BATTERY CHARACTERISTICS LEARNING APPARATUS

• US 20150127281A1
• Filed: 11/06/2014
• Published: 05/07/2015
• Est. Priority Date: 11/07/2013
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: UMEMOTO, Hisashi, AWANO, Naomi, KUSANO, Yoshikazu, YAMADA, Manabu
• Granted Patent: US 10,379,165 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G06N 20/00 Machine learning

Abstract

A battery characteristics learning apparatus is provided for calculating learning values of circuit constants of an equivalent circuit of a rechargeable battery. The apparatus includes: (1) means for acquiring values of terminal voltage of the battery sensed by voltage-sensing means and values of current of the battery sensed by current-sensing means and storing the acquired values in time series; (2) means for determining, based on the acquired values of the current, whether there has occurred a predetermined change in the current; and (3) means for calculating, when it is determined that the predetermined change has occurred, the learning values of the circuit constants based on those values of the terminal voltage and the current which are acquired at sampling time points or during sampling periods, each of the sampling time points and the sampling periods being set according to a corresponding one of time constants defined by the circuit constants.

Claims

1. A battery characteristics learning apparatus for calculating learning values of a plurality of circuit constants of an equivalent circuit of a rechargeable battery, the plurality of circuit constants defining a plurality of time constants that are different from each other, the battery characteristics learning apparatus comprising:

means for acquiring values of terminal voltage of the rechargeable battery which is sensed by voltage-sensing means and values of current flowing through the rechargeable battery which is sensed by current-sensing means and storing the acquired values of the terminal voltage and the current in time series;

means for determining, based on the values of the current acquired by the acquiring means, whether there has occurred a predetermined change in the current flowing through the rechargeable battery; and

means for calculating, when it is determined by the determining means that the predetermined change has occurred, the learning values of the circuit constants based on those values of the terminal voltage and the current which are acquired by the acquiring means at a plurality of sampling time points or during a plurality of sampling periods, each of the sampling time points being set to a time point that is distant from an initial time point, at which the predetermined change in the current starts, by a length of time equal to a corresponding one of the time constants, each of the sampling periods being set so as to include a time point that is distant from the initial time point by a length of time equal to a corresponding one of the time constants.

2. The battery characteristics learning apparatus as set forth in claim 1, wherein the determining means determines that the predetermined change has occurred in the current flowing through the rechargeable battery when the current has increased or decreased after being kept at a constant value for a time period not shorter than a predetermined time.

3. The battery characteristics learning apparatus as set forth in claim 2, wherein the determining means determines that the predetermined change has occurred in the current flowing through the rechargeable battery when the rechargeable battery is brought into a steady state after the increase or decrease of the current,

in the steady state, both the current flowing through the rechargeable battery and the terminal voltage of the rechargeable battery being constant.

4. The battery characteristics learning apparatus as set forth in claim 1, further comprising means for determining whether the rechargeable battery is in a charge state or in a discharge state based on the values of the current sensed by the current-sensing means, wherein

when the rechargeable battery is determined by the battery state determining means as being in the charge state, the calculating means calculates the learning values of the circuit constants in the charge state, and

when the rechargeable battery is determined by the battery state determining means as being in the discharge state, the calculating means calculates the learning values of the circuit constants in the discharge state.

5. The battery characteristics learning apparatus as set forth in claim 1, further comprising:

means for calculating SOC (State of Charge) of the rechargeable battery; and

means for correcting at least one of the learning values of the circuit constants, which is calculated by the learning values calculating means, according to the SOC of the rechargeable battery at the sampling time point or in the sampling period where the values of the terminal voltage and the current used for the calculation of the at least one of the learning values are acquired by the acquiring means.