Abstract:
An electricity supply system and electricity supply element thereof is provided. The electricity supply system is made of a plurality of electricity supply elements by stacking or rolling. Each electricity supply element includes a substrate, two current collector layers and two active material layers. The substrate has a plurality of holes and the current collector layers, the active material layers are disposed on two sides respectively. Therefore, the ion migration is permitted by the holes and the electricity is outputted by the current collector layers. Hence, by this new structure of the electricity supply element, the resistance is decreased.

Description:
RELATED-APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 13/323,825, filed Dec. 13, 2011, which is a continuation-in-part of U.S. patent application Ser. No. 11/755,657, filed May 30, 2007. This application claims priority to all the above-referenced applications. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to an electricity supply system, in particular to a lithium battery having a simplified separator and electrode layers and a lowest amount of the interfaces inside the battery. 
         [0004]    2. Related Art 
         [0005]    In the electronic device industry, portability and wireless design are the major trends. Except the lighter, thinner and smaller designs, the flexibility of the electronics is highly focused as well. Hence, an electricity supply system having smaller volume, lighter weight and higher energy density is imperatively required. However, to prolong the life and to increase the energy density of the electricity supply system, the primary electricity supply system obviously cannot satisfy the demands of the current electronics. And this is the reason why the secondary electricity supply systems such as the lithium battery system, fuel cell system, solar cell system become the main stream for their recharge abilities. The lithium battery system is taken as the example for its highly development. 
         [0006]      FIG. 1A  illustrates the current cell of the lithium battery system. The main structure is constructed by a separator layer sandwiched by a cathode electrode and an anode electrode. The external electrodes of the whole lithium battery system, which are electrically connected to the peripherals, are welded individually to the tabs located in the current collectors of both cathode and anode electrodes. As shown in  FIG. 1A , the lithium battery  1  includes a separator layer  11 , a first active material layer  12 , a second active material layer  13 , a first current collector layer  14 , a second current collector layer  15  and a package unit  16 . The first active material layer  12  is located above the separator layer  11 . The first current collector layer  14  is located above the first active material layer  12 . The second active material layer  13  is located under the separator layer  11 . The second current collector layer  15  is located under the second active material layer  13 . The package unit  16  seals the whole stacking structure mentioned above except the two tabs  141  and  151 . Accordingly, as the lithium battery  1  provides the electricity to an electronic device  2  (the circuit broad illustrated in  FIG. 1A  is only one embodiment and is not a limitation for the electronic device  2 ), the tabs  141  and  151  are electrically connected to the electricity input terminals  21  and  22  of the electronic device  2  so that the electricity stored in the lithium battery  1  is transferred to the electronic device  2 . After that, the electricity is transferred to the element area  23  of the electronic device  2  by the layouts. The element area  23  mentioned here may be the circuit layouts or the surface mounted elements, that is, typically includes the logical circuit, active elements, and passive elements and so on. 
         [0007]    However, the electrical and safety performances of the lithium battery  1  are dramatically influenced by the characteristics of both the interface between the separator layer  11  and the first active material layer  12  and the interface between the separator layer  11  and the second active material layer  13 . Please refer to  FIG. 1A , there have four interfaces of the lithium battery  1 , i.e. the interfaces between the separator layer  11  and the first active material layer  12 , between the separator layer  11  and the second active material layer  13 , between the first current collector layer  14  and the first active material layer  12 , and between the second current collector layer  15  and the second active material layer  13 . For the current lithium battery system, the characteristics of these interfaces are controlled either by solid stacking method or by high-tension winding method (jelly roll) to ensure the good electrical and safety performances of the lithium battery system. Unfortunately, the lithium battery systems made by solid stacking or high-tension winding method are definitely lack of flexibility and even are impossible to be flexed. If the stacked battery or the winded battery is forced to be flexed it would cause the serious damage to the interfaces between the separator layer  11  and the first active material layer  12  and the separator layer  11  and the second active material layer  13 . 
