Abstract:
Described embodiments provide a conductor interface for a photovoltaic module that includes a raised feature on a bottom surface. Methods of forming such structures are also disclosed, as are photovoltaic modules containing the conductor interface.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/615,970, filed Mar. 27, 2012, which is hereby fully incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The disclosed embodiments relate to a conductor interface used with photovoltaic modules and methods for manufacturing photovoltaic modules having a conductor interface. 
       BACKGROUND OF THE INVENTION 
       [0003]    Photovoltaic (PV) modules are becoming increasingly popular for providing renewable energy. In order to provide internally generated electricity to outside the module, a conductor interface (also referred to as a cord plate) is typically provided. The conductor interface is attached to the module over an opening in the module and provides an area for external conductors to be electrically connected to internal conductors of the module. 
         [0004]      FIG. 1  shows a back perspective view of a conventional photovoltaic module  10 . Module  10  is oriented to receive sunlight through a front surface  110  and converts photons in the received sunlight to electricity using internal semiconductors arranged into a plurality of PV cells. The PV cells can be connected in series, parallel, or a combination thereof depending on the desired electrical output from module  10 . Brackets  115  connected to module  10  (for example, to peripheral edges of front surface  110  and back surface  140 ) may be used to fix module  10  to a support structure. 
         [0005]    As shown in  FIG. 1 , external conductors  120 ,  125  extend from a conductor interface  150  that is affixed to the back surface  140  of module  10 . 
         [0006]    External conductors  120 ,  125  provide the electrical current generated by module  10  to external electrical devices or loads. External conductors  120 ,  125  may be any appropriate wires or cables known in the art, and may include insulating jacket(s) surrounding their conductive core. External conductors  120 ,  125  may include industry-compliant connectors  130 ,  135  for ease of installation and interconnection with other elements in a photovoltaic system. 
         [0007]      FIG. 2  shows an exploded view of the conductor interface  150 , which is affixed over an opening  405  in back surface  140 . Conductor interface  150  houses the interconnections of internal conductors  410 ,  415  that are connected to an internal bussing system of module  10  with external conductors  120 ,  125 . Conductor interface  150  includes a base portion  152  and a cover portion  154 . Base portion  152  affixes to back surface  140 , and cover portion  154  attaches to base portion  152  after external conductors  120 ,  125  ( FIG. 1 ) are electrically connected to internal conductors  410 ,  415 . 
         [0008]    The internal conductors  410 ,  415  extend through an opening  405  in back surface  140  of module  10 . Internal conductors  410 ,  415  may be, for example, foil tabs that are connected to an internal bussing system of module  10 , such as a positive and a negative bus terminal within module  10 . Internal conductors  410 ,  415  are folded back against back surface  140 , such that conductor interface  150  can be placed over the opening  405  and internal conductors  410 ,  415 . An adhesive sealant  420 , for example, a dual-sided adhesive foam tape or other adhesive sealant that surrounds the internal conductors  410 ,  415  and opening  405 , is typically used to affix conductor interface  150  to back surface  140 . 
         [0009]      FIG. 3  shows a bottom surface of a conductor interface  150 , which is flat to accommodate adhesive sealant  420  ( FIG. 2 ) and forms a cavity  170 . External conductors  120 ,  125  ( FIG. 1 ) can be inserted into respective wire holes  160 ,  165  of conductor interface  150 , and terminal portions of external conductors  120 ,  125  are welded, soldered, or otherwise electrically connected to a respective one of internal conductors  410 ,  415  within cavity  170  after conductor interface  150  is affixed to back surface  140 . A potting material or other sealant can then be used to fill cavity  170  within conductor interface  150 , in order to prevent moisture and other elements from entering into cavity  170  of conductor interface  150 . Cover portion  154  is then attached to base portion  152  after the potting material fills cavity  170 . 
