TOPCon Solar Cell Contact Structure for Passivation and Light Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing TOPCon solar cells face issues with reduced photoelectric conversion efficiency due to parasitic light absorption and erosion of the polycrystalline silicon layer during high-temperature sintering, which affects the passivation effect and short-circuit current.
Innovation Solution
A solar cell design incorporating a hydrogen barrier layer and a metal barrier layer to prevent hydrogen overflow and electrode erosion, respectively, along with a selective passivation contact structure to enhance the passivation effect and reduce the thickness of the polycrystalline silicon layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick heavily doped polycrystalline silicon layer is used on the back surface, then passivation loss is improved, but parasitic light absorption increases and short-circuit current decreases
Solution Approach 1:
The patent applies local quality by creating a hydrogen barrier layer only in specific regions where hydrogen diffusion needs to be blocked, rather than uniformly throughout the entire structure. This allows the polycrystalline silicon layer to maintain its passivation function while reducing parasitic absorption in areas where the barrier layer prevents hydrogen-induced degradation
Solution Approach 2:
The hydrogen barrier layer acts as an intermediary between the tunneling oxide layer and the heavily doped polycrystalline silicon layer. It mediates the interaction by blocking hydrogen diffusion from the polycrystalline silicon into the tunneling oxide, thereby preserving the passivation effect while allowing optimization of the polycrystalline silicon thickness to reduce parasitic absorption
2Ease of manufacture
If high-temperature sintering is used in screen printing metallization, then metallization process is improved, but passivation quality of phosphorus-doped polycrystalline silicon structure deteriorates
Solution Approach 1:
The hydrogen barrier layer is formed preliminarily before the metallization process. This preliminary structure prevents hydrogen diffusion that would otherwise be caused by subsequent high-temperature sintering, thereby protecting the passivation quality while still allowing the metallization process to proceed at high temperatures
Solution Approach 2:
The hydrogen barrier layer provides preliminary anti-action by blocking hydrogen diffusion before the high-temperature sintering process can cause damage to the passivation structure. This preventive measure counteracts the harmful effects of high-temperature processing on the phosphorus-doped polycrystalline silicon
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 proposed design improves the fill factor efficiency and photoelectric conversion efficiency of the solar cell by minimizing parasitic light absorption and electrode-induced erosion, thereby enhancing the overall performance.
Implementation Method 1
The ultra-thin oxide layer may cause electrons to tunnel into the polycrystalline silicon layer and block transport of holes
Implementation Method 2
a hydrogen barrier layer located on a surface of the tunneling layer away from the semiconductor substrate
Implementation Method 3
a metal barrier layer that are stacked on one another
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A solar cell, a method for manufacturing solar cell, and a photovoltaic module. The solar cell includes: a semiconductor substrate; a tunneling layer located over a rear surface of the semiconductor substrate; a hydrogen barrier layer located over a surface of the tunneling layer; a lightly doped conductive layer located over a surface of the hydrogen barrier layer; and grid-shaped doped conductive layers located on at least part of a surface of the lightly doped conductive layer, wherein each of the grid-shaped doped conductive layers includes a heavily doped conductive layer and a metal barrier layer that are stacked on one another.