Condition monitoring system for batteries

• US 6,384,576 B1
• Filed: 11/17/1999
• Issued: 05/07/2002
• Est. Priority Date: 05/20/1997
• Status: Expired due to Term

• Current Assignee: Usko Jokinen
• Original Assignee: Usko Jokinen
• Inventors: Jokinen, Usko
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US09/441,913
• Time in Patent Office: 902 Days
• Field of Search: 320/122, 320/121, 320/118, 320/132, 340/636
• US Class Current: 320/122
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables

Abstract

The invention relates to a control system of battery health. One or more cells of a float charged battery are shunted periodically through a current generator; or through a switch and a resistor. The system measures impedance and/or state of charge by sampling the change in cell voltage during a shunt period or between sequel shunt periods.

Claims

1. A system for battery health, in which the battery'"'"'s cells'"'"' impedance and state of charge is measured, the system including:

means for shunting one or more of the cells of the battery when the battery is in a floating state, characterized by the fact that, when the battery is in the floating state, a first portion of the cells of the battery is shunted through a current generator, or through a switch and resistor, for successive shunt periods, a second portion of the cells of the battery remaining unshunted, and by the fact that the system measures the state of charge by measuring increases in cell voltage of the second portion of the cells of the battery by sampling successive voltage readings of individual cells of the second portion of the cells of the battery during the successive shunt periods.

2. The system according to claim 1, characterized in that the batteries are held in the correct state of charge on the basis of sampling successive voltage readings by shunting one or more floating cells through the current generator or through the switch, the control of which is based on sampling successive voltage readings such as to cause one or more of the unshunted battery cells to get an equalization charge.

3. The system according to claim 2, characterized in that the system includes two or more current generators, or at least two switches which are connected between battery poles and a connection point between cells, making it able to shunt alternatively the separate cells of a battery by current generators or by switches.

4. The system according to claim 3, characterized in that the periods of sampling the state of charge and the periods of charge equalization follow each other at repeated cycles until any detected low charged cell is fully charged, or until a continuous need to charge is detected and an alarm is given.

5. The system according to claim 2, characterized in that the periods of sampling the state of charge and the periods of charge equalization follow each other at repeated cycles until any detected low charged cell is fully charged, or until a continuous need to charge is detected and an alarm is given.

6. The system according to claim 1, characterized in that the system includes two or more current generators, or at least two switches which are connected between battery poles and a connection between cells, making it able to shunt alternatively the separate cells of a battery by current generators or by switches.

7. The system according to claim 6, characterized in that the periods of sampling the state of charge and the periods of charge equalization follow each other at repeated cycles until any detected low charged cell is fully charged, or until a continuous need to charge is detected and an alarm is given.