Battery overcharging compensation system and method

• US 20050248316A1
• Filed: 05/10/2004
• Published: 11/10/2005
• Est. Priority Date: 05/10/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kangas, P. Daniel, Hiromitsu, Toshiro, Idei, Seiichi
• Granted Patent: US 7,239,112 B2
• Time in Patent Office: Days
• US Class Current: 320/132
• CPC Class Codes: H02J 7/0071 with a programmable schedule

Abstract

A method for compensating for overcharging of at least one battery includes calculating a charge rate for the at least one battery, comparing an overcharge accumulator value for the at least one battery with a maximum time limit value, comparing the calculated charge rate with a nominal charge rate for the at least one battery, if the overcharge accumulator value is less than the maximum time limit value, incrementing the overcharge accumulator value if the calculated charge rate is higher than the nominal charge rate, if the overcharge accumulator value is less than the maximum time limit value, decrementing the overcharge accumulator value if the calculated charge rate is lower than the nominal charge rate (if the overcharge accumulator value is less than the maximum time limit value), setting the charge rate for the at least one battery to the calculated charge rate (if the overcharge accumulator value is less than the maximum time limit value), and setting the charge rate for the at least one battery to the nominal charge rate, or to a charge rate lower than the nominal charge rate, if the overcharge accumulator value equals or exceeds the maximum time limit value. In this manner, battery life may be prolonged.

Claims

1. A method for compensating for overcharging of at least one battery, comprising the steps of:

(a) calculating a charge rate for the at least one battery;

(b) comparing an overcharge accumulator value for the at least one battery with a maximum time limit value;

(c) comparing the calculated charge rate with a nominal charge rate for the at least one battery, if the overcharge accumulator value is less than the maximum time limit value;

(d) incrementing the overcharge accumulator value if the calculated charge rate is higher than the nominal charge rate, if the overcharge accumulator value is less than the maximum time limit value;

(e) decrementing the overcharge accumulator value if the calculated charge rate is lower than the nominal charge rate, if the overcharge accumulator value is less than the maximum time limit value;

(f) setting the charge rate for the at least one battery to the calculated charge rate, if the overcharge accumulator value is less than the maximum time limit value; and

(g) setting the charge rate for the at least one battery to the nominal charge rate, or to a charge rate lower than the nominal charge rate, if the overcharge accumulator value equals or exceeds the maximum time limit value.

2. The method of claim 1, wherein the calculating step (a) comprises:

(a1) determining a status of at least one parameter for the at least one battery, wherein the at least one parameter comprises a closeness to a desired charge level;

(a2) determining if the at least one battery is to be charged during a peak usage time period or an off-peak usage time period;

(a3) calculating a peak charge schedule, if the at least one battery is to be charged during the peak usage time period, comprising;

(a3i) determining a priority rating for the at least one battery based upon the at least one parameter, wherein a battery closer to the desired charge level has a higher priority rating, and

(a3ii) setting the calculated charge rate for the at least one battery based upon the priority rating for the at least one battery; and

(a4) calculating an off-peak charge schedule, if the at least one battery is to be charged during the off-peak, usage time period, comprising;

(a4i) setting the calculated charge rate for the at least one battery based upon the at least one parameter and a time available for charging the at least one battery.

3. A computer readable medium with program instructions for compensating for overcharging of at least one battery, comprising the instructions for:

(a) calculating a charge rate for the at least one battery;

(b) comparing an overcharge accumulator value for the at least one battery with a maximum time limit value;

(c) comparing the calculated charge rate with a nominal charge rate for the at least one battery, if the overcharge accumulator value is less than the maximum time limit value;

(d) incrementing the overcharge accumulator value if the calculated charge rate is higher than the nominal charge rate, if the overcharge accumulator value is less than the maximum time limit value;

(e) decrementing the overcharge accumulator value if the calculated charge rate is lower than the nominal charge rate, if the overcharge accumulator value is less than the maximum time limit value;

(f) setting the charge rate for the at least one battery to the calculated charge rate, if the overcharge accumulator value is less than the maximum time limit value; and

(g) setting the charge rate for the at least one battery to the nominal charge rate, or to a charge rate lower than the nominal charge rate, if the overcharge accumulator value equals or exceeds the maximum time limit value.

4. The medium of claim 3;

wherein the calculating instruction (a) comprises instructions for;

(a1) determining a status of at least one parameter for the at least one battery, wherein the at least one parameter comprises a closeness to a desired charge level;

(a2) determining if the at least one battery is to be charged during a peak usage time period or an off-peak usage time period;

(a3) calculating a peak charge schedule, if the at least one battery is to be charged during the peak usage time period, comprising;

(a3i) determining a priority rating for the at least one battery based upon the at least one parameter, wherein a battery closer to the desired charge level has a higher priority rating, and

(a3ii) setting the calculated charge rate for the at least one battery based upon the priority rating for the at least one battery; and

(a4) calculating an off-peak charge schedule, if the at least one battery is to be charged during the off-peak, usage time period, comprising;

(a4i) setting the calculated charge rate for the at least one battery based upon the at least one parameter and a time available for charging the at least one battery.