Estimation of lithium-ion battery capacity as function of state-of-lithiation swing
A method includes controlling operation of a vehicle in response to an estimation of a capacity loss and capacity of a lithium-ion battery module of the vehicle. The estimation is a function that includes a state-of-lithiation swing and fracture of a solid-electrolyte interphase of an electrode of the lithium-ion battery module. The methodology can be implemented in a vehicle that includes a lithium-ion battery module and a controller that controls operation of the vehicle in response to such an estimation.
1. A method comprising:
controlling operation of a vehicle in response to an estimation of a capacity loss and a capacity of a lithium-ion battery module of the vehicle as a function that includes a state-of-lithiation swing and fracture of solid-electrolyte interphase of an electrode of the lithium-ion battery module, the capacity is represented by Q n , and the function is:
Q
n
=
R
A
C
×
(
Δ
SOL
0
-
(
n
-
1
)
a
(
Δ
SOL
0
)
2
+
(
n
-
1
)
(
n
-
2
)
a
2
(
Δ
SOL
0
)
3
-
∑
i
=
3
n
(
i
-
2
)
(
3
i
-
8
)
a
3
(
Δ
SOL
0
)
4
)
wherein,
R AC is an initial ratio of anode electrode capacity of the lithium-ion battery module to initial cell capacity in a given voltage range,
ΔSOL 0 is an initial state of lithiation,
n is a number of charge-discharge cycles,
a is a constant of the lithium-ion battery module, and
i is a polynomial order derivative.
2. The method as recited in claim 1 , further comprising storing the capacity in a memory module of the vehicle in place of a prior capacity of the lithium-ion battery module.
3. The method as recited in claim 1 , wherein the electrode is a negative electrode of the lithium-ion battery module.
4. The method as recited in claim 1 , wherein the electrode includes a graphite core surrounded by a shell of the solid-electrolyte interphase.
5. A vehicle comprising:
a lithium-ion battery module; and
a controller controlling operation of the vehicle in response to estimation of a capacity loss and a capacity of the lithium-ion battery module as a function that includes a state-of-lithiation swing and fracture of a solid-electrolyte interphase of an electrode of the lithium-ion battery module, the capacity is represented by Q n , and the function is:
Q
n
=
R
A
C
×
(
Δ
SOL
0
-
(
n
-
1
)
a
(
Δ
SOL
0
)
2
+
(
n
-
1
)
(
n
-
2
)
a
2
(
Δ
SOL
0
)
3
-
∑
i
=
3
n
(
i
-
2
)
(
3
i
-
8
)
a
3
(
Δ
SOL
0
)
4
)
wherein,
R AC is an initial ratio of anode electrode capacity of the lithium-ion battery module to initial cell capacity in a given voltage range,
ΔSOL 0 is an initial state of lithiation,
n is a number of charge-discharge cycles,
a is a constant of the lithium-ion battery module, and
i is a polynomial order derivative.
6. The vehicle as recited in claim 5 , further comprising a memory module configured for storing the capacity in place of a prior capacity of the lithium-ion battery module.
7. The vehicle as recited in claim 5 , wherein the electrode is a negative electrode of the lithium-ion battery module.
8. The vehicle as recited in claim 5 , wherein the electrode includes a graphite core surrounded by a shell of the solid-electrolyte interphase.
9. A method comprising:
estimating an instant capacity of a lithium-ion battery module of a vehicle as a function that includes a state-of-lithiation swing and fracture of solid-electrolyte interphase of an electrode of the lithium-ion battery module;
storing the instant capacity in a memory storage module of the vehicle; and
controlling operation of the vehicle in response to the instant capacity stored in the memory storage module, wherein the capacity is represented by Q n , and the function is:
Q
n
=
R
A
C
×
(
Δ
SOL
0
-
(
n
-
1
)
a
(
Δ
SOL
0
)
2
+
(
n
-
1
)
(
n
-
2
)
a
2
(
Δ
SOL
0
)
3
-
∑
i
=
3
n
(
i
-
2
)
(
3
i
-
8
)
a
3
(
Δ
SOL
0
)
4
)
wherein,
R AC is an initial ratio of anode electric capacity of the lithium-ion battery module to initial cell capacity in a given voltage range,
ΔSOL 0 is an initial state lithiation,
n is a number of charge-discharge cycles,
a is a constant of the lithium-ion battery module, and
i is a polynomial order derivative.
10. The method as recited in claim 1 , wherein the controlling of the operation of the vehicle includes controlling a vehicle event that draws current from the lithium-ion battery module.
11. The method as recited in claim 1 , wherein the controlling of the operation of the vehicle includes displaying information based upon the capacity and the capacity loss.
12. The method as recited in claim 11 , wherein the information is a battery health indication.
13. The vehicle as recited in claim 5 , wherein the controlling of the operation of the vehicle includes controlling a vehicle event that draws current from the lithium-ion battery module.
14. The vehicle as recited in claim 5 , wherein the controlling of the operation of the vehicle includes displaying information based upon the capacity and the capacity loss.
15. The vehicle as recited in claim 14 , wherein the information is a battery health indication.