         [0010]    During the electrical connection of the terminal portions of external conductors  120 ,  125  to internal conductors  410 ,  415 , wire portions of external conductors  120 ,  125  are pressed down within cavity  170  and against adhesive sealant  420 . For example, wire portions of the external conductors  120 ,  125  within cavity  170  can be pressed down on adhesive sealant  420  from approximately half the distance between the wire holes  160 ,  165  and the respective electrical connection points. This can prevent potting material from fully encircling external conductors  120 ,  125  along this distance, which can result in an imperfect seal or a seal that can weaken over time between the potting material and the remaining portions of the external conductors  120 ,  125 . If the seal between the potting material and these remaining portions is not completely formed or breaks, moisture or other elements may enter conductor interface  150  and affect the electrical connections or enter the opening  405  of module  10 . 
         [0011]    Accordingly, it is desirable to manufacture a photovoltaic module having a conductor interface that is more thoroughly sealed against moisture ingress. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a bottom perspective view of a photovoltaic module. 
           [0013]      FIG. 2  is an exploded view of a bottom surface of a photovoltaic module. 
           [0014]      FIG. 3  is a bottom perspective view of a conventional conductor interface. 
           [0015]      FIG. 4  is a top perspective view of a conductor interface, in accordance with embodiments described herein. 
           [0016]      FIG. 5  is a bottom perspective view of a conductor interface, in accordance with embodiments described herein. 
           [0017]      FIG. 6  is a bottom perspective view of a conductor interface, in accordance with embodiments described herein. 
           [0018]      FIG. 7  is a bottom perspective view of a conductor interface, in accordance with embodiments described herein. 
           [0019]      FIG. 8  is a bottom perspective view of a conductor interface, in accordance with embodiments described herein. 
           [0020]      FIG. 9  shows a conductor interface mounted on a surface, in accordance with embodiments described herein. 
           [0021]      FIG. 10  is a bottom perspective view of a conductor interface, in accordance with embodiments described herein. 
           [0022]      FIG. 11  is a bottom perspective view of a conductor interface, in accordance with embodiments described herein. 
           [0023]      FIG. 12  is a bottom perspective view of a conductor interface, in accordance with embodiments described herein. 
           [0024]      FIG. 13  is a bottom perspective view of a conductor interface, in accordance with embodiments described herein. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and which illustrate specific embodiments of the invention. These embodiments are described in sufficient detail to enable those of ordinary skill in the art to make and use them. It is also understood that structural, logical, or procedural changes may be made to the specific embodiments disclosed herein. 
         [0026]      FIGS. 4 and 5  respectively show a top and bottom perspective of an embodiment of a conductor interface  250 , which may be used to house interconnections of electrical conductors for a photovoltaic module. Conductor interface  250  includes a base portion  205  and a top portion  210 . Base portion  205  can be mounted adjacent to a mounting surface, such as a back surface  140  of a photovoltaic module  10 . Top portion  210  connects with base portion  205  and defines a pair of cavities  270 ,  275  ( FIG. 5 ) within conductor interface  250  for respectively housing electrical interconnections between module internal and external conductors. Top portion  210  may include openings  272 ,  274  exposing the cavities  270 ,  275  within conductor interface  250 . Cavities  270 ,  275 , respectively, provide areas that allow electrical connection of terminal portions  122 ,  127  of external conductors  120 ,  125  with internal module conductors  410 ,  415 . 
         [0027]    Base portion  205  and top portion  210  may be a single piece, or may be two separate connectable pieces capable of being connected using interlocking connectors (e.g., a snap connector), an adhesive, or other techniques known in the art. Top portion  210  includes downwardly extending sidewalls that meet and interconnect with upwardly extending sidewalls of base portion  205 . In other embodiments, top portion  210  may be a flat plate configured to interconnect with the upwardly extending sidewalls of base portion  205 . 
         [0028]    Conductor interface  250  may be formed from plastic, metal, or other appropriate materials. For example, conductor interface  250  may be formed from a plastic or polycarbonate material shaped through an injection molding process. 
         [0029]    Conductor interface  250  includes wire holes  260 ,  265 , through which external conductors  120 ,  125  ( FIG. 6 ) can respectively be inserted. A silhouette of wire hole  265  is shown because it is on the backside of conductor interface  250  in the perspective shown in  FIG. 4 . Although two wire holes  260 ,  265  are shown in  FIG. 4 , it should be understood that a conductor interface  250  may have fewer or more wire holes to accommodate the number of electrical connections that need to be made to internal conductors of a module  10 . 
