Strain Relief Connectors for Solar Modules
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Solution Overview
Problem
The use of materials like copper in photovoltaic (PV) modules causes issues due to disparate coefficients of expansion with silicon, leading to thermal expansion and contraction problems, which can result in fracturing of connections between solar cell strips, especially under non-uniform heating conditions.
Innovation Solution
The implementation of low mass strain relief connectors with non-linear or curvilinear geometry to connect copper busbars to silicon-based solar cell strings, mitigating the thermal expansion effects by allowing flexibility and reducing strain on joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If copper connectors with large mass are used to transmit current, then electrical conductivity is improved, but thermal expansion effects worsen causing fracturing of connections
Solution Approach 1:
The connector is divided into two distinct parts: a large mass copper connector portion for optimal electrical conductivity and current transmission, and a low mass strain relief connector portion that minimizes thermal expansion. This segmentation allows each part to fulfill its specific function without compromising the other.
Solution Approach 2:
The low mass strain relief connector acts as an intermediary element between the large mass copper connector and the solar cell strings. It mediates the thermal expansion forces by absorbing and isolating them, preventing transmission to the solar cell connections while maintaining electrical continuity.
2Power
If copper materials are used in PV modules, then electrical performance is improved, but connection reliability deteriorates due to disparate expansion coefficients
Solution Approach 1:
The connector system is segmented into a copper portion for electrical performance and a strain relief portion with low thermal mass for reliability. This allows the copper to provide excellent electrical conductivity while the strain relief portion protects against thermal cycling damage.
Solution Approach 2:
The thermal mass parameter is deliberately changed along the connector length. The copper connector portion has high thermal mass for electrical performance, while the strain relief portion has low thermal mass to minimize thermal expansion. This parameter variation resolves the contradiction between electrical performance and connection reliability.
3Reliability
If non-linear geometry connectors are used, then strain relief capability is improved, but manufacturing complexity increases
Solution Approach 1:
The strain relief connector portion features a curved or non-linear geometry that allows it to flex and absorb thermal expansion forces. This curvature provides the necessary strain relief capability while maintaining a relatively simple overall structure that can be manufactured using standard processes.
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 solution effectively alleviates the destructive effects of thermal expansion and contraction, enhancing the durability and longevity of PV modules by absorbing movement and reducing the risk of cracking at joints, while maintaining electrical conductivity.
Implementation Method 1
use of materials such as copper within a PV module can cause problems due to disparate coefficients of expansion with respect to silicon
Implementation Method 2
The geometry can include one or more non-linear shapes, such as curves, such that thermal expansion and contraction of the connectors has a limited effect on the strings
Data Source
AI summary
A photovoltaic module can be constructed from one or more strings, with each of the strings being constructed from a plurality of cascaded solar cells. A connector can electrically connect the strings to one another. The connector can include strain relief connectors that extend between the connector and the strings to help reduce effects caused by thermal expansion.