Method and apparatus for using pulse current to extend the functionality of a battery

Abstract

A method to extend the functionality of a battery, the method comprising drawing power from the battery, and repetitively drawing a current pulse greater than the minimum conditioning current from the battery, thereby conditioning the battery.

What is claimed is:  
     
         1 . A method of conditioning a battery while discharging the battery, the method comprising: 
 drawing power from the battery;    repetitively drawing a current pulse greater than the minimum conditioning current from the battery, thereby conditioning the battery.    
     
     
         2 . The method of  claim 1 , wherein the minimum conditioning current is a function of the battery power remaining in the battery, and decreases as a function of a decrease of the battery voltage.  
     
     
         3 . The method of  claim 2 , further comprising calculating the minimum conditioning current, comprising: 
 drawing a first current level from the battery at a first battery power;    determining whether a conditioning effect has been observed; and    if the conditioning effect has been observed, determining that the first current level is at least at the minimum conditioning current.    
     
     
         4 . The method of  claim 1 , wherein a pulse width is between 5 μs and 500 μs.  
     
     
         5 . The method of  claim 1 , wherein a pulse frequency is between 100 pulses per second and 1 pulse per minute.  
     
     
         6 . The method of  claim 1 , wherein the pulse occurs at irregular intervals.  
     
     
         7 . The method of  claim 1 , wherein the battery is used to drive a device, while the current pulses are being drawn.  
     
     
         8 . The method of  claim 1 , further comprising: 
 isolating a device coupled to the battery from a voltage dip in response to the current pulse.    
     
     
         9 . The method of  claim 8 , wherein the device is powered from an alternative power source while the current pulse is being drawn from the battery.  
     
     
         10 . The method of  claim 9 , wherein the alternative power source is a capacitor, and wherein the capacitor is charged by the battery.  
     
     
         11 . A method of conditioning a battery to eliminate voltage depression, the method comprising: 
 coupling a pulser between the battery and a device during use of the battery, the pulser repetitively drawing a current pulse greater than the minimum conditioning current from the battery, thereby conditioning the battery; and    removing the pulser from between the battery and the device after a period of time, the battery having been conditioned during this process such that the in-use time of the battery corresponds to the in-use time of the new battery.    
     
     
         12 . The method of  claim 11 , wherein the period of time depends on an initial condition of the battery, such that less time is needed to condition a fairly new battery compared to an old battery.  
     
     
         13 . The method of  claim 12 , wherein the period of time ranges from a few minutes to multiple discharge cycles.  
     
     
         14 . The method of  claim 11 , wherein the battery is a rechargeable nickel cadmium (NiCad) battery.  
     
     
         15 . An apparatus to improve functionality of a battery comprising: 
 a pulser to repetitively draw a current pulse greater than a minimum conditioning current from the battery, thereby conditioning the battery.    
     
     
         16 . The apparatus of  claim 15 , wherein the minimum conditioning current is function of the battery power, and decreases as a function of a decrease of the battery voltage.  
     
     
         17 . The apparatus of  claim 16 , wherein the pulser comprises: 
 a pulse generator to generate current pulses; and    such that a battery voltage is reduced to half its normal value.    
     
     
         18 . The apparatus of  claim 17 , further comprising: 
 a switch to disconnect the pulser from a device coupled to the battery while the voltage is reduced; and    a secondary power source to power the device during the pulse.    
     
     
         19 . The apparatus of  claim 18 , wherein the secondary power source comprises a capacitor.  
     
     
         20 . The apparatus of  claim 15 , further comprising: 
 a delay logic to disconnect the pulser from the device prior to the pulse, and to recouple the battery to the device after a voltage spike.    
     
     
         21 . An apparatus to condition a rechargeable battery during use comprising: 
 a pulse generator powered by the battery;    a control circuit for switching the pulse generator into the circuit periodically, to permit the pulse generator to repetitively draw a current pulse greater than the minimum conditioning current from the battery, thereby conditioning the battery.    
     
     
         22 . The apparatus of  claim 21 , wherein the battery is a rechargeable nickel cadmium (NiCad) battery.  
     
     
         23 . The apparatus of  claim 21 , further comprising: 
 a second switch to decouple the pulse generator an output of the apparatus, such that a device coupled to the output of the apparatus is not affected by a voltage dip as a result of the current pulse.    
     
     
         24 . The apparatus of  claim 23 , further comprising: 
 a delay logic to decouple the pulse generator prior to the current pulse, and to recouple the pulse generator after a delay, such that a voltage spike resulting from a decrease in the current after the current pulse does not affect the device.    
     
     
         25 . The apparatus of  claim 21 , wherein the control circuit comprises: 
 a first driver controlling the first switch, the first driver controlled by the pulse generator, the first driver disconnecting the pulse generator from an output of the apparatus during the pulse; and    a second driver controlling a second switch to couple a capacitor to the output of the apparatus during the pulse, such that the capacitor provides power to a device coupled to the output of the apparatus.    
     
     
         26 . A method of conditioning a battery while discharging the battery, the method comprising: 
 drawing a first current level and a first voltage level from the battery;    drawing a current pulse at least ten times the first current level from the battery;    such that the voltage provided by the battery during the current pulse is one half the first voltage level.