Method of monitoring the charging of sealed nickel storage cells, and a charger using the method

• US 5,563,494 A
• Filed: 06/03/1993
• Issued: 10/08/1996
• Est. Priority Date: 05/24/1993
• Status: Expired due to Fees

• Current Assignee: Z124 LLC (Flexis)
• Original Assignee: SAFT SA (Totalenergies Se)
• Inventors: Cuesta, Rosendo, Rouverand, Christophe
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Nappi, Robert E.
• Application Number:
  US08/070,871
• Time in Patent Office: 1,223 Days
• Field of Search: 320/35, 320/36, 320/38, 320/37, 320/20
• US Class Current: 320/150
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method of monitoring rapid charging of sealed nickel storage cells of the nickel-hydride type and of the nickel-cadmium type, said cells optionally being associated in a battery, wherein once said cells have been identified and a relationship for the heating of said cells as a function of charging time for a given charging mode has been determined and stored, the charging of said cells is stopped when the difference between the temperature of said cells and a reference temperature exceeds a predetermined value, the reference temperature being calculated on the basis of said heating relationship and as a function of the charging time that has already elapsed.

Claims

1. A method of monitoring rapid charging of sealed nickel storage cells of a battery, all of the cells of said battery being one of nickel-hydride type and nickel-cadmium type, comprising the step of:

once said cells have been identified and a relationship for heating of said cells as a function of charging time for a given charging mode has been determined and stored, charging of said cells is stopped when a difference between a measured temperature of said cells and a reference temperature exceeds a predetermined value, the reference temperature being calculated on the basis of said heating relationship and as a function of the charging time that has already elapsed and of the temperature of said battery at the beginning of charging.

2. A method according to claim 1, wherein said heating relationship is determined as follows:

a change in the temperature of said cells during a charging operation is measured and recorded;

a mathematical expression is established giving temperature as a function of charging time based on the change and of the temperature of said battery at the beginning of charging; and

the heating relationship for said cells during said charging operation is determined based on said mathematical expression and stored.

3. A method according to claim 1, wherein prior to beginning charging said cells, a step of verifying temperature stability of said cells is performed, so that charging of the cells is inhibited so long as a difference between the measured temperature and a stored earlier measured temperature is greater than a predetermined threshold value.

6. A charger using the method according to claim 1, including:

an electricity power supply system which supplies power for charging said cells,

a temperature sensor which senses the temperature of said cells,

means for converting variations in the temperature of said cells as sensed by said temperature sensor into voltage variations,

a clock for providing a timing, said temperature sensor senses the temperature of said cells at predetermined time intervals determined based on said timing,

means for storing said heating relationship, and

a microprocessor for controlling said charger to perform said method.

4. A method of monitoring rapid charging of sealed nickel storage cells of a battery, all of the cells of said battery being one of nickel-hydride type and nickel-cadmium type, comprising the step of:

once said cells have been identified and a relationship for heating of said cells as a function of charging time for a given charging mode has been determined and stored, charging of said cells is stopped when a difference between a measured temperature of said cells and a reference temperature exceeds a predetermined value, the reference temperature being calculated on the basis of said heating relationship and as a function of the charging time that has already elapsed, wherein the reference temperature is calculated for nickel-hydride type cells only, and a temperature at the beginning of charging is taken as a reference temperature for the nickel-cadmium type cells.

5. A method of monitoring rapid charging of sealed nickel storage cells of a battery, all of the cells of said battery being one of nickel-hydride type and nickel-cadmium type, comprising the step of:

once said cells have been identified and a relationship for heating of said cells as a function of charging time for a given charging mode has been determined and stored, charging of said cells is stopped when a difference between a measured temperature of said cells and a reference temperature exceeds a predetermined value, the reference temperature being calculated on the basis of said heating relationship and as a function of the charging time that has already elapsed, wherein the type of said cells is identified by comparing a change in temperature as measured during a predetermined period of time at the beginning of charging of said cells with a predetermined temperature increase representing the type of said cells.