Abstract:
A method for manufacturing an insulated conductive material includes providing a continuous feed of a conductive material, a first continuous feed of insulating material above a top surface of the conductive strip, and a second continuous feed of insulating material below a bottom surface of the conductive strip. Portions of the first and second continuous feeds of insulating material are compressed against a portion of the conductive material. The portions of the first and second insulating material are cured to thereby provide a continuous feed of insulated conductive material.

Description:
BACKGROUND 
       [0001]    Field of the Invention 
         [0002]    The present invention relates generally to insulated conductors. More specifically, the present invention relates methods for manufacturing insulating busbars. 
         [0003]    Description of Related Art 
         [0004]    A typical mobile device may utilize two or more battery cells to provide power to the mobile device. The batteries may be connected in series or parallel configurations via so-called busbars, which typically correspond to one or more strips of conductive material suitably sized to handle the required amount of current. 
         [0005]    Insulation of the busbar is usually required to prevent a short circuit condition between the busbar and other electrical components of the mobile device. One method for manufacturing and insulated busbar includes cutting a length of a conductive material to a desired length and cutting two portions of an insulating material to the same length. For example, the respective components may be cut to a length of 20 cm. The respective portions of insulating material are placed on the top and bottom surface of the conductive material, respectively, to insulate the conductive material, and thereby provide an insulated busbar. 
         [0006]    However, the operations described above are time consuming and do not lend themselves well to mass production. For example, there may be numerous sections of insulated busbar required in a given assembly. Each insulated busbar may have a different length. As noted above, three cutting steps may be required to manufacture a single busbar. Thus, the number cutting operations involved in manufacturing the assembly of busbars may be three times the number of busbar sections. 
         [0007]    Other problems with existing methods for manufacturing insulated busbars will become apparent in view of the disclosure below. 
       SUMMARY 
       [0008]    In one aspect, a method for manufacturing an insulated conductive material is provided. The method includes providing a continuous feed of a conductive material, a first continuous feed of insulating material above a top surface of the conductive strip, and a second continuous feed of insulating material below a bottom surface of the conductive strip. Portions of the first and second continuous feeds of insulating material are compressed against a portion of the conductive material. The portions of the first and second insulating material are cured to thereby provide a continuous feed of insulated conductive material. 
         [0009]    In a second aspect, a method for manufacturing an insulated conductive material is provided. The method includes providing a continuous feed of a conductive material, and an extrusion mold that defines an extrusion opening sized larger than a cross-section of the conductive material. An insulating material is inserted into the extrusion mold. The continuous feed of the conductive material is run through the extrusion mold and out the extrusion opening. The extrusion mold is configured such that an entire outside surface of the conductive material is covered with the insulating material when the conductive material exits the extrusion mold. The insulated conductive material is cured as it exits the extrusion mold to thereby provide a continuous feed of insulated conductive material. 
         [0010]    In a third aspect, a method for manufacturing an insulated conductive material is provided. The method includes providing a continuous feed of a conductive material and electrically charging the conductive material with a first charge polarity. The method further includes providing a medium of electrically charged insulating material particles that are charged with an opposite polarity. The charged conductive material is passed through the medium, where the insulating material particles bind to the conductive material and cover an entire outside surface of the conductive material. The insulating material particles are cured to thereby provide a continuous feed of insulated conductive material. 
         [0011]    In a fourth aspect, a method for manufacturing an insulated conductive material is provided. The method includes providing a continuous feed of a conductive material and spraying an insulating material over the exterior surface of the conductive material. The insulating material particles are then cured to thereby provide a continuous feed of insulated conductive material. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1A  illustrates a first exemplary embodiment  100  of a system for manufacturing an arbitrarily long insulated busbar in which insulated material is laminated onto a conductive material; 
           [0013]      FIG. 1B  illustrates an insulated busbar with exposed sections of conductive material; 
           [0014]      FIG. 2  illustrates a second exemplary embodiment of a system for manufacturing an arbitrarily long insulated busbar in which insulated material is extruded over a conductive material; 
           [0015]      FIGS. 3 and 4  illustrate third and fourth exemplary embodiments of a system for manufacturing an arbitrarily long insulated busbar in which insulated material is electrically deposited onto a conductive material; 
           [0016]      FIG. 5  illustrates a fifth exemplary embodiment of a system for manufacturing an arbitrarily long insulated busbar in which insulating material is sprayed onto a conductive material; and 
           [0017]      FIG. 6  illustrates a sixth exemplary embodiment of a system for manufacturing an arbitrarily long insulated busbar in which a conductive material is inserted into tubing formed from a heat shrink tubing material. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Methods and systems for manufacturing insulated busbars are described below. In general, the methods and systems facilitate manufacturing an arbitrarily long insulated busbar that can be cut to any desired length. The methods and systems reduce the number of cutting operations necessary to manufacture an assembly of busbars. 
