Porous Passivated Contact Structure for IBC Solar Cell Isolation

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Solution Overview

Problem

Conventional interdigitated back contact (IBC) solar cells face issues such as poor isolation effect, increased recombination, reduced conversion efficiency due to direct contact with the silicon substrate, and scratches during belt transportation, which affect production scalability and efficiency.

Innovation Solution

A passivated contact structure with a porous first passivation layer and a second passivation layer, featuring nano-level holes and openings for conductive layer connection, enhances isolation and reduces recombination, while a protective region prevents scratches during transportation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a tunneling layer is used to isolate doped polysilicon from the silicon substrate, then passivation effect is improved, but the thickness control accuracy becomes difficult and production scalability is reduced

Engineering Contradiction:

Improvepassivation effectVSAvoidthickness control accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs a porous silicon oxide layer instead of a dense tunneling layer. This porous structure provides effective passivation while being less sensitive to thickness variations, thereby resolving the contradiction between achieving good passivation effect and maintaining manufacturing precision for thickness control

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent changes the material parameter from a dense tunneling layer to a porous silicon oxide layer with specific pore size (5-50 nm). This parameter change allows the structure to maintain passivation effectiveness while reducing sensitivity to thickness control, enabling better manufacturing precision

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If the doped polysilicon is directly printed on the silicon substrate, then the fabrication process is simplified, but burn-through occurs during sintering causing direct contact between electrode and silicon substrate which increases recombination

Engineering Contradiction:

Improvefabrication process simplicityVSAvoidrecombination loss

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces a porous silicon oxide layer as an intermediary between the doped polysilicon and the silicon substrate. This intermediary layer prevents burn-through during sintering while maintaining electrical contact through the porous structure, thus avoiding direct contact between the electrode and silicon substrate that would cause recombination

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The porous silicon oxide layer with 5-50 nm pores allows electrical conduction while providing physical separation and protection during sintering, preventing burn-through and the associated recombination losses

Inventive Principle:

Principle #31Porous materials

3Productivity

If the cell is transported by belt during fabrication, then production efficiency is improved, but scratches occur on the cell surface affecting conversion efficiency

Engineering Contradiction:

Improveproduction efficiencyVSAvoidsurface scratches

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies a protective coating or structure to the cell surface before transportation by belt. This beforehand protection prevents scratches from occurring during the high-speed transportation process, maintaining surface quality and conversion efficiency while enabling productive belt-based transport

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 structure improves isolation, reduces recombination, and prevents scratches, leading to enhanced conversion efficiency and reduced surface pollution, with flexible thickness control and cost-effective production.

Implementation Method 1

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS12408470B2Passivated contact structure and solar cell comprising the same, cell assembly, and photovoltaic system

Publication Date: 2025.09.02 ZHEJIANG AIKO SOLAR ENERGY TECH CO LTD

AI summary

A solar cell includes a silicon substrate, a first doped region, and a second doped region. The first doped region includes a first passivated contact region on the silicon substrate and a second passivated contact region on the first passivated contact region. The first passivated contact region includes a first doped layer, a first passivation layer, and a second doped layer. The second passivated contact region includes a second passivation layer and a third doped layer. The second doped region includes a third passivation layer. Each of the first and third passivation layers includes a porous structure. One of the first and second doped regions is a P-type doped region, the other of the first and second doped regions is an N-type doped region, and a hole density of a corresponding passivation layer in the P-type doped region is greater than that in the N-type doped region.