N-Type TOPCon Cell Double-Sided Aluminum Paste Electrodes Cut Cost
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Solution Overview
Problem
N-type TOPCon solar cells face high manufacturing costs and low photoelectric conversion efficiency due to the use of silver paste on both sides, which can be reduced by replacing silver paste with aluminum paste on the back side and optimizing the electrode structure.
Innovation Solution
Implementing double-sided aluminum paste electrodes with aluminum grid lines and segmented silver main grids on the front and back sides of the substrate, using UV laser ablation to minimize passivation film damage and form a desirable field passivation effect without forming a BSF layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver paste is used on both front and back sides of the N-type TOPCon cell, then the double-sided ratio is ensured, but the manufacturing cost increases
Solution Approach 1:
The patent replaces expensive silver paste with cheaper aluminum paste on the back side of the cell. Aluminum paste forms an ohmic contact with the N-type doped polysilicon layer without requiring the formation of a BSF layer, thus reducing material costs while maintaining electrical performance
Solution Approach 2:
The patent applies different paste materials to different sides of the cell: silver aluminum paste on the front side and aluminum paste on the back side. This localized differentiation optimizes both cost and performance for each specific side based on its functional requirements
2Ease of manufacture
If silver paste is used on the front side to reduce cost, then manufacturing cost decreases, but photoelectric conversion efficiency is reduced
Solution Approach 1:
The patent uses silver aluminum paste on the front side instead of pure silver paste. This composite material combines the high conductivity of silver with the cost advantages and functional benefits of aluminum, achieving a balance between cost reduction and efficiency maintenance
Solution Approach 2:
The patent optimizes the front side electrode by using aluminum grid lines with segmented silver main grids. This local differentiation ensures that current collection is optimized where needed while reducing overall silver consumption
3Ease of manufacture
If aluminum paste is used on the back side, then manufacturing cost is reduced, but ohmic contact formation becomes more difficult
Solution Approach 1:
The patent modifies the glass powder composition in the aluminum paste to enable proper ohmic contact formation. By adjusting the chemical parameters of the paste formulation, the paste can effectively contact the N-type doped polysilicon layer without forming a BSF layer, achieving both cost reduction and reliable electrical contact
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
Reduces manufacturing costs and enhances the Voc of the cell by increasing carrier diffusion length, while maintaining or improving efficiency compared to double-sided silver paste cells.
Implementation Method 1
UV laser ablation to minimize passivation film damage
Implementation Method 2
adjusting the components of glass powder in aluminum paste, a desirable ohmic contact is only formed between the aluminum paste and a N-type doped polysilicon layer
Implementation Method 3
form a desirable field passivation effect is formed, thereby increasing a diffusion length of carriers
Data Source
AI summary
Some embodiments of the present disclosure provide an N-type TOPCon cell with double-sided aluminum paste electrodes, and a preparation method therefor. The front side of the cell is provided with a front-side silver main grid and a front-side aluminum fine grid, and the back side is provided with a back-side silver main grid and a back-side aluminum fine grid. The method for preparing the cell includes: texturing→B diffusion→BSG removal→alkali polishing→depositing a tunnel oxide layer and a polysilicon layer on a back side of a substrate by means of LPCVD→P diffusion on the back side→PSG removal→plating removal→deposition of an AlOx preparatory layer and a first SiNxHy preparatory layer on the front side→deposition of a second preparatory layer SiNxHy on the back side→UV laser ablation on the front side of the substrate and the back side of the substrate→screen printing.