Patent Publication Number: US-7719228-B2

Title: Portable battery recharge station for secondary batteries

Description:
The present application is a continuation of U.S. patent application Ser. No. 10/615,300, entitled PORTABLE BATTERY RECHARGE STATION, filed on Jul. 9, 2003 now U.S. Pat. No. 7,405,535, and is herein incorporated by reference in its entirety. U.S. patent application Ser. No. 10/615,300, in turn, is a continuation of U.S. patent application Ser. No. 10/195,560, filed on Jul. 16, 2002 (now issued as U.S. Pat. No. 6,624,616), which is a continuation of U.S. patent application Ser. No. 09/822,510, filed Apr. 2, 2001 (now issued as U.S. Pat. No. 6,441,589). The present application claims priority from U.S. patent application Ser. No. 09/822,510 under 35 USC §120. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates generally to battery chargers. More particularly, the present invention relates to a portable battery recharge station that can utilize a number of different portable power sources for recharging different types of secondary batteries of a variety of portable devices. 
     2. Background of the Invention 
     Many electrical appliances and electronic devices are portable. Specific examples of portable devices include wireless telephones, laptop computers, camcorders, pocket PCs, and toys. Some of these portable devices use primary batteries, e.g., alkaline batteries. Most of them, however, are powered by different types of rechargeable or secondary batteries. Examples of the types of secondary batteries include nickel-cadmium (NiCd), nickel-hydrogen (NiH 2 ), nickel-metal hydride (NiMH), lithium ion (Li-ion), lithium polymer (Li-polymer), and lead acid batteries. Although zinc-air batteries have been widely used as primary batteries, they are also gaining popularity for use as secondary batteries. 
     Portable devices become disabled or inoperable when the power of their batteries drop below certain threshold. At that time, users of the portable devices must either replace depleted primary batteries with new primary batteries, or find a power source to recharge secondary batteries. 
     As known in the art, each portable device that uses a secondary battery is equipped with a unique charger dedicated to recharge the secondary battery. In other words, a typical consumer having three different types of portable devices may have three different battery chargers. For example, the consumer may have a first battery charger for his wireless telephone, a second battery charger for his camcorder, and a third battery charger for his Pocket PC. These three battery chargers are not interchangeable. In other words, the first battery charger may not be used for the camcorder or the Pocket PC. As a result, users of these battery chargers must carry all three chargers along with their portable devices. Accordingly, there is a need for a universal battery charger for multiple portable devices. 
     A typical secondary battery can be recharged using one of two power sources. For example, the typical secondary battery can be recharged by one battery charger adapted to receive energy from an electrical wall outlet. In addition, the typical secondary battery can be recharged by another battery charger adapted to receive electrical energy from a cigarette lighter outlet of an automobile. There are many situations in which neither of the power sources is available. For example, an explorer who is out in the field for days or weeks at a time may endanger himself when his wireless communication device becomes inoperable due to a depleted battery. Similarly, a news crew member can lose valuable opportunities when its camcorder runs out of battery during an important news coverage at a place where no power source is available. Accordingly, there is a need for a portable battery recharge station that can recharge secondary batteries with a portable power source. 
     There are a number of battery chargers known in the art. For example, U.S. Pat. No. 5,343,136 (the “Yamaguchi patent”) discloses a charger having a chargeable battery with a larger current capacity than a target chargeable battery of a cordless telephone. The charger disclosed can only be used to recharge its associated target chargeable battery. 
     U.S. Pat. No. 5,396,162 (the “Brilmyer patent”) discloses a portable battery charger that utilizes an assembly of primary battery cells to recharge the rechargeable battery of a battery appliance. The portable battery charger disclosed is limited to using primary battery cells as its portable power source. 
     U.S. Pat. No. 5,565,756 (the “Urbish patent”) discloses a microprocessor controlled portable battery charger for use with a variety of battery packs. The charger disclosed can use either primary or secondary batteries as its portable power source. The charger requires charging, sensing, identifying, and output means to properly recharge the battery packs. 