         [0030]      FIG. 6  shows a bottom perspective of base portion  205  with external conductors  120 ,  125  inserted into wire holes  260 ,  265 , respectively. As noted above with respect to  FIG. 5 , base portion  205  can be connected to top portion  210 , or base portion  205  and top portion  210  can be formed as a single piece. 
         [0031]    The bottom surface  290  of base portion  205  includes respective connection cavities  270 ,  275  and wire cavities  280 ,  285 . As shown in  FIG. 6 , an external conductor  120  traversing wire hole  260  extends through wire cavity  280  into connection cavity  270 . An external conductor  125  traversing wire hole  265  extends through wire cavity  285  into connection cavity  275 . External conductors  120 ,  125  include respective terminal portions  122 ,  127 , which can be electrically connected to respective internal conductors  410 ,  415  of photovoltaic module  10  ( FIG. 2 ) within the respective connection cavities  270 ,  275 . 
         [0032]    Wire cavities  280 ,  285  surround wire portions of the external conductors  120 ,  125  inserted into respective wire holes  260 ,  265 . Wire cavities  280 ,  285  are enclosed above and open below the respective locations for the wire portions of external conductors  120 ,  125 . Connection cavities  270 ,  275  house the terminal portions  122 ,  127  of external conductors  120 ,  125 , which include the exposed electrically conductive material used to form electrical connections, such as when soldered to internal conductors  410 ,  415  of a photovoltaic module  10  ( FIG. 2 ). Connection cavities  270 ,  275  may be enclosed above the locations for the terminal portions  122 ,  127  by a separate top portion  210  that is attached after electrical connections within connection cavities  270 ,  275  are completed. In other embodiments, connection cavities  270 ,  275  may be exposed through openings  272 ,  274  of top portion  210  ( FIG. 4 ) to permit electrical connection of terminal portions  122 ,  127  to internal conductors  410 ,  415  ( FIG. 2 ) after top portion  210  is attached or if top portion  210  and base portion  205  are formed as a single piece. 
         [0033]    The bottom surface  290  of base portion  205  includes a raised feature  230  partially surrounding connection cavity  270  and wire cavity  280 , and a raised feature  235  partially surrounding connection cavity  275  and wire cavity  285 . These raised features  230 ,  235  act as standoffs and enable the use of a fluid adhesive, such as a glue or paste, to be applied between base portion  205  and a module  10  for bonding conductor interface  250  to the module  10 . 
         [0034]    The fluid adhesive may be, for example, a water, silicone, urethane, or epoxy-based adhesive. The fluid adhesive may be, for example, a one-part adhesive that cures through exposure to air, or may be a two-part adhesive including a resin and a catalyst for stimulating curing of the resin. The fluid adhesive may be selected to have a high adhesive strength to glass and polycarbonate and a high intrinsic tensile strength. For example, the fluid adhesive may have a tensile strength rating (ASTM D412) that is greater than approximately 1.5 MPa, and an adhesive strength to bottom surface  290  of conductor interface  250  and to module  10  that is greater than the tensile strength. The fluid adhesive may be an adhesive capable of withstanding damp heat conditions and having a high flammability rating. For example, the fluid adhesive may be a one or two-part non-slumping paste having a UL Flammability Rating and a Relative Thermal Index greater than or equal to approximately 105° C. In addition, the fluid adhesive may also be resistive to the flow of electricity. For example, the fluid adhesive may have a volume resistivity that is greater than approximately 1×10 13  ohm*cm and a dielectric strength that is greater than 15 Kv/mm. 
         [0035]    The fluid adhesive has a fluid consistency. For example, the fluid adhesive may have a viscosity in a range of approximately 10,000 centiPoise (cP) to approximately 200,000 cP at room temperature. A relatively fluid adhesive can provide higher bond strength between the conductor interface  250  and a photovoltaic module than is achieved with a typical solid adhesive, such as a foam tape. 
         [0036]    Raised features  230 ,  235  maintain a fixed gap between bottom surface  290  of base portion  205  and the module back surface  140  to which conductor interface  250  is bonded ( FIG. 1 ). For example, raised features  230 ,  235  may both have a height of approximately 0.8 mm. 
