Dual-Sided TOPCon Solar Cell Layout to Cut Polysilicon Absorption

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Solution Overview

Problem

Conventional tunnel oxide passivated contact (Topcon) technology in crystalline silicon solar cells is limited by parasitic absorption in polysilicon layers, leading to current loss and is only suitable for back surface passivation, restricting efficiency improvements.

Innovation Solution

A solar cell design that passivates metal-semiconductor contact areas on both the front and back surfaces, with the emitter placed on the back surface, using tunneling layers and doped polysilicon layers to reduce carrier recombination and enhance efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional Topcon technology uses polysilicon layers for passivation, then contact area passivation is improved, but parasitic absorption and current loss increase

Engineering Contradiction:

Improvecontact area passivationVSAvoidcurrent loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The solar cell structure is segmented into front surface and back surface contact regions, with the emitter specifically placed on the back surface. This segmentation allows the front surface to be free of polysilicon layers, eliminating parasitic absorption in light-receiving areas, while the back surface maintains passivation functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The conventional Topcon structure places the emitter on the front surface, but this invention inverts the configuration by placing the emitter on the back surface. This inversion resolves the contradiction by moving the polysilicon layer away from the light-receiving surface, eliminating parasitic absorption while maintaining contact passivation.

Inventive Principle:

Principle #13The other way round (Inversion)

2Illumination intensity

If emitter is placed on front surface, then light-receiving function is maintained, but carrier recombination in non-contact area increases

Engineering Contradiction:

Improvelight-receiving functionVSAvoidcarrier recombination

Core Design Contradiction:

Illumination intensityVSLoss of energy

Solution Approach 1:

The emitter position is inverted from the conventional front surface placement to the back surface placement. This inversion allows the entire front surface to function as a light-receiving surface without carrier recombination losses, while the back surface emitter maintains electrical contact functionality.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The emitter placement is moved from the two-dimensional front surface to the back surface, utilizing the third dimension (depth) of the solar cell structure. This dimensional change allows simultaneous optimization of light reception on the front surface and electrical contact on the back surface.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 design achieves higher open circuit voltage and conversion efficiency compared to conventional Topcon technologies by simultaneously passivating contact areas on both surfaces and reducing recombination in non-contact areas.

Implementation Method 1

tunnel oxide passivated contact (Topcon) technology

Methodology Applied

Scientific EffectQuantum tunneling:

Implementation Method 2

surface recombination and recombination in the metal-semiconductor contact area are key factors that restrict the improvement of solar cell efficiency

Methodology Applied

Scientific EffectSurface passivation:

Implementation Method 3

crystalline silicon solar cells

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentUS20250006853A1Solar cell

Publication Date: 2025.01.02 TRINA SOLAR CO LTD

AI summary

A solar cell is provided. The solar cell includes a semiconductor substrate. The front surface of the semiconductor substrate has a metal contact area and a non-metal contact area. A first tunneling layer, a first doped polysilicon layer and a first metal electrode are sequentially stacked on the metal contact area. The first metal electrode is electrically connected to the first doped polysilicon layer. A second tunneling layer, a second doped polysilicon layer and a second metal electrode are sequentially stacked on the back surface of the semiconductor substrate.