US 11,733,309 B2
Method and system for self-discharge prognostics for vehicle battery cells with an internal short circuit
Yue-Yun Wang, Troy, MI (US); Yangbing Zeng, Troy, MI (US); Taylor R. Garrick, Royal Oak, MI (US); and Andrew C. Baughman, Northville, MI (US)
Assigned to GM Global Technology Operations LLC, Detroit, MI (US)
Filed by GM GLOBAL TECHNOLOGY OPERATIONS LLC, Detroit, MI (US)
Filed on Aug. 18, 2021, as Appl. No. 17/405,488.
Prior Publication US 2023/0055095 A1, Feb. 23, 2023
Int. Cl. G01R 31/3835 (2019.01); G01R 31/396 (2019.01); G01R 31/388 (2019.01)
CPC G01R 31/3835 (2019.01) [G01R 31/388 (2019.01); G01R 31/396 (2019.01)] 9 Claims
OG exemplary drawing
 
1. A system for self-discharge prognostics for vehicle battery cells of a vehicle with an internal short circuit, comprising:
a battery pack including a plurality of battery cells;
for each of the plurality of battery cells, a voltage sensor iteratively measuring open-circuit voltage data through a test period, wherein the open-circuit voltage data is collected at instances where the battery cell is in an open-circuit condition; and
a computerized prognostic controller, operating programming to:
monitor the open-circuit voltage data for each of the plurality of battery cells;
evaluate a voltage drop rate through a time window for each of the plurality of battery cells based upon the open-circuit voltage data;
identify one of the plurality of battery cells to include the internal short circuit based upon the voltage drop rate; and
signal an alert based upon the one of the plurality of battery cells including the internal short circuit; and
wherein evaluating the voltage drop rate for each of the plurality of battery cells includes iteratively applying linear regression at progressively extended time window lengths to estimate a line describing voltage drop per unit time for each of the plurality of battery cells;
wherein identifying the one of the plurality of battery cells to include the internal short circuit includes analyzing a slope of the line describing voltage drop per unit time for each of the plurality of battery cells;
wherein analyzing the slope of the line describing voltage drop per unit time includes comparing the slope of the line describing voltage drop per unit time corresponding to a first cell of the plurality of battery cells through the test period to each of the respective slopes of the lines describing voltage drop per unit time corresponding to each of the plurality of battery cells that are not the first cell through the test period;
wherein the test period is a common test period for the plurality of battery cells, starting at a first instant in time and ending at a second instant in time; and
wherein each of the plurality of battery cells of the battery pack is exposed to common conditions that exist within the battery pack through the test period.