Back-Contact Solar Cell Edge Layout for Minority Carrier Collection

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Solution Overview

Problem

Existing back contact solar cells have low collection efficiency of minority carriers at the edge, which hinders improved operating efficiency.

Innovation Solution

A back contact solar cell design with a minority carrier inversion layer formed by a majority carrier passivation layer on the semiconductor substrate edge, combined with a non-electrode collecting region and electrode collecting region arrangement, enhances carrier collection and reduces recombination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a back contact solar cell structure is used to increase light receiving surface area, then photoelectric conversion efficiency is improved, but minority carrier collection efficiency at the edge is reduced

Engineering Contradiction:

Improvephotoelectric conversion efficiencyVSAvoidminority carrier collection efficiency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces a non-electrode collecting region at the edge of the back surface with different properties from the electrode collecting region. This non-electrode region has no metal electrodes or doped semiconductor portions, creating a localized area with distinct electrical characteristics that prevents carrier recombination at the edge while maintaining the back contact structure's high light utilization.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a dielectric layer as an intermediary structure between the semiconductor substrate and the edge region. This dielectric layer with specific permittivity creates an electric field that repels minority carriers from the edge, forming a virtual barrier that redirects carriers toward the electrode collecting region without direct physical contact, thus improving collection efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the non-electrode collecting region is extended to improve carrier collection, then manufacturing complexity increases

Engineering Contradiction:

Improvecarrier collection efficiencyVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent defines specific parameter ranges for the non-electrode collecting region, including its width (5-20% of the back surface width) and the dielectric layer's permittivity (3-10 times that of the semiconductor substrate). By optimizing these parameters, the structure achieves improved carrier collection without excessive complexity, balancing performance and manufacturability.

Inventive Principle:

Principle #35Parameter changes

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

Improves the efficiency of minority carrier collection and reduces carrier recombination at the edge, leading to enhanced overall performance of the solar cell.

Implementation Method 1

form a minority carrier inversion layer on an inner side of a semiconductor substrate at an edge of a first surface through a majority carrier passivation layer

Methodology Applied

Scientific EffectInversion layer formation:

Implementation Method 2

Under an action of an electric field of the majority carrier passivation layer, the minority carrier inversion layer repels photogenerated minority carriers

Methodology Applied

Scientific EffectElectric field effect: Electric Field

Implementation Method 3

sunlight irradiates onto a semiconductor p-n junction of the solar cell to form new hole-electron pairs. Under an action of a built-in electric field of the p-n junction, photogenerated holes flow to a p-type region, and photogenerated electrons flow to an n-type region

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentUS20260020374A1Back contact solar cell and manufacturing method thereof, and photovoltaic module

Publication Date: 2026.01.15 LONGI GREEN ENERGY TECH CO LTD

AI summary

The present application discloses a back contact solar cell and a manufacturing method thereof, and a photovoltaic module. In one example, a back contact solar cell includes a semiconductor substrate, a first doped semiconductor portion, a second doped semiconductor portion, and a majority carrier passivation layer. A first surface includes a non-electrode collecting region and an electrode collecting region. The electrode collecting region includes minority carrier regions and majority carrier regions distributed alternately along a first direction. An outermost minority carrier region is closer to the non-electrode collecting region than an outermost majority carrier region. The first doped semiconductor portion is arranged in the majority carrier region. The second doped semiconductor portion is arranged in the minority carrier region. The majority carrier passivation layer is arranged in the non-electrode collecting region. A thickness of the majority carrier passivation layer is greater than a thickness of the second doped semiconductor portion.