Solar Cell P-Type Diffusion Layer Warpage Reduction
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Solution Overview
Problem
The high cost of solar cell power generation and the difficulty in achieving mass production due to complex manufacturing processes and substrate warpage issues, particularly with thin silicon substrates, hinder the widespread adoption of photovoltaic power systems.
Innovation Solution
A method involving the diffusion of p-type impurity into a silicon substrate to form a high concentration p-type impurity diffusion layer, followed by etching using a boron silicide or boron silicate glass layer as a mask, which allows for the formation of an anti-reflection structure and reduces substrate warpage, thereby enabling the production of thinner solar cells with improved power generation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the silicon substrate is thinned to reduce material cost, then material cost is reduced, but the silicon substrate becomes greatly warped due to the thick Al-Si alloy layer, resulting in cracks in the solar cell
Solution Approach 1:
The invention extracts the function of forming the high concentration p-type impurity diffusion layer from the aluminum paste sintering process. By separating these functions, the Al-Si alloy layer thickness can be reduced while still achieving the desired impurity diffusion, thereby reducing substrate warpage and cracking in thinned substrates.
Solution Approach 2:
The invention makes the p-type impurity diffusion layer formation a universal process that can be achieved through thermal diffusion independently of the aluminum electrode formation. This multi-functionality allows the same thermal diffusion process to serve both the impurity diffusion requirement and the aluminum paste printing requirement, eliminating the need for a thick Al-Si alloy layer.
2Reliability
If a high concentration p type impurity diffusion layer is formed by thermal diffusion of p type impurity, then substrate warpage is significantly reduced, but the manufacturing process becomes complicated
Solution Approach 1:
The invention merges the thermal diffusion process for forming the high concentration p-type impurity diffusion layer with the existing aluminum paste printing and sintering process. By combining these processes, the patent achieves warpage reduction without significantly complicating the manufacturing workflow, as both functions are accomplished in an integrated manner.
3Loss of energy
If PERC or PERL structures are implemented to improve power generation efficiency, then power generation efficiency is improved, but the manufacturing process becomes complicated and mass production is not achieved
Solution Approach 1:
The invention applies local quality by forming a high concentration p-type impurity diffusion layer at specific locations (just below the electrode) rather than uniformly across the entire surface. This localized approach achieves the carrier recombination prevention benefit of PERC/PERL structures while maintaining a simpler manufacturing process that is compatible with mass production.
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 method enables the cost-effective manufacturing of solar cells with enhanced power generation efficiency by reducing material costs and simplifying the production process, while maintaining the structural integrity of the silicon substrate.
Implementation Method 1
diffusing p type impurity into at least a portion of a first surface, which is one surface of a silicon substrate, to form a high concentration p type impurity diffusion layer
Implementation Method 2
etching one of the first surface of the silicon substrate and a second surface of the silicon substrate opposite to the first surface, using as a mask at least one of the high concentration p type impurity diffusion layer and a film formed on the high concentration p type impurity diffusion layer upon forming the high concentration p type impurity diffusion layer
Data Source
AI summary
The present invention provides a method for manufacturing a solar cell, including: diffusing p type impurity into at least a portion of a first surface, which is one surface of a silicon substrate, to form a high concentration p type impurity diffusion layer; and etching one of the first surface of the silicon substrate and a second surface of the silicon substrate opposite to the first surface, using as a mask at least one of the high concentration p type impurity diffusion layer and a film formed on the high concentration p type impurity diffusion layer upon forming the high concentration p type impurity diffusion layer.