ESTIMATING CONDITION OF BATTERY, RELATED SYSTEM AND VEHICLE

• US 20140214349A1
• Filed: 01/30/2014
• Published: 07/31/2014
• Est. Priority Date: 01/31/2013
• Status: Active Grant

• Current Assignee: Utopus Insights, Inc. (Vestas Wind Systems A/S)
• Original Assignee: International Business Machines Corporation
• Inventors: Dong, Jin, Shao, Jin Yan, Tian, Qi Ming, Xie, Ming, Yin, Wen Jun, Zhao, Li Li, Gammons, Carlton, Yu, Hong Guang
• Granted Patent: US 10,732,228 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health

Abstract

An apparatus for estimating a condition of a battery includes a mode identifying unit configured to identify a usage mode of the battery during a period of time and its corresponding attenuation curve, according to recorded data on battery usage, stored usage modes of the battery and attenuation curves corresponding to the various usage modes, the attenuation curve representing a change of a fully charged capacity of the battery with battery usage; and a condition estimating unit configured to calculate battery degradation according to the recorded data, the identified usage mode and its corresponding attenuation curve, the degradation representing a quantity of the fully charged capacity of the battery that is reduced over the battery usage. The condition of the battery is estimated so as to rationally judge the residual value of the battery in operation.

Claims

1. A method for estimating a condition of a battery, comprising:

identifying a usage mode of the battery during a period of time and a corresponding attenuation curve, according to recorded data on battery usage and stored usage modes of the battery and attenuation curves corresponding to the stored usage modes, wherein each attenuation curve represents a change of a fully charged capacity of the battery over battery usage; and

calculating a degradation of the battery according to the recorded data and the identified usage mode and its corresponding attenuation curve, the degradation representing a quantity of the fully charged capacity of the battery that is reduced over the battery usage.

2. The method of claim 1, wherein, the recorded data on battery usage comprises any one or more of:

a start time and an end time of battery usage, an initial voltage and a final voltage of battery usage, a charge current, a charge level, a temperature, a discharge current, an idle time, and a depth of discharge representing quantity of electricity energy of the battery before idle.

3. The method of claim 2, wherein, in the case that the identified usage mode is a charging mode, the degradation of the battery is calculated according to a charge level L, a charging capacity δ

e, a temperature T, an initial charging voltage U_a and a final charging voltage U_b as follows;

calculating the charging capacity δ

e during the period of time according to the start time of charging t_a, the end time of charging t_b and the charge current I_c of the period of time;

searching the stored charging modes of the battery and attenuation curves corresponding to the charging modes for a set {M_a} of all charging modes matching the charge level L, the initial charging voltage U_a and the temperature T, and a set {M_b} of all charging modes matching the charge level L, the final charging voltage U_b and the temperature T;

searching the set {M_b} and the set {M_a} respectively for a mode m_b and a mode m_a such that a difference between the charging capacity of the mode m_b and the charging capacity of the mode m_a is equal to δ

e;

according to attenuation curves f_a and f_b corresponding to the modes m_a and m_b, calculating slopes s_a and s_b of the attenuation curves f_a and f_b at a point c=c_a respectively, wherein c_a represents a fully charged capacity of the battery at the time t_a, and s_a and s_b respectively represent degradation caused by charging the battery from a standard cut-off voltage to the initial charging voltage U_a and the final charging voltage U_b under a condition of the charge current I_c and the temperature T; and

calculating battery degradation s=s_b−

s_a during the period of time, and obtaining the fully charged capacity c_b=c_a+s of the battery at the time t_b.

4. The method of claim 2, wherein in the case that the identified usage mode is a discharging mode, the degradation of the battery is calculated according to a discharge current I_d, a temperature T, an initial discharging voltage U_a and a final discharging voltage U_b as follows:

searching the stored discharging modes of the battery and attenuation curves corresponding to the discharging modes for a discharging mode m_a matching the discharge current I_d, the initial discharging voltage U_a and the temperature T, and a discharging mode m_b matching the discharge current I_d, the final discharging voltage U_b and the temperature T;

according to attenuation curves f_a and f_b corresponding to the modes m_a and m_b, calculating slopes s_a and s_b of the attenuation curves f_a and f_b at a point c=c_a respectively, wherein c_a represents a fully charged capacity of the battery at the time t_a, and s_a and s_b respectively represent degradation caused by discharging the battery from the initial discharging voltage U_a and the final discharging voltage U_b to a standard cut-off voltage under the condition of the discharge current I_d and the temperature T; and

calculating battery degradation s=s_b−

s_a during the period of time, and obtaining the fully charged capacity c_b=c_a+s of the battery at the time t_b.

