Abstract:
A device of the present invention is used for forming a layered battery cell having at least first electrode and at least one second electrode of charge opposite from said first electrode and a separator layer positioned between the first and second electrodes and at least one of a first current collector connected to at least one of the first and second electrodes and at least one of a second current collector connected to at least one of the first and second electrodes. At least one support member is integrated with an assembly line. A plurality of pins extend from the support member for receiving the first and second electrodes and the first and second current collectors layered with one another to assemble the same into a unitary package.

Description:
RELATED APPLICATIONS 
       [0001]    This non-provisional application claims priority to a provisional application Ser. No. 60/820,146 filed on Jul. 24, 2006 and incorporated herewith by reference in its entirety. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    The subject invention relates to battery cells, and more specifically to a device for and a method of producing multi-layered battery cells. 
       BACKGROUND OF THE INVENTION 
       [0003]    Motor vehicles, such as, for example, hybrid vehicles use multiple propulsion systems to provide motive power. This most commonly refers to gasoline-electric hybrid vehicles, which use gasoline (petrol) to power internal-combustion engines (ICEs), and electric batteries to power electric motors. These hybrid vehicles recharge their batteries by capturing kinetic energy via regenerative braking. When cruising or idling, some of the output of the combustion engine is fed to a generator (merely the electric motor(s) running in generator mode), which produces electricity to charge the batteries. This contrasts with all-electric cars which use batteries charged by an external source such as the grid, or a range extending trailer. Nearly all hybrid vehicles still require gasoline as their sole fuel source though diesel and other fuels such as ethanol or plant based oils have also seen occasional use. 
         [0004]    Batteries and cells are important energy storage devices well known in the art. The batteries and cells typically comprise electrodes and an ion conducting electrolyte positioned therebetween. Lithium batteries are proven to be an attractive energy storage device and have been targeted for various applications such as portable electronics, cellular phones, power tools, electric vehicles, and load-leveling/peak-shaving. The art is replete with various modifications of lithium batteries taught by the U.S. Pat. No. 5,961,672, as related to a stabilized anode for lithium polymer batteries; U.S. Pat. No. 5,952,126 as pertaining to polymer solid electrolyte and lithium secondary cells. Other variations on lithium batteries are described in the U.S. Pat. Nos. 5,853,914 and 5,773,959. 
         [0005]    Typically, the individual cells of the battery pack are placed over studs at every other cell position on the tray. An electrically conductive disk is then placed over each stud until resting on each cell contact surface. The remaining cells are then placed over the studs in the un-occupied positions of the tray, overlapping the previously placed cells. The nut is applied to each stud and is torqued to apply communications from an electrical string of battery cells to a remote electronic controller. It is important to align electrodes, such as cathodes and anodes as the cells are assembled to avoid inconsistent alignment between the electrodes, shifting of the electrodes and bus tabs during handling and assembly, thereby improving energy efficiency. 
         [0006]    Other prior art designs of the lithium polymer batteries suffered from the inconsistent alignment from cell to cell, shifting of cells during handling, and poor energy efficiency. The U.S. Pat. No. 6,242,128 tried to solve the problem of aligning the tab bussings by a fixture frame having plurality of alignment pins used for alignment of the anode and cathode tabs before the tab bussing structure is formed. However, there is a constant need in the area of the battery art for an improved design of devices for and a method of producing multi-layered battery cells. 
       SUMMARY OF THE INVENTION 
       [0007]    In one aspect of the present invention, an alignment device includes a body having a recess on each of the longitudinal sides and multiple ejector bores extending therethrough adjacent alignment bores. The alignment bores include a shank portion and a head portion, with the head portion located adjacent a bottom surface of the body and defining a diameter greater in size than a diameter defined by the shank portion, with the shank portion of the alignment bores extending from the head portion to a top surface of the body. A plurality of alignment pins are disposed within each of the alignment bores and include a head located within the head portion of the alignment bore. 
