Battery, electric apparatus, and charging method and apparatus for battery
Embodiments of this application provide a battery, an electric apparatus, a battery charging method, and an apparatus for charging a battery. The technical solutions provided by the application belong to the field of battery charging technologies. In this application, a historical capacity decline of the battery is determined based on capacity decline in a k-th discharging process and a capacity decline in previous k−1 discharging processes, a full charge voltage in an m-th charging process is determined based on the historical capacity decline, and then m-th charging is performed, based on the determined full charge voltage in the m-th charging process, on the battery. Because the historical capacity decline increases constantly with the use of the battery, in this application, the full charge voltage of the battery in the charging process is increased constantly, or the full charge voltage is opened up constantly.
1. A method for charging a battery, comprising:
obtaining a capacity decline of the battery in a k-th discharging process, wherein the capacity decline is a change of state of health (SOH) of the battery in the k-th discharging process, wherein a start time of the k-th discharging process is an end time of an (m−1)-th charging process of the battery, and an end time of the k-th discharging process is a start time of an m-th charging process of the battery, wherein k is an integer greater than 1, and m is an integer greater than or equal to 1;
obtaining, based on the capacity decline in the k-th discharging process and capacity declines in previous k−1 discharging processes, a historical capacity decline of the battery, wherein the historical capacity decline is a sum of the capacity declines in the k discharging processes;
determining, based on a nominal capacity of the battery and the historical capacity decline of the battery, a full charge voltage of the battery in the m-th charging process; and
performing, based on the full charge voltage of the battery in the m-th charging process, the m-th charging process on the battery;
wherein obtaining the capacity decline of the battery in the k-th discharging process comprises:
obtaining discharging parameters of the battery in the k-th discharging process, wherein the discharging parameters comprise an average current, an average temperature, a battery capacity interval, and a cumulative throughput, wherein an upper limit of the battery capacity interval is a battery capacity of the battery at the end of the (m−1)-th charging process, and a lower limit of the battery capacity interval is a battery capacity of the battery at the beginning of the m-th charging process; and
determining, based on the average current, the average temperature, the battery capacity interval, and the cumulative throughput of the battery in the k-th discharging process, the capacity decline in the k-th discharging process according to the following equation:
Δ
SOH
k
=
C
a
·
e
-
Eb
R
(
1
T
-
1
T
0
)
·
f
(
SOC
upk
)
·
f
(
SOC
lowk
)
·
f
(
C
k
)
·
Δ
C
k
z
wherein ΔSOH k is the capacity decline in the k-th discharging process, C a , Eb and z are predetermined constants of the battery, R is 8.314, T is the average temperature, T 0 is 298.15 degrees kelvin, SOC upk is the upper limit of the battery capacity interval in the k-th discharging process, SOC lowk is the lower limit of the battery capacity interval in the k-th discharging process, C k is the average current in the k-th discharging process, ΔC k is the cumulative throughput in the k-th discharging process, f(SOC upk ) is a function associated with the upper limit of the battery capacity interval in the k-th discharging process, f(SOC lowk ) is a function associated with the lower limit of the battery capacity interval in the k-th discharging process, and f(C k ) is a function associated with the average current in the k-th discharging process.
2. The method according to claim 1 , wherein determining, based on a nominal capacity of the battery and the historical capacity decline, a full charge voltage of the battery in the m-th charging process comprises:
obtaining, based on the nominal capacity and the historical capacity decline, a capacity that the battery needs to reach in the m-th charging process; and
obtaining, based on the capacity that the battery needs to reach in the m-th charging process, the full charge voltage of the battery in the m-th charging process.
3. The method according to claim 1 , wherein determining, based on a nominal capacity of the battery and the historical capacity decline, a full charge voltage of the battery in the m-th charging process comprises:
under the condition that the historical capacity decline is greater than or equal to an m-th preset threshold, determining, based on the nominal capacity of the battery and the historical capacity decline, the full charge voltage of the battery in the m-th charging process.