5. The method of claim 2, wherein, in the case that the identified usage mode is an idle mode, the degradation of the battery is calculated according to a depth of discharge d and the temperature T as follows:

searching the stored idle modes of the battery and attenuation curves corresponding to the idle modes for a discharging mode m matching the depth of discharge d and the temperature T;

according to an attenuation curve f corresponding to the mode m, calculating a slope s of the attenuation curve f at a point c=c_a, wherein c_a represents a fully charged capacity of the battery at the time t_a, and s represents battery degradation during the period of time; and

calculating the fully charged capacity

6. The method of claim 3, wherein, estimating the condition of the battery further comprises:

calculating a rate of depreciation

7. The method of claim 3, wherein, estimating the condition of the battery further comprises:

calculating the remaining quantity of electricity energy of the battery according to the stored usage modes of battery and efficiencies corresponding to the usage modes, wherein the remaining quantity of electricity energy of the battery is obtained by accumulating changes of the remaining quantity of electricity energy caused by battery usage on the basis of a factory electricity energy e₀ of the battery.

8. The method of claim 7, wherein, in the case that the identified usage mode is a charging mode, the remaining quantity of electricity energy is calculated as follows:

calculating the charging capacity δ

e during the period of time according to the start time of charging t_a, the end time of charging t_b and the charge current I_c of the period of time;

searching the stored usage modes of battery and efficiencies corresponding to the usage modes for the charging mode and its corresponding charging efficiency α

according to the data on battery usage recorded during the period of time; and

calculating the remaining quantity of electricity energy

9. The method of claim 7, wherein, in the case that the identified usage mode is a discharging mode, the remaining quantity of electricity energy is calculated as follows:

calculating the discharging capacity δ

e during the period of time according to the start time of discharging t_a, the end time of discharging t_b, and the discharge current I_d of the period of time;

searching the stored usage modes of battery and efficiencies corresponding to the usage modes for the discharging mode and its corresponding discharging efficiency β

according to the data on battery usage recorded during the period of time; and

calculating the remaining quantity of electricity energy of the battery at the time t_b,

10. The method of claim 7, wherein, in the case that the identified usage mode is an idle mode, the remaining quantity of electricity energy of the battery is calculated as follows:

searching the stored usage modes of battery and efficiencies corresponding to the usage modes for the idle mode and its corresponding self-discharging efficiency γ

according to the data on battery usage recorded during the period of time; and

calculating the remaining quantity of electricity energy of the battery at the time t_b,

11. An apparatus for estimating a condition of a battery, comprising:

a mode identifying unit configured to identify a usage mode of the battery during a period of time and its corresponding attenuation curve, according to recorded data on battery usage and stored usage modes of the battery and attenuation curves corresponding to the various usage modes, the attenuation curve representing a change of a fully charged capacity of the battery over battery usage; and

a condition estimating unit configured to calculate degradation of the battery according to the recorded data and the identified usage mode and its corresponding attenuation curve, the degradation representing a quantity of the fully charged capacity of the battery that is reduced over the battery usage.

12. The apparatus of claim 11, wherein the data on battery usage comprises any one or more of:

a start time and an end time of battery usage, an initial voltage and final voltage of battery usage, a charge current, a charge level, a temperature, a discharge current, an idle time, and a depth of discharge representing electricity energy of the battery before idle.

13. The apparatus of claim 12, wherein, in the case that the identified usage mode is a charging mode, the battery degradation is calculated according to a charge level L, a charging capacity δ

e, a temperature T, an initial charging voltage U_a and a final charging voltage U_b as follows;

calculating the charging capacity δ

e during the period of time according to a start time of charging t_a, an end time of charging t_b and a charge current I_c of the period of time;

searching the stored charging modes of the battery and attenuation curves corresponding to the charging modes for a set {M_a} of all charging modes matching the charge level L, the initial charging voltage U_a and the temperature T, and a set {M_b} of all charging modes matching the charge level L, the final charging voltage U_b and the temperature T;

