Method of Controlling Secondary Battery

• US 20160118816A1
• Filed: 10/15/2015
• Published: 04/28/2016
• Est. Priority Date: 10/17/2014
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: HONKURA, Kohei
• Granted Patent: US 10,224,731 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 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 Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H02J 7/007 Regulation of charging or discharging current or voltage
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A positive electrode potential and a negative electrode potential during charge or discharge of a secondary battery are determined, based on potentials of a positive electrode and a negative electrode in an open circuit state corresponding to a SOC of the secondary battery, and internal resistances of the positive electrode and the negative electrode corresponding to the SOC of the secondary battery, and a current of the secondary battery is controlled such that the positive electrode potential and the negative electrode potential fall within a predetermined range.

Claims

1. A method of controlling a secondary battery, the method comprising:

determining at least one of a positive electrode potential and a negative electrode potential during charge or discharge of the secondary battery, based on potentials of a positive electrode and a negative electrode in an open circuit state corresponding to a SOC of the secondary battery, and internal resistances of the positive electrode and the negative electrode corresponding to the SOC of the secondary battery, and controlling a current, an input, or an output of the secondary battery such that at least one of the positive electrode potential and the negative electrode potential falls within a predetermined range.

2. The method of controlling a secondary battery according to claim 1, wherein the current, the input, or the output of the secondary battery is controlled such that an index calculated using a charge time or discharge time of the secondary battery, and at least one of the positive electrode potential and the negative electrode potential during charge or discharge falls within the predetermined range.

3. The method of controlling a secondary battery according to claim 1, wherein the internal resistances of the positive electrode and the negative electrode of the secondary battery are input as a data table or a function associated with the SOC of the secondary battery, and at least one of the positive electrode potential and the negative electrode potential is determined according to the SOC of the secondary battery, based on the data table or the function.

4. The method of controlling a secondary battery according to claim 1, wherein a data table or a function indicating correspondence between the SOC of the secondary battery and the internal resistances of the positive electrode and the negative electrode is generated and input by comparison between reference data tables or reference functions indicating a relationship between a SOC and the internal resistance of the positive electrode alone and of the negative electrode alone, and a data table or a function indicating correspondence between the SOC of the secondary battery and an internal resistance of the secondary battery, and

at least one of the positive electrode potential and the negative electrode potential is determined according to the SOC of the secondary battery, based on the data table or the function indicating correspondence between the SOC of the secondary battery and the internal resistances of the positive electrode and the negative electrode.

5. The method of controlling a secondary battery according to claim 1, wherein a reference data table or a reference function indicating a relationship between a SOC and the internal resistance of the positive electrode alone is a combination or a relational expression of a SOC xp of the positive electrode alone and an internal resistance Rp of the positive electrode alone, a reference data table or a reference function indicating a relationship between a SOC and the internal resistance of the negative electrode alone is a combination or a relational expression of a SOC xn of the negative electrode alone and an internal resistance Rn of the negative electrode alone, a data table or a function indicating correspondence between the SOC of the secondary battery and an internal resistance of the secondary battery is a combination or a relational expression of a SOC x of the secondary battery and an internal resistance R of the secondary battery, and by performing of comparison between the reference data tables or reference functions of the positive electrode alone and the negative electrode alone, and the data table or the function of the secondary battery, using:

x=xp*mp+dp=xn*mn+dn, and

R(x)=r0+ap*Rp(xp)+an*Rn(xn),

using coefficients mp, mn, dp, dn, r0, ap, and an,

values of the coefficients mp, mn, dp, dn, r0, ap, and an are determined, and

a combination or a relational expression of the SOC x of the secondary battery, an internal resistance ap*rp of the positive electrode, and an internal resistance an*rn of the negative electrode, the combination or the relational expression being a data table or a function indicating correspondence between the SOC of the secondary battery and the internal resistances of the positive electrode and the negative electrode, is generated and input, and

at least one of the positive electrode potential and the negative electrode potential is determined according to the SOC of the secondary battery, based on the data table or the function indicating correspondence between the SOC of the secondary battery and the internal resistances of the positive electrode and the negative electrode.