4. The method according to claim 1 , wherein performing, based on the full charge voltage of the battery in the m-th charging process, the m-th charging process on the battery comprises:
monitoring an actual voltage of the battery in the m-th charging process on the battery;
determining whether the actual voltage has risen to the full charge voltage of the battery in the m-th charging process; and
stopping charging the battery when it is determined that the actual voltage has risen to the full charge voltage of the battery in the m-th charging process.
5. An apparatus for charging a battery, comprising:
a processor and a charging circuit;
wherein the processor is configured to:
obtain a capacity decline of the battery in a k-th discharging process, wherein the capacity decline is a change of state of health (SOH) of the battery in the k-th discharging process, wherein a start time of the k-th discharging process is an end time of an (m−1)-th charging process of the battery, and an end time of the k-th discharging process is a start time of an m-th charging process of the battery, wherein k is an integer greater than 1, and m is an integer greater than or equal to 1;
obtain, based on the capacity decline in the k-th discharging process and capacity declines in previous k−1 discharging processes, a historical capacity decline of the battery, wherein the historical capacity decline is a sum of the capacity declines in the k discharging processes; and
determine, based on a nominal capacity of the battery and the historical capacity decline of the battery, a full charge voltage of the battery in the m-th charging process; and
wherein the charging circuit is configured to perform, based on the full charge voltage of the battery in the m-th charging process, the m-th charging process on the battery;
wherein in obtaining the capacity decline of the battery in the k-th discharging process, the processor is configured to:
obtain discharging parameters of the battery in the k-th discharging process, wherein the discharging parameters comprise an average current, an average temperature a battery capacity interval, and a cumulative throughput, wherein an upper limit of the battery capacity interval is a battery capacity of the battery at the end of the (m−1)-th charging process and a lower limit of the battery capacity interval is a battery capacity of the battery at the beginning of the m-th charging process; and
determine, based on the average current, the average temperature, the battery capacity interval, and the cumulative throughput of the battery in the k-th discharging process, the capacity decline in the k-th discharging process according to the following equation:
Δ
SOH
k
=
C
a
·
e
-
Eb
R
(
1
T
-
1
T
0
)
·
f
(
SOC
upk
)
·
f
(
SOC
lowk
)
·
f
(
C
k
)
·
Δ
C
k
z
wherein ΔSOH k is the capacity decline in the k-th discharging process, C a , Eb and z are predetermined constants of the battery, R is 8.314, T is the average temperature, T 0 is 298.15 degrees kelvin, SOC upk is the upper limit of the battery capacity interval in the k-th discharging process, SOC lowk is the lower limit of the battery capacity interval in the k-th discharging process, C k is the average current in the k-th discharging process, ΔC k is the cumulative throughput in the k-th discharging process, f(SOC upk ) is a function associated with the upper limit of the battery capacity interval in the k-th discharging process, f(SOC lowk ) is a function associated with the lower limit of the battery capacity interval in the k-th discharging process, and f(C k ) is a function associated with the average current in the k-th discharging process.
6. The apparatus according to claim 5 , wherein in determining, based on a nominal capacity of the battery and the historical capacity decline, a full charge voltage of the battery in the m-th charging process, the processor is configured to:
obtain, based on the nominal capacity and the historical capacity decline, a capacity that the battery needs to reach in the m-th charging process; and
obtain, based on the capacity that the battery needs to reach in the m-th charging process, the full charge voltage of the battery in the m-th charging process.
7. The apparatus according to claim 5 , wherein in determining, based on a nominal capacity of the battery and the historical capacity decline, a full charge voltage of the battery in the m-th charging process, the processor is configured to:
under the condition that the historical capacity decline is greater than or equal to an m-th preset threshold, determine, based on the nominal capacity of the battery and the historical capacity decline, the full charge voltage of the battery in the m-th charging process.
8. The apparatus according to claim 5 , wherein in performing, based on the full charge voltage of the battery in the m-th charging process, the m-th charging process on the battery, the charging circuit is configured to:
monitor an actual voltage of the battery in the m-th charging process on the battery;
determine whether the actual voltage has risen to the full charge voltage of the battery in the m-th charging process; and
stop charging the battery when it is determined that the actual voltage has risen to the full charge voltage of the battery in the m-th charging process.