     U.S. Pat. No. 6,154,007 (the “Shaver patent”) discloses a battery charging system that enables rapid recharging of a working battery without the need for current limit and/or over-voltage protection. The portable battery charging system disclosed, however, must always have a greater number of cells than the number of cells in the working battery. 
     Various technologies related to rechargeable batteries are further disclosed in other U.S. patents. For example, U.S. Pat. Nos. 5,747,968 and 5,773,959 (the “Merritt patents”) disclose lithium polymer battery charging methods and apparatus. U.S. Pat. No. 5,645,960 (the “Scrosati patent”) discloses a thin film lithium polymer battery. U.S. Pat. Nos. 6,091,230 and 6,166,548 (the “Winzer patents”) discloses a voltage recovery method for a zinc-air battery and a method of detecting battery capacity of a zinc-air battery, respectively. U.S. Pat. No. 6,146,781 (the “Surampudi patent”) discloses a direct methanol feed fuel cell and system. U.S. Pat. No. 5,352,967 (the “Karl-Diether patent”) discloses a charging method for NiCd and NiH cells. U.S. Pat. No. 6,043,631 (the “Tsenter patent”) discloses a method for charging NiCd, NiH 2  and NiMH batteries. 
     Each of the above-referenced U.S. patents is incorporated herein by reference in its entirety. 
     SUMMARY OF THE INVENTION 
     The present invention is a system and method for recharging secondary batteries. One embodiment of the present invention is a portable battery recharge station. The recharge station comprises a supervisory circuit, a voltage converter, a portable power source, and at least one holder that is adapted to receive a specific type of secondary battery of a portable device. 
     In this embodiment, when a secondary battery is placed in the holder, the supervisory circuit that is connected to the holder communicates with the voltage converter to supply an appropriate voltage required to recharge the secondary battery. The voltage converter receives electrical power from the portable power source. The voltage converter can convert the voltage of the portable power source up (i.e., increasing the voltage) or down (i.e., decreasing the voltage) as appropriate to recharge the secondary battery as instructed by the supervisory circuit. 
     The portable power source of the portable battery recharge station can be one of several types of power sources. For example, the portable power source can be replaceable, rechargeable, or renewable. Replaceable power source can comprise a primary battery. Examples of primary batteries are alkaline and zinc-air batteries. When a primary battery is depleted, it is removed from the portable battery recharge station and replaced by a fresh or new primary battery. 
     A rechargeable power source can comprise a secondary battery. Examples of secondary batteries include NiCd, NiH 2 , NiMH, Li-ion, Li-polymer, and zinc-air batteries. A depleted secondary battery can be recharged by an external power source through a recharger of the portable battery recharge station. 
     A renewable power source can comprise a renewable battery. Examples of renewable batteries include a methanol fuel cell and other fuel cell whose electrolyte can be replenished or otherwise replaced. When a renewable battery is depleted, an appropriate fuel can be added or old electrolyte can be renewed to supply energy to the portable power source. For example, zinc electrolyte cells can be renewed by replacing the electrolyte in the cell. 
     Preferably, the portable battery recharge station has more than one holder. Each holder can be adapted to receive a specific type of secondary battery. For example, a first holder can be adapted to receive a Ni—Cd battery, a second holder can be adapted to receive a NiMH battery, a third holder can be adapted to receive a Li-ion battery, a fourth holder can be adapted to receive a Li-polymer battery, and so on. The holders must be designed to accommodate the physical dimensions of the battery, as well as the placement of the contacts on the battery. Optionally, some of the battery holders may be modified with exchangeable plates designed to accommodate different battery dimensions and contact placements. The supervisory circuit connected to the holders can detect which holder or holders have received a secondary battery. The supervisory circuit can then inform the voltage converter to supply an appropriate voltage to each of the holders that has received a secondary battery. Of course, different batteries (e.g., a NiCd and a Li-ion battery) having the same dimensions could be used with the same holder, because the supervisory circuit can detect the appropriate voltage required for the battery. 
