Solar Cell Back Surface Field Discontinuous Regions
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Solution Overview
Problem
Conventional solar cells face inefficiencies due to the formation of heavily doped back surface field regions, which can lead to increased recombination of carriers and reduced short-circuit current and open-circuit voltage, while also increasing contact resistance.
Innovation Solution
A solar cell design featuring a back surface field region with discontinuous regions at specific locations, such as crossings of electrodes, where the impurity concentration is lower than in the rest of the back surface field region, allowing for a Gaussian distribution and optimized dimensions to balance carrier collection and transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heavily doped back surface field region is formed to protect carriers, then carrier protection is improved, but contact resistance increases and short-circuit current decreases
Solution Approach 1:
The patent applies local quality by creating discontinuous regions within the back surface field region where impurity concentration is reduced. Specifically, at electrode crossing points, the impurity concentration is lowered to form low-impurity regions that reduce contact resistance locally, while the rest of the back surface field region maintains high impurity concentration for carrier protection. This spatial variation in impurity concentration resolves the contradiction between carrier protection and contact resistance.
Solution Approach 2:
The patent changes the impurity concentration parameter spatially within the back surface field region. By forming discontinuous regions with lower impurity concentration at specific locations (electrode crossings) while maintaining high impurity concentration in other areas, the patent optimizes both carrier protection and contact resistance characteristics through parameter variation.
2Reliability
If a heavily doped back surface field region is formed to prevent recombination, then carrier protection is improved, but short-circuit current and open-circuit voltage decrease
Solution Approach 1:
The patent creates local quality variations by forming discontinuous regions with reduced impurity concentration at electrode crossing points. These low-impurity regions minimize carrier recombination locally, while the overall back surface field region maintains high impurity concentration for comprehensive carrier protection, thus improving short-circuit current without sacrificing carrier protection.
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 enhances the solar cell's efficiency by increasing short-circuit current and open-circuit voltage while maintaining a reduced fill factor, improving overall performance by strategically forming the back surface field region to minimize carrier recombination and optimize contact resistance.
Implementation Method 1
A solar cell is a power generating device obtaining photovoltaic power using a photoelectric effect and collects electrons and holes produced in a semiconductor substrate forming a p-n junction
Data Source
AI summary
A solar cell includes a substrate having a front surface and a back surface; an emitter formed on the front surface of the substrate; a plurality of first electrodes positioned on the emitter and extended in first direction; a plurality of first bus lines positioned on the emitter and extended in second direction crossing to the first direction; a plurality of back surface field regions formed on the back surface of the substrate and extended in the first direction; a plurality of second electrodes positioned on the plurality of back surface field regions and extended in the first direction; and, a plurality of second bus lines extended in the second direction.