9. A battery, comprising a charging apparatus, wherein the charging apparatus is configured to:
obtain a capacity decline of the battery in a k-th discharging process, wherein the capacity decline is a change of state of health (SOH) of the battery in the k-th discharging process, wherein a start time of the k-th discharging process is an end time of an (m−1)-th charging process of the battery, and an end time of the k-th discharging process is a start time of an m-th charging process of the battery, wherein k is an integer greater than 1, and m is an integer greater than or equal to 1;
obtain, based on the capacity decline in the k-th discharging process and capacity declines in previous k−1 discharging processes, a historical capacity decline of the battery, wherein the historical capacity decline is a sum of the capacity declines in the k discharging processes;
determine, based on a nominal capacity of the battery and the historical capacity decline of the battery, a full charge voltage of the battery in the m-th charging process; and
perform, based on the full charge voltage of the battery in the m-th charging process, the m-th charging process on the battery;
wherein in obtaining the capacity decline of the battery in the k-th discharging process, the charging apparatus is configured to:
obtain discharging parameters of the battery in the k-th discharging process, wherein the discharging parameters comprise an average current an average temperature, a battery capacity interval, and a cumulative throughput, wherein an upper limit of the battery capacity interval is a battery capacity of the battery at the end of the (m−1)-th charging process, and a lower limit of the battery capacity interval is a battery capacity of the battery at the beginning of the m-th charging process; and
determine, based on the average current, the average temperature, the battery capacity interval, and the cumulative throughput of the battery in the k-th discharging process, the capacity decline in the k-th discharging process according to the following equation:
Δ
SOH
k
=
C
a
·
e
-
Eb
R
(
1
T
-
1
T
0
)
·
f
(
SOC
upk
)
·
f
(
SOC
lowk
)
·
f
(
C
k
)
·
Δ
C
k
z
wherein ΔSOH k is the capacity decline in the k-th discharging process, C a , Eb and z are predetermined constants of the battery, R is 8.314, T is the average temperature, T 0 is 298.15 degrees kelvin, SOC upk is the upper limit of the battery capacity interval in the k-th discharging process, SOC lowk is the lower limit of the battery capacity interval in the k-th discharging process, C k is the average current in the k-th discharging process, ΔC k is the cumulative throughput in the k-th discharging process, f(SOC upk ) is a function associated with the upper limit of the battery capacity interval in the k-th discharging process, f(SOC lowk ) is a function associated with the lower limit of the battery capacity interval in the k-th discharging process, and f(C k ) is a function associated with the average current in the k-th discharging process.
10. The battery according to claim 9 , wherein in determining, based on a nominal capacity of the battery and the historical capacity decline, a full charge voltage of the battery in the m-th charging process, the charging apparatus is configured to:
obtain, based on the nominal capacity and the historical capacity decline, a capacity that the battery needs to reach in the m-th charging process; and
obtain, based on the capacity that the battery needs to reach in the m-th charging process, the full charge voltage of the battery in the m-th charging process.
11. The battery according to claim 9 , wherein in determining, based on a nominal capacity of the battery and the historical capacity decline, a full charge voltage of the battery in the m-th charging process, the charging apparatus is configured to:
under the condition that the historical capacity decline is greater than or equal to an m-th preset threshold, determine, based on the nominal capacity of the battery and the historical capacity decline, the full charge voltage of the battery in the m-th charging process.
12. The battery according to claim 9 , wherein in performing, based on the full charge voltage of the battery in the m-th charging process, the m-th charging process on the battery, the charging apparatus is configured to:
monitor an actual voltage of the battery in the m-th charging process on the battery;
determine whether the actual voltage has risen to the full charge voltage of the battery in the m-th charging process; and
stop charging the battery when it is determined that the actual voltage has risen to the full charge voltage of the battery in the m-th charging process.