Abstract:
A connecting structure for exteriorly connecting a battery cell and a load circuit by using two graphite connecting graphite blocks, wherein the positive and negative electrode terminals of the battery cell are made of nickel, the battery cell is connected to the load circuit by the two connecting graphite blocks, respectively. The graphite is inexpensive and resistant to oxidation; whereas, the connecting graphite blocks and the nickel-plated metal made electrode terminals of the battery cell will dissolve in each other to form a carbon-nickel alloy after being brought into contact with one another, thus ensuring a smooth large-current discharge because of the reduction in resistance of external connection.

Description:
This application is a continuation in part of U.S. patent application Ser. No. 12/834,834, which claims the benefit of the earlier filing date of Jul. 12, 2010. Claims 1-4 of this application are revised from claims 1 and 4-6 of the U.S. patent application Ser. No. 12/834,834, respectively. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a non-welding and oxidation resistant connecting structure for exteriorly connecting a battery cell and a load circuit at a high conductivity. 
     Description of the Prior Art 
     Referring to  FIG. 1  showing a conventional connecting structure for exteriorly connecting a single battery cell and a load circuit, wherein the single battery cell  10  and the load circuit  11  are connected in such a manner that a positive electrode terminal  12  and a negative electrode terminal  13  of the battery cell  10  each are brought into direct contact with a metal terminal  14  first, and then the metal terminals  14  will be connected to the load circuit  11 . Due to direct contact between the electrode terminals and the metal terminals, a high contact resistance will be caused at the respective contact portions of the electrode terminals and the metal terminals, so that when the battery cell is switched on, the contact portion will heat up and consume power of the battery cell. To reduce the contact resistance, referring to  FIG. 2 , the battery cell  10  is connected to nickel sheets  15  by spot welding, and then the nickel sheets  15  are connected to the load circuit  11  to create the connection between the battery cell and the load circuit, greatly reducing the contact resistance while improving the non-oxidizability. 
     It is to be noted that, intense heat caused during the spot welding will be transmitted to the battery cell to cause damages to interior of the battery cell, such as: breakage of the seal gasket, and rupture of the isolating layers, and etc, thus leading to failure of the battery. In addition, the cost of the welding procedure is relatively high. 
     U.S. Pat. No. 4,382,116 discloses a conventional battery, wherein the electrodes of the battery are made of graphite and connected to the terminals by graphite current collectors, and the graphite current collectors are a necessary part of the battery and disposed inside the battery cell. U.S. Pat. No. 4,382,116 fails to disclose an external connecting structure for exteriorly connecting the battery to a load circuit by using two graphite blocks. 
     U.S. Pat. Pub. No. 2004/0265683 discloses a battery whose negative and positive terminals are made of nickel but without disclosing an external connecting structure for exteriorly connecting the battery to a load circuit by using two graphite blocks. 
     U.S. Pat. Pub. No. 2007/0092792 discloses a battery, wherein the negative and positive current collectors are a necessary part of the battery despite they are located outside the battery. 
     Hence, it can be found that the conventional connection between a battery cell and a load circuit cannot satisfy the basic requirements of the cost economics, high conductivity and high relativity. However, it will be a breakthrough to the existing battery-connection technique if the connection conductivity can be improved without the use of welding. 
     Hereafter, the present invention has arisen to mitigate and/or obviate the afore-described disadvantages. 
     SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide a high conductivity connecting structure for exteriorly connecting a battery cell and a load circuit by using two connecting graphite blocks. In the present invention, the connecting graphite blocks are connected to the electrode terminals of the battery cell in a direct contact manner to realize a highly conductive connection without the use of the welding. Furthermore, the graphite is less-expensive compared to nickel so that the production cost can be greatly reduced. 
     The secondary objective of the present invention is to provide a connecting structure for exteriorly connecting a battery cell and a load circuit which mainly utilizes a first connecting graphite block and a second connecting graphite block that are respectively connected to a positive electrode terminal and a negative electrode terminal of a battery cell in a close contact manner to connect the battery cell and a load circuit. After being brought into contact with one another, the connecting graphite blocks and the positive, the negative electrode terminals of the battery cell will start a process of dissolving in each other, that is, carbon particles of the connecting graphite blocks will substitute for the foreign matters on the negative and the positive electrode terminals of the battery cell and fill the voids of the negative and the positive electrode terminals of the battery cell, forming a carbon-nickel alloy, thus ensuring a smooth large-current discharge due to reduction of the external connection resistance. 
