Patent ID: 11860235
Assignee: DENSO CORPORATION
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G

Claim 5:
6. A battery state estimation apparatus, comprising:
one or more memories; and
one or more processors communicably coupled with the one or more memories,
the one or more processors being configured to:
acquire repeatedly a temperature, a current value and a voltage value of a secondary battery;
calculate a current change amount and a voltage change amount of the secondary battery, respectively, using the current value and the voltage value;
calculate a measured DC resistance value of a DC resistance based on the current change amount and the voltage change amount;
perform a calculation of, as a calculated constant value, (i) a non-temperature dependent constant, which indicates a temperature independent component of the DC resistance of the secondary battery independent of the temperature, and (ii) a constant of a temperature dependent function, which indicates a component of the DC resistance of the secondary battery dependent on the temperature,
based on (i) the measured DC resistance value, and (ii) an estimated DC resistance value being an estimated value of the measured DC resistance value,
the estimated DC resistance value being represented as a sum of (i) the non-temperature dependent constant, and (ii) the temperature dependent function,

wherein a plurality of the calculations of a plurality of the non-temperature dependent constants and a plurality of the constants of the temperature dependent functions are performed at corresponding time points in a predetermined period up to a present time point; and

determine whether or not the calculated constant value has converged based on a first condition and a second condition,
wherein the first condition is that
a total number of times of the calculations of the non-temperature dependent constants and the constants of the temperature dependent functions is equal to or greater than a predetermined number,

wherein the second condition is that
(i) a slope of an approximate straight line, which is obtained by a plot acquired from (a) the non-temperature dependent constants calculated at the corresponding time points up to the present time point in the predetermined period and (b) the corresponding time points up to the present time point, is equal to or less than a threshold value, and
(ii) a slope of an approximate straight line, which is obtained by a plot acquired from (a) the constants of the temperature dependent functions calculated at the corresponding time points up to the present time point in the predetermined period and (b) the corresponding time points up to the present time point, is equal to or less than a threshold value;

and wherein:
in response to determining that the calculated constant value has not converged, the one or more processors are further configured to continue to perform the calculations of the plurality of the non-temperature dependent constants and the plurality of the constants of the temperature dependent functions while retaining logs of the calculated plurality of the non-temperature dependent constants and the calculated plurality of constants of the temperature dependent functions; and
in response to determining that the calculated constant value has converged, the one or more processors are further configured to determine the non-temperature dependent constant and the constant of the temperature dependent function for use in the calculation of the estimated DC resistance value as the sum of (i) the non-temperature dependent constant and (ii) the temperature dependent function.