     In another embodiment, the present invention is a battery charging system comprising a portable battery recharge station and a device-specific charging cord. The portable battery recharge station of this embodiment has a universal connector socket in addition to or in lieu of the holder described above. The universal connector socket is adapted to mate with a universal connector plug that is on one end of the device-specific charging cord. The universal connector plug comprises a programming resistor that identifies the type of secondary battery that is used by a portable device associated with the device-specific charging cord. The other end of the device-specific charging cord has a device-specific charge connector that is adapted to mate with a normal device charger connector of the portable device. Preferably, the portable battery recharge station has more than one universal connector socket so that multiple secondary batteries of a plurality of portable devices can be recharged concurrently. 
     Accordingly, it is an object of the present invention to provide a portable battery recharge station that can recharge different types of secondary batteries of various portable devices. 
     It is another object of the present invention to provide a portable battery recharge station that can use a variety of portable power sources. 
     It is another object of the present invention to provide a portable battery recharge station than can recharge two or more types of secondary batteries concurrently. 
     These and other objects of the present invention are described in greater detail in the detailed description of the invention, the appended drawings, and the attached claims. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating an embodiment of the present invention comprising a portable battery recharge station having a plurality of holders. 
         FIG. 2  is a schematic diagram illustrating another embodiment of the present invention comprising a battery charging system having a portable battery recharge station and a device-specific charging cord. 
         FIG. 3  is a schematic diagram illustrating another embodiment of the present invention comprising a renewable portable power source. 
         FIG. 4  is an exemplary flowchart illustrating the steps involved in using an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a schematic diagram illustrating an embodiment of the present invention comprising a portable battery recharge station having a plurality of holders. 
     Portable battery recharge station  100  comprises supervisory circuit  110 , voltage converter  120 , portable power source  130 , holders  140  and  142 , and optionally recharger  150 . Although for the purposes of illustration,  FIG. 1  shows two holders  140  and  142 , portable battery recharge station  100  could comprise only one holder, and preferably comprises two, three, four or more holders. 
     Each of holders  140  and  142  can be adapted to receive a specific type of secondary battery of a portable device. In other words, holder  140  can be adapted to receive a first type of secondary battery and holder  142  can be adapted to receive a second type of secondary battery. Types of secondary batteries that may be placed in holders  140  and  142  include NiCd, NiH 2 , NiMH, Li-ion, Li-polymer, zinc-air, and lead acid batteries. Preferably, each of holders  140  and  142  is adapted to receive only one type of secondary battery. Preferably, holders  140  and  142  are equipped with programming resistors  141  and  143 , respectively. Each of programming resistors  141  and  143  is selected according to one type of secondary battery and an associated voltage requirement of the secondary battery. 
     Supervisory circuit  110  is connected to programming resistors  141  and  143 . When a secondary battery is placed in holder  140 , supervisory circuit  110  determines the voltage requirement of the secondary battery from the value of the resistance of programming resistor  141  using, for example, a look-up table (that associates voltage requirements with different values of resistances of the programming resistor) or an equation or formula (that calculates the voltage requirement based upon the value of the resistance of the programming resistor). Similarly, when a different secondary battery is placed in holder  142 , supervisory circuit  110  knows the voltage requirement of the different secondary battery through programming resistor  143 . 
     Supervisory circuit  110  is connected to voltage converter  120 . Supervisory circuit  110  reports the voltage requirements of the secondary batteries in holders  140  and  142  to voltage converter  120 . For example, when a 4.5-volt secondary battery of a wireless telephone is placed in holder  140 , supervisory circuit  110  instructs voltage converter  120  to supply the appropriate voltage (for example, 6 volts) to holder  140 . Similarly, when a 12-volt secondary battery of a laptop computer is received by holder  142 , supervisory circuit  110  instructs voltage converter  120  to supply the appropriate voltage (for example, 14 volts) to holder  142 . Preferably, voltage converter  120  can concurrently supply different voltages to holders  140  and  142 . In other words, station  110  is adapted to recharge two (or more) different types secondary batteries concurrently. 
