Solar Cell Step Structure for Passivation and Carrier Tunneling

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Solution Overview

Problem

Existing solar cells have low photoelectric conversion efficiency due to a smooth substrate surface in the non-metal pattern region, which reduces the tunneling channel area and carrier transport efficiency.

Innovation Solution

A solar cell design with a step structure on the substrate surface, where the non-metal pattern region is lower than the metal pattern region, increasing the surface area and tunneling channel for carriers, and incorporating a passivation contact structure with a tunneling layer and doped conductive layer to enhance carrier transport and collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the substrate surface in the non-metal pattern region is made smooth, then the passivation effect is improved, but the tunneling channel area is reduced and carrier transport efficiency deteriorates

Engineering Contradiction:

Improvepassivation effectVSAvoidcarrier transport efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by creating different surface characteristics in different regions: the non-metal pattern region has a smooth surface for good passivation, while the metal pattern region has a rough surface for large tunneling channel area. This regional differentiation resolves the contradiction by optimizing each region for its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a height dimension difference between the non-metal pattern region and metal pattern region, creating a stepped structure. This dimensional change allows the smooth non-metal region to be at a lower height, providing passivation while the elevated rough metal region provides extensive tunneling surface area, thus resolving the contradiction between smoothness and surface area.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If the substrate surface is made rough to increase tunneling channel area, then carrier transport is improved, but the passivation effect deteriorates

Engineering Contradiction:

Improvetunneling channel areaVSAvoidpassivation effect

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Productivity

If the surface area is increased by creating uneven structure, then tunneling efficiency is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improvetunneling efficiencyVSAvoidsurface structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the substrate surface into distinct regions (metal pattern region and non-metal pattern region) with different surface characteristics. This segmentation allows each region to be optimized independently and simplifies the manufacturing process by using standardized patterning techniques to create the regions, rather than requiring complex continuous surface modification.

Inventive Principle:

Principle #1Segmentation

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 step structure increases the surface area and tunneling efficiency of carriers, improving photoelectric conversion performance by enhancing the short-circuit current, open-circuit voltage, and fill factor of the solar cell.

Implementation Method 1

The tunneling oxide layer further provides a tunneling channel for the carriers which tunnels through the tunneling oxide layer to the substrate

Methodology Applied

Scientific EffectTunneling effect:

Implementation Method 2

The tunneling oxide layer has good chemical passivation effect

Methodology Applied

Scientific EffectChemical passivation:

Implementation Method 3

the doped conductive layer has good field passivation effect

Methodology Applied

Scientific EffectField passivation:

Implementation Method 4

Solar cells have excellent photoelectric conversion capability

Methodology Applied

Scientific EffectPhotoelectric conversion: Photovoltaic Effect

Data Source

PatentEP4383356A1Solar cell and photovoltaic module

Publication Date: 2024.06.12 ZHEJIANG JINKO SOLAR CO LTD

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AI summary

Disclosed are a solar cell and a photovoltaic module. The solar cell includes a substrate (100), having a first surface and a second surface opposite to the first surface. The first surface includes a metal pattern region (10) and a non-metal pattern region (11). The first surface is uneven and has a first maximum height with respect to the second surface in the non-metal pattern region (11) and a second maximum height with respect to the second surface in the metal pattern region (10), and the first maximum height is lower than the second maximum height. The solar cell includes at least one passivation contact structure (110, 20, 30), covered on the first surface and including a tunneling layer (111, 21, 31) and a doped conductive layer (112, 22, 32) stacked in a direction away from the substrate (100).