Abstract:
An ultracapacitor electrode termination contact interface adapted for use in an energy storage device is disclosed. The disclosed apparatus and article of manufacture function to lower equivalent series resistance of the ultracapacitor electrode termination contact interface. In one embodiment of the present teachings, an ultracapacitor electrode termination contact interface, adapted to increase reliability and manufacturing yield of such devices is disclosed.

Description:
BACKGROUND  
       [0001]    1. Field 
         [0002]    The disclosed method of making, apparatus, and article of manufacture relates generally to high performance energy storage devices, and particularly to increasing ultracapacitor electrode interface efficiency and lowering equivalent series resistance of such interfaces. 
         [0003]    2. Related Art 
         [0004]    Double layer capacitors, also referred to as electrochemical double layer capacitors, are energy storage devices that are able to store more energy per unit weight and unit volume than traditional capacitors. Additionally, they can typically deliver the stored energy at a higher power rating than rechargeable batteries. 
         [0005]    Double layer capacitors consist of two porous electrodes that are isolated from electrical contact by a porous separator. Both the separator and the electrodes are impregnated with an electrolytic solution. This allows ionic current to flow between the electrodes through the separator at the same time that the separator prevents an electrical or electronic (as opposed to ionic) current from shorting the cell. Coupled to the back of each of the active electrodes is a current collecting element. One purpose of the current collecting element is to reduce ohmic losses in the double layer capacitor. 
         [0006]    Specifically, improvements are needed in the techniques and methods for fabricating double layer capacitor electrodes so as to lower electrode resistance of the double layer capacitor and maximize the operating voltage. For example, the method used to connect the current collector element of the capacitor to the electrode is important because the interface between the electrode and the current collector element is a source of internal resistance of the double layer capacitor. Since capacitor energy density increases with the square of the operating voltage, higher operating voltages thus translate directly into significantly higher energy densities and, as a result, higher power output ratings. Equation 1 shows a mathematical expression for energy stored in a capacitor, wherein energy is measured in joules. Equation 2 below shows a mathematical equation for average power output of a capacitor in watts. It is apparent that improved techniques and methods are needed to lower the internal resistance of the electrodes used within a double layer capacitor and increase the operating voltage. 
         [0000]        E=CV   2 /2   Equation 1: 
         [0000]        P   av   =CV   2 /2 t    Equation 2: 
         [0007]    There is a continuing need for improved double layer capacitor design. Such improved double layer capacitors need to deliver large amounts of useful energy at a very high power output and energy density ratings within a relatively short period of time. Such improved double layer capacitors should also have a relatively low electrode interface equivalent series resistance (ESR) and yet be capable of yielding a relatively high operating voltage. 
         [0008]    An ESR rating for a capacitor is a rating of quality. A theoretically perfect capacitor would have an ESR of zero. Ideal capacitors therefore have exactly 90 degree phase shift of voltage with respect to current which implies zero dissipation factor (“DF”). However, all real capacitors have some amount of ESR. Hence, a real-world challenge for capacitor designers is minimizing ESR. ESR is modeled like a resistor in series with a capacitor. Capacitor designs that appear optimally functional in theory, can fail when manufactured due to ESR. Increasingly, modern electronic designs rely on low ESR capacitors to function optimally in a real-world environment. Low ESR means low charge and discharge time constant which is very important in applications that require high power to energy ratios, such as hybrid electric vehicles, electric power assist steering, brake system support, and most industrial applications. 
         [0009]    An interface point of termination from a capacitor electrode foil to an end cap, such as a terminal cap, is an issue in assembly and manufacturing. Modern laser welding techniques, for example, may only fuse 15%-40% of the available foil wraps inside a double layer capacitor, leading to part to part manufacturing variability in ESR, as well as loss of integrity with age. 
         [0010]    Therefore, a need exists to improve consistency of manufacturing variability and therefore improve manufacturing yield, as well as improve reliability of an energy storage device, such as for example a double layer capacitor, as it ages. The present teachings provide a method for making an electrode termination interface for solving the aforementioned problems and issues by providing a highly reliable, low cost, solution to improve electrode termination interface ESR, which is more efficient than prior art solutions. 