     In order to achieve the above objectives, a connecting structure for exteriorly connecting a battery cell and a load circuit in accordance with the present invention comprises: a battery cell, a first connecting graphite block, and a second connecting graphite block. 
     The battery cell is exteriorly provided with a positive electrode terminal and a negative electrode terminal which are made of nickel-plated metal and served as power output terminals of the battery cell. 
     The first connecting graphite block is connected to the positive electrode terminal of the battery cell and a load circuit. 
     The second connecting graphite block is connected to the negative electrode terminal of the battery cell and the load circuit. 
     By such arrangements, the battery cell can be connected to the load circuit through the first and the second connecting graphite blocks. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a conventional connecting structure for exteriorly connecting a battery cell and a load circuit which utilizes metal terminals to connect the battery cell and the load circuit; 
         FIG. 2  is a schematic view of a conventional connecting structure for exteriorly connecting a battery cell and a load circuit which utilizes nickel sheets to connect the battery cell and the load circuit; 
         FIG. 3  is a schematic view of a connecting structure for exteriorly connecting a battery cell and a load circuit in accordance with the present invention utilizes two connecting graphite blocks to connect the battery cell and the load circuit; 
         FIG. 4A  shows the respective electrode terminals of the battery cell being covered with foreign matters in accordance with the present invention; 
         FIG. 4B  shows carbon particles substituting for the foreign matters after the first and the second connecting graphite blocks are brought into contact with the electrode terminals in accordance with present invention; and 
         FIG. 5  is a schematic view showing that the connecting structure for exteriorly connecting a battery cell and a load circuit in accordance with the present invention utilizes two connecting graphite blocks to connect a coffee-bagged battery cell packaged in an aluminum bag to the load circuit. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will be easily comprehended from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention. 
     Referring to  FIG. 3 , a connecting structure for exteriorly connecting a battery cell  20  and a load circuit  30  in accordance with the present invention comprises a first connecting graphite block  40  and a second connecting graphite block  50  which are electrically connected to a positive electrode terminal  21  and a negative electrode terminal  22  of the battery cell  20 , and then connected to the load circuit  30 . This connecting structure provides a relatively high electric conductivity between the battery cell  20  and the load circuit  30 . 
     The battery cell  20  is a cylindrical battery cell and exteriorly provided on both ends thereof with the positive electrode terminal  21  and the negative electrode terminal  22  which are made of nickel-plated metal and served as power output terminals of the battery cell  20 . 
     The first connecting graphite block  40  is made of a material selected from the group consisting of pure graphite, graphite alloy and conductive carbon. The graphite alloy can be a silver graphite (silver-carbon alloy), a copper graphite (copper-carbon alloy), and etc. The first connecting graphite block  40  is electrically connected to the positive electrode terminal  21  of the first battery cell  20  in a close contact manner. 
     The second connecting graphite block  50  is made of a material selected from the group consisting of pure graphite, graphite alloy and conductive carbon. The second connecting graphite block  50  is electrically connected to the positive electrode terminal  21  of the first battery cell  20  in a close contact manner. The battery cell  20  and the load circuit  30  are then electrically connected through the first and the second connecting graphite blocks  40 ,  50 . 
     The first and the second connecting graphite blocks  40 ,  50  each are interiorly provided with a wire  60  serving as a power output wire of the battery cell  20 , so that the first and the second connecting graphite blocks  40 ,  50  can be connected to the load circuit  30  through the wires  60 . 
     The aforementioned is the summary of the positional and structural relationship of the respective components of the preferred embodiment in accordance with the present invention. 
