US 12,291,124 B2
Method for initializing the charge state of a battery
Driemeyer Franco Ana-Lucia, Montigny le Bretonneux (FR); and Akram Eddahech, Guyancourt (FR)
Assigned to AMPERE S.A.S., Boulogne-Billancourt (FR); and NISSAN MOTOR CO., LTD., Yokohama (JP)
Appl. No. 17/600,482
Filed by RENAULT s.a.s., Boulogne-Billancourt (FR); and NISSAN MOTOR CO., LTD., Yokohama (JP)
PCT Filed Mar. 24, 2020, PCT No. PCT/EP2020/058058
§ 371(c)(1), (2) Date Sep. 30, 2021,
PCT Pub. No. WO2020/200897, PCT Pub. Date Oct. 8, 2020.
Claims priority of application No. 1903547 (FR), filed on Apr. 3, 2019.
Prior Publication US 2022/0212563 A1, Jul. 7, 2022
Int. Cl. B60L 58/13 (2019.01); G01R 31/36 (2020.01); G01R 31/374 (2019.01); G01R 31/3835 (2019.01)
CPC B60L 58/13 (2019.02) [G01R 31/3648 (2013.01); G01R 31/374 (2019.01); G01R 31/3835 (2019.01)] 14 Claims
OG exemplary drawing
 
1. A method for estimating a state of charge of a battery, comprising:
initializing the state of charge of the battery, including estimating an initial value of the state of charge, the initializing comprising:
receiving a stored state-of-charge value of the battery when the battery enters sleep mode,
calculating a state-of-charge value using a measurement of a no-load voltage at terminals of the battery when the battery wakes, and
calculating an error in the measurement of the no-load voltage due to relaxation of the battery, in which the error is calculated as a function of a current temperature of the battery and a target relaxation time of the battery modeled for each temperature, wherein
the estimating of the initial value of the state of charge is calculated based on a comparison between the stored values and calculated values of the state of charge and as a function of the calculated error,
the calculating the error caused by relaxation comprises:
storing map data correlating a given state of charge with a given no-load voltage of the battery, for a given temperature of the battery,
determining a maximum error in the measurement of the no-load voltage corresponding to the error between the battery voltage on waking for a minimum relaxation time and the battery voltage on waking for the target relaxation time,
providing error calibration data describing a variation of a margin of error in the state of charge in relation to a state-of-charge value provided by the map data, as a function of the maximum error,
designating a plurality of zones within the error calibration data, each of the zones including a predefined range of the state-of-charge values,
determining a zone of the plurality of zones that includes the state-of-charge value provided by the map data,
selecting maximum error data describing a maximum value of the variation of the margin of error in the state of charge within the zone, and
calculating the error caused by relaxation using the no-load voltage measurement when the battery wakes and the error calibration data maximum error data for the zone, and
the initializing further comprises determining a state of relaxation of the battery on waking.