Moisture-Resistant Solar Cells for Roof Tiles

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Solution Overview

Problem

Conventional solar roof tiles face significant moisture ingress issues due to the susceptibility of transparent conductive oxide (TCO) materials, leading to degradation of solar cell performance, as they lose material properties and can act as pathways for moisture to reach the solar cell junction.

Innovation Solution

Incorporating a moisture-resistant transparent conductive oxide (TCO) layer with a grain size of at least 40 nm, such as indium tin oxide (ITO), or using alternative doped materials like Ti doped indium oxide, Si doped ZnO, or Ga and In co-doped ZnO, and applying a dielectric coating like silicon oxide or silicon nitride using plasma-enhanced chemical vapor deposition (PECVD) to create a barrier against moisture ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional transparent conductive oxide (TCO) materials are used for electrical contact in solar cells, then electrical conductivity is achieved, but moisture resistance deteriorates as TCO materials lose their properties when exposed to moisture and can serve as pathways for moisture ingress

Engineering Contradiction:

Improvemoisture resistanceVSAvoidmoisture ingress susceptibility

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies composite materials by combining transparent conductive oxide (TCO) layers with moisture barrier layers to create a multi-layer structure. The TCO layer provides electrical conductivity while the moisture barrier layer (such as aluminum oxide, titanium oxide, or silicon oxide) provides moisture resistance. This composite structure resolves the contradiction by integrating two materials with complementary properties, allowing the solar cell to achieve both electrical conductivity and moisture resistance simultaneously.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If frameless solar roof tiles are used to maintain conventional roofline appearance, then aesthetic appeal is improved, but moisture protection deteriorates as moisture may permeate the encapsulant from the edges under wet conditions

Engineering Contradiction:

Improveaesthetic integrationVSAvoidmoisture permeation

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by implementing moisture barrier layers at specific critical locations where moisture ingress is most likely to occur, such as at the edges and interfaces of the frameless solar roof tile. Rather than requiring a complete enclosure, the moisture barrier is strategically placed at vulnerability points, maintaining the aesthetic frameless appearance while providing localized protection against moisture permeation from edges.

Inventive Principle:

Principle #3Local quality

3Productivity

If TCO-based SHJ solar cells are used to achieve high efficiency, then energy conversion is improved, but moisture resistance deteriorates as TCO materials can act as mediums for moisture to reach the junction

Engineering Contradiction:

Improveenergy conversion efficiencyVSAvoidmoisture resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies the intermediary principle by introducing a moisture barrier layer as a mediator between the TCO layer and the underlying solar cell junction. This intermediate layer does not interfere with the electrical function of the TCO layer but provides a protective interface that prevents moisture from reaching the junction through the TCO material, thus resolving the contradiction between maintaining high efficiency TCO-based SHJ cells and achieving moisture resistance.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution effectively reduces moisture reaching the solar cell junction, enhancing the long-term reliability and efficiency of solar roof tiles by preventing degradation caused by moisture exposure.

Implementation Method 1

a moisture barrier layer positioned on a first side of the emitter layer, thereby reducing the amount of moisture that reaches a junction between the base layer and the emitter layer

Methodology Applied

Scientific EffectMoisture barrier:

Implementation Method 2

applying a dielectric coating like silicon oxide or silicon nitride using plasma-enhanced chemical vapor deposition (PECVD) to create a barrier against moisture ingress

Methodology Applied

Scientific EffectPlasma-enhanced chemical vapor deposition: Plasma Enhanced Chemical Vapour Deposition

Data Source

PatentUS10672919B2Moisture-resistant solar cells for solar roof tiles

Publication Date: 2020.06.02 TESLA INC

AI summary

One embodiment can provide a solar module. The solar module can include one or more moisture-resistant photovoltaic structures. A respective photovoltaic structure can include a base layer, an emitter layer positioned on a first side of the base layer, and a moisture barrier layer positioned on a first side of the emitter layer, thereby reducing the amount of moisture that reaches a junction between the base layer and the emitter layer.