Abstract:
A battery terminal connector and process of manufacture. The battery terminal includes a connector body formed of an alloy comprising up to about 8.8 percent aluminum, up to 0.06 about percent magnesium, up to about 0.075 percent iron, up to about 0.006 percent lead, up to about 0.006 percent cadmium, up to 0.003 percent tin, up to 1.3 percent copper, the balance being zinc, all of said percentages being by weight of the composition. The connector is gravity molded or pressure cast, resulting in a battery terminal connector having high strength and electrical conductivity and good corrosion resistance.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to terminals or connectors for batteries. In particular, the invention relates to a lead alternative insert molded battery post terminal connector. 
       BACKGROUND OF THE INVENTION 
       [0002]    Many batteries, such as vehicular lead acid batteries, have posts that extend upward from the battery to provide an external electrical connection point. To establish an electrical connection between the battery and the appliance or electrical system that draws power from the battery, terminals are fastened to the posts, and electrical cables are attached to the terminals. 
         [0003]    For vehicular applications, these terminals have traditionally been made of lead. Since the posts in vehicular batteries are typically made of lead or lead alloy, lead terminals make a good electrical connection to the battery. Lead is also resistance to sulfuric acid. 
         [0004]    For decades, the SAE J537 and SAE J1811 Standards have combined to define the requirements for the interfacing connection of a 12-24V DC battery-cable assembly as used in the electrical starting system for on and off road vehicles. 
         [0005]    In recent years, some vehicle manufacturers have moved away from lead tapered post batteries to threaded versions, or have opted for copper-alloy and plated steel “crimp-on” clamp terminals to handle RoHS compliance and waste stream issues at end of life on battery cables. Currently, unlike batteries that have a near 100% recycling program, battery cables are not recycled and any lead content moves into the waste stream. 
         [0006]    Current RoHS compliance requires that assemblies have a maximum of 0.1% lead, as well as other targeted elements. To achieve that level of compliance on battery cables, complete elimination of lead based alloys from terminals is required. 
         [0007]    It would, therefore, be beneficial to provide a lead-free battery post terminal which is durable, corrosion resistant, cost effective and which can be manufactured in different configurations. It would also be beneficial to provide a terminal in which the lead-free alloy is molded and encapsulates an end of the cable. 
       SUMMARY 
       [0008]    An embodiment is directed to a zinc-zinc alloy diecast battery post clamp terminal. 
         [0009]    An embodiment is directed to a zinc-zinc alloy diecast battery post clamp terminal with a metal clip insert to meet clamping force and unloading requirements. 
         [0010]    An embodiment is directed to a zinc-zinc alloy diecast battery post clamp terminal with a protective coating or plating to resist environmental corrosion attack. 
         [0011]    An embodiment is directed to a zinc-zinc alloy diecast battery post clamp terminal for accommodating multiple single electrical conductors. 
         [0012]    An embodiment is directed to a zinc-zinc alloy diecast battery post clamp terminal manufactured using but limited to gravity and pressure casting process methods. 
         [0013]    An embodiment is directed to a tin-zinc alloy pre-solder dipped electrical conductor insert molded into a zinc-zinc alloy diecast battery post clamp terminal. 
         [0014]    An embodiment is directed to a thermoplastic or thermoset insulated electrical conductor insert molded into a zinc-zinc alloy diecast battery post clamp terminal. 
         [0015]    An embodiment is directed to a zinc-zinc alloy diecast insert over molded splice with multiple terminating electrical conductors, such as, but not limited to, tin-zinc pre-solder dipped conductors. The over molded splice may be over molded with an insulating layer of thermoplastic or thermoset plastics. 
         [0016]    An embodiment is directed to a battery terminal connector which includes a connector body which has a clamping end for mounting to a terminal post and a termination end for terminating to a cable. The termination end is overmolded over a termination end of the cable. The connector body is formed of an alloy comprising up to 4.7 percent aluminum, up to 0.06 percent magnesium, up to 0.05 percent iron, up to about 0.005 percent lead, up to 0.04 percent cadmium, up to 0.002 percent tin, up to 0.1 percent copper, the balance being zinc, all of said percentages being by weight of the composition. The connector is gravity molded or pressure cast, resulting in a battery terminal connector having high strength and electrical conductivity and good corrosion resistance. 
