Passivation Contact Solar Cell Structure for Metal Region Absorption
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Solution Overview
Problem
Existing solar cells have low photoelectric conversion efficiency due to strong parasitic absorption by the doped conductive layer in the metal pattern region, which reduces light utilization and hinders further improvement in photoelectric conversion performance.
Innovation Solution
A solar cell design featuring a first passivation contact structure in the metal pattern region and a second passivation contact structure covering both the non-metal pattern region and the first passivation contact structure, with the second passivation contact structure acting as a continuous film layer to enhance carrier transport and reduce parasitic light absorption, thereby improving light absorption utilization and photoelectric conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the doped conductive layer thickness is increased to prevent metal electrode penetration, then reliability is improved, but parasitic light absorption increases and photoelectric conversion efficiency deteriorates
Solution Approach 1:
The doped conductive layer is divided into two separate layers: a first doped conductive layer in contact with the substrate and a second doped conductive layer above it. This segmentation allows the first layer to provide penetration resistance while the second layer has optimized thickness to minimize parasitic absorption, resolving the contradiction between reliability and energy loss.
Solution Approach 2:
Different regions of the doped conductive structure have different thicknesses and doping concentrations optimized for their specific functions. The first doped conductive layer has higher doping concentration for field passivation and penetration resistance, while the second layer has lower doping concentration and optimized thickness for minimal parasitic absorption, achieving local quality optimization.
2Productivity
If the doped conductive layer thickness is increased to enhance carrier collection, then productivity is improved, but photoelectric conversion efficiency deteriorates due to parasitic absorption
Solution Approach 1:
The doped conductive layer is segmented into two layers with different thicknesses and positions. The first layer provides carrier collection from the substrate interface, while the second layer collects carriers from upper regions. This segmentation enables effective carrier collection throughout the structure without requiring excessive total thickness that would cause parasitic absorption.
Solution Approach 2:
Instead of increasing thickness in one dimension, the solution uses a two-layer structure distributed vertically at different heights. This dimensional distribution allows carrier collection from multiple regions without concentrating absorption losses in a single thick layer, resolving the productivity-efficiency contradiction.
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 effectively reduces the probability of metal electrode penetration, increases carrier collection capability, and enhances photoelectric conversion performance by balancing the thickness of the doped conductive layers to minimize parasitic absorption and maximize light utilization.
Implementation Method 1
The tunneling oxide layer has good chemical passivation effect
Implementation Method 2
the doped conductive layer has good field passivation effect
Implementation Method 3
a metal paste coated on a metal pattern region is treated by using a sintering process such that the metal paste is burned through into the doped conductive layer
Implementation Method 4
Solar cells have excellent photoelectric conversion capability
Data Source
AI summary
Disclosed are a solar cell and a photovoltaic module. The solar cell includes a substrate, having a first surface, having a metal pattern region and a non-metal pattern region, a first passivation contact structure, located in the metal pattern region and including a first tunneling layer and a first doped conductive layer stacked in a direction away from the substrate, and a second passivation contact structure, including a second tunneling layer and a second doped conductive layer stacked in the direction away from the substrate, and having a first portion over the non-metal pattern region and a second portion over the first passivation contact structure, and a top surface of the first portion of the second passivation contact structure is not further away from the substrate than a top surface of the second portion of the second passivation contact structure.