         [0008]    A support of the device includes a generally rectangular shape having a pair of laterally space longitudinal sides and a pair of laterally spaced end walls. The support defines a recess in each of the longitudinal sides of the support, identical in size and shape and disposed adjacent the recesses defined by the longitudinal sides of the body. 
         [0009]    A cover plate of the device includes a generally rectangular shape having a pair of laterally spaced longitudinal sides and a pair of laterally spaced end walls. The cover plate also defines a recess in each of the longitudinal sides identical in size and shape and disposed over the recesses defined by the body and the support. The cover plate defines at least two alignment bores concentric with the alignment bores defined by the body. The alignment bores are defined by the cover plate and include a diameter equal to the diameter of the shank portion of the alignment bore defined by the body. The cover plate further defines a fastener passage corresponding to each of the ejector bores defined by the body and the support. 
         [0010]    An ejector shaft is disposed in each of the ejector bores, and extends from a bottom surface of the cover plate to near a bottom surface of the support. A fastener, such as a screw, is disposed within each of the fastener passages and is in threaded engagement with the ejector shaft, thereby connecting the ejector shafts to the cover plate. 
         [0011]    In another aspect of the present invention, a battery assembly of the present invention is adaptable to be utilized in various configurations including and not limited to an overlapping battery cell packaging configuration and a vertical stack battery cell packaging configuration. The battery assembly includes a first cell and a second cell adjacent the first cell. A cell for a battery pack has a first electrode adjacent a first current collector and a second electrode of charge opposite from the first electrode and adjacent a second current collector. A separator layer is positioned between the first and second electrodes. The first and second electrodes conduct electrolyte therebetween. A first insulator extends over the first electrode and a second insulator extends over the second electrode. 
         [0012]    An envelope has an upper wall and a lower wall defining a pocket therebetween and extending over the first and second insulators thereby encapsulating the first and second insulators. The envelope terminates into a negative terminal and a positive terminal opposed the negative terminal. The positive and negative terminals define at least one contact with each of the negative and positive terminals defining a pair of openings transversely extending through the upper and lower walls of the envelope. A conductor device or electrically-conductive disk is formed from a copper is disposed between the upper and lower walls at the positive and negative terminals. The conductor device extends through each of the openings to define a boss around and above each of the openings. 
         [0013]    An advantage of the present invention is to provide an alignment device to align electrodes, such as cathodes and anodes, of the cell as the cells are assembled to avoid inconsistent alignment between the electrodes, shifting of the electrodes and bus tabs during handling and assembly, thereby improving energy efficiency. 
         [0014]    Another advantage of the present invention is to provide a battery cell having a conductor or an electrically-conductive device mechanically engaged therein which provides improved surface-to-surface contact with the electrically-conductive disk of adjacent cell thereby improving the electrically conductive characteristics of the battery cells as the individual battery cells are placed over the studs at every other cell position to form a battery pack. 
