Parallel Silicon Solar Cells with Integrated P-N Junctions
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Solution Overview
Problem
Silicon-based solar cells have low light absorbing efficiency due to partial photons being absorbed by the front electrode and N-type silicon layer, resulting in a relatively low photoelectric conversion efficiency.
Innovation Solution
A solar cell system comprising two solar cells connected in parallel, with P-type and N-type silicon layers arranged in specific configurations to form an integrated structure, where the electrodes are designed to minimize light obstruction, allowing incident light to directly reach the P-N junction, and an antireflection layer and reflector are used to enhance light absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional silicon-based solar cell structure with front electrode and N-type silicon layer is used, then the solar cell can be manufactured with standard processes, but the light absorbing efficiency of the P-N junction is low due to photon absorption by the front electrode and N-type silicon layer
Solution Approach 1:
The solar cell structure is divided into multiple independent solar cells arranged in parallel, with each cell having its own P-type and N-type silicon layers. This segmentation allows light to reach multiple P-N junctions simultaneously while reducing the burden on each individual layer, thereby improving overall light absorption efficiency without compromising manufacturability
Solution Approach 2:
The invention transitions from a single-layer to a multi-layer parallel structure, adding a dimensional aspect to light absorption. By stacking multiple P-N junctions in parallel with alternating P-type and N-type layers, the system captures photons across different depths and angles, converting harmful absorption by individual layers into beneficial multi-point absorption across the entire structure
2Reliability
If the front electrode and N-type silicon layer are present in the conventional structure, then electrical contact and photoelectric conversion are enabled, but photoelectric conversion efficiency is reduced due to partial photon absorption before reaching the P-N junction
Solution Approach 1:
Multiple solar cells with P-type and N-type silicon layers are merged into an integrated parallel structure where adjacent cells share common electrodes. This merging creates multiple P-N junctions that work simultaneously, increasing the total photoelectric conversion efficiency while maintaining reliable electrical contact through the shared electrode structure
Solution Approach 2:
The shared electrodes between adjacent solar cells act as intermediaries that facilitate both electrical connection and light transmission. These electrodes are designed to provide electrical contact while minimizing light obstruction, serving as mediators that balance the competing requirements of electrical reliability and optical efficiency
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 configuration increases the light absorbing efficiency of the P-N junction, generating more electron-hole pairs and improving the overall photoelectric conversion efficiency of the solar cell system, allowing for greater current application to an external load.
Implementation Method 1
An operating principle of a solar cell is photoelectric effect of a semiconducting material. In use, light directly irradiates the front electrode, and reaches the P-N junction through the front electrode and the N-type silicon layer. Consequently, a plurality of electron-hole pairs (carriers) can be generated in the P-N junction due to photon excitation.
Implementation Method 2
an antireflection layer and reflector are used to enhance light absorption
Implementation Method 3
an antireflection layer and reflector are used to enhance light absorption
Data Source
AI summary
A solar cell system includes two solar cells. The two solar cells are located in contact with each other and connected in parallel. Each of the two solar cells includes a first electrode layer, a P-type silicon layer, an N-type silicon layer, and a second electrode layer. The first electrode layer, the P-type silicon layer, the N-type silicon layer, and the second electrode layer are arranged in series side by side along a first direction and in contact with each other, thereby cooperatively forming a integrated structure. A P-N junction is formed near an interface between the P-type silicon layer and the N-type silicon layer. The integrated structure has a first surface substantially parallel to the first direction and a second surface opposite to the first surface. The first surface is used as a photoreceptive surface to directly receive incident light.