Abstract:
A system and method of recovering unused energy from a source power cell and transferring the recovered energy to a rechargeable target power cell. A controller controls operation of the charging circuit that is coupled between the two power cells for regulating transfer of energy between the two power cells.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a system for recovering remaining energy from a power cell by draining the remaining power from the power cell into a new power cell. 
         [0002]    Many articles of electronic equipment use power cells for batteries as a power source. Some electronic devices use battery packs by virtue of their relatively small size and modular nature. Electronic devices may be hand held, such as for instance cell phones, pagers, while others are relatively large, such as for instance laptop computers, television sets, signs and the like. 
         [0003]    Some batteries are disposable, that is they are thrown out after the stored energy is used up, while others have recharging capabilities. In many instances, the users proactively dispose of batteries and battery packs before the battery power runs out in anticipation of the forthcoming extended need. One of such examples is a common advice to change batteries in a smoke detector every six months even though it is conceivable that the batteries will work additional several months. As a consequence, many power cells that have unused energy are thrown out. 
         [0004]    Of course, battery consumption can vary greatly, depending upon usage levels within the same time period. However, the wasted stored battery energy can range from 15 to 90%, depending on the type of use and application. The cost and environmental impact of the discarded power cells rises every year, as the industries become more and more dependent on portable electronic devices. 
         [0005]    While rechargeable batteries offer a reasonable alternative, it is no secret that many field conditions prevent their use, particularly where municipal AC power is unavailable. As a consequence, rechargeable batteries are limited in their application to those instances where the conditions permit their recharging in a relatively inexpensive and convenient manner. 
         [0006]    Currently, the only available and reliable chargers rely on AC and/or DC power supplies, typically from vehicles or generators. Though addressing many of the weight and cost challenges associated with the disposable versions of these batteries, some problems remain, such as the problem of requiring fuel to run the vehicles and generators which recharge the batteries, and the risk of draining a vehicle battery if a portable battery is being charged without the motor running. The lack of an efficient charger is tantamount to having no batteries at all. Solar power and fuel cells have also been tested for battery charging, but both at this time have major drawbacks with lack of mobility, efficiency, and reliability 
         [0007]    The present invention contemplates the elimination of drawbacks associated with conventional power cell charging and provision of a system that allows draining of energy from used batteries to charge or recharge another battery. 
       SUMMARY OF THE INVENTION 
       [0008]    It is, therefore, an object of the present invention to provide a system of recovering energy from a power cell. 
         [0009]    It is another object of the present invention to provide a system for recovering unused energy from a power cell and transferring the recovered energy into a rechargeable power cell. 
         [0010]    These and other objects of the invention are achieved through a provision of a system and method of recovering unused energy from a source power cell and transferring the recovered energy to a rechargeable target power cell. A controller controls operation of the charging circuit that is coupled between the two power cells for regulating transfer of energy between the two power cells. The target power cell is a rechargeable battery. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Reference will now be made to the drawings, wherein like parts are designated by like numerals, and wherein 
           [0012]      FIG. 1  is a diagram of the system of the present invention. 
           [0013]      FIG. 2  is a front view of the housing, within which electric/electronic components of the invention are positioned. 
           [0014]      FIG. 3  is a schematic of one exemplary embodiment of the system of the present invention. 
           [0015]      FIG. 4  is a detail schematic of one exemplary embodiment of the system of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Turning now to the drawings in more detail, numeral  10  designates the system of transferring energy from a power cell according to the present invention. As can be seen in the drawing, the system comprises a charging circuit, or power converter  12  operationally connected between a source battery  14  and a target battery  16 . The power converter  12  may be a low loss type power converter that forms a charging circuit for receiving input from the source power cell  14  and transferring the energy to the target power cell  16 . The power converter  12  supplies the load power from the source power cell  14  to all electrical and electronic components of the system  10 . 
         [0017]    The source battery  14  is electrically connected to a voltage regulator  18 , which comprises a voltage sense logic module for controlling the voltage regulator  18 . The source battery is also connected to an electrical current sensor, or current sense module  20 , which is adapted to measure the DC current level in the power cell  14 . The current sense module  20  receives current inputs and provides outputs as analog voltage signals, analog current levels, switches, or audible signals. Depending on the selection, the current sense circuit  20  can also provide frequency and modulated frequency outputs. In one aspect of this invention the current sensor  20  is an open loop sensor. 
         [0018]    The current sense module  20  is mounted between the source battery  14  and the power converter  12 , while the voltage sense module  18  is mounted between the source battery  14  and controller  22 . The controller  22  receives signals from both source battery  14  and the target battery  16 . The controller  22  processes all monitored signals and provides control stimulus to the power controller  12 . 
         [0019]    The target battery, or power cell  16  is similarly connected to the power converter  12  through a current sense module  24 , which is capable of measuring DC current level in the target power cell  16 . An independent voltage sense module  26  is mounted between the target power cell  16  and the controller  22 . 
         [0020]    The controller  22  provides a means for controlling transfer of power from the source cell  14  to the target cell  16 . The controller  22  monitors the source voltage and current, based on the source battery type, so as to determine “end of discharge” for the source power cell  14 . The controller  22  also monitors the load voltage and current as well as the load battery type to determine “state of charge” for the target power cell  16 . 
         [0021]    The controller  22  comprises a microchip DSP processor, which is programmed for the specific batteries used as the source batteries and the target batteries. The power cells  14  and  16  can be AA or AAA batteries or any other type of batteries, depending on specifications. Any type of rechargeable battery can be used, including, but not limited to NiCad, NiMH, and Li-Ion. 
         [0022]    The controller  22  also comprises a charge controller circuitry to determine status of the charge process. To help facilitate ease of use, the system  10  can be mounted in a housing  30  with connectors A marked as “power out” and connectors B marked as “power in.” An arrow  32  on the outside of the housing  30  indicates the desired flow of energy direction. An LED indicator light  34  shows the “energy transferring status,” while an LED indicator light  36  shows “energy transfer complete” operational stage of the energy recovery process. Other LED indicator lights may show various operational stages, charging status states, and/or charging error conditions. 
         [0023]    The system  10  is not an equilibrium system that is it does not aim to achieve equilibrium in energy capacity between the source battery and the target battery. The system  10  uses the power of the source power cell  14  to completely deplete the energy from the source and transfer the recovered energy to the target power cell  16 . The system  10  maximizes the available battery power for the user by collecting the remaining energy of all partially spent, and unusable, batteries and consolidating that power into a rechargeable battery until its charge state is at a usable level once again. The target power cell  16  can be connected to more than one source power cell in order to take advantage of all available partially depleted batteries. 
         [0024]    As used herein, “battery” can refer to a single battery, one or more batteries used in series or in parallel arrangement, or any other modular power source. Because the power from the source power cell can be transferred to the target power cell, energy normally lost by discharge of the partially used batteries is saved. The schematic examples illustrated in  FIGS. 3 and 4  are for illustration purposes only. It will be understood that the size, capacities, number, and particular layout of the individual switches, capacitors, transistors, etc. will vary due to the individual battery requirements. 
         [0025]    The system  10  is a direct-transfer dc-to-dc energy transfer system; it does not use a “holding” step, wherein the recovered energy could be stored until the need arises. In the use of the system  10 , a source battery is connected to the target battery immediately through the system  10 . 
         [0026]    Many changes and modifications can be made in the design of the present invention without departing from the spirit thereof. I, therefore, pray that my rights to the present invention be limited only by the scope of the appended claims.