Tandem Solar Cell Lay-Up Using Low-Temperature ECA Interconnection
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Solution Overview
Problem
The fabrication of tandem solar modules faces challenges due to the lack of standard tooling, damage from handling and misalignment of cells, and thermal/mechanical damage from high temperatures and pressures typically used in single-junction silicon solar cell processes.
Innovation Solution
A novel method for interconnecting two-terminal (2T) tandem cells using a single processing tool that applies electrically conductive adhesive (ECA) to both sides of cells, pre-cures at low temperatures (80-150°C), and laminates the lay-up to produce a solar module, minimizing mechanical and thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If standard high-temperature soldering and lamination processes are used for tandem solar cells, then interconnection strength is improved, but thermal damage to functional layers occurs
Solution Approach 1:
The patent changes the temperature parameter from standard high-temperature soldering (>100°C) to low-temperature ECA processing (80-150°C). This parameter change allows achieving adequate interconnection strength while avoiding thermal damage to the delicate perovskite functional layers in tandem solar cells.
Solution Approach 2:
The patent replaces the traditional mechanical soldering process with a chemical adhesive bonding process using ECA. This substitution eliminates the need for high-temperature heating and mechanical pressure, thereby preventing thermal and mechanical damage to the tandem cell structure while still achieving strong interconnection.
2Adaptability or versatility
If cells are transferred between multiple tools during fabrication, then manufacturing flexibility is improved, but cell damage and misalignment increase
Solution Approach 1:
The patent merges multiple separate fabrication tools into a single integrated tool that performs ECA application, pre-curing, and lamination operations. This consolidation eliminates intermediate transfer steps between tools, thereby preventing cell damage and misalignment while maintaining manufacturing flexibility through integrated process control.
Solution Approach 2:
The patent performs preliminary actions (ECA application and pre-curing) within the same tool before final lamination. This preliminary bonding secures cells in position early in the process, preventing misalignment and damage during subsequent operations without requiring multiple tool transfers.
3Object-affected harmful factors
If low-temperature ECA processing is used for tandem solar cells, then thermal damage is reduced, but interconnection strength may be compromised
Solution Approach 1:
The patent optimizes the ECA processing parameters by controlling temperature within the specific range of 80-150°C and managing pressure conditions. This parameter optimization ensures that the adhesive achieves adequate bonding strength while the temperature remains low enough to prevent thermal damage to the perovskite functional layers.
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 reduces cell damage, achieves high throughput, and minimizes thermal damage to tandem solar cells by using low-temperature processing, thereby improving the efficiency and reliability of tandem solar module fabrication.
Implementation Method 1
pre-curing the ECA at low temperature in a range from 80° C.-150° C.
Implementation Method 2
electrically conductive adhesive (ECA) cell interconnections
Data Source
AI summary
Disclosed is a method for fabricating a solar module. The method involves providing a single processing tool (which may be a system) a plurality of tandem solar cells, electrically conductive adhesive (ECA) and a protective assembly. The tool produces an assembled lay-up of protected, interconnected, partially cured cells by forming a string by aligning the cells and applying ECA to both sides of the cells, placing the string on the protective assembly, and pre-curing the ECA at low temperature (80° C.-150° C.). Thereafter, external connections are formed, a protective assembly is applied to a second side of each cell, opposite the first side, and the lay-up is laminated to produce a solar module