Abstract:
Embodiments of the invention relate to a galvanic cell comprising a first electrode, a second electrode, an electrolyte in contact with both the electrodes, a substrate adapted to support and separate the electrodes while allowing the electrolyte to move within it and contacts electrically coupled to the electrodes, wherein one or more of the electrodes comprises one or more highly reactive metals and wherein at least one of the electrodes is printed on the substrate.

Description:
RELATED APPLICATION 
       [0001]    This application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 60/804,852 filed Jun. 15, 2006, which application is incorporated herein by reference and made a part hereof. 
     
    
     TECHNICAL FIELD 
       [0002]    Embodiments of the present invention relate to printable batteries and specifically, to small, flexible printable batteries. 
       BACKGROUND 
       [0003]    The use of plastic electronics is rapidly expanding worldwide. A primary factor in this development is that the plastic electronics are able to be printed in large volumes. In more than one environment, the printed electronics will need an independent power supply. 
         [0004]    One application of a printable battery is in use with a RFID (radio frequency identification) tag. RFID tags are currently being used or considered for advancements in supply-chain management, logistics and asset tracking, baggage-tracking and security, for example. Next-generation technology in RFID tags may produce cost savings, reduced inventory loss, increased security and improved customer satisfaction that will be beneficial for a number of differing industries. Passive RFID tags do not provide the versatility and robustness of active RFID tags, but are more commonly used due to the much higher costs and bulkiness associated with the power supply needed for active RFID tags. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    In the drawings, which are not necessarily drawn to scale, like numerals describe substantially similar components throughout the several views. Like numerals having different letter suffixes represent different instances of substantially similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document. 
           [0006]      FIG. 1  illustrates a perspective view of a printable battery, according to some embodiments. 
           [0007]      FIG. 2  illustrates a cross-sectional view of a printable battery, according to some embodiments. 
           [0008]      FIG. 3  illustrates a block flow diagram of a method of using a printable battery, according to some embodiments. 
           [0009]      FIG. 4  illustrates a block flow diagram of a method of manufacturing a printable battery, according to some embodiments. 
           [0010]      FIG. 5  illustrates a perspective view of an RFID tag utilizing a printable battery, according to some embodiments. 
       
    
    
     SUMMARY 
       [0011]    Embodiments of the invention relate to a galvanic cell comprising a first electrode, a second electrode, an electrolyte in contact with both the electrodes, a substrate adapted to support and separate the electrodes while allowing the electrolyte to move within it and contacts electrically coupled to the electrodes, wherein one or more of the electrodes comprises one or more highly reactive metals and wherein at least one of the electrodes is printed on the substrate. 
         [0012]    Further embodiments relate to a method of manufacturing a printable battery, comprising printing a first electrode onto a substrate, printing a second electrode onto the substrate, positioning an electrolyte onto or within the substrate such that the electrolyte is in contact with the electrodes and forming contacts electrically coupled to the electrodes, wherein one or more of the electrodes comprises one or more highly reactive metals. 
         [0013]    An additional embodiment relates to a method of using a printable battery, comprising electrically coupling a printable battery to an external load and powering the load. 
       DETAILED DESCRIPTION 
       [0014]    The following detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments, which are also referred to herein as “examples,” are described in enough detail to enable those skilled in the art to practice the invention. The embodiments may be combined, other embodiments may be utilized, or structural, and logical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents. 
         [0015]    In this document, the terms “a” or “an” are used to include one or more than one and the term “or” is used to refer to a nonexclusive or unless otherwise indicated. In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Furthermore, all publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference should be considered supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls. 
         [0016]    Embodiments of the invention relate to a printable battery using highly reactive metals as electrodes that allow for printing resolution and power outputs not seen before. The size of the printable battery may be less than 100 microns. Due to the ability of such a printable battery to perform as a larger battery allows for its implementation into any number of plastic electronics or for the further miniaturization of electronics not yet considered. The highly reactive metals, and even an electrolyte, may be suspended in a solvent for accurate and repeatable printing. 