         [0017]    An embodiment is directed to a battery terminal connector which includes a connector body which has a clamping end for mounting to a terminal post and a termination end for terminating to a cable. The termination end is overmolded over a termination end of the cable. The connector body is formed of an alloy comprising up to about 8.8 percent aluminum, up to 0.06 about percent magnesium, up to about 0.075 percent iron, up to about 0.006 percent lead, up to about 0.006 percent cadmium, up to 0.003 percent tin, up to 1.3 percent copper, the balance being zinc, all of said percentages being by weight of the composition. The connector is gravity molded or pressure cast, resulting in a battery terminal connector having high strength and electrical conductivity and good corrosion resistance. 
         [0018]    An embodiment is directed to a terminal connector or splice which includes a connector body formed of an alloy comprising up to 4.7 percent aluminum, up to 0.06 percent magnesium, up to 0.05 percent iron, up to about 0.005 percent lead, up to 0.04 percent cadmium, up to 0.002 percent tin, up to 0.1 percent copper, the balance being zinc, all of said percentages being by weight of the composition. The connector is gravity molded or pressure cast, resulting in a battery terminal connector having high strength and electrical conductivity and good corrosion resistance. 
         [0019]    An embodiment is directed to a terminal connector or splice which includes a connector body formed of an alloy comprising up to about 8.8 percent aluminum, up to 0.06 about percent magnesium, up to about 0.075 percent iron, up to about 0.006 percent lead, up to about 0.006 percent cadmium, up to 0.003 percent tin, up to 1.3 percent copper, the balance being zinc, all of said percentages being by weight of the composition. The connector is gravity molded or pressure cast, resulting in a battery terminal connector having high strength and electrical conductivity and good corrosion resistance. 
         [0020]    An embodiment is directed to a process of forming a battery terminal connector, the process comprising; heating a reduced lead alloy; gravity molding or pressure casting the alloy into a mold; overmolding the alloy over a termination end of a cable; solidifying the alloy; and removing the alloy with the overmolded cable from the mold. The process may optionally include pretreating the termination end of the cable with solder to bond individual conductors of the cable together. The process may optionally include applying a coating to a surface of the battery terminal connector to seal the surface against penetration and corrosion by sulphuric acid. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a perspective view of an illustrative embodiment of a battery terminal connector attached to a battery post of a battery. 
           [0022]      FIG. 2  is a perspective view of an illustrative embodiment of a battery terminal connector with a battery post exploded therefrom. 
           [0023]      FIG. 3  is a perspective view of an alternate illustrative embodiment of a battery terminal connector with a strengthening clip positioned therein. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. In the drawings, the relative sizes of regions or features may be exaggerated for clarity. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
         [0025]    It will be understood that spatially relative terms, such as “top”, “upper”, “lower” and the like, may be used herein for ease of description to describe one element&#39;s or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “over” other elements or features would then be oriented “under” the other elements or features. Thus, the exemplary term “over” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
         [0026]    An embodiment is directed to a battery terminal connector for connecting and disconnecting to a terminal post, such as a battery terminal post or to a terminal for splicing electrical wires. Referring to  FIGS. 1 and 2 , an exemplary embodiment of a battery terminal connector  10  of the present invention is shown. The connector  10  includes a connector body  12  which includes a clamping end or stirrup  16  and an opposed termination end  17  extending therefrom. 
         [0027]    The clamping end  16  includes an aperture  18  extending therethrough which is designed for accommodation over an upstanding terminal post  20  of a battery  22 . The aperture  18  forms nearly a full circle to encompass the post  20 . The clamping end  16  further includes a pair of spaced apart outwardly extending movable clamping arms or lugs  24 ,  26  which provide for clamping engagement about the post  20 . 
         [0028]    The clamping arms  24 ,  26  are separated by a slot  36  which extends to the aperture  18 . The width of the slot  36  may vary depending upon whether the connector  10  is in a clamped (closed) or an unclamped (open) position, as will be more fully described. 
         [0029]    The clamping arms  24 ,  26  are generally rectangular with a curved outer end. A mounting opening  30  (as best shown in  FIG. 2 ) extends through the clamping arms  24 ,  26  adjacent the curved outer end. The clamping arms  24 ,  26  have an inner surface adjacent the slot  36  and an outer surface opposite the inner surface. 