         [0037]    Raised features  230 ,  235  may be spaced approximately 2 mm away from the respective connection cavities  270 ,  275  and wire cavities  280 ,  285 . The ends of raised features  230 ,  235  extend partially but not completely to the edge of bottom surface  290 , to allow for a layer of adhesive material to be applied between raised features  230 ,  235  and the edges of bottom surface  290 . For example, raised feature  230  may extend to approximately 11 mm from the edge of bottom surface  290  in which wire hole  260  is located, and raised feature  235  may extend to approximately 11 mm from the edge of bottom surface  290  in which wire hole  265  is located. Raised features  230 ,  235  may have substantially uniform or varying widths along their respective lengths. For example, raised features  230 ,  235  may be approximately 1.5 mm wide along their lengths. 
         [0038]    Raised features  230 ,  235 , in addition to providing a fixed space between bottom surface  290  the back surface  140  of photovoltaic module  10  ( FIG. 1 ) for a fluid adhesive material to occupy, also prevents the fluid adhesive from leaking into connection cavities  270 ,  275  or wire cavities  280 ,  285 . Adhesive leaking into connection cavities  270 ,  275  can interfere with the electrical connection of external conductors  120 ,  125  to internal conductors  410 ,  415  ( FIG. 2 ). Adhesive leaking into wire cavities  280 ,  285  may also come into contact with the external conductors  120 ,  125  as they are inserted into the conductor interface  250 , resulting in the adhesive being transferred on the wires into the connection cavities  270 ,  275 . 
         [0039]    Raised features  230 ,  235  also ensure that there is space between external conductors  120 ,  125  and the back surface  140  of the module  10  to which conductor interface  250  is bonded ( FIG. 1 ). This allows potting material used to fill conductor interface  250  to completely surround external conductors  120 ,  125 . For example, longer sections of external conductors  120 ,  125  can be completely surrounded by potting material, providing a more robust seal to prevent moisture ingress and electrical leakage. Furthermore, the open space beneath internal conductors  120 ,  125  that is provided by the raised features  230 ,  235  ensures that potting material also contacts the surface of module  10  to which conductor interface  250  is bonded, thereby creating an even stronger and better sealed bond between conductor interface  250  and the module surface. In addition, the fixed space provided by raised features  230 ,  235  creates a predetermined volume to be filled by the potting material, such as the volume within cavities  270 ,  275 ,  280 ,  285  and between these cavities and the back surface  140  of the module  10 , which helps to ensure complete potting material fillage and facilitates automation of the manufacturing process by allowing a fixed amount of potting material to be used. 
         [0040]    As shown in  FIGS. 5 and 6 , base portion  205  may also include raised features  240 ,  245  at opposing corners of bottom surface  290  to provide greater stability when conductor interface  250  is mounted to a module  10 . Raised features  240 ,  245  may be approximately the same height as raised features  230 ,  235 . For example, raised features  230 ,  235 ,  240 ,  245  may all have a height of approximately 0.8 mm. Raised features  240 ,  245  may have a circular surface area, as shown in  FIGS. 5 and 6 , or have other shapes, such as an elliptical or polygon shape. In one example, raised features  240 ,  245  may have circular surface areas with radii of approximately 0.25 mm. Raised features  240 ,  245  are located at a distance from the opposing corners of bottom surface  290  sufficient to allow for a layer of adhesive material to be applied between raised features  240 ,  245  and the edges of bottom surface  290 . For example, raised features  240 ,  245  may be located in a range of at least 5 to 10 mm from the opposing corners of bottom surface  290 . 
         [0041]    One or more of raised features  230 ,  235 ,  240 ,  245  may also have a secondary adhesive material, such as a quick bonding hot or room temperature adhesive, a pressure-sensitive adhesive material, or a dual-sided foam tape, affixed to its surface. The secondary adhesive on one or more of raised features  230 ,  235 ,  240 ,  245  can be used to hold base portion  205  in place on a module to which it is mounted while the fluid adhesive cures and solidifies. 