       DEFINITIONS 
       [0017]    As used herein, “highly reactive metals” or “Rieke highly reactive metals” refers to zerovalent (having a valence of zero) metal atoms in a finely divided powder form. Rieke highly reactive metals are prepared by the Rieke method. The high reactivity of the metals may be in relation to reactivity in organic reactions, such as oxidative addition reactions. Examples of highly reactive metals include highly reactive forms of zinc, copper and nickel. Further examples of highly reactive metals and methods of preparation are found in U.S. Pat. Nos. 5,964,919; 5,852,200; 5,756,653; 5,581,004; 5,507,973; 5,498,734; 5,490,952; 5,490,951; 5,463,018; 5,436,315; 5,384,078; 5,358,546; 5,330,687; 5,231,205; 5,211,889; and 5,211,886, whose disclosures are herein incorporated in there entirety. 
         [0018]    As used herein, “electrode” refers to a conductor used to make contact with a nonmetallic part of a circuit, such as an electrolyte. Examples of electrodes are anodes and cathodes. 
         [0019]    As used herein, “anode” refers to the electrode where oxidation takes place, and in which electrons may be lost. An anode may be a negative electrode, for example. 
         [0020]    As used herein, “cathode” refers to the electrode where reduction takes place in which electrons are accepted. A cathode may be a positive electrode, for example. 
         [0021]    As used herein, “electrolyte” refers to a substance that dissociates into free ions when dissolved (or molten), to produce an electrically conductive medium. An electrolyte serves as a conductor between electrodes, electrically connecting them, for example. 
         [0022]    As used herein, “contacts” refer to a component that provides a connection between two conductors that permits a flow of current or heat. Contacts on a battery provide a connection to a conductor on an external load, for example. 
         [0023]    As used herein, “substrate” refers to the base material that images or solutions are printed onto. These materials may include films, foils, textiles, fabrics, plastics or polymers, and any variety of paper (lightweight, heavyweight, coated, uncoated, paperboard, cardboard, etc.). 
         [0024]    As used herein, “galvanic cell” or “electrochemical cell” refers to an apparatus for creating an electromotive force (voltage) in a conductor separating two reactions. An example of a galvanic cell includes a battery, such as a primary (single discharge) or secondary battery (rechargeable). 
         [0025]    As used herein, “printable” refers to being capable of being printed. Electrodes in a printable battery may be printed by ink-jet printing, roll-to-roll printing or screen printing, for example. 
         [0026]    As used herein, “electrically couple” refers to a positioning in which two or more components are electrically connected. 
         [0027]    As used herein, “positioning” refers to putting in place, position or to locate. 
         [0028]    As used herein, “powering” refers to the ability to power or be powered, such as providing electrical energy. 
         [0029]    Referring to  FIG. 1 , a perspective view of a printable battery  100  is shown, according to some embodiments. A first electrode  104  may be positioned near a second electrode  106  on or within a substrate  108 . Arrows indicating the movement of electrolyte  110  through the substrate  108  are shown between the electrodes. Contacts  102  electrically couple the electrodes to an external load. 
         [0030]    The first electrode  104  and second electrode  106  may be an anode or cathode. The printable battery  100  may comprise more than two electrodes. The electrodes may comprise one or more highly reactive metals. The cathode may comprise highly reactive zinc, for example. The anode may comprise highly reactive MnO/Carbon or MnO. The highly reactive metals may be Rieke highly reactive metals prepared by the Rieke method. The contacts  102  may be zinc foil at the cathode and copper or tin foil at the anode, for example. 