         [0015]    Still another advantage of the present invention is to provide a battery cell that reduces manufacturing costs due to simplified assembly pattern. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0017]      FIG. 1  is an exploded end view of a battery cell showing several component layers of the battery cell and a pair of bussing tabs; 
           [0018]      FIG. 2  is a cross sectional side view of an alignment device of the present invention; 
           [0019]      FIG. 3  is a cross sectional view of the alignment device of  FIG. 2  with multiple electrodes of the battery cell layered on the alignment device; 
           [0020]      FIG. 4  is a top view of the alignment device; 
           [0021]      FIG. 5  is a top view of a body of the alignment device; 
           [0022]      FIG. 6  is a cross sectional side view of the body; 
           [0023]      FIG. 7  is a top view of a support of the alignment device; 
           [0024]      FIG. 8  is a cross sectional view of the support; 
           [0025]      FIG. 9  is a top view of a cover plate of the alignment device; 
           [0026]      FIG. 10  is a cross sectional view of the cover plate; 
           [0027]      FIG. 11  is a perspective view of an inventive conductor device defined by a tubular member having a radial lip integral with and extending outwardly from the tubular member; 
           [0028]      FIG. 12  is a perspective view of the conductor device of  FIG. 1  having folded terminal ends presenting a contact portion; 
           [0029]      FIG. 13  is a cross sectional view of a battery cell having a pair of insulators disposed therein and extending through the openings defined in the battery cell and the conductor device disposed between the insulators and extending outwardly and transversely through the openings with the conductor device being folded over the insulators to form a contact surface; 
           [0030]      FIG. 14  is a cross sectional view of the pair of battery cell of  FIG. 13  with the battery cells being interconnected by a pin; and 
           [0031]      FIG. 15  is an exploded view of the alignment device of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0032]    Referring to the FIGS., wherein like numerals indicate like or corresponding parts, a battery cell, generally shown at  10  in  FIGS. 13 and 14  is assembled by an alignment device of the present invention, which is generally shown at  20  in  FIGS. 2 and 3 . The alignment device  20  is an integrated part of an assembly line  21 , defined by a conveyor without limiting the scope of the present invention.  FIG. 15  shows an exploded view of the alignment device  20  of  FIGS. 2 and 3 . Referring to  FIG. 1 , the multi-layered battery cell  10  comprises several component layers  24 , sandwiched together to define the battery cell  10 , as is well known in the battery art. The several component layers include a first electrode  26  adjacent a first current collector  28 , and a second electrode  30  adjacent a second current collector  32 . The first electrode  26  and the second electrode  30  are oppositely charged, i.e., one is positively charged and the other is negatively charged. The first electrodes  26 , the first current collectors  28 , the second electrodes  30 , and the second current collectors  32  are moved by the assembly line  21  and are placed thereupon in a predetermined fashion by a multi-axial robotic device. The battery cell  10  of the present invention is adaptable to be utilized in various configurations including and not limited to an overlapping battery cell packaging configuration and a vertical stack battery cell packaging configuration used in an automotive vehicle applications. 
         [0033]    A separator layer (not shown) is disposed between the first electrode  26  and the second electrode  30 , with the first electrode  26  and the second electrode  30  conducting an electrolyte therebetween. A first insulator (not shown) and a second insulator (not shown) are disposed on opposite sides of the first electrode  26  and the second electrode  30  to sandwich the first electrode  26 , the separator layer  34 , and the second electrode  30  between the first insulator and the second insulator. 
         [0034]    An envelope extends around the periphery of the first insulator and the second insulator and encapsulates the several component layers  24  of the battery cell  10  in a protective covering. The envelope terminates into a positive terminal and a negative terminal opposite the positive terminal as is known in the art. As best shown in  FIG. 3 , each of the several component layers  24  include at least two alignment apertures  42 , located near the periphery of the several component layers  24  and concentric with the alignment apertures  42  defined by the several component layers  24  disposed above and below, i.e., the several component layers  24  cooperate together to define at least two concentric alignment apertures  42  extending through the several component layers  24  as a whole. 
         [0035]    As shown in the  FIG. 3 , each of the several component layers  24  include four alignment apertures  42 , located near the corners of each of the several rectangular shaped component layers  24 . The alignment device  20  aligns the several different component layers  24  of the multi-layered battery cell  10  during production. The alignment device  20  includes a body  44 . The body  44  is generally rectangular shaped having a pair of laterally spaced longitudinal sides and a pair of laterally spaced end walls. The body  44  further includes a recess  46  on each of the longitudinal sides. The body  44  defines at least one ejector bore  48  extending therethrough. 