         [0008]    Moreover, the active anode material may expand or shrink its volume on charge or discharge to exhibit mechanical stress to both sides of the active anode material. Please refer to  FIG. 1A , for example, if the second active material layer  13  is the active anode material, the second active material layer  13  is disposed between the separator  11  and the second current collector layer  15 . Therefore, the second active material layer  13  exhibits mechanical stress to the separator  11  and the second current collector layer  15  on charge or discharge. After a certain period of time, it is difficult to maintain the same quality of interfaces due to suffer of the repeating volume expansion and shrinkage. 
         [0009]    Also, the tab  141  is usually made of aluminum. Because the aluminum can not be soldered directly, the tab  141  have to be connected with a nickel sheet by ultrasonic. Furthermore, the tabs  141 ,  151  have to extend outside of the package unit  16 . The thickness of the tabs  141 ,  151  is 100 to 150 um (micro meter), and the thickness of the package unit  16  including the glues is 60 to 120 um. Therefore, there may have a gap between the tabs  141 ,  151  and the package unit  16  to make the moisture resistance and the liquid barrier weaker, which may cause the outside moisture to permeate inside, or the inside electrolyte to leak out and damage the circuit. 
         [0010]    Please refer to  FIG. 1B , the stack type battery is provided with a plurality of unit cells (the lithium battery  1 ) stacked in a stack direction. Due to each lithium battery  1  has four interfaces as above mentioned, the total number of the interfaces would be increased accordingly. Along with the active anode material may expand or shrink on charge or discharge to exhibit mechanical stress, the reliability of the stack type battery may be influenced when one of the interfaces does not contact well. Also, the amount of the interfaces would influence the fluidity and permeability of the electrolyte. When the amount of the interfaces is increased, it costs more time to make the electrolyte permeate uniformly. Moreover, the electrolyte distribution may be not uniform even after long time that will decrease the efficiency of the battery. 
         [0011]    Also, the leads of each battery  1  have to be connected in parallel before the tabs  141  and  151  are electrically connected to the electricity input terminals  21  and  22  of the electronic device  2 . When the number of the leads is increased, the reliability and the yield rate of the welding are decreased. 
       SUMMARY OF THE INVENTION 
       [0012]    It is an objective of this invention to provide an electricity supply element and its related electricity supply system. The current collector layers are disposed on the substrate. Therefore, the active material layers may be rapidly and precisely formed on the current collector layers to form the electricity supply element. The electricity supply element mentioned in this invention may be produced under higher yield rate and faster production rate. 
         [0013]    Another objective of this invention is to provide an electricity supply element and its related electricity supply system. The current collector layers can be integrated with the substrate to form the external circuit area and the internal circuit area on the substrate. Therefore, the electricity supply element is able to be directly electrically connected to the external electrical elements or connected to each other so that the amounts of the elements exerted in the electronic may be reduced. The stack type or jelly roll type electricity supply system may be manufactured with a simplified process. Also, the aluminum or nickel tab, which is utilized in conventional battery to connect to the external electrical elements, can be eliminated. The substrate is able to become thinner, and the reliability of the package structure of the electricity supply system is increased. 
         [0014]    It is also an objective of this invention is to provide an electricity supply element and its related electricity supply system. The package structure may be integrated with the electricity supply element so that the amounts of the total interfaces inside the electricity supply system are reduced to reduce the inner resistance of the electricity supply system and to increase the electrical performance of the electricity supply system as well. 
         [0015]    In order to implement the abovementioned, this invention discloses an electricity supply element. The electricity supply element includes a substrate, a first current collector layer, a second current collector layer, a first active material layer and a second active material layer. The substrate includes a plurality of holes. The first and the second current collector layers are deposed on the two opposite sides of the substrate and have holes according to the holes of the substrate. The active material layers are disposed on the outer side of the current collector layers respectively. Therefore, the substrate is served as a separator to permit ion migration between the first active material layer and the second active material layer. The electric charge is outputted through the current collector layers which disposed on the substrate. 
