Heterojunction Solar Cell Scanning to Limit Passivation Heating

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Heterojunction photovoltaic cells face efficiency issues due to defects at the interface between crystalline silicon and amorphous silicon layers, which are exacerbated by high temperatures and prolonged exposure to luminous flux, making it challenging to maintain the stability and efficiency of the cells during manufacturing.

Innovation Solution

A method involving linear scanning of electromagnetic radiation over the surface of the photovoltaic cell stack, which reduces overall heating and limits temperature increases, thereby preventing degradation of the amorphous silicon layers and improving passivation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the photovoltaic cell is subjected to high irradiance luminous flux to improve efficiency, then the energy conversion efficiency improves, but the temperature increases causing degradation of amorphous silicon layers

Engineering Contradiction:

Improveenergy conversion efficiencyVSAvoidstack temperature

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The treatment area is divided into multiple zones along a scanning line, with different energy densities applied to different segments. The first portion receives higher energy density for improved passivation, while the second portion receives lower energy density to avoid degradation, resolving the contradiction between achieving efficiency improvement and preventing temperature-induced damage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the photovoltaic cell stack are subjected to different treatment conditions. The first portion (emitter region) receives intense localized irradiance to improve passivation quality, while the second portion receives reduced irradiance to maintain structural integrity, allowing local optimization without global overheating.

Inventive Principle:

Principle #3Local quality

2Productivity

If the irradiance is increased to reduce treatment time, then productivity improves, but the heating effect worsens causing amorphous silicon degradation

Engineering Contradiction:

Improvetreatment speedVSAvoidheating effect

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The irradiation path is segmented into treatment and non-treatment zones. High irradiance is applied only in the first portion where passivation improvement is needed, while the second portion is scanned at lower irradiance or skipped entirely, maintaining high processing speed without excessive heating.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The scanning mechanism rapidly moves through portions of the stack that do not require intensive treatment, minimizing exposure time and heat accumulation in those areas while concentrating energy only where needed for passivation improvement.

Inventive Principle:

Principle #21Skipping (Rushing through)

3Ease of manufacture

If uniform irradiance is applied across the entire stack, then treatment simplicity is maintained, but localized overheating occurs degrading the amorphous silicon

Engineering Contradiction:

Improvetreatment simplicityVSAvoidamorphous silicon stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The irradiance distribution is automatically segmented into high and low intensity zones along the scanning direction, achieving differentiated treatment without complex manual intervention. The scanning system inherently creates this gradient by controlling exposure duration at different positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The irradiance applied to different portions of the stack is dynamically adjusted based on position during scanning. The system transitions from static uniform irradiance to dynamic spatially-varying irradiance, automatically preventing overheating in sensitive regions while treating other regions intensively.

Inventive Principle:

Principle #15Dynamics

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 approach effectively minimizes overheating, reduces the degradation of amorphous silicon, and enhances the efficiency and stability of the photovoltaic cells by maintaining lower temperatures across most of the stack while allowing controlled heating in specific areas, thus improving the overall performance of the heterojunction photovoltaic cells.

Implementation Method 1

exposing one face of the stack to electromagnetic radiation emitted by a radiation source

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

the electromagnetic radiation being applied to the face of the stack along a line, the stack and the radiation source being animated by a relative translational movement

Methodology Applied

Scientific EffectDielectric heating: Dielectric Heating

Data Source

PatentEP4186110B1Process for treating a heterojunction photovoltaic cell by scanning

Publication Date: 2024.05.22 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

Figure 1~2
Figure 3~4
Figure 5A~5B

AI summary

The invention relates to a process for treating a stack (10') comprising a substrate of crystalline silicon and a passivation layer of hydrogenated amorphous silicon disposed on the substrate, the process comprising a step of exposing a surface of the stack (10') to electromagnetic radiation emitted by a radiation source, the electromagnetic radiation being applied to the surface of the stack (10') along a line (50), the stack (10') and the radiation source being translated relatively in a direction of travel (D) such that the line (50) scans at least a portion of the surface of the stack (10').