         [0036]    As shown in the Figures, the body  44  defines four ejector bores  48  therethrough. The body  44  further defines at least two alignment bores  50 . Preferably, and as shown in the Figures, the body  44  defines four alignment bores  50 . The alignment bores  50  include a shank portion  52  and a head portion  54 , with the head portion  54  located adjacent a bottom surface of the body  56  and defining a diameter greater in size than a diameter defined by the shank portion  52 , with the shank portion  52  of the alignment bores  50  extending from the head portion  54  to a top surface of the body  58 . 
         [0037]    Referring to  FIGS. 2 and 3 , an alignment pin  60  is disposed within each of the alignment bores  50  defined by the body  44 . The alignment pins  60  each include a head  62  located within the head portion  54  of the alignment bore  50 , and a shank  64  located within the shank portion  52  of the alignment bore  50  and extending above the top surface of the body  58 . The alignment pin  60  extends from the heat to a distal end  66  having a generally conical point. 
         [0038]    Referring to  FIGS. 7 and 8 , a support  68  is disposed adjacent the bottom surface of the support  68 . The support  68  defines at least one ejector bore  48  therethrough. Preferably, and as shown in the Figures, the body  44  defines four ejector bores  48  therethrough, with the ejector bores  48  of the support  68  concentric with the ejector bores  48  defined by the body  44 . The support  68  includes a generally rectangular shape having a pair of laterally space longitudinal sides and a pair of laterally spaced end walls. The support  68  defines a recess  46  in each of the longitudinal sides of the support  68 , identical in size and shape and disposed adjacent the recesses  46  defined by the longitudinal sides of the body  44 . It should be understood, with reference to the Figures, that the heads  62  of the ejector pins rest on and are sandwiched between the body  44  and the support  68 , thereby securing the alignment pins  60  in position. 
         [0039]    Preferably, the alignment pins  60  are press fit into the alignment bores  50  defined by the body  44 . However, it should be understood that the alignment pins  60  may be attached to the body  44  by other methods, such as a set screw, tangent pin, glue, or some other method known to those skilled in the art. 
         [0040]    Referring to  FIGS. 9 and 10 , a cover plate  70  is disposed adjacent the top surface of the body  58 . The cover plate  70  includes a generally rectangular shape having a pair of laterally spaced longitudinal sides and a pair of laterally spaced end walls. The cover plate  70  also defines a recess  46  in each of the longitudinal sides identical in size and shape and disposed over the recesses  46  defined by the body  44  and the support  68 . The cover plate  70  defines at least two alignment bores  50  concentric with the alignment bores  50  defined by the body  44 . The alignment bores  50  defined by the cover plate  70  include a diameter equal to the diameter of the shank portion  52  of the alignment bore  50  defined by the body  44 . The cover plate  70  further defines a fastener passage  72  corresponding to each of the ejector bores  48  defined by the body  44  and the support  68 . Preferably, and as shown in the Figures, the cover plate  70  defines four fastener passages  72  therethrough. Each of the fastener passages  72  is countersunk on a top surface of the cover plate  74 . 
         [0041]    Referring to  FIGS. 2 and 3 , an ejector shaft  76  is disposed in each of the ejector bores  48 , and extends from a bottom surface of the cover plate  78  to near a bottom surface of the support  80 . A fastener  82 , such as a screw  82 , is disposed within each of the fastener passages  72  and is in threaded engagement with the ejector shaft  76 , thereby connecting the ejector shafts  76  to the cover plate  70 . A head  62  of each of the fasteners is disposed within the countersunk portion of the fastener passage  72 , below the top surface of the cover plate  74 , to not interfere with movement of the several component layers  24  of the battery cell  10  over the top surface of the cover plate  74 . The subject invention also provides a method of manufacturing the multi-layered battery cell  10 . 