     Voltage converter  120  is connected to supervisory circuit  110  and holders  140  and  142 . In addition, voltage converter  120  is connected to portable power source  130 . Voltage converter  120  can convert energy received from portable power source  130  up or down. For example, if portable power source  130  comprises a 12-volt battery and the appropriate voltage for recharging secondary battery in holder  140  is 6 volts (e.g., to charge a 4.5 volt battery), voltage converter  120  can convert the 12 volts received from portable power source  130  down to 6 volts for the secondary battery in holder  140 . Similarly, if portable power source  130  comprises a 6-volt battery and the appropriate voltage for recharging secondary battery in holder  142  is 14 volts (e.g., to charge a 12 volt secondary battery), voltage converter  120  can convert the 6 volts received from portable power source  130  up to the 14 volts necessary to charge the secondary battery in holder  142 . 
     Portable power source  130  can be replaceable, rechargeable, or renewable. Replaceable batteries can include alkaline and zinc-air batteries. Rechargeable batteries can include NiCd, NiH 2 , NiMH, Li-ion, Li-polymer, zinc-air, and lead acid batteries. Renewable batteries can include methanol fuel cells and renewable electrolyte type cells. When portable power source  130  is depleted, it can be replaced, recharged, or renewed accordingly. 
     Recharger  150  is an optional component that is adapted to receive electrical energy from external power source  160  to recharge portable power source  130  that comprises a rechargeable battery. External power source  160  can be one of several external power sources. For example, external power source  160  can be a wall electrical outlet or the cigarette lighter outlet of an automobile. 
       FIG. 2  is a schematic diagram illustrating another embodiment of the present invention comprising a battery charging system  200  having portable battery recharge station  210  and device-specific charging cord  270 . Components of station  210  are similar to components of station  100  described above. In lieu of or in addition to holders  140  and  142 , station  210  further comprises one or more sockets  240  and  242 . Sockets  240  and  242  are preferably universal connector sockets. 
     Like holders  140  and  142 , sockets  240  and  242  are connected to supervisory circuit  110  and voltage converter  120 . Sockets  240  and  242  are adapted to receive or mate with plug  272  of cord  270 . Plug  272  is preferably a universal connector plug that is connected to a first end of cord  270 . Plug  272  comprises programming resistor  241  that identifies the type and the voltage requirement of secondary battery  284  of portable device  280 . The second end of cord  270  comprises connector  274 , which is adapted to mate with connector  282  of portable device  280 . When plug  272  and connector  274  are in contact with socket  240  and connector  282 , respectively, electric current can flow from voltage converter  120  to secondary battery  284  through cord  270 . 
     Station  210  can have one, two or more sockets although two sockets are depicted in  FIG. 2 . Preferably, sockets  240  and  242  are identical. In other words, secondary battery  284  residing within portable device  280  can be recharged by station  210  regardless of whether plug  272  is mated with socket  240  or  242 . Programming resistor  241  of plug  272  reports the voltage requirements of secondary battery  284  (that has been placed in portable device  280 ) to supervisory circuit  110 . 
     Portable device  280  can be any electronic device that can be powered by secondary battery  284 . For example, portable device  280  can be a wireless telephone, a camcorder, or a CD player. Secondary battery  284  can be one of NiCd, NiH 2 , NiMH, Li-ion, Li-polymer, zinc-air, and other rechargeable batteries. 
     It is noted that each of sockets  240  and  242  can receive other plugs of different device-specific charging cords for a variety of portable devices. 
       FIG. 3  is a schematic diagram illustrating another embodiment of the present invention comprising a renewable portable power source. 