       SUMMARY  
       [0011]    In one embodiment of the present teachings, a method of making an ultracapacitor electrode termination contact interface to a terminal cap is disclosed. The method of making comprises the steps of forming a first electrode foil having a plurality of active carbon deposits disposed upon predetermined portions of the first electrode foil, the electrode foil further having a plurality of current collecting tab portions disposed thereon; defining a plurality of fold zones thereupon the first electrode foil, wherein the fold zones are bounded by a plurality of fold lines; folding the first electrode foil symmetrically about alternating fold lines; defining a plurality of fold zone outer radius folds, wherein the plurality of fold zone outer radius folds all lie at a fixed position relative to a winding center axis; interposing at least one separator sheet between the plurality of fold zones, wherein the at least one separator sheet electrically isolate the plurality of fold zones; defining a plurality of fold zone inner radius folds, wherein the plurality of fold zone inner radius folds are linearly spaced toward an annular core, and collecting the plurality of current collecting tab portions for each of the plurality of fold zones into a first plurality of gatherings. 
         [0012]    In one another embodiment of the present teachings, an ultracapacitor electrode structure is disclosed. The ultracapacitor electrode structure comprises a first electrode foil having a plurality of active carbon deposits disposed upon predetermined portions of the first electrode foil, the electrode foil further having a plurality of current collecting tab portions disposed thereon, a plurality of fold zones thereupon the first electrode foil, wherein the fold zones are bounded by a plurality of fold lines; a plurality of fold zone outer radius folds, wherein the plurality of fold zone outer radius folds all lie at a fixed position relative to a winding center axis; at least one separator sheet between the plurality of fold zones, wherein the at least one separator sheet electrically isolate the plurality of fold zones, and; a plurality of fold zone inner radius folds, wherein the plurality of fold zone inner radius folds are linearly spaced toward an annular core. 
         [0013]    In another embodiment of the present teachings, an article of manufacture comprising an ultracapacitor electrode termination contact interface and a terminal cap assembly is disclosed. The article of manufacture comprises a first electrode foil having current collecting tab portions oriented in a first direction; a separator; a second electrode foil having current collecting tab portions oriented in a second direction; a first terminal cap, comprising a plurality of terminal cap opening tabs, wherein the plurality of terminal cap opening tabs open in a first direction; a threading disposed circumferentially about the first terminal cap, wherein the threading is wound in a first orientation; a second terminal cap, comprising, a plurality of terminal cap opening tabs, wherein the plurality of terminal cap opening tabs open in a second direction, and a threading disposed circumferentially about the first terminal cap, wherein the threading is wound in a second orientation, wherein the second orientation is approximately opposite from the first orientation. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0014]    Embodiments of the disclosed method and apparatus will be more readily understood by reference to the following figures, in which like reference numbers and designations indicate like elements. 
           [0015]      FIG. 1A  illustrates a front plan view of an unfolded electrode termination foil showing current collecting tab portions oriented in a positive vertical direction. 
           [0016]      FIG. 1B  illustrates a front plan view of an unfolded electrode termination foil showing current collecting tab portions oriented in a negative vertical direction. 
           [0017]      FIG. 1C  illustrates a perspective view of a folded electrode termination foil showing current collecting tab portions oriented in a positive vertical direction. 
           [0018]      FIG. 1D  illustrates a perspective view of a folded electrode termination foil showing current collecting tab portions oriented in a negative vertical direction. 
           [0019]      FIG. 1E  illustrates a front plan view of a separator. 
           [0020]      FIG. 1F  illustrates a perspective view of the folded electrode termination foil of  FIG. 1C  folded together with the folded electrode termination foil of  FIG. 1D , having the separator of  FIG. 1E  therebetween. 
           [0021]      FIG. 2A  illustrates a top plan view of a first terminal cap, showing a plurality of terminal cap opening tab opening in a first direction. 
           [0022]      FIG. 2B  illustrates a top plan view of a second terminal cap, showing a plurality of terminal cap opening tabs opening in a second direction. 
