Braided Busbar Thermal Stress Absorption

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Solution Overview

Problem

Photovoltaic apparatuses face efficiency reduction and potential damage due to environmental stresses like temperature changes, wind, and snow, which cause deformations and delamination around busbars, leading to exposure to moisture and corrosion.

Innovation Solution

The use of a braided or wavy busbar structure with vias and conductive layers to distribute stress evenly and reduce resistance, combined with a sealing assembly to protect the apparatus from environmental factors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid busbar structure is used, then electrical connection is stable, but the photovoltaic apparatus is vulnerable to deformations and delamination under environmental stresses

Engineering Contradiction:

Improveelectrical connection stabilityVSAvoidenvironmental stress damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The busbar is designed with a flexible structure featuring a neutral axis running through its length, allowing it to bend and deform elastically in response to environmental stresses such as thermal expansion and contraction. This flexibility prevents rigid stress transmission that would cause delamination and electrical connection failure, while maintaining continuous electrical contact with the photovoltaic cells.

Inventive Principle:

Principle #30Flexible shells and thin films

2Object-affected harmful factors

If a flexible busbar structure is used, then environmental stress resistance is improved, but manufacturing precision and electrical contact quality may deteriorate

Engineering Contradiction:

Improveenvironmental stress resistanceVSAvoidelectrical contact quality

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The busbar's mechanical properties are optimized by controlling the position of the neutral axis within its cross-section. By adjusting geometric parameters such as the thickness and width distribution relative to the neutral axis, the busbar achieves optimal flexibility while maintaining sufficient rigidity for precise electrical contact during manufacturing and operation.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If the busbar is made more flexible to absorb thermal stress, then delamination is reduced, but structural strength may be compromised

Engineering Contradiction:

Improvelayer adhesionVSAvoidbusbar structural strength

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The busbar is constructed as a composite structure with multiple layers or materials having different mechanical properties. This composite design allows the neutral axis region to provide flexibility for stress absorption while other regions maintain structural strength, achieving a balance between preventing delamination and ensuring overall structural integrity.

Inventive Principle:

Principle #40Composite materials

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 configuration enhances the mechanical flexibility and electrical efficiency of the photovoltaic apparatus by absorbing thermal stresses in multiple directions, reducing deformations and improving longevity by preventing moisture exposure.

Implementation Method 1

Large changes in temperature can cause stress in a photovoltaic apparatus as different components expand and contract at different rates

Methodology Applied

Scientific EffectThermal stress: Thermal Expansion

Implementation Method 2

The use of a braided or wavy busbar structure with vias and conductive layers to distribute stress evenly

Methodology Applied

Scientific EffectStress distribution: Elasticity

Implementation Method 3

combined with a sealing assembly to protect the apparatus from environmental factors

Methodology Applied

Scientific EffectSealing: Physical Containment

Implementation Method 4

The use of a braided or wavy busbar structure with vias and conductive layers to distribute stress evenly and reduce resistance

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3391418B1Solar module busbar

Publication Date: 2022.11.16 FLISOM AG

Figure 1A
Figure 1B
Figure 2A~2B

AI summary

A photovoltaic apparatus (200) is provided including a photovoltaic device (100). The photovoltaic device includes an array of photovoltaic cells (101-114) having a first end and a second end, the array extending in a first direction from the first end (1101) to the second end (1102). Each photovoltaic cell includes a first contact layer (150), a second contact layer (120), and an absorber layer (130) disposed between the first contact layer and the second contact layer. The photovoltaic apparatus further includes a first busbar (180) extending from a first side of the photovoltaic device to a second side of the photovoltaic device in a second direction. The first busbar includes a plurality of strands (1851) that are intertwined to form a flexible electrically conductive structure.