Solar Cell Edge Interconnects for Active Area Optimization
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Solution Overview
Problem
The existing methods for interconnecting solar cells leave a significant gap between adjacent cells, which reduces the active area of photovoltaic modules and consequently decreases the power output and efficiency of solar cell modules.
Innovation Solution
The solution involves applying a dielectric layer over the edges of solar cells, followed by a busbar and an electrically conductive adhesive, with an interconnection element such as a solder paste or solder-coated ribbon to minimize the gap between solar cells, thereby increasing the active area and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder-coated copper ribbon is used to interconnect busbars, then electrical connection is achieved, but a gap of 1-2 mm is left between adjacent solar cells reducing active area
Solution Approach 1:
The patent transitions from planar interconnection to three-dimensional edge interconnection by depositing conductive adhesive on the vertical edges of solar cells. This dimensional change allows the interconnect to extend into the gap space, reducing the horizontal gap between adjacent cells while maintaining electrical connection reliability.
Solution Approach 2:
The patent uses a composite structure combining dielectric material (for insulation) and conductive adhesive (for electrical connection) applied to the cell edges. This composite approach enables simultaneous achievement of electrical connectivity and gap reduction without compromising insulation properties.
2Reliability
If solder-coated copper ribbon is used for interconnection, then busbars are electrically connected, but excessive temperatures are exposed to the solar cell surface
Solution Approach 1:
The patent introduces a dielectric layer as an intermediary between the solar cell surface and the interconnection structure. This dielectric barrier protects the solar cell from excessive temperatures generated during soldering while still allowing the conductive adhesive to establish electrical connection on the edge.
Solution Approach 2:
The patent separates the interconnection function into distinct components: dielectric material for thermal protection and insulation, and conductive adhesive for electrical connection. This segmentation allows the soldering process to occur away from the solar cell surface, reducing thermal exposure.
3Productivity
If gap between adjacent solar cells is reduced, then active area and efficiency are increased, but manufacturing complexity increases
Solution Approach 1:
The conductive adhesive serves multiple functions simultaneously: it provides electrical connection, acts as a structural bond between cells, and fills the gap space. This multi-functionality reduces the need for separate interconnection components, simplifying the overall manufacturing process despite the reduced gap.
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 the series resistance and enhances the fill factor and efficiency of solar cell modules by minimizing the gap between adjacent solar cells, resulting in approximately 2% absolute module efficiency improvement compared to traditional methods.
Implementation Method 1
an electrically conductive adhesive overlying at least a portion of the busbar and overlying at least a portion of the dielectric layer
Data Source
AI summary
Edge interconnects for interconnecting solar cells are disclosed. The edge interconnects include a layer of an electrically conductive adhesive overlying an insulating dielectric layer applied to edge of a solar cell and electrically interconnected to a busbar. Solar cell modules include adjacent solar cells comprising edge interconnects interconnected using an interconnection element. An interconnection element can be a solder paste or a solder containing electrically conductive ribbon. Methods of forming solar cell edge interconnects include applying an insulating dielectric coating to edges of a solar cell, depositing a busbar in proximity to the insulated edges of the solar cell, depositing an electrically conductive adhesive over at least portion of the busbar an over at least a portion of the dielectric layer. Solar cell modules can be formed by interconnecting adjacent solar cells using an interconnection element.