           [0023]      FIG. 2C  illustrates a perspective view of the first terminal cap of  FIG. 2A . 
           [0024]      FIG. 2D  illustrates a perspective view of the second terminal cap of  FIG. 2B . 
           [0025]      FIG. 2E  illustrates a perspective view showing the first terminal cap of  FIG. 2A  fitting together with the second terminal cap of  FIG. 2B . 
           [0026]      FIG. 2F  illustrates a perspective view of a portion of the first terminal cap fitted onto the current collecting tab portions of  FIG. 1C . 
           [0027]      FIG. 2G  illustrates a perspective view of a portion of the second terminal cap fitted onto the current collecting tab portions of  FIG. 1C . 
           [0028]      FIG. 2H  illustrates a perspective view of a portion of the first terminal cap and the second terminal cap fitted together onto the current collecting tab portions of  FIG. 1C . 
           [0029]      FIG. 2I  illustrates an exploded view of an assembly of the first terminal cap and the second terminal cap fitted together onto an electrode termination contact interface. 
           [0030]      FIG. 2J  illustrates an exploded view of one embodiment of the present teachings. 
           [0031]      FIG. 3  illustrates a method for making an electrode termination contact interface. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]      FIG. 1A  illustrates a front plan view of an unfolded electrode termination foil  100  showing, a plurality of current collecting tab portions  104  oriented in a positive vertical direction. In one illustrative exemplary embodiment the unfolded electrode termination foil  100  of the present teachings comprises a first electrode foil  102 , a plurality of active carbon deposits  112 , the plurality of current collecting tab portions  104 , and a plurality of fold zones bounded by fold lines  106   a - h.  The fold lines  106   a - h  comprise a plurality of fold lines including a plurality of fold zone inner radius folds  110  and further bounded by a plurality of fold zone outer radius folds  108 . The plurality of current collecting tab portions  104  have a tab width of “D”, as shown in  FIG. 1A . A distance “x” measured laterally away from each of the plurality of fold zone outer radius folds  108  marks a position for each of the plurality of current collecting tab portions  104 . Using the techniques described herein, an implementation of employing the plurality of current collecting tab portions  104 , wherein the tab portions  104  are symmetrically located about electrode foil lines, leads to a current collector contact for each of the plurality of active carbon deposits  112  on the first electrode foil. The disclosed technique ensures that each of the plurality of active carbon deposits  112  has a current collecting tab associated therewith. This will ensure high quality terminations and tighter tolerance for ESR. 
         [0033]      FIG. 1B  a front plan view of an unfolded electrode termination foil  101  showing a plurality of current collecting tab portions  105  oriented in a negative vertical direction in one illustrative exemplary embodiment the unfolded electrode termination foil  101  of the present teachings comprises a first electrode foil  103 , a plurality of active carbon deposits  113 , the plurality of current collecting tab portions  105 , and a plurality of fold zones bounded by fold lines  107   a - h.  The fold lines  107   a - h  comprise a plurality of fold lines including a plurality of fold zone inner radius folds  111  and further bounded by a plurality of fold zone outer radius folds  109 . The plurality of current collecting tab portions  105  have a tab width of “D”, as shown in  FIG. 1B . A distance “x” measured laterally away from each of the plurality of fold zone outer radius folds  109  marks a position for each of the plurality of current collecting tab portions  105 . 
         [0034]      FIG. 1C  illustrates a perspective view of a folded electrode termination foil  120  showing die plurality of current collecting tab portions  104  oriented in a positive vertical direction, corresponding to the unfolded electrode termination foil  100  of  FIG. 1A . The folded electrode termination foil  120  of  FIG. 1C  is a view of how  FIG. 1A  looks when the unfolded electrode termination foil  100  is folded along the fold lines  106   a - g.  In one embodiment, the fold lines  106   a,    106   c,    106   e,  and  106   g  comprise outer radius fold lines, lying at a fixed outer radial position (“r b ”) relative to a winding center axis  125 , which defines one boundary of the plurality of fold zones. The fold lines  106   b,    106   d,  and  106   f  comprise inner radius fold lines, bounding the fold zones on another side, which are linearly spaced (at a distance “r a ”) toward an annular core of the wound volume, which will be described further below. 
