Granted Patent B2

US 6,844,704 · App. 09/972,073 · Granted Jan 18, 2005

Abstract

Claims (6)

1. Am active voltage limiting and failure detection system for an energy storage cell of a multiple energy storage cell pack, the energy storage cell having a cell voltage Vcell, the system comprising: a first electrical circuit connected to and powered by the energy storage cell, the first electrical circuit drawing a significant amount of power from the energy storage cell when a cell voltage Vcell reaches a maximum voltage Vmax to reduce the cell voltage Vcell, to stop drawing the significant amount of power to reduce the cell voltage Vcell when the cell voltage Vcell reaches a minimum voltage Vmin, and to draw no power when the cell voltage Vcell reaches a shutdown voltage Vshutdown; and a second electrical circuit connected to the energy storage cell and indicating a cell active condition when the cell voltage Vcell is above a threshold active voltage Vactive, and to indicate a cell inactive condition when the cell voltage Vcell drops below the threshold active voltage Vactive.

2. An active voltage limiting and failure detection system for an energy storage cell of a multiple energy storage cell pack, the energy storage cell having a cell voltage Vcell, the system comprising: a first electrical circuit connected to and powered by the energy storage cell, the first electrical circuit includes means for drawing a significant amount of power from the energy storage cell when a cell voltage Vcell reaches a maximum voltage Vmax to reduce the cell voltage Vcell, means for stopping the drawing of the significant amount of power to reduce the cell voltage Vcell when the cell voltage Vcell reaches a minimum voltage Vmin, and means for drawing no power when the cell voltage Vcell reaches a shutdown voltage Vshutdown; and a second electrical circuit connected to the energy storage cell and including means for indicating a cell active condition when the cell voltage Vcell is above a threshold active voltage Vactive, and means for indicating a cell inactive condition when the cell voltage Vcell drops below the threshold active voltage Vactive.

3. An active voltage limiting and failure detection system for an energy storage cell of a multiple energy storage cell pack, the energy storage cell having a cell voltage Vcell, the system comprising: a first electrical circuit connected to and powered by the energy storage cell, the first electrical circuit includes means for drawing a significant amount of power from the energy storage cell when a cell voltage Vcell reaches a maximum voltage Vmax to reduce the cell voltage Vcell, and means for stopping the drawing of the significant amount of power to reduce the cell voltage Vcell when the cell voltage Vcell reaches a minimum voltage Vmin.

4. The active voltage limiting and failure detection system of claim 3 , further including means for drawing no power when the cell voltage Vcell reaches a shutdown voltage Vshutdown.

5. The active voltage limiting and failure detection system of claim 3 , further including a second electrical circuit connected to the energy storage cell, and indicating a cell active condition when a cell voltage Vcell is above a threshold active voltage Vactive, and indicating a cell inactive condition when the cell voltage Vcell drops below the threshold active voltage Vactive and the circuit including a voltage threshold device to set the threshold active voltage Vactive.

6. The system of claim 5 , wherein the voltage threshold device is a zener diode.

Assignments (11)