Solar Cell Electrodes with Copper Gridlines and Single Busbar
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Solution Overview
Problem
Conventional solar cells suffer from reduced energy conversion efficiency due to shading caused by metal grids, which block sunlight and increase series resistance, leading to power loss and higher costs.
Innovation Solution
The use of bifacial tunneling junction solar cells with electroplated Cu gridlines and a single busbar or tab configuration to reduce shading and series resistance, along with high-aspect ratio gridlines and maximum power point tracking (MPPT) devices for improved efficiency and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal grid is used for current collection, then electrical conductivity is improved, but light absorption is reduced due to shading
Solution Approach 1:
The patent changes the material parameter from conventional metal (silver, aluminum) to copper, which has superior electrical conductivity. This allows for thinner grid lines that provide the same electrical performance, thereby reducing shading losses. The copper electrodes enable lower series resistance while maintaining adequate current collection, resolving the contradiction between electrical conductivity and light absorption.
2Use of energy by moving object
If the number of busbars is reduced to a single busbar, then shading is reduced and light absorption is improved, but series resistance increases
Solution Approach 1:
The patent utilizes copper's superior electrical conductivity parameter to compensate for the increased current path length resulting from a single busbar configuration. The lower resistivity of copper allows the single busbar to collect current effectively from all finger lines without excessive series resistance, while maximizing the active area for light absorption by eliminating one less busbar.
3Reliability
If conventional metal grids are used, then current collection is achieved, but fabrication cost increases
Solution Approach 1:
The patent replaces expensive conventional metals (silver, aluminum) with copper, which is significantly cheaper while providing equal or superior electrical performance. This material substitution directly reduces fabrication costs while maintaining adequate current collection capability through the copper electrodes and grid structure.
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 configuration results in up to an 18% gain in power output and reduces power loss from shading, while also lowering fabrication costs and recouping 30% of lost power through MPPT technology, enhancing overall solar module performance.
Implementation Method 1
electroplated Cu gridlines serving as front- and back-side electrodes
Implementation Method 2
A solar cell converts light into electricity using the photovoltaic effect
Data Source
AI summary
One embodiment of the present invention provides a solar module. The solar module includes a front-side cover, a back-side cover, and a plurality of solar cells situated between the front- and back-side covers. A respective solar cell includes a multi-layer semiconductor structure, a front-side electrode situated above the multi-layer semiconductor structure, and a back-side electrode situated below the multi-layer semiconductor structure. Each of the front-side and the back-side electrodes comprises a metal grid. A respective metal grid comprises a plurality of finger lines and a single busbar coupled to the finger lines. The single busbar is configured to collect current from the finger lines.