         [0035]      FIG. 1D  illustrates a perspective view of a folded electrode termination foil  121  showing current collecting tab portions  105  oriented in a negative vertical direction, corresponding to the unfolded electrode termination foil  101  of  FIG. 1B . The folded electrode termination foil  121  of  FIG. 1D  is a view of how  FIG. 1B  looks when the unfolded electrode termination foil  101  is folded along the fold lines  107   a - g.  In one embodiment, the fold lines  107   a,    107   c,    107   e,  and  107   g  comprise outer radius fold lines, lying at a fixed outer radial position (“r b ”) relative to a winding center axis  125 , which defines one boundary of the plurality of fold zones. The fold lines  107   b,    107   d,  and  107   f  comprise inner radius fold lines, bounding the fold zones on another side, which are linearly spaced (at a distance “r a ”) toward an annular core of the wound volume, which will be described further below. 
         [0036]      FIG. 1E  illustrates a front plan view of a separator  110 . The separator  110  has dimensions of length and width approximately identical to the electrode termination foils described above. In the completed assembly of the electrode termination contact interface, the separator  110  is interposed between the first electrode foil  102  and the second electrode foil  103 . The separator  110  functions to prevent foil  102  from electronic shorting to foil  103 , while simultaneously allowing ionic current to flow therebetween. When the foil  102  and foil  103  are folded, the separator  110  is positioned therebetween, and prevents electronic shorting thereof. 
         [0037]      FIG. 1F  illustrates a perspective view of the folded electrode termination foil  120  of  FIG. 1C  folded together with the folded electrode termination foil  121  of  FIG. 1D , having the separator  110  of  FIG. 1E  therebetween (not shown) to form a capacitor electrode termination contact interface  140 , adapted for interfacing with a terminal cap. It will be appreciated that when fully assembled, the electrode termination contact interface forms an annular ring volume coaxial with the winding center axis  125 , as will be described further below. 
         [0038]      FIG. 2A  illustrates a top plan view of a first terminal cap  200 , showing a plurality of terminal cap opening tabs  202  and  204  opening in a first direction. In one embodiment, the first terminal cap  200  is a conductive retention ring, wherein the plurality of terminal cap opening tabs  202  and  204  comprise three-sided punchings, each having the same radial displacement as a plurality of current collecting tab portions  104  and  105  (not shown in  FIG. 2A ).  FIG. 2A  shows the winding center axis  125  oriented orthogonally outward with respect to the page. The plurality of terminal cap opening tabs  202  and  204  each have a flap opening upward, wherein all the opening tabs  202  and  204  open in a first direction, as shown in  FIG. 2A . As will be described in more detail below, the plurality of current collecting tab portions  104  and  105  are adapted to be collected and secured into the first terminal cap  200  via the opening tabs  202  and  204 , such as for example clamping the opening tabs  202  and  204  against the plurality of current collecting tab portions  104  and  105 . An outer edge  208  of the first terminal cap  200  is at a distance r b  radially outward from the winding center axis  125 . The width of the three-sided punchings is shown at the opening tab  204  as D+∂D, where D is the width of the plurality of current collecting tab portions  104  and  105 . Also, the width ∂D is a small distance set to ensure the plurality of current collecting tab portions  104  and  105  do not gather and jam upon insertion therethrough. 
