STATE OF HEALTH RECOGNISTION OF SECONDARY BATTERIES

• US 20100039116A1
• Filed: 10/19/2009
• Published: 02/18/2010
• Est. Priority Date: 03/28/2006
• Status: Active Grant

• Current Assignee: GEM Power LLC
• Original Assignee: GEM Power LLC
• Inventors: James, John E., Tsenter, Boris J.
• Granted Patent: US 8,427,166 B2
• Time in Patent Office: Days
• US Class Current: 324/427
• 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

Abstract

An invention is provided for determining a state of health of a battery. The invention includes applying a predefined load profile to a battery, and obtaining a plurality of battery response voltage data corresponding to points along the predefined load profile. The battery electrical double layer capacity data is calculated from the battery response voltage data, and thereafter utilized to determine the state of health of the battery.

Claims

1. A method for determining a state of health of a battery, comprising the operations of:

applying a predefined load profile to a battery; and

obtaining a battery electrical double layer capacity value utilizing a response from the load profile,

wherein the battery electrical double layer capacity value is a product of a depolarization current and a time interval in the range of about 1-10 milliseconds (ms) divided by a battery voltage difference for the time interval.

2. A method as recited in claim 1, further comprising the operation of utilizing the battery electrical double layer capacity value to predict an end to remaining useful life of the battery.

3. A method as recited in claim 2, wherein the battery is a lead-acid battery, and wherein the end to the remaining useful life of the battery occurs when a sharp rise occurs in the battery electrical double layer capacity value when a battery state of charge is about 100%.

4. A method as recited in claim 2, wherein the battery is a Li-ion battery, and wherein the end to the remaining useful life of the battery is predicted based on relative values of the battery electrical double layer capacity value after a plurality of charging-discharging cycles.

5. A method as recited in claim 2, wherein the electrical double layer capacity value of a Li-ion battery decreases with each charging-discharging cycle regardless of battery state of charge.

6. A system for determining a state of health of a battery, comprising:

a switching circuit coupled to a power source and a battery load, the switching circuit capable of applying a predefined load profile to a battery; and

a battery management module coupled to the switching circuit, the battery management module comprising;

logic that obtains a plurality of battery response voltage data corresponding to points along the predefined load profile;

logic that calculates a battery electrical double layer capacity data from the battery response voltage data, wherein the battery electrical double layer capacity value; and

logic that predicts a remaining useful life of the battery based on the battery electrical double layer capacity data.

7. A system as recited in claim 6, wherein the battery management module predicts the remaining useful life of a lead-acid battery when a sharp rise occurs in the battery electrical double layer capacity data when the battery state of charge is about 100%.

8. A system as recited in claim 6, wherein the battery management module predicts the remaining useful life of a Li-ion battery based on relative values of the battery electrical double layer capacity value after a plurality of charging-discharging cycles.