Tandem Solar Cell Passivation Contact Layout for Bifacial Efficiency

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Solution Overview

Problem

Current solar cells have limited photoelectric conversion efficiency due to a restricted wavelength range of light absorption and differences in efficiency between the front and back surfaces, necessitating improvements in light absorption rate and photoelectric conversion efficiency.

Innovation Solution

A solar cell design featuring a substrate with alternating electrode and non-electrode regions, where a doped conductive layer and dielectric layer are positioned in both regions, including platform structures and pyramid structures to enhance passivation and light absorption, reducing carrier recombination and improving carrier collection efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the doped conductive layer is formed over the entire first surface including non-electrode regions, then carrier collection efficiency is improved, but light absorption rate of the first surface deteriorates

Engineering Contradiction:

Improvecarrier collection efficiencyVSAvoidlight absorption rate

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The doped conductive layer is selectively formed only in electrode regions and specific portions of non-electrode regions, creating different local properties: areas with the layer for carrier collection and areas without for light absorption. This local differentiation resolves the contradiction by optimizing each region's function rather than applying a uniform structure across the entire surface.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If the first surface is made completely flat for uniform layer formation, then manufacturing precision is improved, but light absorption rate deteriorates

Engineering Contradiction:

Improveuniformity of dielectric and conductive layersVSAvoidlight absorption rate

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The first surface is segmented into different regions with different topographies: flat regions (first surface structure) where uniform layer formation is critical for carrier collection, and textured regions (second surface structure with pyramid structures) where light absorption is prioritized. This segmentation allows each region to be optimized for its primary function.

Inventive Principle:

Principle #1Segmentation

3Reliability

If non-electrode regions are completely covered with conductive layers for passivation, then carrier recombination loss is reduced, but bifaciality deteriorates

Engineering Contradiction:

Improvecarrier recombination reductionVSAvoidbifaciality

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of completely covering all non-electrode regions with conductive layers, the patent applies partial coverage only in specific portions where carrier collection is beneficial. This partial action maintains sufficient passivation to reduce carrier recombination while leaving other areas exposed to enhance light absorption and maintain high bifaciality.

Inventive Principle:

Principle #16Partial or excessive action

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 increases open circuit voltage and photoelectric conversion efficiency by approximately 0.05% and bifaciality by approximately 7.7%, enhancing overall carrier collection and light absorption.

Implementation Method 1

a dielectric layer and a doped conductive layer are sequentially stacked on the first surface in the electrode regions and in a part of each of the non-electrode regions so as to form a passivation contact structure

Methodology Applied

Scientific EffectPassivation:

Implementation Method 2

A part (i.e., a second part) of the first surface not aligned with the doped conductive layer has a second surface structure including a plurality of first pyramid structures, so that a light absorption rate of the second part is improved

Methodology Applied

Scientific EffectLight trapping:

Implementation Method 3

The solar cell includes a substrate, a doped conductive layer and a dielectric layer... improving the photoelectric conversion efficiency of the front surface

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentUS20250255033A1Solar cell, tandem solar cell, and photovoltaic module

Publication Date: 2025.08.07 ZHEJIANG JINKO SOLAR CO LTD

AI summary

Provided are a solar cell, a method for preparing a solar cell, a tandem solar cell, and a photovoltaic module. The solar cell includes a substrate, a doped conductive layer, and a dielectric layer. The substrate has a first surface, where the first surface includes electrode regions and non-electrode regions that are alternatingly arranged along a first direction. The doped conductive layer is formed over the first surface of the substrate. The doped conductive layer includes first conductive portions and at least one second conductive portion. Each respective first conductive portion of the first conductive portions is formed over a respective electrode region of the electrode regions, and each respective second conductive portion of the at least one second conductive portion is formed over a part of a non-electrode region of the non-electrode regions. The dielectric layer is between the first surface and the doped conductive layer.