Electronic device and method for detecting the state of health of a battery

Patent metadata

Field	Value
Publication number	US-11181585-B2
Application number	US-201916550586-A
Country	US
Kind code	B2
Filing date	Aug 26, 2019
Priority date	Apr 11, 2019
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

A method for detecting state of health of a battery of an electronic device is provided. An initial capacity of the battery is obtained when the battery is charged or discharged with a predetermined current and in a predetermined temperature, and a first State of Charge (SOC) value is calculated when the battery is discharged to a discharge cutoff voltage. An available capacity of the battery is calculated with the predetermined current and in the predetermined temperature based on a maximum capacity of the battery, the first State of Charge value, and a second State of Charge value, and a capacity fade is obtain based on a ratio of the available capacity and the initial capacity. Thus, the state of health is detected based on the capacity fade.

First claim

What is claimed is:

1. An electronic device comprising:
a battery;
a storage device;
at least one processor; and
the storage device storing one or more programs that, when executed by the at least one processor, cause the at least one processor to:
obtain an initial capacity of the battery when the battery is charged or discharged with a predetermined current and in a predetermined temperature;
calculate a first State of Charge (SOC) value when the battery is discharged to a discharge cutoff voltage;
obtain a Second State of Charge value by an open-circuit voltage table based on a detected voltage when the battery is fully charged;
calculate an available capacity of the battery with the predetermined current and in the predetermined temperature based on a maximum capacity of the battery, the first State of Charge value, and the second State of Charge value;
obtain a capacity fade of the battery based on a ratio of the available capacity and the initial capacity, and Fading=FCC/FCC 0 , wherein Fading is the capacity fade, FCC is the available capacity, FCC 0 is the initial capacity; and
determine the state of health of the battery based on the capacity fade.

2. The electronic device according to claim 1 , wherein the at least one processor is further caused to:
obtain an open-circuit voltage by an open-circuit voltage table when the first State of Charge value is equal to X, and the X is greater than zero and less than one;
obtain an impedance by an impedance table when the first State of Charge value is equal to X;
calculate a first voltage with the first State of Charge value, and the first voltage is equal to a difference between the open-circuit voltage and a product of the predetermined current and the impedance;
determine whether the first voltage is less than or equal to the discharge cutoff voltage;
obtain the first State of Charge value X when the first voltage is less than or equal to the discharge cutoff voltage; and
update the first State of Charge value as the first State of Charge value X minus a variable value ΔX when the first voltage is greater than the discharge cutoff voltage, and continue to determine whether the first voltage is less than or equal to the discharge cutoff voltage when the first State of Charge value is equal to the first State of Charge value X minus the variable value ΔX, wherein ΔX is greater than zero and less than one.

3. The electronic device according to claim 1 , wherein the maximum capacity of the battery is calculated when the battery is rest for a first time period, and is charged for a second time period, and is still rest for a third time period, or the maximum capacity of the battery is calculated when the battery is rest for a first time period, and is discharged for a second time period, and is still rest for a third time period.

4. The electronic device according to claim 3 , wherein the maximum capacity of the battery is calculated based on formula: Q max =ΔQ/(SOC 2 −SOC 1 ), and Q max is the maximum capacity, ΔQ is capacity change when the battery is charged or discharged for the second time period, SOC 1 is the State of Charge value when the battery being rest for the first time period, and SOC 2 is the State of Charge value when the battery being rest for the third time period.

5. The electronic device according to claim 4 , wherein the capacity change is calculated by:
dividing the second time period based on a predetermined time period;
detecting the current when the battery is discharged for each predetermined time period;
obtaining a discharge capacity when the battery is charged or discharged for each predetermined time period, and the discharge capacity is equal to the detected current minus the predetermined time period; and
obtaining the capacity change by accumulating the discharge capacity.

6. The electronic device according to claim 1 , wherein the available capacity is calculated based on formula: FCC=Q max ×(ASOC_full−ASOC_end)/100%, and FCC is the available capacity, Q max is the maximum capacity, ASOC_full is the second State of Charge value and ASOC_end is the first State of Charge value.

7. The electronic device according to claim 6 , wherein the second State of Charge value is obtained by an open-circuit voltage table based on a voltage, and the voltage is detected when the battery is fully charged and enters a resting state.

8. The electronic device according to claim 7 , wherein the state of health of the battery is determined by:
setting the state of health equal to the capacity fade;
calculating the state of health based on formula: SOH=(Fading−EOL)/(100%−EOL), and SOH is the state of health, Fading is the capacity fade of the battery, and EOL is a predetermined capacity fade.

9. A battery health detecting method applied in an electronic device, the electronic device comprising a battery, the method comprising:
obtaining an initial capacity of the battery when the battery is charged or discharged with a predetermined current and in a predetermined temperature;
calculating a first State of Charge value when the battery is discharged to a discharge cutoff voltage;
obtaining a Second State of Charge value by an open-circuit voltage table based on a detected voltage when the battery is fully charged;
calculating an available capacity of the battery with the predetermined current and in the predetermined temperature based on a maximum capacity of the battery, the first State of Charge value, and the second State of Charge value;
obtaining a capacity fade of the battery based on a ratio of the available capacity and the initial capacity, and Fading=FCC/FCC 0 , wherein Fading is the capacity fade, FCC is the available capacity, FCC 0 is the initial capacity; and determining the state of health based on the capacity fade.

10. The method according to claim 9 , wherein the method further comprising:
obtaining an open-circuit voltage by an open-circuit voltage table when the first State of Charge value is equal to X, and the X is greater than zero and less than one;
obtaining an impedance by an impedance table when the first State of Charge value is equal to X;
calculating a first voltage with the first State of Charge value, and the first voltage is equal to a difference between the open-circuit voltage and a product of the predetermined current and the impedance;
determining whether the first voltage is less than or equal to the discharge cutoff voltage;
obtaining the first State of Charge value X when the first voltage is less than or equal to the discharge cutoff voltage; and
updating the first State of Charge value as the first State of Charge value X minus a variable value when the first voltage is greater than the discharge cutoff voltage, and continue to determine whether the first voltage is less than or equal to the discharge cutoff voltage when the first State of Charge value is equal to the first State of Charge value X minus the variable value ΔX, wherein ΔX is greater than zero and less than one.

11. The method according to claim 9 , wherein the maximum capacity of the battery is calculated when the battery is rest for a first time period, and is charged for a second time period, and is still rest for a third time period, or the maximum capacity of the battery is calculated when the battery is rest for a first time period, and is discharged for a second time period, and is still rest for a third time period.

12. The method according to claim 11 , wherein the maximum capacity is of the battery calculated based on formula: Q max =ΔQ/(SOC 2 −SOC 1 ) and Q max is the maximum capacity, ΔQ is capacity change when the battery is charged or discharged for the

Assignees

• Dongguan Amperex Tech Ltd

Inventors

• Yao Yuan

Classifications

• G01R31/3842 Primary

  combining voltage and current measurements · CPC title

• G01R31/392 Primary

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