Method and apparatus for estimating soc-ocv profile

Patent metadata

Field	Value
Publication number	US-2020150183-A1
Application number	US-201916624057-A
Country	US
Kind code	A1
Filing date	Jan 28, 2019
Priority date	Mar 7, 2018
Publication date	May 14, 2020
Grant date	—

Abstract

An apparatus estimating a state of charge (SOC)-open circuit voltage (OCV) profile, including: a storage unit storing: a beginning of life (BOL) positive electrode (PE) half-cell SOC-OCV profile and available range (AR), a BOL negative electrode (NE) half-cell SOC-OCV profile and AR, and a BOL full-cell SOC-OCV profile and total capacity (TC), and a control unit estimating a full-cell SOC-OCV profile at middle of life (MOL), including: an AR determination module for: calculating an MOL full-cell TC while a secondary battery is fully charged/discharged at MOL, and determining the MOL PE and NE ARs so a ratio of the MOL to the BOL full-cell TCs equals a ratio of the MOL to the BOL PE ARs and a ratio of the MOL to the BOL NE ARs, and a profile management module for: estimating, as an MOL full-cell SOC-OCV profile, a differential profile, and updating the BOL full-cell SOC-OCV profile.

First claim

1 . An apparatus for estimating a state of charge (SOC)-open circuit voltage (OCV) profile, comprising:
a storage unit configured to store:
a beginning of life (BOL) positive electrode half-cell SOC-OCV profile,
a BOL positive electrode available range;
a BOL negative electrode half-cell SOC-OCV profile;
a BOL negative electrode available range;
a BOL full-cell SOC-OCV profile; and
a BOL full-cell total capacity; and
a control unit configured to estimate a full-cell SOC-OCV profile at middle of life (MOL), the control unit including:
an available range determination module configured to:
calculate an MOL full-cell total capacity while a secondary battery is fully charged or fully discharged between a lower limit of discharge voltage and an upper limit of charge voltage when the secondary battery is at MOL; and
determine the MOL positive electrode available range and the MOL negative electrode available range such that a ratio of the MOL full-cell total capacity to the BOL full-cell total capacity is equal to each of a ratio of the MOL positive electrode available range to the BOL positive electrode available range and a ratio of the MOL negative electrode available range to the BOL negative electrode available range; and

a profile management module configured to:
estimate, as an MOL full-cell SOC-OCV profile, a differential profile corresponding to a difference between:
a positive electrode half-cell SOC-OCV profile part corresponding to the MOL positive electrode available range; and
a negative electrode half-cell SOC-OCV profile part corresponding to the MOL negative electrode available range; and

update the BOL full-cell SOC-OCV profile stored in the storage unit to be the estimated MOL full-cell SOC-OCV profile.

2 . The apparatus for estimating an SOC-OCV profile according to claim 1 , wherein the available range determination module is further configured to:
determine, as an invariable value, a maximum allowable SOC value of the MOL positive electrode available range and a minimum allowable SOC value of the MOL negative electrode available range based on the BOL positive electrode available range and the BOL negative electrode available range; and determine the MOL positive electrode available range and the MOL negative electrode available range by calculating a minimum allowable SOC value (p i ) in the BOL positive electrode half-cell SOC-OCV profile and a maximum allowable SOC value (n f ) in the BOL negative electrode half-cell SOC-OCV profile using the following Equation:

p
i

=

p

f
,
0

-

(

p

f
,
0

-

p

i
,
0

)



Q
f

Q

f
,
0





n
f

=

n

i
,
0

+

(

n

f
,
0

-

n

i
,
0

)



Q
f

Q

f
,
0

.

(
Equation
)

where:
p f,0 is the maximum allowable SOC value of the positive electrode half-cell at BOL,
p i,0 is the minimum allowable SOC value of the positive electrode half-cell at BOL,
n f,0 is the maximum allowable SOC value of the negative electrode half-cell at BOL,
n i,0 is the minimum allowable SOC value of the negative electrode half-cell at BOL,
Q f,0 is the total capacity of the full-cell at BOL, and
Q f is the total capacity of the full-cell at MOL.

3 . The apparatus for estimating an SOC-OCV profile according to claim 2 , wherein the available range determination module is further configured to:
calculate an integrated current amount by accumulating and integrating a current of a secondary battery while the secondary battery is fully charged or fully discharged between the lower limit of discharge voltage and the upper limit of charge voltage; and determine the calculated integrated current amount as the MOL full-cell total capacity.

4 . The apparatus for estimating an SOC-OCV profile according to claim 1 , wherein the profile management module is further configured to:
shift the BOL positive electrode half-cell SOC-OCV profile and the BOL negative electrode half-cell SOC-OCV profile r

Assignees

• Lg Chemical Ltd

Inventors

• Yoon Du-Seong
• Lim Jin-Hyung
• Ko Yo-Han
• Kim Yong-Jun
• Kim Hyeong-Seok
• Nam Gi-Min
• Seo Se-Wook
• Joe Won-Tae
• Chae Su-Hyun

Classifications

• G01R31/382

  Arrangements for monitoring battery or accumulator variables, e.g. SoC · CPC title

• G01R31/367 Primary

  Software therefor, e.g. for battery testing using modelling or look-up tables · CPC title

• G01R31/392

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

• G01R31/3842 Primary

  combining voltage and current measurements · CPC title

• G01R31/387

  Determining ampere-hour charge capacity or SoC · CPC title