         [0039]      FIG. 2B  illustrates a top plan view of a second terminal cap  201 , showing a plurality of terminal cap opening tabs  203  and  205  opening in a second direction. In one embodiment, the second terminal cap  201  is a conductive retention ring, wherein the plurality of terminal cap opening tabs  203  and  205  comprise three-sided punchings, each have the same radial displacement as the plurality of current collecting tab portions  104  and  105  (not shown in  FIG. 2B ).  FIG. 2B  shows the winding center axis  125  oriented orthogonally outward with respect to the page. The plurality of terminal cap opening tabs  203  and  205  each have a flap opening upward, wherein all the opening tabs  203  and  205  open in a second direction, as shown in  FIG. 2B . As will be described in more detail below, the plurality of current collecting tab portions  104  and  105  are adapted to be collected and secured into the first terminal cap  201  via the opening tabs  203  and  205 , such as for example clamping the opening tabs  203  and  205  against the plurality of current collecting tab portions  104  and  105 . An outer edge  209  of the second terminal cap  201  is at a distance r b  radially outward from the winding center axis  125 . The width of the three-sided punchings is shown at the opening tab  205  as D+∂D, where D is the width of the plurality of current collecting tab portions  104  and  105 . Also, the width ∂D is a small distance set to ensure the plurality of current collecting tab portions  104  and  105  do not gather and jam upon insertion therethrough. 
         [0040]      FIG. 2C  illustrates a perspective view of the first terminal cap  200  of  FIG. 2A . Similarly,  FIG. 2D  illustrates a perspective view of the second terminal cap  201  of  FIG. 2B . In one embodiment of the present disclosure, the first terminal cap  200  comprises a mechanical inner threading in approximately a circumferential orientation, about the inside of the first terminal cap  200  (not shown). In this embodiment, the second terminal cap  201  comprises a mechanical outer threading in approximately a circumferential orientation, about the outside of the second terminal cap  201  (not shown). In this embodiment, the second terminal cap  201  comprises a slightly smaller diameter than the first terminal cap  200 , such that the first terminal cap  200  is threaded onto the second terminal cap  201 . It will be appreciated that the relative positioning of the plurality of terminal cap opening tabs  203  and  205  are configured such that the plurality of current collecting tab portions  104  and  105  fit therethrough without jamming upon insertion. 
         [0041]      FIG. 2E  illustrates a perspective view showing the first terminal cap  200  of  FIG. 2A  fitting together with the second terminal cap  201  of  FIG. 2B . In one embodiment, the plurality of terminal cap opening tabs  202  and  203  are made in symmetrical pairs. In one variation of the embodiment, the first terminal cap  200  is a left hand ring (left threaded) that is disposed atop the electrode foils  120  and  121  (not shown) and is adapted to accept a large fraction of the plurality of current collecting tab portions  104  and  105  (not shown) therethrough. The second terminal cap  201  a right hand ring (right threaded) is adapted to fit atop the first terminal cap  200 , such that when the threadings are tightened, the plurality of current collecting tab portions  104  and  105  are pinched together mechanically. In this manner, the pinched current collecting tab portions  104  and  105  and terminal caps  200  and  201  may be crimped, staked, welded, clinched, or otherwise affixed such that a high quality electrode termination contact interface is created. 
         [0042]      FIG. 2F  illustrates a perspective view of a portion of the first terminal cap  200  fitted onto the plurality of current collecting tab portions  104  of  FIG. 1C . As shown in  FIG. 2F , the plurality of current collecting tab portions  104  are collected into a plurality of gatherings  104 ′. The terminal cap opening tab  202  is shown applying mechanical pressure, in a first direction, against the plurality of gatherings  104 ′, as the first terminal cap  200  is mechanically tightened. 
         [0043]      FIG. 2G  illustrates a perspective view of a portion of the second terminal cap  201  fitted onto the plurality of current collecting tab portions  104  of  FIG. 1C . As shown in  FIG. 2G , the plurality of current collecting tab portions  104  are pressed into a plurality of gatherings  104 ′. The terminal cap opening tab  203  is shown applying mechanical pressure, in a second direction, against the plurality of gatherings  104 ′, as the second terminal cap  201  is mechanically tightened. 
