Accumulator device, and state of charge evaluation apparatus and method for accumulator

• US 10,209,313 B2
• Filed: 06/22/2010
• Issued: 02/19/2019
• Est. Priority Date: 09/30/2009
• Status: Active Grant

• Current Assignee: Hitachi Chemical Company Limited (Resonac Holdings Corp.)
• Original Assignee: Hitachi Chemical Company Limited (Resonac Holdings Corp.)
• Inventors: Abe, Keiko, Kobayashi, Yasuhiro, Watanabe, Masahiro, Takabayashi, Hisaaki, Hirose, Yoshikazu
• Primary Examiner(s): Ishizuka, Yoshihisa
• Application Number:
  US13/059,891
• Publication Number:
  US 20110196633A1
• Time in Patent Office: 3,164 Days
• Field of Search: 702 63, 320101, 320132, 324431, 324429, 324426, 72 63
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An accumulator and state of charge evaluation method for preparing, during charging and discharging, models for each of deterioration degrees, each representing a relationship between terminal voltage, current and state of charge, for selecting respective models for the times during charging and discharging in accordance with a total charging/discharging amount (Ah), a deterioration degree or an elapsed time of an operation of the accumulator, for further estimating state of charge from current accumulation, and for determining a final state of charge from estimated states of charge including a present state of charge estimated from the models for the times during charging and discharging of the accumulator, while using a time or a total charging/discharging amount (Ah) from a time of full-charging by equal charging of the accumulator up to present time to determine the final state of charge from the plurality of states of charge.

Claims

1. An accumulator device, comprising:

an accumulator and a state of charge evaluation apparatus for the accumulator;

a terminal voltage measurement unit configured to measure a terminal voltage of the accumulator;

a current measurement unit configured to measure a current flowing in the accumulator;

a first transition measurement unit configured to measure a total charging and discharging amount (Ah), a deterioration degree or an elapsed time from a time of first use of the accumulator, wherein the deterioration degree is an amount of deterioration of accumulator total capacity that varies over time depending on operational conditions for the accumulator;

first multi-dimensional characteristic models in which a plurality of relational models each between the terminal voltage, current and a state of charge during charging are prepared for each of deterioration degrees;

a first selecting means configured to select a characteristic model from among the first multi-dimensional characteristic models in accordance with the total charging and discharging amount (Ah), the deterioration degree or the elapsed time measured by the first transition measurement unit;

a first estimation unit configured to estimate the state of charge from the characteristic model selected by the first selecting means;

a second transition measurement unit configured to measure a transition time from a time of equal charging to a time when the accumulator is fully charged by equal charging or the total charging and discharging amount (Ah) from a time of equal charging to a time when the accumulator is fully charged by equal charging;

second multi-dimensional characteristic models in which a plurality of relational models each between the terminal voltage, current and the state of charge during discharging are prepared for each of the deterioration degrees;

a second selecting means configured to select a characteristic model from among the second multi-dimensional characteristic models in accordance with the total charging and discharging amount (Ah), the deterioration degree or the elapsed time measured by the first transition measurement unit;

a second estimation unit configured to estimate the state of charge from the characteristic model selected by the second selecting means;

a third estimation unit configured to estimate the state of charge from current accumulation;

a weight determining means configured to determine respective weights to be imparted to the outputs of the first estimation unit and the second estimation unit and to an output of the third estimation unit from the transition time or the total charging and discharging amount (Ah) from the time when the accumulator is fully charged by equal charging obtained by the second transition measurement unit; and

a determining means configured to finally determine the state of charge in accordance with the outputs of the first estimation unit, the second estimation unit, and the third estimation unit that are produced in consideration of the weights determined by the weight determining means.

2. A state of charge evaluation method for an accumulator, comprising the steps of:

charging and discharging an accumulator;

preparing, during charging and during discharging of the accumulator, a plurality of charge models for each deterioration degree, each representing a relation between a terminal voltage and a current and a state of charge;

preparing, during charging and during discharging of the accumulator, a plurality of discharge models for each deterioration degree, each representing a relation between a terminal voltage and a current and a state of charge;

selecting one of the plurality of charge models for a time during charging and one of the plurality of discharge models for a time during discharging for the accumulator in accordance with a total charging and discharging amount (Ah), a deterioration degree or an elapsed time of an operation of the accumulator, wherein the deterioration degree is an amount of deterioration of accumulator total capacity that varies over time depending on operational conditions for the accumulator;

estimating the state of charge from current accumulation from time of equal charging;

determining, based on an elapsed time of an operation of the accumulator or a total charging and discharging amount (Ah) from a time of equal charging, weights to be applied to each of the selected one of the plurality of charge models for a time during charging, the selected one of the plurality of discharge models for a time during discharging, and the state of charge from current accumulation from time of equal charging;

determining a final state of charge from the selected one of the plurality of charge models for a time during charging, the selected one of the plurality of discharge models for a time during discharging, and the state of charge from current accumulation from time of equal charging considering the determination of the weights applied to each of the selected one of the plurality of charge models for a time during charging, the selected one of the plurality of discharge models for a time during discharging, and the state of charge from current accumulation from time of equal charging; and

operating the accumulator based on the determination the final state of charge.