Monolithic Metallization Backplane for Solar Cell Sub-Cell Interconnection
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Solution Overview
Problem
Current solar cell manufacturing techniques face challenges in increasing efficiency and cost-effectiveness, particularly when dealing with larger wafers, as they require thicker metal for current transport, leading to increased costs and complexity, and existing methods of dicing cells into smaller diodes result in handling and interconnection complications.
Innovation Solution
Implementing a monolithic metallization structure as a backplane to connect sub-cells before singulation, which allows for inter-cell connections without individual handling and reduces the need for additional metal interconnects, while using encapsulants and strain-relief designs to mitigate risks of power loss and shunting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solar cells are manufactured on larger wafers, then productivity and efficiency are improved, but thicker metal is required for current transport increasing cost and complexity
Solution Approach 1:
The patent segments the solar cell into multiple sub-cells that are electrically connected through a common metallization backplane. This segmentation allows current from multiple sub-cells to converge at the backplane, reducing the current density and thickness requirements for metal interconnects while maintaining high productivity on larger wafers
Solution Approach 2:
The patent moves the metallization structure to the backside of the solar cell, creating a rear-contact configuration. This dimensional reorganization allows current collection to occur in a different spatial plane, enabling thinner metal layers to suffice for current transport across larger wafer areas
2Productivity
If cells are diced into smaller diodes, then efficiency is improved, but handling and interconnection complications increase
Solution Approach 1:
The patent combines multiple sub-cells into a single integrated structure with a common metallization backplane that provides both electrical connection and mechanical support. This merging eliminates the need for separate handling and interconnection of individual small diodes, as the entire array can be processed and handled as one unit while maintaining the efficiency benefits of smaller effective diode areas
Solution Approach 2:
The metallization backplane serves multiple functions simultaneously: it collects current from multiple sub-cells, provides mechanical support for the diced structure, and acts as a singulation guide during the dicing process. This multi-functionality resolves the handling complications that would otherwise arise from creating multiple small separate diodes
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 enables scalable solar cell production on larger wafers with reduced metal usage, improved reliability, and lower costs by maintaining consistent voltage and current across sub-cells, while minimizing power loss and handling complexities.
Implementation Method 1
The groove between adjacent ones of the singulated and physically separated semiconductor substrate portions exposes a portion of the metallization structure, allowing the metallization structure to act as an inter-cell connection
Implementation Method 2
Solar radiation impinging on the surface of, and entering into, the substrate creates electron and hole pairs in the bulk of the substrate. The electron and hole pairs migrate to p-doped and n-doped regions in the substrate, thereby generating a voltage differential between the doped regions
Data Source
AI summary
Solar cells having a plurality of sub-cells coupled by metallization structures, and singulation approaches to forming solar cells having a plurality of sub-cells coupled by metallization structures, are described. In an example, a solar cell, includes a plurality of sub-cells, each of the sub-cells having a singulated and physically separated semiconductor substrate portion. Adjacent ones of the singulated and physically separated semiconductor substrate portions have a groove there between. The solar cell also includes a monolithic metallization structure. A portion of the monolithic metallization structure couples ones of the plurality of sub-cells. The groove between adjacent ones of the singulated and physically separated semiconductor substrate portions exposes a portion of the monolithic metallization structure.