Selective Passivated Contact Cell for Lower Polysilicon Light Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solar cells face challenges with severe parasitic absorption of light by polysilicon layers in passivated contact structures, leading to reduced light utilization and short-circuit current, necessitating a solution that balances metal and non-metal region interactions.
Innovation Solution
A selective passivated contact cell structure is developed, featuring a thicker polysilicon layer in metal contact regions to prevent corrosion and a thinner layer in non-metal regions, with a second silicon oxide layer to protect the polysilicon and optimize light utilization, along with a grid structure and passivation layers to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick polysilicon layer is used in the passivated contact structure, then metal contact corrosion is prevented and electrical performance is improved, but light absorption increases and light utilization rate decreases
Solution Approach 1:
The patent applies different polysilicon layer thicknesses to different regions: a first polysilicon layer with thickness of 5-20 nm in non-metal contact regions to minimize light absorption, and a second polysilicon layer with thickness of 20-50 nm in metal contact regions to prevent corrosion. This local differentiation resolves the contradiction between corrosion resistance and light utilization.
Solution Approach 2:
The patent divides the polysilicon contact structure into two distinct layers with different functions and thicknesses: the first polysilicon layer for light region passivation and the second polysilicon layer for metal contact protection. This segmentation allows each layer to be optimized for its specific function, resolving the contradiction.
2Loss of energy
If a thin polysilicon layer is used to reduce light absorption, then light utilization rate is improved, but metal contact corrosion protection is insufficient
Solution Approach 1:
The patent implements region-specific polysilicon thickness: 5-20 nm in non-metal regions for light transmission and 20-50 nm in metal regions for corrosion protection. This local quality differentiation ensures both light utilization and corrosion resistance are optimized in their respective regions.
Solution Approach 2:
The contact structure is segmented into two functional layers: a thin first polysilicon layer for optical performance and a thicker second polysilicon layer for electrical and corrosion performance. This segmentation resolves the contradiction between thin and thick requirements.
3Reliability
If the polysilicon layer thickness is uniformly increased to ensure corrosion protection, then metal contact reliability is improved, but overall light utilization and short-circuit current decrease
Solution Approach 1:
The patent applies different polysilicon thicknesses to different functional regions: 5-20 nm in light-active regions to maintain high light utilization and short-circuit current, and 20-50 nm in metal contact regions to ensure corrosion protection and reliability. This local differentiation resolves the contradiction between overall reliability and productivity.
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 approach effectively increases voltage and filling factor, reduces recombination, and improves photoelectric efficiency while ensuring light utilization, offering a simple and repeatable preparation process.
Implementation Method 1
The passivation tunneling layer, the doped polysilicon layer and the first antireflection film layer of the utility model are positioned between the positive electrode and the silicon wafer, so that the passivation effect is effectively exerted
Implementation Method 2
provide a thicker polysilicon layer in the metal contact regions to block corrosion of a metal slurry
Implementation Method 3
the polysilicon layer has severe parasitic absorption to light in the passivated contact structure, and a thick polysilicon layer grown over the surface of the silicon wafer may greatly reduce a utilization rate of light by the cell
Implementation Method 4
provide a second silicon oxide layer in the middle of a second polysilicon layer to protect the second polysilicon layer
Data Source
AI summary
Provided in the present invention are a selective passivated contact cell and a preparation method therefor. The selective passivated contact cell comprises a substrate, wherein a first silicon oxide layer and a first polysilicon layer are sequentially arranged on the surface of one side of the substrate in a stacked manner, the surface of the substrate comprises a non-metal contact region and at least two metal contact regions; in the metal contact regions, a second silicon oxide layer and a second polysilicon layer are further sequentially arranged the surface of the side of the first polysilicon layer that is away from the substrate, and a first electrode is arranged on the second polysilicon layer; and the first polysilicon layer has a greater thickness in the metal contact regions than in the non-metal contact region. The present invention has the characteristics of simple structure, simple preparation process, a high efficiency, etc.