US 12,416,676 B2
Battery pack state of charge estimation
Jun-mo Kang, Ann Arbor, MI (US); Hanho Yun, Oakland Township, MI (US); and Insu Chang, Troy, MI (US)
Assigned to GM GLOBAL TECHNOLOGY OPERATIONS LLC, Detroit, MI (US)
Filed by GM Global Technology Operations LLC, Detroit, MI (US)
Filed on Jul. 11, 2023, as Appl. No. 18/350,484.
Prior Publication US 2025/0020723 A1, Jan. 16, 2025
Int. Cl. G01R 31/367 (2019.01); B60L 50/60 (2019.01); B60L 58/12 (2019.01); G01R 31/3835 (2019.01)
CPC G01R 31/367 (2019.01) [B60L 50/60 (2019.02); B60L 58/12 (2019.02); G01R 31/3835 (2019.01)] 20 Claims
OG exemplary drawing
 
1. A battery monitoring system for a vehicle comprising:
a processor and a memory, the memory storing instructions for causing the processor to estimate a state of charge of a battery based on a current cell pressure of the battery while the state of charge of the battery is below a threshold state of charge and to estimate the state of charge of the battery based on a voltage output by the battery while the state of charge of the battery is greater than or equal to the threshold state of charge;
wherein estimating the state of charge of the battery based on the current cell pressure of the battery includes estimating via a first procedure while the battery is charging, wherein the first procedure comprises:
estimating the state of charge using a voltage based state of charge estimator and estimating the state of charge using a cell pressure based state of charge estimator;
comparing the voltage based state of charge estimation and the cell pressure based state of change estimation;
determining that the voltage based state of charge is accurate when a difference between the voltage based state of charge estimation and the cell pressure based state of charge estimation is below a threshold, and determining that the voltage based state of charge is inaccurate when the difference between the voltage based state of charge estimation and the cell pressure based state of charge estimation is greater than or equal to the threshold; and
learning a bias and slope of a cell pressure response to determining that the voltage based state of change estimate is accurate, and applying the learned bias and slope of the cell pressure when estimating the state of charge using the cell pressure based state of charge estimator.