US 12,287,374 B2
Method for estimating direct current internal resistance of battery
Shih Fa Hung, Kaohsiung (TW); Chong-Yong Wu, Kaohsiung (TW); and Wen-Fan Chang, Kaohsiung (TW)
Filed by STL TECHNOLOGY CO., LTD., Kaohsiung (TW)
Filed on Jul. 10, 2023, as Appl. No. 18/219,997.
Claims priority of application No. 111130498 (TW), filed on Aug. 12, 2022.
Prior Publication US 2024/0053406 A1, Feb. 15, 2024
Int. Cl. G01R 31/389 (2019.01); G01R 31/3842 (2019.01); H02J 7/00 (2006.01)
CPC G01R 31/389 (2019.01) [G01R 31/3842 (2019.01); H02J 7/0047 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method for estimating a direct current internal resistance, applied to a battery, and comprising:
defining a depth of discharge detection interval comprising a first depth of discharge threshold value and a second depth of discharge threshold value;
executing a direct current internal resistance estimation process via a direct current internal resistance estimation program when the battery is in a discharge state, the direct current internal resistance estimation process comprising:
periodically measuring a currently discharge current and a currently battery voltage of the battery;
calculating a currently depth of discharge according to the periodically measured currently discharge current;
querying an open-circuit voltage corresponding to the currently depth of discharge from an open-circuit voltage curve or a lookup table;
subtracting the currently battery voltage from the open-circuit voltage corresponding to the currently depth of discharge to obtain a voltage difference, and continuously accumulating the voltage difference to obtain a currently accumulated voltage difference;
if the currently depth of discharge is greater than or equal to the first depth of discharge threshold value, the currently accumulated voltage difference being a first accumulated voltage difference;
if the currently depth of discharge is greater than or equal to the second depth of discharge threshold value, the currently accumulated voltage difference being a second accumulated voltage difference; and
dividing a difference value between the first accumulated voltage difference and the second accumulated voltage difference by a discharging amount in the depth of discharge detection interval to obtain the direct current internal resistance.