Method of charging a battery utilizing dynamic cable compensation

• US 6,479,968 B1
• Filed: 09/27/2000
• Issued: 11/12/2002
• Est. Priority Date: 09/27/2000
• Status: Expired due to Term

• Current Assignee: Cosette Pharmaceuticals, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Ramsden, Martin Hague, Pozsgay, Brian Thomas, Heng, Ang Teik, Frazier, Taneka
• Primary Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/672,125
• Time in Patent Office: 776 Days
• Field of Search: 320/137, 324/430
• US Class Current: 320/137
• CPC Class Codes: H02J 7/0071 with a programmable schedule

Abstract

This invention includes a method for sensing the parasitic impedance in a battery charging system and compensating for these parasitic impedances. In one embodiment, the voltage of the system is measured with no charging current applied. Next, a charging current is applied and a second voltage is measured. The parasitic impedance is then extrapolated and multiplied by a predetermined rapid charging current. The product is added to a predetermined cell termination voltage. The charging means remains in a rapid charge current mode until a voltage equal to the sum of the impedance-current product and the predetermined voltage is reached, wherein the current is reduced to a maintenance charging level.

Claims

1. A method for charging a battery, the method comprising the steps of:

a. providing a system for charging, wherein the system comprises

i. a means for charging; and

ii. at least one rechargeable battery cell;

b. determining a parasitic impedance of the system for charging; and

c. compensating for the parasitic impedance while charging the at least one rechargeable battery cell;

wherein the determining a parasitic impedance comprises the steps of;

a. applying a first charging current and sensing a first voltage;

b. applying a second charging current and sensing a second voltage; and

c. extrapolating the parasitic impedance.

2. The method of claim 1, wherein the compensating for the parasitic impedance comprises the steps of:

a. determining a product of the charging current and the parasitic impedance;

b. determining a sum of the product of the charging current and the parasitic impedance and a predetermined termination voltage; and

c. reducing charging current when the sum of the product of the charging current and the parasitic impedance and a predetermined termination voltage is reached.

3. A method for charging a battery, the method comprising the steps of:

a. providing a system for charging, wherein the system comprises

i. a means for charging; and

ii. at least one rechargeable battery cell;

b. determining a parasitic impedance of the system for charging; and

c. compensating for the parasitic impedance while charging the at least one rechargeable battery cell;

wherein the determining a parasitic comprises the steps of;

a. sensing a first voltage when no charging current is being applied;

b. applying a first charging current and sensing a second voltage; and

c. calculating the parasitic impedance.