         [0042]      FIG. 7  shows a bottom perspective of another embodiment of a base portion  205   b  for conductor interface  250 . Base portion  205   b  includes similar features as base portion  205  discussed in connection with  FIGS. 5-6 , including raised features  230 ,  235 ,  240 ,  245 . In addition, bottom surface  290   b  of base portion  205   b  includes a surface texture  295  to enhance the bond strength of the fluid adhesive applied to bottom surface  290   b . The surface texture  295  may be, for example, a random surface character or other roughness character having a depth in a range of 25 μm to 100 μm, and can be applied by the injection molding process during the formation of conductor interface  250 . The surface texture  295  may be applied to substantially all of bottom surface  290   b , or to a portion of bottom surface  290   b.    
         [0043]      FIG. 8  shows a bottom perspective of base portion  205   b  with fluid adhesive  292  applied to bottom surface  290   b . As described above, fluid adhesive  292  may be a non-slumping paste with a fluid consistency. Fluid adhesive  292  may be, for example, a water, silicone, urethane, or epoxy-based one-part or two-part adhesive, which may be selected to have a high adhesive strength to glass and polycarbonate and a high intrinsic tensile strength, capable of withstanding damp heat conditions, having a high flammability rating, and electrically resistive. 
         [0044]    The fluid adhesive  292  may be applied covering substantially all of bottom surface  290   b  outside of raised features  230 ,  235 , or alternatively may be applied covering a portion of bottom surface  290   b . For example, as shown in  FIG. 8 , a layer of fluid adhesive  292  may be applied surrounding the perimeter of bottom surface  290   b . The layer of fluid adhesive  292  may be applied in a pattern with a diameter in a range of approximately 5 mm to 10 mm. When applied, the fluid adhesive will typically expand to cover a larger portion of bottom surface  290   b , and therefore should be applied with some distance, for example, 2 mm, from the edge of bottom surface  290   b  to prevent adhesive from spreading beyond bottom surface  290   b  and/or under wire holes  260 ,  265 . If fluid adhesive  292  is a two-part adhesive, a resin portion may be applied first, and then a catalyst portion applied to the resin portion. 
         [0045]    Multiple layers of fluid adhesive may be applied to bottom surface  290   b . For example, in addition to a layer of fluid adhesive  292  applied surrounding the perimeter of bottom surface  290 , addition layers of fluid adhesive  294 ,  296  may be applied on inner areas of bottom surface  290   b , such as layer  294  applied between raised feature  235  and raised feature  240 , and layer  296  applied between raised feature  230  and raised feature  245 . The layers of fluid adhesive  292 ,  294 ,  296  may be applied using a hot or cold automated applicator or dispenser, through a manual application process, or through other known techniques. Similar arrangements for fluid adhesive  292 ,  294 ,  296  may also be applied to bottom surface  290  of base portion  205  ( FIGS. 5-6 ). 
         [0046]      FIG. 9  shows a conductor interface  250  affixed to back surface  140  of a photovoltaic module  10  above an opening  405  exposing one or more internal conductors  410 ,  415  ( FIG. 2 ). A secondary adhesive on the surface area of one or more of the raised features  230 ,  235 ,  240 ,  245  ( FIG. 5 ) may be used to affix conductor interface  250  to surface  500  while a fluid adhesive bond is formed with the adhesive provided between the bottom surface  290  of conductor interface  250 . Conductor interface  250  includes base portion  205  and top portion  210 , although it should be understood that conductor interface  250  could instead include base portion  205   b  discussed in connection with  FIGS. 7-8 . 
         [0047]    As shown in  FIG. 9 , fluid adhesive  550  (e.g., from adhesive layers  292 ,  294 ,  296  of  FIG. 8 ) fills the space between back surface  140  and conductor interface  250  that is maintained by raised features  230 ,  235 ,  240 ,  245  ( FIGS. 5-8 ). The applied fluid adhesive is cured to form a bond between conductor interface  250  and back surface  140 , such as by allowing it to harden through exposure to air or other elements, applying a heat or cooling source, and/or other known types of curing treatments. Raised features  230 ,  235  prevent fluid adhesive from entering connection cavities  270 ,  275  and wire cavities  280 ,  285 . 