searching the set {M_b} and the set {M_a} respectively for a mode m_b and a mode m_a such that a difference between the charging capacity of the mode m_b and the charging capacity of the mode m_a is equal to δ

e;

according to attenuation curves f_a and f_b corresponding to the modes m_a and m_b, calculating slopes s_a and s_b of the attenuation curves f_a and f_b at a point c=c_a respectively, wherein c_a represents a fully charged capacity of the battery at the time t_a, and s_a and s_b respectively represent degradation caused by charging the battery from a standard cut-off voltage to the initial charging voltage U_a and the final charging voltage U_b under a condition of the charge current I_c and temperature T; and

calculating battery degradation s=s_b−

s_a during the period of time, and obtaining the fully charged capacity c_b=c_a+s of the battery at the time t_b.

14. The apparatus of claim 12, wherein in the case that the identified usage mode is a discharging mode, the battery degradation is calculated according to a discharge current I_d, a temperature T, an initial discharging voltage U_a and a final discharging voltage U_b as follows:

searching the stored discharging modes of the battery and attenuation curves corresponding to the discharging modes for a discharging mode m_a matching the discharge current I_d, the initial discharging voltage U_a and the temperature T, and a discharging mode m_b matching the discharge current I_d, the final discharging voltage U_b and the temperature T;

according to attenuation curves f_a and f_b corresponding to the modes m_a and m_b, calculating slopes s_a and s_b of the attenuation curves f_a and f_b at a point c=c_a respectively, wherein c_a represents a fully charged capacity of the battery at the time t_a, and s_a and s_b respectively represent degradation caused by discharging the battery from the initial discharging voltage U_a and the final discharging voltage U_b to a standard cut-off voltage under a condition of the discharge current I_d and the temperature T; and

calculating battery degradation s=s_b−

s_a during the period of time, and obtaining the fully charged capacity c_b=c_a+s of the battery at the time t_b.

15. The apparatus of claim 12, wherein, in the case that the identified usage mode is an idle mode, the battery degradation is calculated according to a depth of discharge d and a temperature T as follows:

searching the stored idle modes of the battery and attenuation curves corresponding to the idle modes for a discharging mode m matching the depth of discharge d and the temperature T;

according to an attenuation curve f corresponding to the mode m, calculating a slope s of the attenuation curve f at a point c=c_a, wherein c_a represents a fully charged capacity of the battery at the time t_a, and s represents battery degradation during the period of time; and

calculating the fully charged capacity

16. The apparatus of claim 13, wherein, estimating the condition of the battery further comprises:

calculating a rate of depreciation caused by using the battery once,

17. The apparatus of claim 13, wherein, estimating the condition of the battery further comprises:

calculating a remaining quantity of electricity energy of the battery according to the stored usage modes of battery and efficiencies corresponding to the usage modes, wherein the remaining quantity of electricity energy of the battery is obtained by accumulating changes of the remaining quantity of electricity energy caused by battery usage on the basis of a factory electricity energy e₀ of the battery.

18. The apparatus of claim 17, wherein, in the case that the identified usage mode is a charging mode, the remaining quantity of electricity energy is calculated as follows:

calculating the charging capacity δ

e during the period of time according to the start time of charging t_a, the end time of charging t_b and the charge current I_c of the period of time;

searching the stored usage modes of battery and efficiencies corresponding to the usage modes for the charging mode and its corresponding charging efficiency α

according to the data on battery usage recorded during the period of time; and

calculating the remaining quantity of electricity energy of the battery at the time t_b,

19. The apparatus of claim 17, wherein, in the case that the identified usage mode is a discharging mode, the remaining quantity of electricity energy is calculated as follows:

calculating the discharging capacity δ

e during the period of time according to the start time of discharging t_a, the end time of discharging t_b and the discharge current I_d of the period of time;

searching the stored usage modes of battery and efficiencies corresponding to the usage modes for the discharging mode and its corresponding discharging efficiency β

according to the data on battery usage recorded during the period of time; and

calculating the remaining quantity of electricity energy of the battery at the time t_b,

20. The apparatus of claim 17, wherein, in the case that the identified usage mode is an idle mode, the remaining quantity of electricity energy of the battery is calculated as follows:

searching the stored usage modes of battery and efficiencies corresponding to the usage modes for the idle mode and its corresponding self-discharging efficiency γ

according to the data on battery usage recorded during the period of time; and

calculating the remaining quantity of electricity energy of the battery at the time t_b,