         [0030]    A bolt, screw, lever or other activation device  37  ( FIG. 1 ) may be positioned in the mounting openings  30 . The activation device is provided to move the battery connector  10  from the open or unclamped position to the closed or clamped position in which the connector body  12  is clamped to the terminal post  20  of battery  22 . As the activation device is moved, the deformable clamping arms  24 ,  26  are moved inwardly to clamp the connector body  12  about terminal post  20 . The activation device may create a gradient force which causes the clamping arms  24 ,  26  to provide secure clamping engagement about the post  20 . The activation device  37  also creates a controlled, specific and repeatable force which causes a specific movement or deformation of the clamping arms  24 ,  26  and the aperture  18 , which in turn provides a controlled, specific and repeatable electrical connection between the connector  10  and the terminal post  20 . 
         [0031]    As the connector  10  of the present invention is designed to terminate an electrical cable, such as a battery cable, to the terminal post  20  of the battery  22 , the body  12  of the connector  10  is formed of an electrically conductive metal. 
         [0032]    The termination end or cable mount  17  allows accommodation of the stripped end of an electrical cable  40 , such as a battery cable. The termination end  17  is the point of contact between the terminal and the electrical cables. The termination end  17  refers generically to the portion of the terminal that makes electrical contact with the cable or cables. As shown in  FIG. 1 , the termination end  17  is overmolded over the battery cable. This provides a secure mechanical and electrical connection. As the cable is insert molded, the connection between the cable and termination end  17  of the terminal connector  10  is sealed and resistant to corrosion. Alternatively, other configurations of the termination end  17  may be used without departing from the scope of the invention. 
         [0033]    In illustrative embodiments, the termination end  44  of the cable  40  may be pretreated to facilitate a better mechanical and/or electrical connection with the overmolded connector  10 . As an example, a tin, zinc, tin/zinc alloy or solder may be applied to the exposed conductors of the cable prior to the overmold process to form a solder member  42 . The application of the solder bonds the individual conductor or wires of the cable together, thereby strengthening the termination end and solidifying the irregular shapes of the wires. In addition, the solder solidifies to provide a rough outer surface which cooperates with the overmolded connector  10  to enhance the mechanical bond there between. 
         [0034]    Examples of such a solder used to provide an adequate wetting surface for the zinc alloy over mold in the conductor cable include a 60/40 tin-zinc alloy solder and a 70/30 tin-zinc alloy solder. In most cases the copper conductor cable strands begin to fail before the solder itself pulls off or fails. 
         [0035]    The present invention can be used with many different types of batteries and battery terminals. For instance, the illustrative embodiment shows a right angle terminal connector  10 . However, other types of the terminal connectors, such as but not limited to, straight, vertical and T cut can be used. 
         [0036]    In various illustrative embodiments, such as shown in  FIG. 3 , an optional clip or spring member  50  may be provided. The clip  50  is configured to approximate the general shape of the clamping end  16  of the connector  10 . The clip  50  may be insert molded in the clamping end  16  to provide enhanced strength and durability of the clamping end  16 . The clip  50  is generally U-shaped with a semi-circular section  52  and generally parallel planar ends  54 ,  56 . The ends  54 ,  56  have aligned apertures or openings  56  which are aligned with apertures or opening  30  of clamping arms  24 ,  26  when the clip  50  is positioned in the clamping end  16 . The clip  50  may be stamped and formed from any material having the appropriate strength and resilient characteristics required. 
         [0037]    However, although an internal spring clip  50  may be used in certain applications, such clips are not required in many applications. If point stresses are properly minimized in certain areas of the clamping end  16  of the connector  10 , the clip  50  is not needed. 
         [0038]    The battery terminal connectors  10  may be manufactured from any suitable lead-free or reduced lead (0.1% or less by weight) material compatible with the environment in which they are intended to be used. The battery terminal connectors can be made from, but are not limited one of the following alloys which exhibit good electrical conductivity, proper corrosion resistance and sufficient strength. The following three examples represent compositions suitable for use for the clamping end  16  and the termination end  17  of the connector body  12  of the battery terminal connector  10 : 
       EXAMPLE I 
       [0039]    Aluminum 4.3 to 4.7% 
         [0040]    Copper Up to 0.035% maximum 
         [0041]    Magnesium 0.005 to 0.012% 
         [0042]    Iron Up to 0.03% maximum 
         [0043]    Lead Up to 0.003% maximum 
         [0044]    Cadmium Up to 0.002% maximum 
         [0045]    Tin Up to 0.001% maximum 
         [0046]    Zinc Balance 
       EXAMPLE II 
       [0047]    Aluminum 3.7 to 4.3% 
         [0048]    Copper Up to 0.1% maximum 
         [0049]    Magnesium 0.02 to 0.06% 
         [0050]    Iron Up to 0.05% maximum 
         [0051]    Lead Up to 0.005% maximum 
         [0052]    Cadmium Up to 0.004% maximum 
         [0053]    Tin Up to 0.002% maximum 
         [0054]    Zinc Balance 
       EXAMPLE III 
       [0055]    Aluminum 8.0 to 8.8% 
         [0056]    Copper 0.8 to 1.3% 
         [0057]    Magnesium 0.01 to 0.03% 
         [0058]    Iron Up to 0.075% maximum 
         [0059]    Lead Up to 0.006% maximum 
         [0060]    Cadmium Up to 0.006% maximum 
         [0061]    Tin Up to 0.003% maximum 
         [0062]    Zinc Balance 
         [0063]    In each of the above examples, the percentages are by weight of the composition, and it will be noted that in each case the major portion of the composition comprises zinc which is the balance of the composition in each of the three examples. The percentages of the various minerals in each of the above alloys may be varied slightly without departing from the scope of the present invention. 
