Capacity degredation in a lead acid battery method and apparatus

• US 20060197504A1
• Filed: 03/01/2005
• Published: 09/07/2006
• Est. Priority Date: 03/01/2005
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Palanisamy, Thirumalai G., Singh, Harmohan N., Hoenig, Steven, Atehortua, Hector M.
• Granted Patent: US 7,345,453 B2
• Time in Patent Office: Days
• US Class Current: 320/132
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/379 for lead-acid batteries
• CPC Class Codes: G01R 31/385 Arrangements for measuring battery or accumulator variables for monitoring G01R31/382
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health

Abstract

In accordance with the invention, there is a battery defect detection method comprising applying a current ramp to a battery; determining a first time (t₁) when a current of the battery reaches a maximum current (I_peak), and determining a second time (t₂) when a terminal voltage of the battery reaches a maximum voltage (V_peak). The method also includes determining a differential (d), wherein (d)=/(t₁)−(t₂)/, and wherein (d) corresponds to a magnitude of defects in the battery.

Claims

1. A battery defect detection method comprising:

applying a current to a battery;

determining a first time (t₁) when a current of the battery reaches a maximum current (I_peak);

determining a second time (t₂) when a terminal voltage of the battery reaches a maximum voltage (V_peak); and

determining a differential (d), wherein

(d)=/(t₁)−

(t₂)/

and wherein (d) corresponds to a magnitude of defects in the battery.

2. The battery defect detection method of claim 1 further comprising:

determining whether

(d)≧

(D),

wherein (D) corresponds to a delay above which indicates the battery has an unacceptable magnitude of defects.

3. The battery defect detection method of claim 1, wherein the step of applying the current comprises applying an increasing current ramp.

4. The battery defect detection method of claim 1, wherein the step of applying the current comprises linearly increasing the current.

5. The battery defect detection method of claim 3 further comprising:

determining a safe voltage, wherein the increasing current ramp is applied until the battery reaches the safe voltage; and

applying a decreasing current ramp when the current ramp reaches the zero value.

6. The battery defect detection method of claim 5 further comprising:

measuring the battery terminal voltage while the current is applied; and

determining a gassing point based on the battery terminal voltage.

7. The battery defect detection method of claim 2, wherein (D) is at least 3.0 seconds.

8. The battery defect detection method of claim 2, wherein the indication that the battery has an unacceptable magnitude of defects is based on a determination of a percentage of (D) to (t₁).

9. The battery defect detection method of claim 1, wherein (D) is determined for each of a variety of types of batteries and wherein (D) is published with a capacity rating of the batteries.

10. The battery defect detection method of claim 1, wherein the defect determination is applied to the battery without removing the battery from the battery'"'"'s operating position.

11. A battery defect detection apparatus comprising:

a control module comprising an analog-to-digital converter, a digital-to-analog converter, and an electronics control system;

a power supply that supplies a current ramp to a battery;

a sensor electrically connected to the battery to measure the battery current; and

a processor that determines a first time (t₁) when a current of the battery reaches a maximum current (I_peak) and that determines a second time (t₂) when a terminal voltage of the battery reaches a maximum voltage (V_peak), wherein the processor determines a differential (d), wherein

(d)=/(t₁)−

(t₂)/

and wherein (d) corresponds to a magnitude of defects in the battery.

12. The battery defect detection apparatus of claim 11 wherein the processor further determines whether

(d)≧

(D),

wherein (D) corresponds to a delay above which indicates the battery has an unacceptable magnitude of defects.

13. The battery defect detection apparatus of claim 11, wherein the current comprises an increasing current ramp.

14. The battery defect detection apparatus of claim 11, wherein the current increases linearly.

15. The battery defect detection apparatus of claim 11, wherein the processor is adapted to measure the battery terminal voltage while the current is applied and wherein the processor is adapted to determine a gassing point based on the battery terminal voltage.

16. The battery defect detection apparatus of claim 11 further comprising a display that indicates the battery is defective.

17. A computer readable medium containing program code that configures a processor to perform a method for determining the magnitude of defects in a battery, said program code comprising:

program code for controlling application of a current to a battery;

program code for determining a first time (t₁) when a current of the battery reaches a maximum current (I_peak);

program code for determining a second time (t₂) when a terminal voltage of the battery reaches a maximum voltage (V_peak); and

program code for determining a differential (d), wherein

(d)=/(t₁)−

(t₂)/

and wherein (d) corresponds to a magnitude of defects in the battery.

18. The computer readable medium containing program code of claim 17 further comprising:

program code for determining whether

(d)≧

(D),

wherein (D) corresponds to a delay above which indicates the battery has an unacceptable magnitude of defects.

19. The computer readable medium containing program code of claim 17 further comprising:

program code for measuring the battery terminal voltage while the current is applied; and

program code for determining a gassing point, wherein the gassing point is determined from the battery terminal voltage.