         [0048]    After conductor interface  250  is affixed to back surface  140 , external conductors  120 ,  125  ( FIG. 6 ) may be inserted into wire holes  260 ,  265 , where they can be electrically connected to internal conductors  410 ,  415  ( FIG. 2 ) of the photovoltaic module  10 , for example by welding or soldering the terminal portions  122 ,  127  of external conductors  120 ,  125  to internal conductors  410 ,  415  prior to affixing cover portion  210  to base portion  205 , or by welding or soldering the terminal portions  122 ,  127  to internal conductors  410 ,  415  through openings  272 ,  274  when base portion  205  and cover portion  210  are formed as a single piece. Alternatively, external conductors  120 ,  125  may be inserted into wire holes  260 ,  265  and electrically connected to internal conductors  410 ,  415  prior to affixing conductor interface  250  to back surface  140 . 
         [0049]    After electrical connection is made between the external conductors  120 ,  124  and internal conductors  410 ,  415 , connection cavities  270 ,  275  and wire cavities  280 ,  285  are then filled with potting material, for example through openings  272 ,  274  or wire holes  260 ,  265 . Together with fluid adhesive  550 , the potting material filling the cavities of conductor interface  250  electrically isolates the electrical connections and prevents moisture from entering into conductor interface  250 . Because raised features  230 ,  235  form a fixed volume surrounding external conductors  120 ,  125 , a known amount of potting material can be used to fill the cavities  270 ,  275 ,  280 ,  285 . In addition, raised features  230 ,  235  allow potting material to completely surround portions of internal conductors  120 ,  125  within conductor interface  250 . 
         [0050]      FIG. 10  shows a bottom perspective of another embodiment of a conductor interface  350 . Conductor interface  350  can be mounted adjacent to back surface  140  of a photovoltaic module  10  ( FIG. 1 ). Conductor interface  350  includes a base portion  305  and a top portion  210 . Base portion  305  can be mounted adjacent to a mounting surface, such as a back surface  140  of a photovoltaic module  10 . Top portion  210  has similar features as the top portion  210  discussed above in connection with  FIG. 5 . Conductor interface  350  may be formed from plastic, metal, or other appropriate materials. For example, conductor interface  350  may be formed from a plastic or polycarbonate material shaped through an injection molding process. 
         [0051]    Conductor interface  350  includes wire holes  260 ,  265  through which external conductors  120 ,  125  ( FIG. 6 ) can be inserted. Although two wire holes  260 ,  265  are shown in  FIG. 10 , it should be understood that a conductor interface  350  may have fewer or greater wire holes to accommodate the number of desired electrical connections. 
         [0052]    The bottom surface  390  of conductor interface  350  includes respective connection cavities  270 ,  275  and wire cavities  280 ,  285 , which have similar features as connection cavities  270 ,  275  and wire cavities  280 ,  285  discussed in connection with  FIGS. 5-9 . Bottom surface  390  of conductor interface  350  includes a raised feature  330  at an outer end of wire cavity  280 , and a raised feature  335  at an outer end of wire cavity  285 . As discussed further below, raised features  330 ,  335  are arranged to, accommodate a secondary adhesive  380  ( FIG. 12 ), such as a dual-sided tape, that can be used to affix conductor interface  350  to a module surface while a fluid adhesive, such as a glue or paste, forms a bond between conductor interface  350  and the back surface  140 . 
         [0053]    Raised features  330 ,  335  may have similar heights and widths as raised features  230 ,  235  discussed above in connection with  FIGS. 5-9 . For example, raised features  330 ,  335  may both have a height of approximately 0.8 mm, and may be approximately 1.5 mm wide along their lengths. Raised features  330 ,  335  may be spaced approximately 2 mm away from the respective wire cavities  280 ,  285 . 
         [0054]    Raised features  330 ,  335  provide a fixed space between bottom surface  390  of conductor interface  350  and a back surface  140  to which it is to be bonded. The fixed space forms a cavity for fluid adhesive material to bond conductor interface  350  to back surface  140 . Raised features  330 ,  335  also help prevent the fluid adhesive from leaking into wire cavities  280 ,  285 . As discussed in connection with  FIGS. 5-9 , raised features  330 ,  335  also ensure that there is space between external conductors  120 ,  125  inserted into wire holes  260 ,  265  and the back surface  140 , allowing potting material to completely surround external conductors  120 ,  125 . Furthermore, the open space beneath external conductors  120 ,  125  allows the potting material to also contact the back surface  140 . 