         [0019]      FIG. 1A  illustrates a first exemplary embodiment  100  of a system for manufacturing an arbitrarily long insulated busbar. Shown is a reel of conductive material  105 , first and second reels of insulation material  107   ab,  a compression section  119 , a curing station  112 , and a cutting station  115 . 
         [0020]    The conductive material  106  on the reel of conductive material  105  may be copper or a different conductive material or composition of conductive materials. The conductive material  105  may have a thickness of about 0.1-2 mm, and a width about 2-12 mm. Other dimensions are possible. 
         [0021]    The insulation material  108   ab  on the reels of insulation material  107   ab  may correspond to a thermoplastic film such as polyolefin, polyvinyl chloride, nylon, polyester, fluoride polymer, and PEI, or a different material with similar insulating properties. The insulation material  108   ab  may have a thickness of about 15-100 μm and a width of about 2-12 mm. Other dimensions are possible and may be selected to complement the dimensions of the conductive material  106 . For example, the width of the insulation material  108   ab  may be slightly larger than the width of the conductive material  106  to facilitate covering the side surfaces of the conductive material  106  along with the top and bottom surfaces of the conductive material  106 . 
         [0022]    In some implementations, the insulation material  108   a  on the first reel  107   a  may be different from the insulation material  108   b  on the second reel  107   b.  For example, one the insulation materials  108   b  may have adhesive properties to facilitate adhering the final busbar product to a surface. 
         [0023]    The compression section  119  may correspond to a pair of rollers arranged above and below the conductive material  106  configured to apply pressure to the insulation material  108   ab  to thereby press the insulation material  108   ab  against the top and bottom surfaces of the conductive material  106 . For example, the rollers may be configured to apply a pressure of about 150 PSI to the insulation material  108   ab.  Other methods for compressing the insulation material  108   ab  against the conductive material  106  may be utilized. An arbitrarily long insulated busbar  120 , that is insulated on all sides, may exit the compression section  119 . 
         [0024]    In some implementations, a curing section  112  may be provided to cure the insulation material  108   ab  of the insulated busbar  120  after it has been applied to the conductive material  106 . For example, the curing section  112  may be configured to heat to the insulated busbar  120  to a temperature of about  60 - 100  degrees. In other implementations, the curing section  112  may correspond to a cooling station configured to cool previously heated insulation material  108   ab  of the insulated busbar  120 . 
         [0025]    In some implementations, a cutting station  115  may be provided to cut the insulated busbar  120  into arbitrary or fixed length sections. For example, a cutting knife may cut the insulated busbar  120 . Other cutting methods may be employed to cut the insulated busbar  120 . 
         [0026]    In yet other implementations, an etching station (not shown) may be provided to etch portions  150   ab  of the insulation material  108   ab  from the insulated busbar  120  to expose the conductive material  106 , as illustrated in  FIG. 1A . For example, a laser may be utilized to selectively remove portions of the insulation material  108   ab.  Other methods may be used to selectively remove the portions  150   ab  of insulation material. The exposed sections of conductive material  106  may be joined to expose sections of other insulated busbars, battery terminals, circuit boards, etc., via soldering, welding, and the like. 
         [0027]    Additionally, or alternatively, one or more openings (not shown) may be pre-cut into the insulation material  108   ab  such that areas of the conductive material  106  below the openings are exposed prior to curing. 
         [0028]    In operation, the respective materials may roll off their respective reels towards the compression section  119 . In some implementations, the insulation material  108   ab  may be pre-heated so that the insulation material  108   ab  conforms to the conductive material  106  and any irregularities that may be present on the conductive material  106  during compression. The pressure applied by the compression section  119  maybe about 150 PSI. The feed rate at which the conductive material  106  and insulation material  108  roll off the respective reels may be about 3-10 feet per minute. The feed rate may be adjusted in conjunction with the temperature of the insulation material  108   ab  and/or the compressive force applied by the compression section  119  to control the thickness of the insulation material  108   ab.    
