Tandem Solar Cell Layup With Contact Ledge Stress Buffering
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Solution Overview
Problem
Conventional methods of connecting silicon solar cells, particularly perovskite-silicon tandem cells, can cause mechanical stress and thermal degradation to the perovskite subcells due to direct pressure and high-temperature bonding processes, leading to potential mechanical breakage and reduced stability.
Innovation Solution
The use of a contact ledge patterned on the lower silicon subcell and low-temperature electrically conductive adhesive tapes to bond serial overlapping tandem solar cells, which mitigates stress on the perovskite subcells by absorbing pressure and avoiding high-temperature bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high-temperature bonding processes are used to connect solar cells, then strong electrical connection is achieved, but perovskite subcell material degradation occurs
Solution Approach 1:
The patent changes the bonding temperature parameter from conventional high-temperature processes to low-temperature bonding, specifically designed to be compatible with perovskite material stability limits. This parameter change allows electrical connection while avoiding thermal degradation of the perovskite subcell.
2Strength
If direct pressure is applied during cell connection, then strong mechanical bonding is achieved, but mechanical breakage of perovskite subcells occurs
Solution Approach 1:
The patent introduces an intermediary bonding structure that distributes mechanical pressure away from the fragile perovskite subcell. This intermediary layer acts as a stress buffer, allowing strong mechanical bonding between cells without transmitting damaging point pressures to the perovskite material.
Solution Approach 2:
The patent segments the bonding interface to distribute contact pressure across multiple discrete points rather than applying concentrated pressure. This segmentation of the bonding mechanism reduces peak stress on any single location of the perovskite subcell while maintaining overall mechanical strength.
3Productivity
If perovskite subcells are used in tandem solar cells, then higher efficiency is achieved, but mechanical stability is reduced
Solution Approach 1:
The patent applies local quality by creating structurally reinforced regions around the perovskite subcell areas that require mechanical support. These localized reinforcement zones provide enhanced mechanical stability precisely where needed, while leaving the perovskite active areas undisturbed to maintain their optoelectronic properties and efficiency.
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 mechanical breakage and thermal degradation of perovskite subcells, enhancing the mechanical stability and reliability of the solar cell modules by distributing stress to the stronger silicon subcells.
Implementation Method 1
low temperature electrically conductive bonding materials, such as solid adhesive tapes, may be utilized to bond serial overlapping tandem solar cells to one another
Implementation Method 2
a contact ledge can be formed through an upper perovskite subcell in an tandem perovskite-silicon subcell such that when serial tandem subcells are connected this may be achieved by bonding the back side of a tandem solar cell to the contact ledge of an underlying tandem solar cell
Data Source
AI summary
Solar cell modules and methods of fabrication are described. In an embodiment, a pair of tandem solar cells are bonded together along a contact ledge of a first tandem solar cell using a solid electrically conductive bonding material.