         [0016]    This invention discloses an electricity supply system, including a plurality electricity supply elements to stack. The same substrate may be utilized for all the electricity supply elements. Therefore, the internal circuit area, formed on the substrate, is utilized to electrically connect with each other for parallel or serial connection. Only one of the electricity supply elements has the external circuit area to connect to the external electrical elements for outputting electricity. The complicate process of the conventional electricity supply elements to connect each lead is eliminated. The electricity supply system may be produced under higher yield rate and faster production rate, and the reliability and the electrical performance of the electricity supply system is increased. 
         [0017]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The present invention will become more fully understood from the detailed description given hereinbelow illustration only, and thus are not limitative of the present invention, and wherein: 
           [0019]      FIG. 1A  illustrates the example of the cell of the prior-art lithium battery system. 
           [0020]      FIG. 1B  illustrates the example of the conventional stack type lithium battery system. 
           [0021]      FIG. 2  illustrates the cross-sectional view of the electricity supply element of this invention. 
           [0022]      FIGS. 3A and 3B  illustrate embodiments of the external circuit layout of the electricity supply element according to the present invention. 
           [0023]      FIG. 4  illustrates the cross-section configuration view of the electricity supply element with package structure of this invention. 
           [0024]      FIGS. 5 ,  6 A and  6 B illustrate embodiments of the electricity supply system of the present invention. 
           [0025]      FIG. 7A  illustrates the cross-sectional view of the electricity supply system of this invention. 
           [0026]      FIG. 7B  illustrates the respective view of the electricity supply element of this invention. 
           [0027]      FIG. 8  illustrates an embodiment of the electricity supply system with package structure of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    The invention provides an electricity supply element, which is integrated in a flexible circuit board or a rigid circuit board, and an electricity system with low cost, high electric capacity, thermal stability, and extra mechanic characteristic, such as repeat bends. Due to the electricity supply unit is integrated in a circuit substrate, the carrier or the solder pad are not necessary. Also, the circuit substrate is utilized as a separator. The thermal stability temperature of the circuit substrate is over 300° C. Therefore, reflow soldering method to continuously proceed SMT process, even a metal-metal eutectic process for IC, for mass-production is possible. 
         [0029]      FIG. 2  illustrates the cross-sectional view of the electricity supply element of this invention. The electricity supply element  3  of this invention includes a substrate  31 , a first current collector layer  32 , a second current collector layer  33 , a first active material layer  34  and a second active material layer  35 . The substrate  31  has a separating area  311  and an external circuit area  312  adjacent thereof. The substrate  31  has a plurality of holes  313  at the separating area  311 . The first current collector layer  32  is disposed on one side of the circuit substrate  31 , and has a plurality of holes  321  according to the holes  313  of the substrate  31 . The second current collector layer  33  is disposed on another side of the circuit substrate  31 , and has a plurality of holes  331  according to the holes  313  of the substrate  31 . The first active material layer  34  and the second active material layer  35  are disposed at the outside surfaces of the first current collector layer  32  and the second current collector layer  33  respectively. And the first active material layer  34  and the second active material layer  35  are separated by the first current collector layer  32 , the substrate  31  and the second current collector layer  33 . The electrolyte impregnated into the first active material layer  34  and the second active material layer  35 . The electrolyte is a solid electrolyte, a liquid electrolyte, or a gelled electrolyte. Due to the first current collector layer  32 , the substrate  31  and the second current collector layer  33  have the holes  313 ,  321  and  331 , the electrolyte is easier to impregnate into therein. 
         [0030]    In this embodiment, the circuit substrate  31  is a flexible circuit board or a rigid circuit board. As refer to  FIG. 2 , the first current collector layer  32  and the second current collector layer  33  have a first terminal  36  and a second terminal  37  respectively at the external circuit area  312 . The substrate  31  may be a multilayer circuit board. The material of the first terminal  36  and the second terminal  37  is copper (Cu), Aluminum (Al), nickel (Ni) or an alloy comprised of at least one of the foregoing metals. However, to simplify the manufacture process, the material of the first terminal  36  and the second terminal  37  is the same with the material of the first current collector layer  32  and the second current collector layer  33 , such as copper (Cu), Aluminum (Al), or nickel (Ni), tin (Sn), silver (Ag), gold (Au), or an alloy comprised of at least one of the foregoing metals. Also, the material of the first terminal  36  and the second terminal  37  may be different with the material of the first current collector layer  32  and the second current collector layer  33 . And the first terminal  36  and the second terminal  37  are connected to the first current collector layer  32  and the second current collector layer  33  respectively by wiring, electrical lead, or connecting directly. The material of the substrate  31  is insulating materials, includes polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), glass fiber, and liquid crystal polymer, or the combination thereof. 
