Apparatus and method for accurate energy device state-of-health (SoH) monitoring

• US 8,838,401 B2
• Filed: 08/15/2012
• Issued: 09/16/2014
• Est. Priority Date: 08/15/2011
• Status: Active Grant

• Current Assignee: Ultrasonic Energy Efficiency Solutions, LLC
• Original Assignee: Ultrasonic Energy Efficiency Solutions, LLC
• Inventors: Kelly, Shawn P.
• Primary Examiner(s): Raymond, Edward
• Application Number:
  US14/236,944
• Publication Number:
  US 20140188415A1
• Time in Patent Office: 762 Days
• Field of Search: 702 63- 66, 702182-185
• US Class Current: 702/63
• CPC Class Codes: G01R 31/36 Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
• 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

A device and associated testing method for testing state of health of an 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 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).

Claims

1. A method for testing the state-of-health 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 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).

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(θ

_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(θ

_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. A apparatus for testing the state-of-health 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

_m) 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 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).

10. The apparatus of claim 9, 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).

11. The apparatus of claim 10, wherein:

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

θ

=Δ

θ

_e(ω

_e)−

Δ

_e(ω

_m) 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.

12. The apparatus of claim 10, wherein:

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

θ

=Δ

θ

_e(ω

_e)−

Δ

θ

_e(ω

_m)→

0°

.

13. The apparatus of claim 9, 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.

14. The apparatus of claim 13, wherein:

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

15. The apparatus of claim 14, wherein a magnitude of decline in said state of health is deduced substantially in proportion to said diminution.

16. The apparatus of claim 9, 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;