         [0064]    In the Examples recited above, the battery terminal connector  10  is formed of a zinc base alloy comprising aluminum, copper, cadmium, tin, lead, magnesium, iron and zinc within certain critical ranges. During forming of the terminal connector  10 , the zinc alloy is heated to a molten state and the molten alloy is then pressure or gravity molded. 
         [0065]    In the present invention, the method of making the electrical connector  10  includes the steps of heating one of the lead-free or reduced lead alloy to a molten state at a particular temperature. Either pressure or gravity molding the molten alloy at a particular pressure and for a specific time to form an electrical connector. Specifically, the method of making the electrical connector includes the steps of heating one of the one of the zinc alloys to a molten state at about 800 degrees Fahrenheit. 
         [0066]    During the molding process, the termination end  44  of the cable  40  is maintained in the mold cavity, thereby allowing the molten alloy to flow about the termination end  44  and the solder member  42 . In so doing the connector  10  is overmolded over the termination end  44  of the cable  40 . As the termination end  44  is molded into the connector  10 , a secure, rigid mechanical and electrical connection is provided between the connector  10  and the cable  40  when the connector  10  when the alloy is solidified and removed from the mold. The use of the solder member  42  at the termination end  44  of the cable  40  interacts with the molded connector  10  to enhance the mechanical and electrical connection between the connector  10  and the cable. As the solder member  42  has micro peaks and valleys in the outer surface, the molten alloy flows into the valleys to create a more secure bond therebetween when the alloy solidifies. 
         [0067]    As the insulation  46  of the cables  40  are exposed to the molten alloy during the formation of the one piece connector  10  and cable, the insulation  46  is preferably made of a material which can withstand the heat of the molten alloy, such as, but not limited to, thermoset insulation. In addition, thermoplastic insulation with a melt temperature higher than the melt temperature of the alloy may be used. 
         [0068]    In various illustrative embodiments, the connector  10  may be subject to fast chilling to keep the grain structure of the connector very fine. 
         [0069]    In various illustrative embodiments, the alloy or metal is subjected to a chemical treatment or coating to seal the surface of the metal against penetration and intergranular corrosion by sulphuric acid and the like. Such coating may be, but is not limited to nickel or zinc. However, in many application, un-treated alloy diecast terminal connectors can perform well electrically and mechanically for the life expectancy of the product. 
         [0070]    In addition, surface treating may be necessary to eliminate visual performance differences in the alloy versus connectors made from lead or other known materials. 
         [0071]    The grain structure for alloys, such as zinc alloys, must be minimized in order to provide the correct strength for performance elements such as torque testing. Alloy modifying elements such as silica can provide for better mold flow characteristics, as well as grain size reduction modification. In various illustrative embodiments, the amount of magnesium in the alloy may be adjusted to help prevent intergranular corrosion. 
         [0072]    In various illustrative embodiments, the amount of aluminum in the alloy may be adjusted to allow the alloy to have a proper, predictable and reliable flow as the alloy is poured into the mold. 
         [0073]    While the invention has been described with reference to an illustrative 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 spirit and scope of the invention as defined in the accompanying claims. In particular, it will be clear to those skilled in the art that the present invention may be embodied in other specific forms, structures, arrangements, proportions, sizes, and with other elements, materials, and components, without departing from the spirit or essential characteristics thereof. One skilled in the art will appreciate that the invention may be used with many modifications of structure, arrangement, proportions, sizes, materials, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. The presently disclosed embodiments and methods are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims, and not limited to the foregoing description or embodiments.