Adhesive-Coated EV Charger Transformer for Compact Coil Assembly
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Solution Overview
Problem
Conventional transformers for on-board chargers in electric vehicles are large in size, deteriorate in productivity due to complex assembly processes, and suffer from EMI performance issues due to misaligned coil windings.
Innovation Solution
The transformer design uses adhesive-coated rectangular copper stranded wires for primary and secondary coils, bonded through fusion bonding to form a compact, face-to-face adhesion, with insulating envelopes and bonding layers, and is stabilized by support tubes and mounts, reducing assembly processes and minimizing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the secondary coil is wound coaxially over the primary coil with insulation tape wrapping, then the transformer provides adequate insulation, but the size of the transformer is significantly large
Solution Approach 1:
The patent places the primary coil and secondary coil in a nested configuration where they share the same cylindrical space around the bobbin, rather than stacking them coaxially. This nesting approach allows both coils to occupy the same radial space, significantly reducing the overall transformer volume while maintaining proper insulation through the bobbin structure and winding arrangement.
Solution Approach 2:
The patent transitions from a radial stacking arrangement (one coil outside another) to a side-by-side winding arrangement where both coils are wound in the same dimensional space around the bobbin. This dimensional reorganization reduces the transformer's external dimensions while maintaining insulation integrity through the winding structure itself.
2Reliability
If insulation tape is wrapped around each coil layer to ensure insulation, then the transformer provides reliable insulation, but the assembly processes are increased and productivity is deteriorated
Solution Approach 1:
The patent removes the insulation tape wrapping step from the assembly process by designing the bobbin and coil structure to provide inherent insulation. The bobbin serves as the insulating barrier between coils, eliminating the need for additional insulation tape layers and the complex multi-step assembly process that would be required to apply and secure them.
Solution Approach 2:
The transformer structure is designed to be self-insulating through the bobbin and coil winding arrangement, eliminating the need for separate insulation components and assembly steps. The structure serves its own insulation function, simplifying the manufacturing process and improving productivity.
3Ease of manufacture
If manual winding of the primary and secondary coils is performed, then the transformer can be assembled, but misalignment occurs and EMI performance is deteriorated
Solution Approach 1:
The patent replaces manual mechanical winding operations with automated winding machinery that uses the bobbin as a precision guide. The mechanical structure of the bobbin ensures consistent coil placement and alignment during automated winding, eliminating the misalignment problems associated with manual winding while maintaining ease of manufacture through automation.
Solution Approach 2:
The bobbin serves as an intermediary structure that facilitates precise coil winding. It provides a defined geometric template that guides the winding process, ensuring consistent spacing and alignment between turns and between coils. This intermediary structure eliminates the precision problems of manual winding while keeping the manufacturing process straightforward.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves a compact size, improved adhesion, reduced leakage current, and enhanced efficiency, while maintaining insulation at high voltages, thus reducing the overall size and weight of the on-board charger.
Implementation Method 1
bonded through fusion bonding to form a coil shape
Implementation Method 2
a transformer which transforms the high-frequency AC voltage output from the second converter to a higher voltage and physically isolates the 220 V AC and the high-voltage battery
Data Source
AI summary
Provided relates to a transformer for an on-board charger of an electric vehicle, including a primary coil receiving power from the charger of the electric vehicle; and a secondary coil outputting induced current to the high-voltage battery, wherein the primary coil is formed by winding a first adhesive-coated rectangular wire in a coil shape, and the secondary coil is formed by winding the second adhesive-coated rectangular wire in a coil shape. The first and second adhesive-coated rectangular wires include: copper stranded wires formed by twisting multiple strands of copper wires and arranged to be in contact with each other; copper stranded wire rectangular bundles formed to have a rectangular shape of the arrangement of the copper stranded wires; insulating envelopes applied along the outer surface of the copper stranded wire rectangular bundles; and bonding layers formed by applying adhesive on the outer surface of the insulating envelopes.