         [0031]    The substrate  31  is served as the separator to maintain separation between the first active material layer  34  and the second active material layer  35 . The separating area  311  is utilized for insulation electrically and to permit ion migration between the first active material layer  34  and the second active material layer  35 . The first active material layer  34  and the second active material layer  35  are used to perform electrochemistry reaction to convert Electrical energy into Chemical energy or Chemical energy into Electrical energy. The first current collector layer  32  and the second current collector layer  33  are utilized to output electric charge, produced by the first active material layer  34  and the second active material layer  35 , to the first terminal  36  and the second terminal  37 . The substrate  31  has the holes  313  to permit ion migration. The holes  313  are formed by through holes, ant holes, or porous material, and filled with ceramic insulation materials. The ceramic insulation materials include particulates of TiO 2 , Al 2 O 3 , SiO 2  with nanometer and micrometer scale, or alkylation. The holes  313  may be further filled with a polymer adhesive, which is selected from the group consisting of Polyvinylidene fluoride (PVDF), polyvinylidene fluoride co-hexafluoropropylene (PVDF-HFP), Polytetrafluoroethene (PTFE), acrylic acid glue, epoxy resin, polyethylene oxide (PEO), polyethylene naphthalate (PEN), and polyimide (PI). 
         [0032]    Please see the structure of the electricity supply element  3  of this invention, the first current collector layer  32  and the second current collector layer  33  are disposed on the substrate. Therefore, it only has two interfaces for this structure, i.e. the interface between the first current collector layer  32  and the first active material layer  34 , and between the second current collector layer  33  and the second active material layer  35 . The interface management of this structure is easier to control than the interface management of the conventional structure which has four interfaces, see  FIG. 1A . Also, for example, if the second active material layer  35  is the active cathode material, the second active material layer  35  has a free side due to the second current collector layer  33  and the substrate  31  are disposed on the same side. When the active anode material, the second active material layer  35 , may expand or shrink on charge or discharge, the stress exhibited is released easily. Therefore, the reliability, the stability and the safety performances of the electricity supply element  3  are improved. 
         [0033]    The substrate  31  has the separating area  311  and the external circuit area  312  adjacent thereof to be with the following main functions. 
         [0034]    The separating area  311  is utilized for insulation electrically and to permit ion migration between the first active material layer  34  and the second active material layer  35 . The first active material layer  34  and the second active material layer  35  are used to perform electrochemistry reaction to convert Electrical energy into Chemical energy or Chemical energy into Electrical energy. The first current collector layer  32  and the second current collector layer  33  are utilized to output electric charge, produced by the first active material layer  34  and the second active material layer  35 , to the first terminal  36  and the second terminal  37 , pleases see  FIG. 3A . 
         [0035]    The external circuit area  312  is utilized to output electricity directly by etched traces connecting to the outside circuit directly without extra pads, see  FIG. 3B . Also, the tabs of the conventional structure are eliminated. 
         [0036]    Due to the separating are  311  could be served as a carrier or matrix for other inside electric elements, the outside circuit and electric elements are integrated in the circuit substrate  31  by the external circuit area  312 . Besides, the substrate  31  with high thermal stability. Therefore, reflow soldering method to continuously proceed SMT process, even a metal-metal eutectic process for IC, for mass-production is possible. 
         [0037]    Please refer to  FIG. 4 , the first package unit  41  is located outside and around the first active material layer  34 . The second package unit  42  is located outside and around the second active material layer  35 . The material of the first package unit  41  and the second package unit  42  is polymer, metal, fiberglass, and combinations thereof. 
