IBC Solar Cell Front Passivation with Surface Field Regions

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Solution Overview

Problem

Existing interdigitated back contact (IBC) solar cells have limited passivation effects on the front surface, leading to adverse effects on conversion efficiency due to high recombination rates of photogenerated carriers before reaching the back surface.

Innovation Solution

The implementation of front surface field regions and passivation layers on the front surface of the solar cell, combined with back passivation layers on the conductive regions, to reduce recombination rates and enhance the passivation effect, while minimizing interference with the chemical passivating effect of the front surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a passivation layer is deposited on the front surface of the solar cell, then the passivation effect on the front surface is improved, but carrier recombination still occurs significantly before reaching the back surface

Engineering Contradiction:

Improvepassivation effectVSAvoidcarrier recombination

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating front surface field regions with specific doping concentrations that differ from other areas. These field regions are formed by doping the front surface with a doping concentration of 1×10^18 to 1×10^20 atoms/cm³, creating localized areas with enhanced electric field effects that improve carrier collection while maintaining overall passivation quality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters by optimizing the doping concentration in the front surface field regions to 1×10^18 to 1×10^20 atoms/cm³ and controlling the thickness of the passivation layer to 50-200 nm. These parameter adjustments create the right balance between passivation and carrier collection, reducing recombination losses while maintaining effective surface passivation.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the emitters and metal contacts are located on the back surface of the solar cell, then the structural limitations of front-contact solar cells are broken and aesthetic appearance is improved, but the passivation effect on the front surface becomes insufficient

Engineering Contradiction:

Improvestructural flexibilityVSAvoidpassivation effect

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies inversion by placing the metal contacts and emitters on the back surface instead of the front surface, creating an interdigitated back contact (IBC) structure. This inverted configuration allows the entire front surface to be dedicated to light absorption and passivation, while the back surface handles electrical contact functions, thus resolving the contradiction between structural flexibility and passivation effectiveness.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent segments the solar cell structure by separating the functional regions: the front surface is divided into light-receiving areas with passivation layers and field regions, while the back surface contains the metal contacts and emitters. This segmentation allows each surface to optimize its specific function, with the front surface providing excellent passivation and the back surface providing electrical contact.

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

Significantly improves the passivation effect on the front surface of the solar cell, leading to enhanced conversion efficiency by effectively driving photogenerated carriers away from the front surface and reducing recombination.

Implementation Method 1

the front surface field regions are each corresponds to one of the P-type conductive regions or one of the N-type conductive regions... enhance the passivation effect on the front surface

Methodology Applied

Scientific EffectField effect passivation: Electric Field

Implementation Method 2

at least one front passivation layer located on the front surface of the silicon substrate... improve the passivation effect on the front surface of the solar cell

Methodology Applied

Scientific EffectChemical passivation: Adsorption

Implementation Method 3

photogenerated carriers are generated mainly on a front surface (i.e., light receiving surface) of the solar cell

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentUS20240250204A1Solar cell and photovoltaic module

Publication Date: 2024.07.25 JINKO SOLAR (HAINING) CO LTS

AI summary

A solar cell and a photovoltaic module is disclosed. The solar cell includes a silicon substrate, and the silicon substrate includes a front surface and a back surface arranged opposite to each other. P-type conductive regions and N-type conductive regions are alternately arranged on the back surface of the silicon substrate. Front surface field regions are located on the front surface of the silicon substrate and spaced from each other. The front surface field regions each corresponds to one of the P-type conductive regions or one of the N-type conductive regions. At least one front passivation layer is located on the front surface of the silicon substrate. At least one back passivation layer is located on surfaces of the P-type conductive regions and N-type conductive regions.