Solar Cell Emitter Pyramid Structure for Low Resistance Contact
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Solution Overview
Problem
Existing solar cells have poor photoelectric conversion performance due to high contact resistance between the metal electrode and the emitter, which is exacerbated by increased doping concentration leading to recombination centers.
Innovation Solution
A solar cell design featuring a P-type emitter with a first portion having a concave or convex pyramid structure and a second portion with plane inclined surfaces, reducing sheet resistance without increasing doping concentration, and maintaining good passivation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If doping concentration of the emitter is increased to reduce sheet resistance, then sheet resistance decreases, but recombination centers increase and passivation performance deteriorates
Solution Approach 1:
The emitter surface is divided into two distinct regions: a first region with a pyramid structure that has lower doping concentration for good passivation, and a second region with a textured structure that has higher doping concentration for low sheet resistance. This local differentiation allows each region to optimize its function without compromising the other.
Solution Approach 2:
The emitter is segmented into functionally distinct areas with different structural characteristics and doping levels. The pyramid-structured first region and the textured-structured second region are spatially separated, enabling independent optimization of passivation and electrical contact properties.
2Reliability
If doping concentration is increased to improve ohmic contact, then contact resistance decreases, but photoelectric conversion performance deteriorates due to recombination
Solution Approach 1:
The pyramid region provides low doping concentration to maintain photoelectric conversion performance, while the textured region provides high doping concentration for improved ohmic contact. Each region's local properties are optimized for its specific function.
Solution Approach 2:
The emitter surface is segmented into a first region for photoelectric conversion and a second region for electrical contact, allowing the solar cell to achieve both good ohmic contact and high photoelectric conversion performance simultaneously.
3Ease of manufacture
If a single uniform emitter structure is used, then manufacturing is simple, but both low sheet resistance and good passivation cannot be achieved simultaneously
Solution Approach 1:
The emitter incorporates two distinct structural regions with different morphologies and doping characteristics, allowing simultaneous achievement of low sheet resistance and good passivation performance that cannot be obtained with a uniform structure.
Solution Approach 2:
The emitter functions as a composite structure combining two different regional characteristics - the pyramid-structured low-doping region and the textured-structured high-doping region - to achieve properties that neither region could provide alone.
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 design improves ohmic contact and photoelectric conversion efficiency by reducing sheet resistance and suppressing recombination, leading to higher open-circuit voltage and short-circuit current.
Implementation Method 1
the carriers transporting in the emitter can be collected by the metal electrode
Implementation Method 2
Solar cells have good photoelectric conversion capabilities
Implementation Method 3
a tunnel layer and a doped conductive layer, wherein the tunnel layer and the doped conductive layer are located on a second surface of the N-type substrate
Data Source
Figure 1~2
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Figure 5~6
AI summary
Embodiments of the present disclosure relates to the field of solar cells, and in particular to a solar cell and a production method thereof, and a photovoltaic module. The solar cell includes: a N-type substrate; a P-type emitter provided on a first surface of the N-type substrate and including a first portion and a second portion, a top surface of the first portion includes a first pyramid structure, and at least a part of at least one inclined surface of the first pyramid structure is concave or convex relative to a center of the first pyramid structure, a top surface of the second portion includes a second pyramid structure, and inclined surfaces of the second pyramid structure are planes; and a tunnel layer and a doped conductive layer located on a second surface of the N-type substrate. The present disclosure can improve the photoelectric conversion performance of solar cells.