         [0055]    Conductor interface  350  may also include raised features  340 ,  345  at opposing corners of bottom surface  390  to provide added stability when conductor interface  350  is mounted to a module  10 . Raised features  340 ,  345  may be approximately the same height and width as raised features  330 ,  335 . Raised features  340 ,  345  may have a horseshoe or other polygonal shape, or may have a circular surface area similar to raised features  240 ,  245  discussed in connection with  FIGS. 5 and 6 . Raised features  340 ,  345  may be located at a distance from the opposing corners of bottom surface  390  sufficient to allow for a layer of adhesive material to be applied between raised features  340 ,  345  and the edges of bottom surface  390 , or may be located at a lateral distance from wire and connection cavities  270 ,  275 ,  280 ,  285  sufficient to allow for a layer of adhesive material to be applied between the cavities  270 ,  280  and raised feature  345 , and for a layer of adhesive material to be applied between cavities  275 ,  285  and raised feature  340 . 
         [0056]      FIG. 11  shows a bottom perspective of another embodiment of a base portion  305   b  for conductor interface  350 . Base portion  305   b  includes similar features as base portion  305  discussed in connection with  FIG. 10 , including raised features  330 ,  335 ,  340 ,  345 . In addition, bottom surface  390   b  of base portion  305   b  includes an area  392  in which a fluid adhesive can be applied, and an area  394  in which a secondary adhesive material  380  ( FIG. 12 ), such as a pressure-sensitive adhesive material or a dual-sided foam tape, can be affixed to bottom surface  390 . Area  392  in which the viscous material can be applied may have a surface texture  395  to enhance the bond strength of the fluid adhesive, such as a random surface character or other roughness character having a depth in a range of 25 μm to 100 p.m. Area  394  may be substantially flat to accommodate a dual-sided foam tape or pressure-sensitive adhesive. 
         [0057]      FIG. 12  shows a bottom perspective of base portion  305   b  with secondary adhesive  380  applied over area  394  ( FIG. 11 ) of bottom surface  390   b . As discussed above, secondary adhesive  380  may be, for example, a dual-sided foam tape or a pressure-sensitive adhesive. Secondary adhesive  380  can be used to hold conductor interface  350  in place on a back surface  140  to which it is mounted while the fluid adhesive  396 ,  397 ,  398 ,  399  ( FIG. 13 ) cures and solidifies. Secondary adhesive  380  has a thickness that is approximately the same or greater than the height of raised features  330 ,  335 , to permit secondary adhesive  380  to make contact with the back surface  140  of a module  10 , and to serve as a barrier to prevent the fluid adhesive from entering connection cavities  270 ,  275  and wire cavities  280 ,  285 . Secondary adhesive  380  includes openings to expose connection cavities  270 ,  275 , in order to permit electrical connection of external conductors  120 ,  125  ( FIG. 6 ) inserted into wire openings  260 ,  265  with respective internal conductors  410 ,  415  ( FIG. 2 ). Secondary adhesive  380  is shaped to permit a fluid adhesive to be applied on area  392  of bottom surface  390   b.    
         [0058]      FIG. 13  shows a bottom perspective of base portion  305   b  with a secondary adhesive  380  applied to area  394  ( FIG. 11 ) of bottom surface  390   b  and fluid adhesive applied to area  392  of bottom surface  390   b . For example, layers of fluid adhesive  396 ,  397 ,  398 ,  399  may be applied surrounding the perimeter of bottom surface  390   b . The layers of fluid adhesive  396 - 399  may be, for example, applied with a width in a range of approximately 5 mm to 10 mm. When applied to back surface  140 , the fluid adhesive will typically expand to cover a larger portion of area  392 , and therefore should be applied with some distance, for example, 2 mm, from the edge of bottom surface  390   b.    
         [0059]    Details of one or more embodiments are set forth in the accompanying drawings and description. Other features, objects, and advantages will be apparent from the description, drawings, and claims. It should also be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features and basic principles of the invention. Although a number of embodiments of the invention have been described, it will be understood that various modifications may be made without departing from the spirit and scope of the invention.