US 11,656,288 B2
Method for monitoring battery cells of a primary on-board electrical system battery, on-board electrical system and motor vehicle
Jose Lopez De Arroyabe, Munich (DE); and Gerhard Woelfl, Geltendorf (DE)
Assigned to Bayerische Motoren Werke Aktiengesellschaft, Munich (DE)
Filed by Bayerische Motoren Werke Aktiengesellschaft, Munich (DE)
Filed on Feb. 16, 2022, as Appl. No. 17/672,969.
Claims priority of application No. 10 2021 103 989.4 (DE), filed on Feb. 19, 2021.
Prior Publication US 2022/0268846 A1, Aug. 25, 2022
Int. Cl. G01R 31/389 (2019.01); H02J 7/00 (2006.01); B60L 50/60 (2019.01); G01R 31/396 (2019.01); G01R 31/3835 (2019.01); B60L 58/20 (2019.01)
CPC G01R 31/389 (2019.01) [B60L 50/60 (2019.02); B60L 58/20 (2019.02); G01R 31/3835 (2019.01); G01R 31/396 (2019.01); H02J 7/0013 (2013.01); H02J 7/0047 (2013.01); H02J 7/0063 (2013.01); B60L 2210/10 (2013.01); H02J 2207/20 (2020.01)] 10 Claims
OG exemplary drawing
 
1. A method for monitoring battery cells of a primary on-board electrical system battery of a motor vehicle by galvanostatic impedance spectroscopy, the method comprising:
impressing an AC signal having alternating currents of different frequencies onto the battery cells as an excitation signal,
detecting cell voltage signals of the battery cells as frequency-dependent response signals to the excitation signal,
determining impedance spectra of the battery cells depending on the excitation signal and the response signals, and
dividing the primary on-board electrical system battery into at least two subsections each having at least one battery cell in order to provide the excitation signal, wherein:
the primary on-board electrical system battery is electrically connected to a secondary on-board electrical system battery of the motor vehicle,
two cycles alternating at the different frequencies are carried out, in which at least one of:
two different currents are drawn in alternation from the subsections and a secondary-side constant current formed from the two currents over the cycles is supplied to the secondary on-board electrical system battery, or
a constant current provided on the secondary side by the secondary on-board electrical system battery is provided on the primary side and two different currents formed from the constant current are supplied to the subsections in alternation, and
a differential current formed on the primary side from the two currents is supplied to the battery cells as the excitation signal, wherein the direction of the differential current alternates with the cycles.