Intelligent battery charging system

• US 20050248314A1
• Filed: 04/06/2005
• Published: 11/10/2005
• Est. Priority Date: 05/08/2004
• Status: Active Grant

• Current Assignee: GEM Power LLC
• Original Assignee: GEM Power LLC
• Inventors: James, John E.
• Granted Patent: US 7,446,509 B2
• Time in Patent Office: Days
• US Class Current: 320/131
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: H01M 10/4207 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An invention is provided for detecting polarization in a battery during battery charging. The invention includes applying a waveform to a battery, and obtaining a plurality of battery response voltage readings corresponding to points along the applied waveform. A battery response voltage curve is calculated based on the voltage differences between the plurality of battery response voltage readings. A battery polarization point is then identified when the slope of the battery response voltage curve stops increasing at an increasing rate. To enhance accuracy, a plurality of battery response voltage curves can be calculated, each based on voltage differences between battery response voltage readings taken along the waveform. The battery polarization point can then be identified when the slopes of all the battery response voltage curves stop increasing at an increasing rate.

Claims

1. A method detecting polarization in a battery, comprising the operations of:

applying a waveform to a battery;

obtaining a plurality of battery response voltage readings corresponding to points along the waveform;

calculating a battery response voltage curve based on voltage differences between the plurality of battery response voltage readings; and

identifying a battery polarization point when a slope of the battery response voltage curve stops increasing at an increasing rate.

2. A method as recited in claim 1, wherein each data point along the battery response voltage curve is calculated by performing the operations comprising:

selecting a first battery response voltage reading taken along the waveform;

selecting a second battery response voltage reading taken along the waveform; and

calculating a difference between the first battery response voltage and the second battery response voltage.

3. A method as recited in claim 1, further comprising the operations of:

calculating a plurality of battery response voltage curves based on voltage differences between battery response voltage readings taken along the waveform; and

identifying the battery polarization point when slopes of all the battery response voltage curves stop increasing at an increasing rate.

4. A method as recited in claim 1, wherein the waveform comprises an initial rest period, followed by a first charging pulse, followed by a first rest period, followed by a first depolarization pulse, followed by a second rest period, followed by a second charging pulse, followed by a third rest period, followed by a second depolarization pulse.

5. A method as recited in claim 1, wherein the operations of claim 1 occur during a fast charge operation.

6. A method as recited in claim 5, wherein the fast charge operation is followed by a normal charge operation.

7. A method as recited in claim 6, wherein the normal charge operation is followed by a pre end-of-charge operation.

8. A method for detecting polarization in a battery, comprising:

applying a waveform to a battery;

calculating a battery response voltage curve based on voltage differences between battery response voltage readings corresponding to points along the waveform;

applying a first Gaussian filter and a second Gaussian filter to data of the battery response voltage curve, wherein the second Gaussian filter averages a greater number of data points than the first Gaussian filter;

calculating a trigger peak curve based on subtracting results of a first Gaussian filter from results of a second Gaussian filter; and

identifying a battery polarization point when a maximum peak occurs in the trigger peak curve.

9. A method as recited in claim 8, further comprising the operations of

calculating a plurality of battery response voltage curves based on voltage differences between battery response voltage readings taken along the waveform;

and

applying the first Gaussian filter and the second Gaussian filter to each battery response voltage curve.

10. A method as recited in claim 9, further comprising the operations of:

calculating a plurality of trigger peak curves each based on subtracting results of the first Gaussian filter from results of the second Gaussian filter applied to corresponding battery response voltage curves; and

identifying the battery polarization point when a maximum peak occurs in each trigger peak curve of the plurality of trigger peak curves.

11. A method as recited in claim 8, wherein the waveform comprises an initial rest period, followed by a first charging pulse, followed by a first rest period, followed by a first depolarization pulse, followed by a second rest period, followed by a second charging pulse, followed by a third rest period, followed by a second depolarization pulse.

12. A method as recited in claim 8, wherein the operations of claim 8 occur during a fast charge operation.

13. A method as recited in claim 12, wherein the fast charge operation is followed by a normal charge operation.

14. A method as recited in claim 13, wherein the normal charge operation is followed by a pre end-of-charge operation.

15. A system for charging a battery, comprising:

a switching circuit coupled to a power source and a battery load, the switching circuit capable of applying a waveform 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 readings corresponding to points along the waveform;

logic that calculates a battery response voltage curve based on voltage differences between the plurality of battery response voltage readings; and

logic that initiates termination of application of the waveform when a slope of the battery response voltage curve stops increasing at an increasing rate.

16. A system as recited in claim 15, wherein the battery management module further comprises:

logic that calculates a plurality of battery response voltage curves based on voltage differences between battery response voltage readings taken along the waveform; and

logic that initiates termination of application of the waveform when slopes of all the battery response curves of the plurality of battery response curves stop increasing at an increasing rate.

17. A system as recited in claim 15, wherein the waveform comprises an initial rest period, followed by a first charging pulse, followed by a first rest period, followed by a first depolarization pulse, followed by a second rest period, followed by a second charging pulse, followed by a third rest period, followed by a second depolarization pulse.

18. A system as recited in claim 15, wherein the battery management module conducts a fast charge operation followed by normal charge operation.

19. A system as recited in claim 18, wherein the battery management module conducts a pre end-of-charge operation following the normal charge operation.

20. A system as recited in claim 19, wherein the battery management module terminates each of the fast charge operation, normal charge operation, and pre end-of-charge operation when in each operation a slope of a battery response voltage curve stops increasing at an increasing rate.