Rear-Electrode Solar Cell With Thinned Substrate
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Solution Overview
Problem
Conventional solar cells face significant shading and electrical losses due to the large distance charges must travel to reach the rear electrode, which limits efficiency improvement despite efforts to reduce shading loss.
Innovation Solution
A rear-electrode solar cell design with a semiconductor substrate having a thinner first portion where the emitter extends to the rear surface and a thicker second portion, featuring a concave rear surface and through-hole for the first electrode, reducing charge movement distance and preventing re-coupling losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a first electrode is formed on the front surface of the semiconductor substrate, then the electrical connection is established, but shading loss increases significantly reducing solar cell efficiency
Solution Approach 1:
The patent inverts the conventional electrode arrangement by moving the first electrode from the front surface to the rear surface of the semiconductor substrate. This inversion eliminates shading loss on the light-receiving front surface while maintaining electrical connection through the extended emitter layer that reaches the rear surface, thereby resolving the contradiction between reducing shading loss and ensuring reliable electrical connection.
2Loss of energy
If a non-defective semiconductor substrate is used to prevent electrical loss, then electrical loss is reduced, but manufacturing cost increases due to impossibility of manufacturing perfectly non-defective substrates
Solution Approach 1:
The patent changes the thickness parameter of the semiconductor substrate, creating a first portion with smaller thickness optimized for charge collection. This parameter modification allows the use of conventional semiconductor substrates with acceptable defect levels, as the optimized thickness and extended emitter structure compensate for potential defects, thereby reducing electrical loss without requiring prohibitively expensive perfectly non-defective substrates.
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 effectively reduces electrical losses and enhances solar cell efficiency by minimizing charge movement distance and re-coupling, while maintaining a simple structure applicable to various solar cell configurations.
Implementation Method 1
A solar cell generates electric energy using solar energy. The solar cell includes a silicon solar cell and a dye-sensitized solar cell. The silicon solar cell includes a semiconductor substrate and an emitter layer that have different conductive types to form a PN junction
Data Source
AI summary
A solar cell includes: a semiconductor substrate having a first portion and a second portion; an emitter portion of the semiconductor substrate arranged on a front surface of the semiconductor substrate and extending to a rear surface of the first portion of the semiconductor substrate; a first electrode electrically connected to the emitter portion of the semiconductor substrate and arranged on the rear surface of the semiconductor substrate; and a second electrode electrically connected to the semiconductor substrate and arranged on the rear surface of the semiconductor substrate. The first portion of the semiconductor substrate is thinner than the second portion of the semiconductor substrate.