Back-Junction Solar Cell Ground Layer Segmentation
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Solution Overview
Problem
The existing methods for forming separating grooves in back-junction solar cells using laser machining often result in excessive irradiation at intersecting scanning paths, leading to damage of semiconductor layers and reduced photoelectric conversion efficiency.
Innovation Solution
A back-junction solar cell design where the ground layer is separated by a first and second separating groove extending in different directions, with a bridge portion that separates these grooves at their intersection, preventing excessive laser irradiation and minimizing damage during the laser machining process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser machining is used to form a separating groove in the ground layer, then the ground layer can be completely separated into n-side and p-side ground layers, but the scanning paths intersect and cause excessive laser irradiation that damages the semiconductor layer
Solution Approach 1:
The separating groove is divided into multiple segments (first separating portion and second separating portion) that do not intersect with each other. The first separating portion extends in a first direction and the second separating portion extends in a second direction, with a bridge portion separating them. This segmentation eliminates the intersecting scanning paths that cause excessive laser irradiation while still achieving complete separation of the ground layer.
Solution Approach 2:
The separating groove structure is extended into multiple dimensions by having portions extending in different directions (first direction and second direction). This multi-directional arrangement allows the groove to achieve complete separation functionality without requiring intersecting linear paths, thereby avoiding the harmful concentrated laser irradiation at intersection points.
2Reliability
If the ground layer is completely separated by a separating groove, then electrical isolation between n-side and p-side electrodes is achieved, but laser scanning paths must intersect which causes excessive irradiation and reduces photoelectric conversion efficiency
Solution Approach 1:
The separating groove is segmented into multiple non-intersecting portions (first separating portion and second separating portion) that extend in different directions. This segmentation maintains the electrical isolation function while eliminating the intersecting laser paths that would reduce photoelectric conversion efficiency through excessive irradiation.
Solution Approach 2:
A bridge portion is introduced as an intermediary element that separates the first separating portion and the second separating portion. This bridge portion allows the groove to achieve complete separation and electrical isolation without requiring the separating portions to intersect, thereby preventing excessive laser irradiation and maintaining high photoelectric conversion efficiency.
3Speed
If laser output is continuous during scanning to ensure complete groove formation, then machining speed is maintained, but intersecting paths cause excessive irradiation that damages the semiconductor structure
Solution Approach 1:
The separating groove is segmented into multiple portions (first separating portion and second separating portion) that extend in different directions and do not intersect. This allows the laser to scan each portion continuously at high speed without the harmful effect of intersecting paths causing excessive irradiation and semiconductor layer damage.
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 design minimizes damage to the semiconductor layers and enhances the photoelectric conversion efficiency by preventing excessive laser irradiation at intersecting scanning paths during the manufacturing process.
Implementation Method 1
laser machining is employed
Data Source
AI summary
A solar cell (1) includes a semiconductor substrate (10) having a light-receiving surface (10a) and a back surface (10b); an n-type semiconductor layer (13n) and a p-type semiconductor layer (12p) provided on the back surface (10b) of the semiconductor substrate (10), the n-type semiconductor layer (13n) and the p-type semiconductor layer (12p) extending in a first direction and being adjacent to each other in a second direction intersecting with the first direction; and a ground layer (14) provided on the n-type semiconductor layer (13n) and the p-type semiconductor layer (12p). The ground layer (14) includes an n-side ground layer (14n) and a p-side ground layer (14p) separated from each other by a first separating groove (17) having a first separating portion (17a) and a second separating portion (17b) as well as a first bridge portion (18) separating the first separating portion (17a) and the second separating portion (17b). The first bridge portion (18) separates the first separating portion (17a) and the second separating portion (17b) at at least one of a border on the n-side ground layer (14n) or a border on the p-side ground layer (14p) in the first direction.