         [0044]      FIG. 2H  illustrates a perspective view of a portion of the first terminal cap  200  and the second terminal cap  201  fitted together onto the plurality of current collecting tab portions  104  of FIG  1 C, wherein the terminal cap opening tab  203  of the terminal cap  201  fits therethrough the terminal cap opening tab  202  of the terminal cap  200 . As shown in  FIG. 2G , the current collecting tab portions  104  are collected into a plurality, of gatherings  104 ′. The terminal cap opening tab  202  is shown applying mechanical pressure, in a first direction, against the plurality of gatherings  104 ′, while the terminal cap opening tab  203  is shown applying mechanical pressure, in a second direction against the plurality of gatherings  104 ′. Moreover, as the terminal caps  200  and  201  are tightened against one another respectively via the threading described above, the mechanical force exerted by the tabs  202  and  203  against the plurality of gatherings  104 ′ increases, therefore the electrical connectivity is proportionally increased thereby, as will be appreciated by those of skill in the art. The plurality of gatherings  104 ′ are then crimped, clamped, or pinched and can then be laser welded, conductive adhesive bonded 
         [0045]      FIG. 2I  illustrates an exploded view of an assembly  250  of the first terminal cap  200  and the second terminal cap  201  fitted together onto an electrode termination contact interface  260 . In one embodiment, a first plurality of current collecting tab portions  104  have a directional orientation approximately identical to a second plurality of current collecting tab portions  105 , with respect to the electrode termination contact interface  260 , as shown in  FIG. 2I . The plurality of current collecting tab portions  104  and  105  are adapted to fit through terminal cap opening tabs  203  of the terminal cap  201 , and receive mechanical pressure therefrom, as described above with respect to  FIG. 2F . Further, the plurality of current collecting tab portions  104  and  105  are further adapted to fit through the terminal cap opening tabs  202  of the terminal cap  200 , and receive mechanical pressure therefrom, as described above with respect to  FIG. 2G  and  FIG. 2H . In one embodiment, the terminal cap  201  is threaded such that the terminal cap  201  is adapted to be threaded onto a body  252  of the electrode termination contact interface  260 . Similarly, the terminal cap  200  is threaded such that the terminal cap  200  is adapted to be threaded onto the terminal cap  201 , whereby the plurality of current collecting tab portions  104  and  105  fit therethrough the terminal tab openings of both terminal cap  201  and terminal cap  200 , respectively. In one embodiment, the present teachings are adapted for use in a capacitor device, such as for example an ultracapacitor. In one alternate embodiment, the present teachings are adapted for use in a lithium ion battery. 
         [0046]      FIG. 2J  illustrates an exploded view of one embodiment of the present teachings. This embodiment is similar to that described above, with respect to  FIG. 2I , except that the first plurality of current collecting tab portions  104  protrude from an electrode termination contact interface  261  and the second plurality of current collecting tab portions  105  protrude from an electrode contact termination interface  262 . The terminal caps  200  and  201  are threaded and fitted to a double-sided body  253  in a manner similar to that described above with respect to  FIG. 2I . That is, the terminal caps  200  and  201  are first fitted to the electrode termination contact interface  261  and tightened, such that the first plurality of current collecting tab portions  104  first protrude through the terminal cap opening tabs  203  of the terminal cap  201 , and then the first plurality of current collecting tab portions  104  secondly protrude through the terminal cap opening tabs  202  of the terminal cap  200 . Similarly, the second plurality of current collecting tab portions  105  protruding from the electrode contact termination interface  262  are fitted through the terminal cap opening tabs  203  and  202  of the terminal caps  201  and  200 , respectively. In one embodiment, the present teachings are adapted for use in a capacitor device, such as for example an ultracapacitor. In one alternate embodiment, the present teachings are adapted for use in a lithium ion battery. 
         [0047]      FIG. 3  illustrates a method for making  300  an electrode termination contact interface. At a forming STEP  302 , a first electrode foil is formed, having a plurality of active carbon deposits disposed upon predetermined portions of the first electrode foil, the electrode foil further having a plurality of current collecting tab portions disposed thereon. Next, at a defining STEP  304 , a plurality of fold zones thereupon the first electrode foil are defined, wherein the fold zones are bounded by a plurality of fold lines. At a folding STEP  306 , the first electrode foil is folded symmetrically about alternating fold lines. Next, at a defining STEP  308 , a plurality of fold zone outer radius folds are defined, wherein the plurality of fold zone outer radius folds all lie at a fixed position relative to a winding center axis. At a next interposing STEP  310 , at least one separator sheet is interposed between the plurality of fold zones, wherein the at least one separator sheet electrically isolate the plurality of fold zones. At a next defining STEP  312  a plurality of fold zone inner radius folds are defined, wherein the plurality of fold zone inner radius folds are linearly spaced toward an annular core. Lastly, at a collecting STEP  314  the plurality of current collecting tab portions for each of the plurality of fold zones is collected into a first plurality of gatherings. In one embodiment, the present teachings are adapted for use in a capacitor device, such as for example an ultracapacitor. In one alternate embodiment, the present teachings are adapted for use in a lithium ion battery. 
