Solar Cell Lead Wire Manufacturing with Direct Resistance Heating
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Solution Overview
Problem
The existing methods for manufacturing lead wires for solar cells face challenges in reducing the 0.2% proof stress, which leads to warping or breakage due to thermal expansion coefficient differences between lead wires and silicon cells, and require lengthy heat treatment processes that increase production time and costs.
Innovation Solution
A method and apparatus that utilize direct resistance heating or induction heating to reduce the 0.2% proof stress of lead wires while conveying them, allowing for simultaneous preheating and plating, thereby shortening the process time and eliminating the need for a separate preheating step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If indirect heating is used to reduce 0.2% proof stress, then sufficient thermal energy can be applied to the conductor, but the heating time becomes lengthy (30 seconds or more)
Solution Approach 1:
The patent replaces indirect heating (thermal conduction through medium) with direct resistance heating (electrical energy conversion to heat within the conductor itself). This substitution allows rapid heating by converting electrical energy directly into thermal energy within the conductor material, achieving the required 0.2% proof stress reduction in significantly shorter time compared to indirect heating methods
Solution Approach 2:
The patent changes the heating method parameter from indirect thermal conduction to direct electrical resistance heating. By applying electrical current directly to the conductor, the heating efficiency is dramatically improved, reducing the heating time from 30 seconds or more to a much shorter duration while still achieving sufficient thermal energy application to reduce 0.2% proof stress
2Manufacturing precision
If a separate preheating apparatus is provided for uniform plating, then all surfaces can be plated uniformly, but the installation cost and running cost increase
Solution Approach 1:
The patent merges the preheating function and plating function into a single integrated process. The direct resistance heating that reduces 0.2% proof stress simultaneously serves as the preheating step before plating, eliminating the need for a separate preheating apparatus. This combination maintains plating uniformity while significantly reducing installation and operating costs
Solution Approach 2:
The heating process serves multiple functions: it reduces the 0.2% proof stress of the conductor and simultaneously preheats the conductor for uniform plating. This multi-functionality eliminates the need for dedicated separate equipment, reducing both device complexity and operational costs while achieving the desired plating quality
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 method effectively reduces the 0.2% proof stress of lead wires within 5 seconds, improving production efficiency and ensuring uniform plating, which enhances the mechanical properties and reduces the risk of warping or breakage.
Implementation Method 1
heating a wire material by a direct resistance heating or by an induction heating to reduce a 0.2% proof stress of the wire material
Implementation Method 2
heating a wire material by a direct resistance heating or by an induction heating to reduce a 0.2% proof stress of the wire material
Implementation Method 3
plating the wire material that is in a heated condition obtained by the direct resistance heating or by the induction heating
Data Source
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AI summary
A method of manufacturing a lead wire for a solar cell includes heating a wire material by a direct resistance heating or by an induction heating to reduce a 0.2% proof stress of the wire material while conveying the wire material and plating the wire material that is in a heated condition obtained by the direct resistance heating or by the induction heating while further conveying the wire material. An apparatus is configured to implement the method, and includes a plating bath, a conveyor mechanism configured to convey the wire material, a heater configured to heat the wire material, and a controller configured to control the conveyor mechanism and the heater.