PV Module Junction Box Resin Composition for Heat and Impact Resistance

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Solution Overview

Problem

Photovoltaic power generation module junction boxes and connectors face challenges in achieving good design, reduced size, and sufficient heat resistance, impact resistance, and long-term reliability, particularly at low temperatures and in high humidity environments.

Innovation Solution

A connection structure using a thermoplastic resin composition with a relative thermal index (RTI) of tensile impact strength at 1.5 mm of 115°C or higher and Charpy impact strength at -40°C of 6.5 kJ/m² or more, comprising polyphenylene ether, styrenic-based resin, and hydrogenated block copolymer, with specific mass ratios, to enhance heat resistance and impact resistance while maintaining a reduced wall thickness and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a heat-dissipating plate is installed or wall thickness is increased to improve heat resistance, then long-term heat resistance is improved, but device size increases

Engineering Contradiction:

Improvelong-term heat resistanceVSAvoidjunction box size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent changes the material parameters by using a thermoplastic resin composition with specific RTI (115°C or higher) and Charpy impact strength (6.5 kJ/m² or more), allowing the material itself to provide heat resistance without additional heat-dissipating plates, thus reducing device size while maintaining reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite thermoplastic resin composition combining multiple polymers (polyphenylene ether, styrenic-based resin, hydrogenated block copolymer) to achieve both heat resistance and impact resistance properties, eliminating the need for separate heat-dissipating components

Inventive Principle:

Principle #40Composite materials

2Strength

If wall thickness is increased to improve impact resistance, then impact resistance is improved, but device size and weight increase

Engineering Contradiction:

Improveimpact resistanceVSAvoidjunction box size

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

The patent changes the material strength parameters by selecting a thermoplastic resin composition with Charpy impact strength of 6.5 kJ/m² or more at -40°C, enabling thin-walled structures to achieve sufficient impact resistance without increasing device size

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent achieves uniform high-quality material properties throughout the junction box body, where the thermoplastic resin composition provides consistent impact resistance across the entire structure, eliminating the need for localized thickening

Inventive Principle:

Principle #3Local quality

3Volume of moving object

If device size is reduced for good design, then design quality and space reduction are improved, but heat resistance and impact resistance deteriorate

Engineering Contradiction:

Improvejunction box sizeVSAvoidheat resistance and impact resistance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent employs a composite thermoplastic resin composition that integrates multiple functional properties (heat resistance, impact resistance, low-temperature toughness) into a single material system, enabling compact design without sacrificing reliability

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent specifies critical material parameters (RTI ≥ 115°C, Charpy impact strength ≥ 6.5 kJ/m²) that ensure minimum performance thresholds are met even in reduced-size designs, allowing compact dimensions while maintaining reliability

Inventive Principle:

Principle #35Parameter changes

4Strength

If wall thickness is increased to improve low-temperature impact resistance, then low-temperature impact resistance is improved, but device complexity and size increase

Engineering Contradiction:

Improvelow-temperature impact resistanceVSAvoidstructure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent changes the material's low-temperature toughness parameter by selecting a thermoplastic resin composition with Charpy impact strength of 6.5 kJ/m² or more at -40°C, maintaining simple structure while achieving required low-temperature performance

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9284452B2Connection structure for photovoltaic power generation module

Publication Date: 2016.03.15 ASAHI KASEI CHEM CORP

AI summary

To provide a connection structure for a photovoltaic power generation module which is excellent in long-term heat resistance and which is excellent in low-temperature impact resistance even if the structure is reduced in wall thickness and size. There is provided a connection structure (1) for a photovoltaic power generation module which at least joins a photovoltaic power generation module to a cable for connecting to the photovoltaic power generation module, the connection structure for the photovoltaic power generation module comprising a thermoplastic resin composition having, as an index of long-term heat resistance, a relative thermal index (RTI) of tensile impact strength at a thickness of 1.5 mm of 115° C. or higher, and a Charpy impact strength at −40° C. of 6.5 kJ/m2 or more.