         [0038]    To enhance the flexibility of the electricity supply element  3 , the first package unit  41  and the second package unit  42  may be made of PI, PET, PS, PP, PEN, PVC, acrylic acid or epoxy. Furthermore, the material of the first package unit  41  and the second package unit  42  may be non-metal with low polarity to enhance the acid or alkali resistance to prevent erosion. 
         [0039]    Also, the electricity supply element  3  may have package structure as the conventional package structure, refer to  FIG. 1A  and  FIG. 3A . Due to electricity supply element  3  is connected to the electronic device  2  by the first terminal  36  and the second terminal  37 , which is extended from the substrate  31 . Therefore, the structure is thinner than the conventional structure with the tabs  141 ,  151  and easier to package without defects. Furthermore, the substrate  31  may be shaped by pressing to reduce the width of the package area, see  FIG. 6A . The package performance could be improved. 
         [0040]    When forming the electricity supply system of this invention, please refer to  FIGS. 5 and 6A , a plurality of the electricity supply elements  3  are formed on the substrate  31 . Each electricity supply element  3  includes an internal circuit area  38 . The internal circuit area  38  includes a first lead  53  and a second lead  54  thereon. The first lead  53  and the second lead  54  are electrically connected with the first current collector layer  32  and the second current collector layer  33  of the adjacent electricity supply elements  3  for parallel or serial connection. Please see  FIG. 6A , the current collector layers  32 ,  33  with the same polarity of the adjacent electricity supply elements  3  is connected by the leads  53 ,  54  for parallel connection. Please see  FIG. 6B , the current collector layers  32 ,  33  with the different polarity of the adjacent electricity supply elements  3  is connected by the leads  53 ,  54  for serial connection. Also, the current collector layers  32 ,  33  may have different polarity on the same side. As the  FIG. 5  shown, the electricity supply elements  3  have the same substrate  31 . The electricity supply elements  3  may have individual substrates  31 . 
         [0041]    The substrate  31  is the flexible circuit board and can be bent to a Z-type stack, please refer to  FIGS. 7A and 7B . The active material layers  34 ,  35  with the same polarity are faced to each other. On the other hand, the first active material layers  34  faces to the first active material layers  34 . The second active material layers  35  faces to the second active material layers  35 . Due to the first current collector layer  32 , the substrate  31  and the second current collector layer  33  have the holes  313 ,  321  and  331 , the electrolyte is easier to impregnate into the whole electricity supply system. Also, only two interfaces are presented, i.e. the interface between the first current collector layer  32  and the first active material layer  34 , and between the second current collector layer  33  and the second active material layer  35 , for each electricity supply elements  3 . And the active material layers  34 ,  35  with the same polarity are faced to each other for the adjacent electricity supply elements  3 . Therefore, the interface management of the electricity supply system is very easy. When the active anode material, the second active material layer  35 , may expand or shrink on charge or discharge, the second active material layer  35  will only touch or push the adjacent second active material layer  35 . The stress exhibited is released easily, and the structure would be maintained. Therefore, the reliability, the stability and the safety performances of the electricity supply system are improved. 
         [0042]    Only one of the electricity supply elements  3  has the external circuit area  312 , also see  FIG. 6A , to connect to the external electrical elements for outputting electricity through the terminals  36 ,  37  by anisotropic conductive adhesive (ACA). The complicate process of the conventional electricity supply elements to connect each lead is eliminated, as shown in  FIG. 1B . The electricity supply system may be produced under higher yield rate and faster production rate, and the reliability and the electrical performance of the electricity supply system is increased. The first terminal  36  and the second terminal  37  may be formed on the same side of the first current collector layer  32  and the second current collector layer  33 , as shown in  FIG. 6A . On the other hand, the first terminal  36  and the second terminal  37  are located at opposite surface. Also, the first terminal  36  and the second terminal  37  may be located at the same surface by the through hole, as shown in  FIG. 6B . Furthermore, only one pair of terminals  36 ,  37  has to be package. Please compare  FIG. 8  and  FIG. 1B , the package of the electricity supply system is simplified. The electricity supply system may be produced under higher yield rate. Moreover, the electricity supply system may also be a jelly roll type battery. 
         [0043]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.