Remaining battery life prediction device and battery pack

Patent metadata

Field	Value
Publication number	US-2016149272-A1
Application number	US-201514943417-A
Country	US
Kind code	A1
Filing date	Nov 17, 2015
Priority date	Nov 20, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

Provided is a low-cost battery pack capable of predicting a remaining battery life of a rechargeable battery with high accuracy. A remaining battery life prediction device includes: a voltage detection unit configured to measure a battery voltage and a battery temperature of the battery; a calculation unit configured to perform predictive calculation of a remaining battery life based on the battery voltage and the battery temperature; and a control unit configured to control operation of the remaining battery life prediction device and the calculation unit, the remaining battery life prediction device being configured to predict a remaining life of the battery with a calculation flow of for a predetermined time period, recursively calculating the remaining battery life based on the measured battery voltage and battery temperature and an internal impedance of the battery in a battery equivalent circuit.

First claim

What is claimed is:

1 . A remaining battery life prediction device configured to measure a voltage and a temperature of a battery, to thereby predict a remaining life of the battery, the remaining battery life prediction device comprising:
a voltage detection unit configured to measure a battery voltage and a battery temperature of the battery; a calculation unit configured to perform predictive calculation of a remaining battery life based on the battery voltage and the battery temperature; and a control unit configured to control operation of the remaining battery life prediction device and the calculation unit, the remaining battery life prediction device being further configured to predict the remaining life of the battery with a calculation flow of, for a predetermined time period, recursively calculating the remaining battery life based on the measured battery voltage and battery temperature and an internal impedance of the battery in a battery equivalent circuit.

2 . A remaining battery life prediction device according to claim 1 , wherein the battery equivalent circuit comprises:
a voltage source configured to output a battery open circuit voltage; a first resistor connected to the voltage source in series; and the internal impedance that is connected to the first resistor in series and includes an impedance element formed by a resistor and a capacitor connected in parallel to each other.

3 . A remaining battery life prediction device according to claim 2 , wherein the calculation flow comprises:
measuring an initial battery terminal voltage and an initial battery temperature when the battery is mounted; calculating an initial remaining battery life based on the initial battery terminal voltage and the initial battery temperature; measuring a battery terminal voltage and a battery temperature for the predetermined time period; calculating, for the predetermined time period, the remaining battery life and the battery open circuit voltage based on a currently measured battery terminal voltage and battery temperature, a last measured battery terminal voltage and battery temperature, and a last calculated remaining battery life and battery open circuit voltage; and holding, in a storage device, the currently measured battery terminal voltage and battery temperature and the currently calculated remaining battery life and battery open circuit voltage for the predetermined time period.

4 . A remaining battery life prediction device according to claim 2 , wherein the internal impedance in the battery equivalent circuit comprises a plurality of the impedance elements connected in series.

5 . A remaining battery life prediction device according to claim 4 , wherein the calculation flow comprises:
measuring an initial battery terminal voltage and an initial battery temperature when the battery is mounted; calculating an initial remaining battery life based on the initial battery terminal voltage and the initial battery temperature; setting an initial value to a voltage applied to the impedance element; measuring a battery terminal voltage and a battery temperature for the predetermined time period; calculating, for the predetermined time period, the remaining battery life and the voltage applied to the impedance element based on a currently measured battery terminal voltage and battery temperature and a last calculated remaining battery life and voltage applied to the impedance element; and holding, in a storage device, the currently calculated remaining battery life and voltage applied to the impedance element for the predetermined time period.

6 . A remaining battery life prediction device according to claim 1 , wherein the predetermined time period for which the predictive calculation of the remaining battery life is performed is 2 N seconds, where N is an integer.

7 . A battery pack, comprising:
a MOSFET configured to control a load current and a battery connected in series between a first external terminal and a second external terminal to which a load is connected; a control circuit that is connected to both ends of the battery and is configured to monitor a state of the battery and control the MOSFET; and the remaining battery life prediction device of claim 1 , which is connected to both the ends of the battery and is configured to predict a remaining life of the battery.

Assignees

• Seiko Instr Inc

Inventors

• Imaizumi Eiki

Classifications

• H01M10/48 Primary

  Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) · CPC title

• G01R31/392

  Determining battery ageing or deterioration, e.g. state of health · CPC title

• G01R31/389

  Measuring internal impedance, internal conductance or related variables · CPC title

• G01R31/3835

  involving only voltage measurements · CPC title

• H01M50/569

  Constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals (battery terminal connectors with integrated measuring arrangements G01R31/364) · CPC title