         [0031]    The highly reactive metals may be suspended in a variety of solvents suitable for printing. Water is an example of solvent used to suspend the highly reactive metals. One or more of the electrodes may be printed on or within the substrate  108  by ink-jet printing, roll-to-roll printing or screen printing, for example. The electrolyte  110  may also be dissolved in the solvent for printing, or separately applied. Ammonium chloride is an example of an acceptable electrolyte  110 . The electrolyte  110  may also be in the form of a paste. The electrolyte  110  may also be used to wet the substrate  108  between the electrodes, creating an electrical connection. 
         [0032]    The substrate  108  may comprise films, foils, textiles, fabrics, plastics, and any variety of paper (lightweight, heavyweight, coated, uncoated, paperboard, cardboard, etc.). The printable battery  100  may be printed on the substrate  108  to a resolution of about 50 microns, for example. Further, the resolution may be about 25-30 microns, about 30-40 microns or about 40-50 microns, for example. The size of the printable battery may be less than 200 microns or less than 100 microns, for example. The printable battery  100  may have a potential of about 1.5 volts with highly reactive zinc as the cathode and highly reactive Mn/O as the anode. More than one printable battery may be printed in series, producing potentials of about 3 volts, about 4.5 volts, about 6 volts, etc. Using highly reactive copper for the anode may provide an electromotive force of about 1.08 volts, for example. Numerous combinations of the highly reactive metals are possible. 
         [0033]    By using highly reactive nickel with an alkaline electrolyte  110 , nickel oxide would be produced when charged, creating an electromotive force of about 1.1 volts and would be rechargeable. This would be an example of a secondary battery. 
         [0034]    Referring to  FIG. 2 , a cross-sectional view of a printable battery  100  is shown, according to some embodiments. A first electrode  104  may be positioned near a second electrode  106  on or within a substrate  108 . Arrows indicating the movement of electrolyte  110  through the substrate  108  are shown between the electrodes. Contacts  102  electrically couple the electrodes to an external load. An optional sealable layer  202 , such as a cover, may provide a barrier between the battery components and ambient. An optional backing layer  204  may provide a barrier to ambient from the opposite side of substrate  108  as the sealable layer  202 . 
         [0035]    The sealable layer  202  may provide a barrier between the battery components and ambient. The contacts  102  may be in the same plane as the sealable layer  202  or at an angle to it, such as perpendicular. The sealable layer  202  may be comprised of one or more porous sections or layers, such as a porous section comprising the electrolyte  110 . The backing layer  204  may provide a barrier between the substrate  108  and ambient. The sealable layer  202  and backing layer  204  may be comprised of any number of materials, including polymers or papers. The sealable layer  202  may also be a resin, such as an epoxy. 
         [0036]    Referring to  FIG. 3 , a block flow diagram of a method  300  of using a printable battery is shown, according to some embodiments. A printable battery may be electrically coupled  302  to an external load. The external load may then be powered  304  by the printable battery. Examples of an external load may be a RFID (radio frequency identification) tag, cellular phone, or other electronics. 
         [0037]    Referring to  FIG. 4 , a block flow diagram of a method  400  of manufacturing a printable battery is shown, according to some embodiments. A first electrode may be printed  402  onto a substrate. A second electrode may be printed  404  onto a substrate. An electrolyte may be positioned  404  onto or within the substrate, such that the electrolyte is in contact with the electrodes. Contacts may be formed  408  which may be electrically coupled to the electrodes. 
         [0038]    Referring to  FIG. 5 , a perspective view of an RFID tag  500  utilizing a printable battery is shown, according to some embodiments. The RFID tag  500  may be printed on a substrate and comprise such components as circuitry  502 , printable battery  504  and antenna  506 . By utilizing a printable battery  504  according to the present embodiments, an RFID tag  500  can be manufactured at smaller sizes than previously utilized. The highly reactive metals used in the printable battery  504  allow for a stronger energy source in a smaller form. 
         [0039]    The Abstract is provided to comply with 37 C.F.R. §1.72(b) to allow the reader to quickly ascertain the nature and gist of the technical disclosure. The Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.