     For a better understanding of the present invention, its operation and function, reference should be made to the following description: 
     The positive and the negative electrode terminals  21 ,  22  of the battery cell  20  are both made of the nickel-plated metal, as shown in  FIG. 4A , the positive and the negative electrode terminals  21 ,  22  each might be covered with foreign matters  70  or oxides, which will increase the connection resistance during the discharging process of the battery cell  20  while reducing the discharging power efficiency of the battery cell  20 . Referring to  FIG. 4B  showing how to achieve high conductivity connection between the battery cell and the load circuit, the first and the second connecting graphite blocks  40 ,  50  are resistant to oxidation and electrically connected to the positive and the negative electrode terminals  21 ,  22  of the battery cell  20 . The first and second connecting graphite blocks  40 ,  50  and the positive and negative electrode terminals  21 ,  22  of the battery cell  20  will dissolve in each other after being brought into contact with one another, that is, the carbon particles  80  of the first and the second connecting graphite blocks  40 ,  50  will substitute for the foreign matters  70  or oxides on the positive and negative electrode terminals  21 ,  22  made of nickel-plated metal so as to fill in the voids in the positive and the negative electrode terminals  21 ,  22  of the battery cell  20 , forming a carbon-nickel alloy, which improves the connection conductivity between the first, the second connecting graphite blocks  40 ,  50  and the battery cell  20 . In other words, after the battery cell  20  in accordance with the present invention is switched on, electric current will circulate through the battery cell  20 , the first connecting graphite block  40  and the second connecting graphite block  50  smoothly without being affected by the inherent resistance caused by the oxides or the foreign matters  70 , thus not only reducing the external connection resistance between the battery cell  20  and the load circuit  30 , but facilitating discharge of the battery cell  20 . 
     It is to be noted that the first and second connecting graphite blocks  40 ,  50  of the present invention are independent (separated) from and not necessary parts of the battery cell  20 , the load circuit  30  is also independent from and not a necessary part of the battery cell  20 , and the first and second connecting graphite blocks  40 ,  50  are located outside the battery cell  20  and used as an external connecting structure for connecting the battery cell  20  to the load circuit  30 . 
     Furthermore, the “dissolving in each other” phenomenon will occur when and only when graphite material is brought into contact with nickel material. With that in mind, the author of the present invention came up with the idea of providing a high conductivity connecting structure which exteriorly connects a battery cell  20  with nickel terminals to a load circuit  30  by using two connecting graphite blocks  40 ,  50 . When the connecting graphite alloy blocks  40 ,  50  are brought into contact with the nickel-made electrode terminals  21 ,  22  of the battery cell  20 , it will start the process of “dissolving in each other”. The process of “dissolving in each other” can remove oxidation or foreign matters from the electrode terminal  21 ,  22  of the battery cell  20  and will consequently improve the external contact conductivity of the battery cell  20 . So far, no prior art was found teaching or suggesting the improvement of external contact conductivity of a battery cell  20  by bringing graphite alloy blocks  40 ,  50  (which are independent from and not necessary parts of the battery cell) into contact with nickel terminals  21 ,  22  of the single battery cell  20 . 
     In addition to the cylindrical battery cell with metal jacket, as shown in  FIG. 5 , the present invention is also applicable to a coffee-bagged battery cell  90  which is packaged in an aluminum bag. The positive and the negative electrodes of the coffee-bagged battery cell  90  are normally stamp-formed into a positive electrode tab  91  and a negative electrode tab  92  that are both made of nickel-plated metal. When the coffee-bagged battery cell  90  is connected to the load circuit  30 , a third connecting graphite block  100  and a fourth connecting graphite block  200  will be electrically connected to the positive and the negative electrode tabs  91 ,  92  of the coffee-bagged battery cell  90 , respectively. It is to be noted that, the battery cell with metal jacket and the coffee-bagged battery cell, although having different shapes, are the same in terms of electrical connection effects. In other words, the technology of the present invention is independent to the internal configuration of the battery cell as long as the positive and the negative electrode terminals of the battery cell are made of the nickel-plated metal, hence, the battery cell and the load circuit can be connected through the connecting graphite blocks of the present invention to realize the high conductivity external connection therebetween. 
     While we have shown and described various embodiments in accordance with the present invention, it is comprehensive to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.