         [0029]      FIG. 2  illustrates a second exemplary embodiment  200  of a system for manufacturing an arbitrarily long insulated busbar. Shown is a reel of conductive material  105 , an extrusion mold  205 , a curing station  112 , and a cutting station  115 . 
         [0030]    In the second exemplary embodiment, an extrusion mold  205  is utilized to apply a pelletized version of insulation material  210  to the conductive material  105 . In this regard, the pelletized insulation material  210  may correspond to a thermoplastic such as polyolefin, polyvinyl chloride, nylon, polyester, and fluoride polymer, or a different material with similar insulating properties. The pelletized insulation material  210  may be loaded into a hopper  207  of the extrusion mold  205 . 
         [0031]    The extrusion mold  205  may have an input  209  through which the conductive material  106  enters and an outlet side  212  through which the insulated busbar exits. In this regard, the opening of the input  209  may be sized to be slightly larger than a cross section of the conductive material  106 . For example, the dimensions of the opening of the input  209  may be about 0.5 by 6mm for a conductive material 106 having 1%-3% shrinkage from the opening dimensions. 
         [0032]    The opening of the output  212  may be sized to control the final cross-section of the insulated busbar  120 . The extrusion mold  205  may be configured so that the conductive material  106  is substantially centered within the opening of the output  212  as it exits so that the conductive material  106  is uniformly covered with melted insulation material  108  on all sides. 
         [0033]    A curing section  112 , such as the curing section described above, may be provided in some embodiments to cure the insulated busbar  120  as it exits the extrusion mold  205 . In other embodiments, the insulated busbar  120  begins to cure upon exiting the extrusion mold  205 . 
         [0034]    A cutting station  115 , such as the cutting station described above, may be provided to cut the insulated busbar  120  into arbitrary of fixed length sections. An etching station (not shown) may be provided to etch portions of the insulation material  108  from the insulated busbar  120  to expose the conductive material  106 . 
         [0035]    In operation, the conductive material  106  may roll off the reel of conductive material  105  and into the extrusion mold  205 . The pelletized insulation material  210  may be heated within the extrusion mold  205  to a temperature of about 200C to melt the pelletized insulation material  210 . A pressure of about 300 PSI may be applied to the melted insulation material  108  to cause the insulation material  108  to exit the output  212  of the extrusion mold  205  along with the conductive material  106 . The feed rate at which the conductive material  106  and insulation material  108  exit the extrusion mold  205  may be about 2-5 feet per minute. 
         [0036]      FIGS. 3 and 4  illustrate third and fourth exemplary embodiments ( 300 ,  400 ) of a system for manufacturing an arbitrarily long insulated busbar. Shown is a reel of conductive material  105 , an insulation deposition chamber ( 310 ,  410 ), a curing station  112 , and a cutting station  115 . 
         [0037]    In the third exemplary embodiment  300 , the insulation deposition chamber  310  utilizes and cathodic electrodeposition method in which colloidal insulation material particles  312  are suspended in a liquid medium, such as acrylic base resins. The medium is coupled to a first polarity of a DC power source  305 . The opposite polarity of the DC power source  305  is electrically coupled to the conductive material  106 . The DC power source  305  may generate a voltage of about 20-80 Vdc. The insulation material particles  312  in the medium migrate under the influence of the electric field generated by the DC power source  305  to the outside surface of the conductive material  106  to thereby cover the entire outside surface of the conductive material  106  with the colloidal insulation material particles  312 . 
         [0038]    The insulation material particles  312  may correspond to any colloidal particles capable of forming a stable suspension, which can carry a charge. For example, the insulation material particles  312  may correspond to various polymers, pigments, dyes, and ceramics. Different materials with similar properties may be utilized. 
         [0039]    The third exemplary embodiment is capable of producing an insulated busbar  120  having an insulation layer with a thickness of least 0.014 mm, a leakage current of less than 10 mA, and an insulation resistance of at least 100 MΩ when measured with 500V DC applied across the insulated busbar  120 . In addition, the insulation  108  of the insulated busbar  120  maintains an ISO grade 0 cross-hatch adhesion rating to the conductive material  106  after the insulated busbar  120  is exposed to an environment of 60° C. having a relative humidity of 95% for 500 hours, and after cycling the temperature of the insulated busbar 120 one hundred times between −40° C. and 90° C. 
