Capacity degredation in a lead acid battery method and apparatus

• US 7,345,453 B2
• Filed: 03/01/2005
• Issued: 03/18/2008
• Est. Priority Date: 03/01/2005
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Palanisamy, Thirumalai G., Singh, Harmohan N., Hoenig, Steven, Atehortua, Hector M.
• Primary Examiner(s): Vu; Bao Q.
• Assistant Examiner(s): Tran; Nguyen
• Application Number:
  US11/067,788
• Publication Number:
  US 20060197504A1
• Time in Patent Office: 1,113 Days
• Field of Search: 320/132, 320/148, 320/149, 320/152, 320/156, 320/157, 320/164, 320/161, 324/522, 324/713, 324/433, 324/429, 324/428, 324/427, 324/426
• US Class Current: 320/134
• 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 for a battery having a lead acid construction, the method comprising:

determining a safe voltage value and a current limit value for the battery;

measuring a battery voltage value in real time at the battery terminals;

applying an increasing current ramp to the battery over a duration of time t₁ that is non-zero until the current reaches a predetermined current value I_peak, wherein I_peak is selected from the current value measured when the safe voltage value is attained and the current limit value;

recording the time (t₁);

applying a decreasing current ramp after I_peak is reached;

recording a time t₂ when the battery voltage value reaches a maximum voltage (V_peak) after I_peak is reached;

calculating a differential (d)=/(t₁)−

(t₂)/;

comparing the differential (d) to a predetermined delay (D)>

0;

accepting the battery as good when (d)<

(D); and

rejecting the battery as bad when (d)≧

(D).

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

3. The battery defect detection method of claim 1, wherein the step of applying a decreasing current ramp is applied until the current ramp reaches the zero value.

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

determining a gassing point based on the battery voltage value.

5. The battery defect detection method of claim 1, wherein (D) is at least 3.0 seconds.

6. The battery defect detection method of claim 1, wherein the battery is acceptable if a percentage value of the delay (D) to a total current ramp time t₁ is greater than a selected percentage.

7. 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.

8. 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.

9. A battery defect detection apparatus for a battery having a lead acid construction, the 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 the battery;

a display having a capacity degradation indicator for the battery;

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

a processor that records a first time (t₁) when a current of the battery reaches a maximum current (I_peak);

records a second time (t₂) after (t₁) when a terminal voltage of the battery reaches a maximum voltage (V_peak), calculates a differential (d)=/(t₁)−

(t₂)/;

compares the differential (d) to a predetermined delay (D);

indicates through the capacity degradation indicator on the display that the battery is unacceptable when (d)≧

(D)>

0; and

indicates through the capacity degradation indicator on the display that the battery is acceptable when (d)<

(D).

10. The battery defect detection apparatus of claim 9, wherein the current comprises an increasing current ramp.

11. The battery defect detection apparatus of claim 9, wherein the current increases linearly.

12. The battery defect detection apparatus of claim 9, 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.

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

program code for controlling application of a current to the battery over a time period that is non-zero;

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

program code for recording a second time (t₂) after the first time (t₁) when a terminal voltage of the battery reaches a maximum voltage (V_peak);

program code for calculating a differential (d)=/(t₁)−

(t₂)/;

program code for comparing the differential (d) to a predetermined non-zero delay (D);

program code for displaying an indicator that the battery is bad when (d)≧

(D); and

program code for displaying an indicator that the battery is good when (d)<

(D).

14. The computer readable medium containing program code of claim 13 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.