Back Contact Solar Cell Moisture Resistance via Segmented Electrode
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Solution Overview
Problem
Conventional back contact solar cells are not resistant to moisture due to etching liquid seeping through the interface between the transparent electrode and the semiconductor layer, leading to void formation and reduced moisture resistance.
Innovation Solution
A solar cell design featuring a semiconductor substrate with overlapping edges of different conductivity type semiconductor layers, an insulating layer, and a separated transparent electrode layer to prevent etching liquid from reaching the semiconductor layers, ensuring the solar cell is resistant to moisture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional back contact solar cell structure is used with a continuous transparent electrode layer, then the manufacturing process is simple, but etching liquid seeps through the interface between the transparent electrode and semiconductor layer causing void formation and poor moisture resistance
Solution Approach 1:
The transparent electrode layer is divided into a first transparent electrode layer and a second transparent electrode layer that are separated in the overlapping region. This segmentation prevents etching liquid from seeping along the interface between the electrode and semiconductor layer, thereby improving moisture resistance without significantly complicating the overall device structure.
2Reliability
If the transparent electrode layer is separated into two layers, then moisture resistance is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The transparent electrode is segmented into two separate layers that can be formed using standard sequential deposition processes. The first transparent electrode layer is formed on the first semiconductor layer, and the second transparent electrode layer is formed on the second semiconductor layer, allowing for controlled separation in the overlapping region while maintaining compatibility with existing manufacturing workflows.
Solution Approach 2:
The insulating layer is formed on the first semiconductor layer before forming the second semiconductor layer. This preliminary action creates a defined interface that guides the separation of the transparent electrode layers and prevents etching liquid infiltration, thereby improving moisture resistance through proactive structural design.
3Ease of manufacture
If etching liquid is used in the manufacturing process, then the transparent electrode can be formed, but the liquid seeps through interfaces creating voids and reducing moisture resistance
Solution Approach 1:
By separating the transparent electrode into two distinct layers positioned on different semiconductor layers, the patent eliminates the continuous interface that would allow etching liquid to seep in. The separation creates a barrier that prevents liquid infiltration while still allowing the transparent electrode to be formed using conventional etching processes.
Solution Approach 2:
The insulating layer acts as an intermediary structure between the first and second semiconductor layers. It provides a controlled interface that prevents etching liquid from penetrating into the overlapping region, thereby protecting the internal structure from liquid infiltration while maintaining the functionality of the transparent electrode formation process.
Data Source
AI summary
A solar cell includes: a semiconductor substrate having a light receiving surface and a back surface; a first semiconductor layer of the first conductivity type on the back surface; a second semiconductor layer of the second conductivity type on the back surface; a first electrode electrically connected to the first semiconductor layer; and an insulating layer for electrically insulating the first semiconductor layer and the second semiconductor layer from each other in a region in which an edge of the first semiconductor layer and an edge of second semiconductor layer overlap. The first electrode includes a first transparent electrode layer and a first collection electrode layer on the first transparent electrode layer. The first transparent electrode layer is separated into a primary electrode layer that is on the first semiconductor layer and a separated electrode layer that is on the second semiconductor layer in the region.