Method for estimating parameter of equivalent circuit model for battery, and battery management system

Patent metadata

Field	Value
Publication number	US-11269013-B2
Application number	US-201916616622-A
Country	US
Kind code	B2
Filing date	Jan 15, 2019
Priority date	Feb 1, 2018
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

Provided is a method and a battery management system for estimating the parameters of an equivalent circuit model. The equivalent circuit model includes a first resistor, a second resistor connected in series to the first resistor and a capacitor connected in parallel to the second resistor. The method according to an embodiment of the present disclosure individually estimates the resistance of the first resistor and the resistance of the second resistor based on a first number of terminal voltages and a first number of currents measured in a sequential order at each time step in a sliding time window having a predefined size, and stores data indicating the estimated results in the memory.

First claim

What is claimed is:

1. A method for estimating parameters of an equivalent circuit model for a battery, the equivalent circuit model including a first resistor, a second resistor connected in series to the first resistor, and a capacitor connected in parallel to the second resistor, the method comprising:
reading, from a memory, measurement data indicating a first number of terminal voltages and a first number of currents measured in a sequential order at each time step in a sliding time window having a predefined size;
calculating a voltage variation of a current time step based on a terminal voltage measured at the current time step and a terminal voltage measured at a previous time step included in the first number of terminal voltages;
calculating a current variation of the current time step based on a current measured at the current time step and a current measured at the previous time step included in the first number of currents;
estimating a resistance of the first resistor at the current time step based on a resistance of the first resistor estimated at the previous time step, the voltage variation, and the current variation;
determining whether the first number of currents satisfy a second data filtering condition;
calculating a measured voltage vector based on the first number of terminal voltages and a measured current vector based on the first number of currents, when the second data filtering condition is satisfied; and
estimating a resistance of the second resistor at the current time step based on the measured voltage vector, the measured current vector, the resistance of the first resistor estimated at the current time step, and the resistance of the second resistor estimated at the previous time step.

2. The method according to claim 1 , further comprising:
determining whether the voltage variation and the current variation satisfy a first data filtering condition,
wherein estimating the resistance of the first resistor at the current time step is performed when the first data filtering condition is satisfied.

3. The method according to claim 2 , further comprising setting the resistance of the first resistor estimated at the previous time step as the resistance of the first resistor estimated at the current time step, when the first data filtering condition is not satisfied.

4. The method according to claim 2 , wherein the first data filtering condition is satisfied when:
an absolute value of the current variation is larger than a first threshold; and
a multiplication value of the voltage variation and the current variation is a positive value.

5. The method according to claim 1 , wherein estimating the resistance of the first resistor at the current time step uses a recursive least square algorithm.

6. The method according to claim 5 , wherein the recursive least square algorithm includes the following Equations 1 and 2:

⁢

P
1

⁡

(
n
)

=

1
λ

⁢

{

P
1

⁡

(

n
-
1

)

-

P
1

⁡

(

n
-
1

)

2

⁢
Δ
⁢

⁢

I
⁡

(
n
)

2

λ
+

P
1

⁡

(

n
-
1

)

⁢
Δ
⁢

⁢

I
⁡

(
n
)

2

}

<

⁢
Equation
⁢

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Ahn Hyoung Jun

Classifications

• H01M10/48

  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 title

• G01R19/30

  Measuring the maximum or the minimum value of current or voltage reached in a time interval (G01R19/04 takes precedence) · CPC title

• G01R19/12

  Measuring rate of change · CPC title

• G01R27/2605

  Measuring capacitance (capacitive sensors G01D5/24) · CPC title

• G01R31/374

  with means for correcting the measurement for temperature or ageing · CPC title