Solar Cell Electrode Formation via Metal Mask Bridge Portions
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Solution Overview
Problem
The existing electrode formation systems for solar cells face challenges in improving productivity due to the need for multiple printing and baking processes to form thickened electrodes, which complicates the process and reduces efficiency.
Innovation Solution
A screen printing process using a metal mask with opening and bridge portions, where a squeegee head of a cartridge type supplies paste under pressure, allowing for efficient formation of electrodes in a single process, followed by a baking step to form thick electrodes, thereby improving productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple printing and baking processes are conducted to form thickened electrodes, then the electrode thickness is improved, but the productivity deteriorates
Solution Approach 1:
The invention introduces bridge portions that extend in the width direction (transverse to the longitudinal direction of circuit patterns) to connect opening portions, enabling paste to be supplied not only from above but also from the side surfaces of the base member. This dimensional change allows thick electrodes to be formed in a single printing process by utilizing both vertical and lateral paste flow paths, thereby achieving the desired electrode thickness without requiring multiple printing and baking cycles.
2Manufacturing precision
If multiple printing and baking processes are conducted to form thickened electrodes, then the electrode thickness is improved, but the process complexity increases
Solution Approach 1:
The bridge portions extending in the width direction provide additional paste supply paths from the side surfaces of the base member. This dimensional innovation enables the formation of thick electrodes through a single printing process by allowing paste to flow both vertically through the opening portions and laterally through the bridge portions, thereby simplifying the overall process while achieving the desired electrode thickness.
3Productivity
If the squeegee travels perpendicular to the opening portions alignment, then the paste supply efficiency is improved, but the electrode configuration precision deteriorates
Solution Approach 1:
The invention employs asymmetric bridge portions that extend specifically in the width direction (perpendicular to the longitudinal direction of circuit patterns) rather than symmetrically in all directions. This asymmetric configuration optimizes paste supply efficiency by directing paste flow laterally along the width direction where it is most needed, while the specific geometry and orientation of the bridge portions ensure that the electrode configuration precision is maintained despite the non-symmetric paste flow paths.
4Manufacturing precision
If the aspect ratio of the electrode is increased to 1.0 or higher, then the electrode performance is improved, but the manufacturing difficulty increases
Solution Approach 1:
The bridge portions extending in the width direction create additional paste supply paths that enable the formation of electrodes with aspect ratios of 1.0 or higher. By utilizing both vertical paste flow through the opening portions and lateral paste flow through the bridge portions, the invention achieves the desired high aspect ratio electrodes in a single printing process, thereby improving manufacturability despite the challenging geometric requirements.
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
This approach allows for the formation of thick electrodes through a single screen printing and baking process, significantly reducing man-hours and enhancing productivity while achieving an improved aspect ratio for the electrodes.
Implementation Method 1
a paste for forming the electrode is supplied to an upper surface of the metal mask under a given pressure by a squeegee head of a cartridge type
Implementation Method 2
a baking process in which the paste put on the surface of the base member in a given configuration is baked to form the paste as the electrode
Data Source
AI summary
An electrode formation method for a solar cell to form an electrode of a base member, includes a screen printing process and a baking process. The screen printing process includes: mounting a metal mask on a surface of the base member, wherein the metal mask includes a covering portion configured to cover a part of a surface of the base member, opening portions configured to allow parts of the base member to be exposed therefrom, and bridge portions disposed along a direction intersecting with a longitudinal direction of circuit patterns between the opening portions; and supplying a paste to an upper surface of the metal mask by a squeegee head of a cartridge type, while relatively sliding a squeegee on the upper surface of the metal mask such that the squeegee travels relatively to the metal mask. In the baking process, the paste is baked to form the electrode.