         [0040]    In the fourth exemplary embodiment  400 , the insulation deposition chamber  410  utilizes an electrostatic powder coating method in which ionized air charged with a first polarity of a DC power source  305  flows through insulation material particles  412  to thereby charge the insulation material particles  412 . The opposite polarity of the DC power source  305  is electrically coupled to the conductive material  106 . The DC power source  305  may generate a voltage of about 30-100 KVdc. The charged insulation material particles  412  migrate under the influence of the electric field generated by the DC power source  305  to the outside surface of the conductive material  106  to thereby cover the entire outside surface of the conductive material  106  with insulation material particles  412 . 
         [0041]    The insulation material particles  412  may correspond to any particles capable of carrying a charge. For example, the particles may correspond to various polymers, pigments, dies, and ceramics. Different materials with similar properties may be utilized. 
         [0042]    The fourth exemplary embodiment is capable of producing an insulated busbar  120  having an insulation layer with a thickness of least between 20 μm and 125 μm, a leakage current of less than 10 mA, and an insulation resistance of at least 100 MΩ when measured with 500V DC applied across the insulated busbar  120  having. 
         [0043]    In the third and fourth exemplary embodiments, a curing section  112 , such as the curing section described above, may be provided to cure the insulated busbar  120  as it exits the deposition chamber ( 310 ,  410 ). In the third embodiment, the curing section  112  may apply heat to accelerate the removal of any solvents present in the colloidal insulation material particles  312 . The heat may also cause the colloidal insulation material particles  312  to disperse evenly around the outside surface of the conductive material  106 , to thereby form a lasting bond between the insulation material  108  and the conductive material  106 . 
         [0044]    Similarly, in the fourth embodiment, heat generated in the curing section  112  may be utilized to melt the insulation material particles  412  deposited on the outside surface of the conductive material  106  to thereby form a lasting bond between the insulation material  108  and the conductive material  106 . 
         [0045]    In both embodiments, a cutting station  115 , such as the cutting station described above, may be provided to cut the busbar assembly  120  into arbitrary or fixed length insulated busbar sections. An etching station (not shown) may be provided to etch portions of the insulation material  108  from the insulated busbar  120  to expose the conductive material  106 . Additionally, or alternatively, tape may be provided to certain areas of the conductive material  106  to prevent the particles  312 ,  412  from depositing on the taped areas of the conductive material  106  during the deposition phase. The particles  312 ,  412  may be removed prior to curing by vacuuming the particles  312 ,  412  off the conductive material  106  via one or more vacuum nozzles (not shown). Other processes may be utilized to prevent the particles from depositing on the conductive material  106 , or to remove the particles  312 ,  412  from the conductive material  106  prior to curing. 
         [0046]    In operation, the conductive material  106  may roll off the reel of conductive material  105  and into the deposition chamber ( 310 ,  410 ), where the colloidal insulation material particles  312 /insulation material particles  412  migrate under the influence of the electric field generated by the DC power source  305  toward the conductive material  106 . The feed rate at which the conductive material  106  moves through the deposition chamber ( 310 ,  410 ) may be about 2-5 feet per minute. 
         [0047]      FIG. 5  illustrates a fifth exemplary embodiment  500  of a system for manufacturing an arbitrarily long insulated busbar. Shown is a reel of conductive material  105 , a spray chamber  510 , a curing station  112 , and a cutting station  115 . 
         [0048]    The spray chamber  510  is configured to spray a mixture  512  of colloidal insulation material particles suspended in a solvent, such as xylene, onto the surface of the conductive material  106 . A pair of nozzles  515   ab  in the spray chamber may be provided for spraying the mixture  512 . The tips of the nozzles  515   ab  may be configured to control the amount of spray deposited on the conductive material  106  and the width of the spray pattern. In this way, the insulation material  108  may be deposited on specific regions of the conductive material  106  and the thickness of the insulation material  108  may be adjusted. This in turn may render subsequent etching processes unnecessary. 
         [0049]    A curing section  112 , such as the curing section described above, may be provided to cure the insulated busbar  120  as it exits the spray chamber  510 . The curing section  112  may apply heat to accelerate the removal of any solvents present in the insulation material  108 . The heat may also cause the insulation material  108  to disperse evenly around the outside surface of the conductive material  106 , to thereby form a lasting bond between the insulation material  108  and the conductive material  106 . 
