Apparatus and method for accurate energy device state-of-charge (SoC) monitoring and control using real-time state-of-health (SoH) data

• US 9,325,193 B2
• Filed: 09/15/2014
• Issued: 04/26/2016
• Est. Priority Date: 08/15/2011
• Status: Active Grant

• Current Assignee: Shawn P. Kelly
• Original Assignee: Shawn P. Kelly
• Inventors: Kelly, Shawn P.
• Primary Examiner(s): Raymond, Edward
• Application Number:
  US14/485,865
• Publication Number:
  US 20150002105A1
• Time in Patent Office: 589 Days
• Field of Search: 702 63- 67, 702182-185, 702/188
• US Class Current: 1/1
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: H02J 7/007 Regulation of charging or discharging current or voltage

Abstract

A device and associated testing method for empirically determining the state-of-charge of an electrochemical energy device, comprising: applying electrical excitations to the energy device at a predetermined electrical excitation frequency ω_e; applying mechanical excitations to the energy device at a predetermined mechanical excitation frequency ω_m; measuring an electrically-induced phase difference Δθ_e(ω_e) between voltage (V) and current (I) within the energy device from applying the electrical excitations; measuring a mechanically-induced phase difference Δθ_e(ω_m) between voltage (V) and current (I) within the energy device from applying the mechanical excitations; and deducing the empirical real-time state-of-health of the energy device by comparing the electrically-induced phase difference Δθ_e(ω_e) with the mechanically-induced phase difference Δθ_e(ω_m); and using the deduced state of health to determine the state of charge.

Claims

1. A method for empirically determining the state-of-charge of an electrochemical energy device, comprising:

applying electrical excitations to the energy device at a predetermined electrical excitation frequency ω

_e;

applying mechanical excitations to the energy device at a predetermined mechanical excitation frequency ω

_m;

measuring an electrically-induced phase difference Δ

θ

_e(ω

_e) between voltage (V) and current (I) within the energy device from applying said electrical excitations;

measuring a mechanically-induced phase difference Δ

θ

_e(ω

_m) between voltage (V) and current (I) within the energy device from applying said mechanical excitations; and

deducing the empirical real-time state-of-health of said energy device by comparing said electrically-induced phase difference Δ

θ

_e(ω

_e) with said mechanically-induced phase difference Δ

θ

_e(ω

_m); and

using said deduced state of health to determine the state of charge.

2. The method of claim 1, further comprising:

taking a difference Δ

θ

=Δ

θ

_e(ω

_e)−

Δ

θ

_e(ω

_m) between said electrically-induced phase difference Δ

θ

_e and said mechanically-induced phase difference Δ

θ

_e(ω

_m); and

using said difference as a basis to deduce said SoH.

3. The method of claim 2, further comprising:

deducing the state-of-health of said energy device by determining a magnitude of Δ

θ

=Δ

θ

_e(ω

_e)−

Δ

θ

_e(ω

_m) in relation to 0°

, wherein better state-of-health is deduced from said magnitudes being larger and poorer state-of-health is deduced from said magnitudes being smaller.

4. The method of claim 2, further comprising:

deducing that said energy device is approaching its end of life by determining that Δ

θ

=Δ

θ

_e(ω

_e)−

Δ

θ

_e(ω

_m)→

0°

.

5. The method of claim 1, further comprising:

at a baseline time, determining baseline-time phase differences Δ

θ

_e(ω

_e) and Δ

θ

_e(ω

_m) between current and voltage of said energy device;

at a later time, determining later-time phase differences Δ

θ

_e(ω

_e) and Δ

θ

_e(ω

_m) between current and voltage of said energy device; and

deducing said state of health by comparing said later-time phase difference with said baseline-time phase difference.

6. The method of claim 5, further comprising:

deducing said state of health by determining how much said later-time phase difference has diminished from said baseline time phase difference.

7. The method of claim 6, further comprising deducing a magnitude of decline in said state of health substantially in proportion to said diminution.

8. The method of claim 1, wherein:

a difference between measurements of internal impedance Z_INT the energy device when said electrical excitation frequency ω

_e is applied versus when said mechanical excitation frequency ω

_m is applied, is determined according to;

9. The method of claim 1, further comprising using said state of charge determination to display to a user the degree to which said electrochemical energy device is presently charged.

10. The method of claim 1, further comprising using said state of charge determination to control and optimize the charging and/or discharging of said electrochemical energy device.

11. An apparatus for empirically determining the state-of-charge of an electrochemical energy device, comprising:

an electrical excitation source for applying electrical excitations to the energy device at a predetermined electrical excitation frequency ω

_e;

a mechanical excitation source for applying mechanical excitations to the energy device at a predetermined mechanical excitation frequency ω

_m;

a measurement device for measuring an electrically-induced phase difference Δ

θ

_e(ω

_e) between voltage (V) and current (I) within the energy device from applying said electrical excitations; and

said measurement device for further measuring a mechanically-induced phase difference Δ

θ

_e(ω

_m) between voltage (V) and current (I) within the energy device from applying said mechanical excitations;

wherein

the empirical real-time state-of-health of said energy device is deduced by comparing said electrically-induced phase difference Δ

θ

_e(ω

_e) with said mechanically-induced phase difference Δ

θ

_e(ω

_m); and

said deduced state of health is used to determine the state of charge.

12. The apparatus of claim 11, wherein:

the state-of-health of said energy device is deduced by taking a difference Δ

θ

=Δ

θ

_e(ω

_e)−

Δ

θ

_e(ω

_m) between said electrically-induced phase difference Δ

θ

_e and said mechanically-induced phase difference Δ

θ

_e(ω

_m).

13. The apparatus of claim 12, wherein:

the state-of-health of said energy device is deduced by determining a magnitude of Δ

θ

=Δ

θ

_e(ω

_e)−

Δ

θ

_e(ω

_e) in relation to 0°

, and wherein better state-of-health is deduced from said magnitudes being larger and poorer state-of-health is deduced from said magnitudes being smaller.

14. The apparatus of claim 12, wherein:

said energy device is approaching its end of life is deduced by determining that Δ

θ

=Δ

θ

_e(ψ

_e)−

Δ

θ

_e(ψ

_m)→

0°

.

15. The apparatus of claim 11, wherein:

baseline-time phase differences Δ

θ

_e(ω

_e) and Δ

θ

_e(ω

_m) between current and voltage of said energy device are determined at a baseline time;

later-time phase differences Δ

θ

_e(ω

_e) and Δ

θ

_e(ω

_m) between current and voltage of said energy device are determined at a later time;

said baseline-time phase difference is compared with said later-time phase difference to deduce said state-of-health.

16. The apparatus of claim 15, wherein:

said state of health is deduced by determining how much said later-time phase difference has diminished from said baseline time phase difference.

17. The apparatus of claim 16, wherein a magnitude of decline in said state of health is deduced substantially in proportion to said diminution.

18. The apparatus of claim 11, wherein:

a difference between measurements by said measurement device of internal impedance Z_INT the energy device when said electrical excitation frequency ω

_e is applied versus when said mechanical excitation frequency ω

_m is applied, is determined according to;

19. The apparatus of claim 11, wherein said state of charge determination is used to display to a user the degree to which said electrochemical energy device is presently charged.

20. The apparatus of claim 11, wherein said state of charge determination is used to control and optimize the charging and/or discharging of said electrochemical energy device.