Dynamic Discharging To Detect Derated Battery Cells

• US 20100270975A1
• Filed: 04/24/2009
• Published: 10/28/2010
• Est. Priority Date: 04/24/2009
• Status: Active Grant

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: Wong, Ligong, Chiasson, Shane
• Granted Patent: US 10,132,870 B2
• Time in Patent Office: Days
• US Class Current: 320/136
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A system for dynamic discharging to detected derated battery cells. In such a system, a battery cell capacity, cell voltage, as well as a time to discharge are used in combination to identify good or bad battery cells. More specifically, during a dynamic discharge cycle, an accumulated discharge capacity value is calculated and monitored by a charge level battery gas gauge via analog to digital (A/D) converters and an internal discharge time value is monitored. One of the values is assigned as a fixed value and the other value is used to identify good or bad batter cells.

Claims

1. A method for dynamic discharging of a battery to detect derated battery cells comprising:

determining an accumulated discharge capacity value for the battery;

determining an internal discharge time value for the battery;

assigning one of the accumulated discharge capacity value and the internal discharge time value as a fixed value;

using another of the accumulated discharge capacity value and the internal discharge time value to identify derated battery cells.

2. The method of claim 1 wherein:

the determining an accumulated discharge capacity is performed via a charge level battery gas gauge.

3. The method of claim 1 wherein:

the accumulated discharge capacity is calculated during a dynamic discharge cycle.

4. The method of claim 1 further comprising:

determining start and end voltage for the battery; and

wherein

the assigning the fixed value comprises assigning one of the accumulated discharge capacity value, the start and end voltage and the internal discharge time value as the fixed value;

the using another further comprises using another of the accumulated discharge capacity value, the start and end voltage and the internal discharge time value as the fixed value.

5. The method of claim 1 further comprising:

determining a relative state of charge value for the battery; and

wherein

the assigning the fixed value comprises assigning one of the accumulated discharge capacity value, the relative state of charge and the internal discharge time value as the fixed value; and

,

the using another further comprises using another of the accumulated discharge capacity value, the relative state of charge and the internal discharge time value as the fixed value.

6. An apparatus for dynamic discharging of a battery to detect derated battery cells comprising:

means for determining an accumulated discharge capacity value for the battery;

means for determining an internal discharge time value for the battery;

means for assigning one of the accumulated discharge capacity value and the internal discharge time value as a fixed value;

means for using another of the accumulated discharge capacity value and the internal discharge time value to identify derated battery cells.

7. The apparatus of claim 6 wherein:

determining an accumulated discharge capacity is performed via a charge level battery gas gauge.

8. The apparatus of claim 6 wherein:

accumulated discharge capacity is calculated during a dynamic discharge cycle.

9. The apparatus of claim 6 further comprising:

means for determining start and end voltage for the battery; and

wherein

assigning the fixed value comprises assigning one of the accumulated discharge capacity value, the start and end voltage and the internal discharge time value as the fixed value; and

,

using another further comprises using another of the accumulated discharge capacity value, the start and end voltage and the internal discharge time value as the fixed value.

10. The apparatus of claim 6 further comprising:

means for determining a relative state of charge value for the battery; and

wherein

assigning the fixed value comprises assigning one of the accumulated discharge capacity value, the relative state of charge and the internal discharge time value as the fixed value; and

,

using another further comprises using another of the accumulated discharge capacity value, the relative state of charge and the internal discharge time value as the fixed value.