         [0048]    The present teachings are focused on making the cell terminations with high quality, low variability, and tight manufacturing tolerance thereby leading to a balancer-less module. Moreover, the present teachings are on providing high integrity electrode foil to end cap terminations. In some conceptual embodiments, the disclosed techniques and methods may be readily adapted for robotized assembly. 
         [0049]    The method described concerns a means to attach electrode foil tabs to an end cap termination that is designed to collect at least 60% of the available active area of the electrode thereby significantly reducing contact ESR and reducing part to part variability of this parameter. 
         [0050]    This electrode termination method applies equally well to lithium metal battery construction. In fact, by extension of this assembly technique could be extended to multilayer (“MLC”) such as those offered on the market by AVX and polymer multilayer (“PML”) capacitors such as those manufactured by ITW Paktron. 
         [0051]    Currently lithium-ion cells have an order of magnitude higher ESR in part due to thick electrodes and to losses in the electrode current collectors and termination means. In the lithium cell a carbon anode is needed that provides a lithium intercalation accumulator and this electrode is in effect a double layer capacitor. The teachings described herein applies equally well to fabrication of lithium-ion cell anodes (the positive electrode, conventionally manufactured out of graphite) and therefore make available the potential to lower the ESR of lithium-ion battery packs. 
         [0052]    A more remote application, but not necessarily remote in concept, would be to apply this technique to electric machine, transformer, and dc-dc converter inductor design when ribbon conductors are used and inserted into magnetic cores leaving an open pair of leads that must be interconnected to complete the winding. In one embodiment, the technique is adapted for use on a ribbon wire or flat conductive strip windings that inherently require some means of capturing the single turn ends by pairs (or if multi-strand windings are employed) collecting several such ends and making a high integrity connection via weld, stake, or fuse. The end cap in such use would be non-conductive but with conductive lands and tabs where the winding end leads are captured and lands or frets for interconnection. 
       Conclusion  
       [0053]    The foregoing description illustrates exemplary implementations, and novel features, of aspects of a method of making an apparatus for effectively providing a capacitor electrode termination contact interface to a terminal cap, which improves equivalent series resistance. Given the wide scope of potential applications, and the flexibility inherent in electro-mechanical design, it is impractical to list all alternative inplementations of the method and apparatus. Therefore, the scope of the presented disclosure should be determined only by reference to the appended claims, and is not limited by features illustrated or described herein except insofar as such limitation is recited in an appended claim. 
         [0054]    While the above description has pointed out novel features of the present teachings as applied to various embodiments, the skilled person will understand that various omissions substitutions, permutations, and changes in the form and details of the methods and apparatus illustrated may be made without departing from the scope of the disclosure. These and other variations constitute embodiments of the described methods and apparatus. 
         [0055]    Each practical and novel combination of the elements and alternatives described hereinabove, and each practical combination of equivalents to such elements, is contemplated as an embodiment of the present disclosure. Because many more element combinations are contemplated as embodiments of the disclosure than can reasonably be explicitly enumerated herein, the scope of the disclosure is properly defined by the appended claims rather than by the foregoing description. All variations coming within the meaning and range of equivalency of the various claim elements are embraced within the scope of the corresponding claim. Each claim set forth below is intended to encompass any system or method that differs only insubstantiality from the literal language of such claim, as long as such apparatus or method is not, in fact, an embodiment of the prior art. To this end, each described element in each claim should be construed as broadly as possible, and moreover should be understood to encompass any equivalent to such element insofar as possible without also encompassing the prior art.