         [0042]    Referring to  FIG. 3 , the method includes placing the several component layers  24  on the alignment device  20 . Accordingly, the first insulator  36  layer is placed on the top surface of the cover plate  74 , with the alignment apertures  42  positioned over the alignment pins  60 . Likewise, the first electrode  26  layer is positioned over the first insulator  36  layer, the separator layer  34  is placed over the first electrode  26  layer, the second electrode  30  layer is placed over the separator layer  34 , and the second insulator  38  layer is placed over the second electrode  30 . The first current collector  28  is placed along one longitudinal side of the alignment device  20 , over the second insulator  38  layer, and the second current collector  32  is placed along the other longitudinal side of the alignment device  20 , over the second insulator  38  layer. Just as described for the first insulator  36  layer, the alignment apertures  42  defined by the first electrode  26 , the separator layer  34 , the second electrode  30 , the second isolator layer, the first current collector  28  and the second current collector  32  are positioned over the alignment pin  60 , with the alignment pin  60  extending through the several component layers  24  of the battery cell  10 . In so doing, each of the several component layers  24  are properly aligned relative to each other. The several different component layers  24  are then attached together. 
         [0043]    Preferably, and as is known in the art, the several different component layers  24  are attached by welding. After the several component layers  24  are assembled, i.e., attached together, an actuator (not shown) pushes upward on the ejector shafts  76  to raise the top cover and the assembled component layers  24  disposed thereon above the alignment pins  60 . The assembled component layers  24  are then removed from the alignment device  20  for further manufacturing processes at other work stations. It is contemplated that at least one robotic arm (not shown) may be employed for moving the several different component layers  24  into position on the alignment device  20 , and for moving the assembled component layers  24  from the alignment device  20  to the other manufacturing processes. 
         [0044]    Referring to the  FIGS. 11 through 14 , another aspect of the present invention is shown. As best illustrated in  FIGS. 13 and 14 , each battery cell  10  includes an envelope or shell, generally indicated at  200  formed from a sheet of packaging material, such as aluminum. Those skilled in the lithium battery art will appreciate that the shell  200  may also be fabricated from any other suitable materials without limiting functional characteristics of the present invention. The shell  200  includes an upper wall  202  and a lower wall  204  defining a pocket  206  therebetween and extending over the first and second electrodes thereby encapsulating the first and second conductors with the shell  200  terminating into a negative terminal, defined by a lip  208  and a positive terminal (not shown) defined by another lip opposed the negative terminal with each of the positive and negative  208  terminals defining at least one contact with each of the negative and positive terminals. 
         [0045]    Each of the contacts is provided for each polar contact to divide the current carrying capacity and to provide auxiliary paths for current flow in the event that one or more contacts would develop high resistance or electrically open. Each contact is further defined by an aperture or opening  210  defined in each terminal lip  208  transversely extending through the upper wall  202  and the lower wall  204 . A pair first and second insulators  212  and  214  extend outwardly from the opposed openings  210  to define terminal ends  218  and  220 , respectively. 
         [0046]    A conductor device, generally shown at  230 , formed from a copper or any other electrically conductive material, extends through each of the openings  210 . A stud or the tie rod  234  extends through each opening  210  at each of the terminal lips  208  and is secured by a nut  236 . As further illustrated in  FIGS. 13 and 14 , the device  230  is disposed between the first and second insulators  212  and  214  at the positive and negative terminals to define a boss or rivet, generally indicated at  240 , around and above each of the openings  210 . 
         [0047]      FIG. 11  illustrates the device  230  in a non-folded stage and  FIGS. 12 through 14  illustrate the device  230  in a folded stage. As best shown in  FIG. 11 , the device  230  is further defined by a tube  242  having terminal ends  244  and  246  and a radial lip  248  integral with and extending outwardly from tube  242 . The terminal ends  246  and  248  are folded over the openings  210  and over the terminal ends  218  and  220  of the first and second insulators  212  and  214  to define a contact surface  250  that may include a concave configuration, as shown in  FIGS. 13 and 14 , or a rectangular configuration, as shown in  FIG. 12 , to provide improved “surface-to-surface” contact. 
         [0048]    While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.