The present invention relates generally to insulated conductors. More specifically, the present invention relates to methods for manufacturing insulating busbars.
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.
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 an 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 surfaces of the conductive material, respectively, to insulate the conductive material, and thereby provide an insulated busbar. In subsequent operations, portions of the insulating material may be removed to expose the conductive material to facilitate making an electrical connection with the busbar.
Typical methods for removing the insulating material to expose the conductive material require that the portion being removed be on an outward-facing surface. This is the case, for example, when using laser and/or mechanical means to remove the insulating portion because the methods may require direct line of sight to the portion being removed. However, when the insulating portion to be removed is on an inward-facing surface, use of these methods to remove the insulating material may be impractical.
Other problems with existing methods for manufacturing insulated busbars will become apparent in view of the disclosure below.
In one aspect, a method for manufacturing an insulated conductive material includes applying a masking material to one or more regions of a conductive material. Regions of the conductive material other than the masked regions are coated. The regions are coated by electrically charging the conductive material with a first charge polarity, providing a medium of electrically charged insulating material particles that are charged with an opposite polarity, and passing the charged conductive material through the medium, whereby the insulating material particles bind to areas of the conductive material and form an insulating film on the surface other than the one or more regions. Afterwards, the insulating material film is cured and a solvent is applied to the masking material to thereby remove the masking material. The cured insulated material film is substantially unaffected by the solvent.
In a second aspect, a busbar includes a conductive material and an insulating material that covers first portions of the conductive material. Other portions of the conductive material are exposed. The insulating material is formed on the conductive material by the process described above.
Methods and systems for manufacturing insulated busbars are described below.
During preparation, the conductive material may be provided in various forms. For example, the conductive material may be provided in a wire form. Wires of various shapes and sizes may be utilized. For example, wire gauges from 0.005 mm and greater may be utilized. Wire widths may be 0.05 mm and greater. The cross-section of the wire may define a polygon having an arbitrary number of sides. The corners may be beveled, rounded, etc.
The conductive material may be shaped via various processes into a desired shape such as the conductive bar illustrated in
In preparing the conductive material, the conductive material may be cleaned with an organic solvent or detergent to remove any grease. It may be cleaned with acid to remove the oxide layer on the outside surface of the conductive material that may interfere with the electrophoreses coating operation described below. Other pretreatment processes such as surface phosphating may be applied prior to electrophoretic coating.
At block 105, a masking material may be applied to one or more regions of the conductive material to prevent insulating material from being deposited on those regions in subsequent operations. For example, as illustrated in
In some implementations, the solvent referred to above for cleaning the conductive material may be applied after the masking material 210 is applied. In this regard, the masking material 210 may be selected so as not to be affected by the solvent. For example, where the solvent is acid based, the selected masking material may be impervious to acids. Where the solvent is alkali based, the selected masking material may be impervious to alkali-based solvents.
The masking material 210 may be applied via a printing process whereby a printer sprays the masking material 210 through nozzles onto the conductive material 200. In other implementations, the masking material 210 may be applied via a roller saturated with the masking material 210. The masking material 210 may also be applied via mechanical brushing. In yet other implementations, the masking material 210 may be applied via a screening process.
The masking material 210 may be cured after application. For example, the masking material 210 may be air-dried or baked, subjected to UV rays, or an electron beam to cure the masking material. In some implementations, the masking material 210 may be baked at a temperature of 110° C. for 10 minutes to cure the masking material 210.
At block 110, the conductive material 205 with the applied and cured masking material 210 may be placed in an insulation deposition chamber, such as the insulation deposition chamber 300 illustrated in
The insulating material particles 312 may correspond to any colloidal particles capable of forming a stable suspension, which can carry a charge. For example, the insulating material particles 312 may correspond to various polymers, pigments, dyes, and ceramics. Different materials with similar properties may be utilized.
The process above is capable of producing an insulation layer 215 (
Returning to
During curing, heat may be applied to the insulated conductive material to accelerate the removal of any solvents present in the colloidal insulating material particles of the insulation layer 215. The heat may also cause the colloidal insulating material particles of the insulation layer 215 to disperse evenly around the outside surface of the conductive material 205, to thereby form a lasting bond between the insulation layer 215 and the conductive material 205. The heat may also cause chemical crosslinking of the insulation layer to have better stability. In one implementation, the insulated conductive material may be heated to a temperature of about 180° C. for a period of 30 minutes.
At block 120, the masking material 210 may be removed to expose one or more regions of conductive material 205, as illustrated in
As shown, the implementations described above facilitate preparation of insulated bus bars with complex shapes for which insulation would be difficult if not impossible to remove using the conventional means described above.
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.