202117561750-A
Country	US
Kind code	B2
Filing date	Dec 24, 2021
Priority date	Mar 30, 2020
Publication date	Feb 7, 2023
Grant date	Feb 7, 2023

Abstract

The present application discloses a method, apparatus, device and medium for estimating performance parameters of a battery. The method for estimating performance parameters of a battery includes: generating a first curve segment to be calibrated during a process of adjusting a battery capacity in a first capacity interval with a first capacity value as an endpoint value; determining, in a preset reference curve, a first target curve segment that matches the first curve segment to be calibrated; determining a SOC interval corresponding to the first target curve segment as a SOC interval of the first curve segment to be calibrated; and estimating the performance parameters of the battery based on the SOC interval of the first curve segment to be calibrated, the performance parameters include a current SOC and/or a current battery capacity.

First claim

What is claimed is:

1. A method for estimating performance parameters of a battery, comprising:
generating a first curve segment to be calibrated during a process of adjusting a battery capacity in a first capacity interval with a first capacity value as an endpoint value, wherein the first curve segment to be calibrated represents an actual change of the battery capacity in the first capacity interval with a voltage;
determining, in a preset reference curve, a first target curve segment that matches the first curve segment to be calibrated, wherein the preset reference curve represents a reference change of the battery capacity with a voltage within an output voltage range of the battery;
determining a state of charge (SOC) interval corresponding to the first target curve segment as a SOC interval of the first curve segment to be calibrated; and
estimating the performance parameters of the battery based on the SOC interval of the first curve segment to be calibrated, wherein the performance parameters comprise a current SOC and/or a current battery capacity,
wherein the method further comprises:
generating a second curve segment to be calibrated during a process of adjusting the battery capacity in a second capacity interval with a second capacity value as an endpoint value, wherein the second curve segment to be calibrated represents a change of the battery capacity in the second capacity interval with a voltage;
determining, in the preset reference curve, a second target curve segment that matches the second curve segment to be calibrated;
determining a SOC interval corresponding to the second target curve segment as a SOC interval of the second curve segment to be calibrated,
generating a third curve segment to be calibrated during a process of adjusting the battery capacity in a third capacity interval with a third capacity value as an endpoint value, wherein the third curve segment to be calibrated represents a change of the battery capacity in the third capacity interval with a voltage;
determining, in the preset reference curve, a third target curve segment that matches the third curve segment to be calibrated; and
determining a SOC interval corresponding to the third target curve segment as a SOC interval of the third curve segment to be calibrated,
wherein the performance parameters comprise the current battery capacity, and estimating the performance parameters of the battery based on the SOC interval of the first curve segment to be calibrated comprises:
determining a first SOC corresponding to the first capacity value in the SOC interval of the first curve segment to be calibrated;
determining a second SOC corresponding to the second capacity value in the SOC interval of the second curve segment to be calibrated;
determining a third SOC corresponding to the third capacity value in the SOC interval of the third curve segment to be calibrated;
determining, based on three pairs of first data to be calculated comprising the first capacity value and the first SOC, the second capacity value and the second SOC, and the third capacity value and the third SOC, multiple sets of second data to be calculated, each set of second data to be calculated comprising any two pairs of the three pairs of first data to be calculated; and
performing averaging processing on current battery capacities of the multiple sets of second data to be calculated to obtain the current battery capacity of the battery, wherein the current battery capacity of each set of second data to be calculated is a ratio of a difference of capacity values between the comprised two pairs of first data to be calculated to a difference of SOC between the comprised two pairs of first data to be calculated.

2. The method according to claim 1 , wherein the performance parameters comprise the current SOC, and estimating the performance parameters of the battery based on the SOC interval of the first curve segment to be calibrated comprises:
under a condition that the first capacity value is a starting value of the first capacity interval, using a starting value of the SOC interval of the first curve segment to be calibrated as the current SOC of the battery; or
under a condition that the first capacity value is an end value of the first capacity interval, using an end value of the SOC interval of the first curve segment to be calibrated as the current SOC of the battery.

3. The method according to claim 1 , wherein the performance parameters comprise the current battery capacity, and estimating the performance parameters of the battery based on the SOC interval of the first curve segment to be calibrated comprises:
using a ratio of an interval length of the first capacity interval to an interval length of the SOC interval of the first curve segment to be calibrated as the current battery capacity.

4. The method according to claim 1 , wherein before the generating a first curve segment to be calibrated during a process of adjusting a battery capacity in a first capacity interval with a first capacity value as an endpoint value, the method further comprises:
under a condition that a real-time capacity of the battery is greater than the first capacity value, discharging the battery until the real-time capacity of the battery reduces to the first capacity value; or
under a condition that the real-time capacity of the battery is less than the first capacity value, charging the battery until the real-time capacity of the battery increases to the first capacity value.

5. The method according to claim 1 , wherein the generating a first curve segment to be calibrated during a process of adjusting a battery capacity in a first capacity interval with a first capacity value as an endpoint value comprises:
adjusting the battery capacity from the first capacity value to the other endpoint value of the first capacity interval through constant current charging or constant current discharging, to generate a first curve segment to be processed;
adjusting the battery capacity from the other endpoint value to the first capacity value through constant current charging or constant current discharging, to generate a second curve segment to be processed; and
performing averaging processing on the first curve segment to be processed and the second curve segment to be processed, to obtain the first curve segment to be calibrated.

6. The method according to claim 1 , wherein the determining, in a preset reference curve, a first target curve segment that matches the first curve segment to be calibrated comprises:
performing normalization processing on the first curve segment to be calibrated to obtain the first curve segment to be calibrated after normalization processing;
performing normalization processing on the preset reference curve to obtain a first reference curve, wherein the first reference curve represents a reference change of the SOC with a voltage;
determining a plurality of points on the first reference curve, and acquiring, on the first reference curve, a plurality of first reference curve segments of different lengths with the plurality of points as starting points respectively;
performing normalization processing on the acquired plurality of first reference curve segments, so that a projection of the plurality of first reference curve segments after normalization processing on an ordinate is the same as a projection of the first curve segment to be calibrated after normalization processing on the ordinate; and
calculating deviations between the first curve segment to be calibrated after normalization processing and the plurality of first reference curve segments after normalization processing respectively, and determining a first reference curve segment after normalization processing having a smallest deviation with the f

Assignees

• Contemporary Amperex Technology Co Ltd

Inventors

• Wei Yimin
• Lin Zhen
• Wei Xingsheng

Classifications

• G01R31/388 Primary

  involving voltage measurements · CPC title

• G01R31/367

  Software therefor, e.g. for battery testing using modelling or look-up tables · CPC title

• G01R31/3648

  comprising digital calculation means, e.g. for performing an algorithm · CPC title