Solar Cell Rear-Side Insulating Layer for Shunt Prevention
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Solution Overview
Problem
Solar cells with collecting points at the rear side for charge carriers from the front side suffer from electrical shunting, which decreases their fill factor and efficiency due to the electrical conducting path being in contact with the base layer, leading to emitter current leakage.
Innovation Solution
Incorporating an insulating layer along the electrical conducting path to prevent direct contact between the conductive material and the base layer, reducing the risk of shunting and enhancing the solar cell's efficiency by isolating the electrical conducting path from the base layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the electrical conducting path is provided to carry charge carriers from the front side to collecting points at the rear side, then the shadow effect on the front side is reduced, but electrical shunting occurs between the conducting path and the base layer, decreasing fill factor and efficiency
Solution Approach 1:
An insulating layer is introduced as an intermediary between the electrical conducting path and the base layer. This insulating layer prevents direct electrical contact, thereby eliminating the shunting effect while maintaining the conducting path's function of transporting charge carriers to the rear collecting points.
Solution Approach 2:
The electrical conducting path is segmented into functionally distinct regions: a first portion that maintains electrical contact with the emitter layer for charge carrier collection, and a second portion that is electrically isolated from the base layer through the insulating layer. This segmentation allows the conducting path to perform its charge transport function without causing shunting losses.
2Ease of manufacture
If the electrical conducting path contacts the base layer to provide electrical connection, then manufacturing is simplified, but emitter current leakage occurs, decreasing overall efficiency
Solution Approach 1:
The insulating layer serves as a mediator that prevents unwanted electrical interaction between the conducting path and the base layer. This eliminates emitter current leakage while preserving the necessary electrical connections for charge carrier collection and transport.
Solution Approach 2:
The insulating layer is applied selectively to specific portions of the electrical conducting path where contact with the base layer would cause shunting. This localized application maintains electrical connectivity where needed while preventing leakage in critical regions.
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 insulating layer effectively reduces shunting losses, increasing the fill factor and overall efficiency of the solar cells by preventing emitter current leakage to the base layer, thereby improving the output of the solar cells.
Implementation Method 1
an insulating layer (40) is provided at least along part of the electrical conducting path to provide insulation between the electrical conducting path and the base layer (12)
Implementation Method 2
an electrical conducting path between the front side (10) and at least one collecting point (14') provided at the rear side (20), wherein the electrical conducting path is formed by a via (30)
Data Source
Figure 1a~1b
Figure 1c~2a
Figure 2b~3
AI summary
The invention relates to a solar cell (1) comprising an emitter layer (11) at a front side (10) and a base layer (12) at the rear side (20). The solar collects first charge carriers at the front side (10) and second charge carriers at the rear side (20). The solar cell (1) further comprises at least one collecting point (14') provided at the rear side (20) and a corresponding electrical conducting path to guide the first charge carriers from the front side (10) to the at least one collecting point (14'). An insulating layer (40) is provided between at least part of the electrical conducting path and the base layer (12) to provide electrical insulation between the electrical conductive path and the base layer (12).