         [0050]    A cutting station  115 , such as the cutting station described above, may be provided to cut the insulated busbar assembly  120  into arbitrary or fixed length insulated busbar sections. In some implementations, an etching station (not shown) may be provided to etch portions of the insulation material  108  from the insulated busbar assembly  120  to expose the conductive material  106 , as described above. Additionally, or alternatively, tape may be provided to certain areas of the conductive material  106  to prevent the mixture  512  from depositing on the taped areas of the conductive material  106  during the deposition phase. Other processes may be utilized to prevent the mixture  512  from depositing on the conductive material  106  prior to curing. 
         [0051]    The fifth exemplary embodiment is capable of producing an insulation layer with a thickness of between about 13 μm and 100 μm, having a leakage current of less than 10 mA and an insulation resistance of at least 100 MΩ measured when 500V DC is applied across the insulated busbar  120 . 
         [0052]    In operation, the conductive material  106  may roll off the reel of conductive material  105  and into the spray chamber  510 , where the mixture  512  is sprayed over the surface of the conductive material  105 . The feed rate at which the conductive material  106  moves through the spray chamber  510  may be about 5 feet per minute. 
         [0053]      FIG. 6  illustrates a sixth exemplary embodiment  600  of a system for manufacturing an arbitrarily long insulated busbar. Shown is a reel of conductive material  105 , a reel  602  of heat shrink tubing material  605 , a slitting station  610 , an insertion section  615 , a curing station  112 , and a cutting station  115 . 
         [0054]    The heat shrink tubing material  605  may be formed from a material such as polyolefin, polyvinyl chloride, nylon, polyester, fluoride polymer, or a different material configured to shrink when heated. 
         [0055]    The slitting station  610  is configured to cut a slit in the heat shrink tubing material  605  to provide a continuous feed of slit heat shrink tubing material  607 . For example, the slitting station  610  may include a blade that runs along the heat shrink tubing material  605  to cut the slit. 
         [0056]    The insertion section  610  is configured to insert the conductive material  105  into the slit of the slit heat shrink tubing material  607 . For example, the insertion section  610  may include one or more rollers that press the conductive material  106  into the slit of the slit heat shrink tubing material  607 . 
         [0057]    A curing/shrinking section  112 , such as the curing section described above, may be provided to heat the slit heat shrink tubing material  107  as it exits the insertion section  615 . The curing section  112  may apply a temperature of about 70-250 C to cause the heat shrink tubing to shrink around the conductive material  106 . 
         [0058]    A cutting station  115 , such as the cutting station described above, may be provided to cut the insulated busbar assembly  120  into arbitrary or fixed length insulated busbar sections. In some implementations, an etching station (not shown) may be provided to etch portions of the insulation material  108  from the insulated busbar assembly  120  to expose the conductive material  106 , as described above. 
         [0059]    The sixth exemplary embodiment is capable of producing an insulation layer with a thickness of between about 13 μm and 100 μm, having a leakage current of less than 10 mA and an insulation resistance of at least 100 MΩ measured when 500V DC is applied across the insulated busbar  120 . 
         [0060]    In operation, the conductive material  106  may roll off the reel of conductive material  105 , and the heat shrink tubing material  605  may roll off the reel of heat shrink tubing material  602 . The heat shrink tubing material  605  may be cut via the slitting station  610  to provide a continuous feed of slit heat shrink tubing material  607 . The conductive material  105  and the slit heat shrink tubing material  607  enter the insertion section  615 , which continuously presses the conductive material  106  into the slit of the slit heat shrink tubing material  607 . The feed rate at which the conductive material  106  and the slit heat shrink tubing material  607  move through the insertion section  610  may be about 5 feet per minute. The assembly is cured in the curing station  112  to provide a continuous feed of insulated busbar, which may then be cut at the cutting station  115  into discrete sections of insulated busbar. 
         [0061]    While the method for manufacturing the insulated busbar has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the claims of the application. Other modifications may be made to adapt a particular situation or material to the teachings disclosed above without departing from the scope of the claims. For example, the operations described above may be applied equally well to pre-cut conductive material sections and/or assemblies of pre-cut conductive material sections, which may be welded together to provide an assembly of conductive sections, prior to forming an insulating later over the conductive material. Therefore, the claims should not be construed as being limited to any one of the particular embodiments disclosed, but to any embodiments that fall within the scope of the claims.