     Station  310  of system  300  comprises supervisory circuit  110 , voltage converter  120 , methanol fuel cell  330 , and reservoir  332 . Station  310  also comprises one or more of holder  140  and sockets  240  and  242 . Holder  140  is adapted to receive secondary battery  284  of portable device  280 . Sockets  240  and  242  are adapted to mate with plug  272 , which is part of cord  270  having plug  272  on one end and connector  274  on the other end. Connector  274  is adapted to mate with connector  282 , which is connected to secondary battery  284  of portable device  280 . 
     Methanol fuel cell  330  is connected to reservoir  332 . Optionally, reservoir  332  has an optional gauge  334 , to measure the amount of methanol remaining in reservoir  332 . 
     Methanol fuel cell  330  converts chemical energy in methanol contained in reservoir  332  to electric energy. The electric energy is then used to recharge secondary battery  284 . Secondary battery  284  can either be charged in or out of portable device  280 . For example, secondary battery  284  can remain in portable device  280  and be charged through cord  270 . Alternatively, secondary battery  284  can be taken out of portable device  280  and be placed in holder  140 . 
     As the chemical energy is converted to the electric energy, the amount of methanol in reservoir  332  decreases. The level of methanol in reservoir  332  may be measured by optional gauge  334 . For example, optional gauge  334  may comprise a clear, transparent window of reservoir  332 . Through the transparent window, the level of methanol in reservoir  332  can be visually observed by a user. Alternatively, optional gauge  334  may be an electrical or mechanical means for providing an indication of the level of methanol in reservoir  332 . 
     For example, gauge  334  may comprise one or more light emitting diodes (LEDs). Gauge  334  may emit a green light when reservoir  332  contains more than a threshold amount of methanol. When methanol in reservoir  332  drops below a predetermined level, gauge  334  may emit a red light, indicating that reservoir  332  must be refilled with methanol. 
       FIG. 4  is a flowchart illustrating the steps involved in using an embodiment of the present invention. 
     In step  402 , a depleted secondary battery is connected to or placed in the portable battery recharge station of the present invention. As described above, connection of the secondary battery to the station can be made through a holder or a socket, depending on whether the secondary battery is removed from a portable device. 
     In step  404 , the supervisory circuit measures the value (i.e., the resistance) of a programming resistor, and determines the voltage requirement for charging the secondary battery. The voltage requirement may be determined in any of several ways. For example, a look-up table may be used to associate each resistance of the programming resistor with a specific voltage requirement. Alternatively, a formula or equation may be used to calculate a voltage requirement for each resistance of the programming resistor. More advanced systems may also specify current limits (again, by associating the resistance of the programming resistor with a current limit in a look-up table, or by using equations or formulas). 
     In step  406 , the supervisory circuit conveys the voltage requirement to a voltage converter of the station. 
     In step  408 , the voltage converter receives electrical energy from a portable power source of the station and converts the received energy up or down in accordance with the voltage requirement. 
     In step  410 , the converted energy is supplied to the secondary battery. 
     Steps  402  through  410  can be repeated many times. In other words, more than one secondary battery can be recharged by the portable battery recharge station as long as the portable power source has not depleted its energy in step  412 . 
     In step  414 , the portable power source can be replaced, recharged, or renewed depending on whether the portable power source is replaceable, rechargeable, or renewable. 
     In step  416 , if more secondary batteries are to be recharged, the process returns to step  402 . 
     In an alternative embodiment, the portable battery charger may be configured to supply alternating current (rather than direct current), at the appropriate voltage, to devices which are designed to be recharged with alternating current. 
     In another alternative embodiment, the portable battery recharge station includes circuitry that allows the portable battery recharge station to receive power from a wall outlet (e.g., a 110 or 240 volt outlet, or a car&#39;s cigarette lighter outlet), when such an outlet is available, as an optional alternative to using a primary battery as the replaceable power source. 
     Further, in describing representative embodiments of the present invention, the specification may have presented the method and/or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention. 
     The foregoing disclosure of the preferred embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be obvious to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.