Solar Cell Contact Layout With Local Doping for Lower Resistance
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Solution Overview
Problem
Solar cells face performance limitations due to optical and electrical losses, including reflection, non-absorption of long-wave radiation, and recombination of photogenerated carriers, which affect their photoelectric conversion efficiency.
Innovation Solution
A solar cell design featuring a doped conductive layer with heavily doped regions and a tunneling dielectric layer, where the doping concentration in the heavily doped regions is higher than in other areas, and electrodes contact at least two of these regions, reducing sheet resistance and contact resistance, and enhancing current transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tunneling oxide structure with uniform doped conductive layer is used, then surface passivation is improved, but contact resistance and sheet resistance remain high
Solution Approach 1:
The patent applies local quality by creating heavily doped regions within the doped conductive layer at specific contact locations. These localized high-doping areas reduce contact resistance where metal contacts are applied, while the rest of the layer maintains its passivation function with lower doping concentration. This spatial variation in doping concentration optimizes both passivation and electrical contact performance.
Solution Approach 2:
The patent changes the doping concentration parameter within the doped conductive layer by introducing heavily doped regions with doping concentrations significantly higher than the base layer. This parameter modification enables the formation of low-resistance contact paths while preserving the overall passivation structure, thereby reducing contact resistance without compromising surface passivation quality.
2Productivity
If more metal contacts are added to improve current collection, then current transmission is improved, but light reception area is reduced
Solution Approach 1:
The patent concentrates doping in specific localized regions directly beneath metal contacts, creating highly conductive pathways only where needed for current collection. This localized enhancement allows for effective current transmission through the metal contacts while maintaining large areas of the semiconductor surface free of metal coverage, thus preserving light reception area.
Solution Approach 2:
The patent segments the doped conductive layer into distinct regions: heavily doped contact regions under metal electrodes and lightly doped or intrinsic regions in between. This segmentation allows current collection to be achieved through discrete contact points rather than continuous metal coverage, reducing the shadow effect and maximizing active light-receiving area.
3Productivity
If doped conductive layer thickness is increased to reduce sheet resistance, then current conductivity is improved, but material cost and complexity increase
Solution Approach 1:
Instead of uniformly increasing the thickness or doping concentration of the entire doped conductive layer, the patent introduces heavily doped regions at specific locations where metal contacts are applied. This localized approach reduces contact resistance and improves current transmission efficiency without requiring overall layer thickening, thereby maintaining structural simplicity and reducing material usage.
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 design improves photoelectric conversion efficiency by reducing optical absorption, increasing open-circuit voltage, and enhancing current conductivity, while also allowing for a more efficient use of materials and increased light reception area, thus lowering production costs.
Implementation Method 1
The tunneling oxide structure includes an ultra-thin tunneling dielectric layer and a doped conductive layer. The structure can provide good surface passivation, thereby reducing composite current caused by metal contact
Implementation Method 2
The doped conductive layer has a plurality of first heavily doped regions spaced apart from each other and extending in a first direction. A doping concentration in the plurality of first heavily doped regions is greater than a doping concentration in other regions of the doped conductive layer
Implementation Method 3
The performance of a solar cell (for example, photoelectric conversion efficiency) is subject to optical and electrical losses
Data Source
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AI summary
A solar cell and a photovoltaic module are disclosed, including: a substrate; a tunneling dielectric layer and a doped conductive layer disposed on a surface of the substrate, the tunneling dielectric layer being disposed between the doped conductive layer and the substrate, the doped conductive layer having a N-type or P-type doping element and having a plurality of first heavily doped regions spaced apart from each other and extending in a first direction, a doping concentration in the first heavily doped regions being greater than that in other regions of the doped conductive layer; a passivation layer disposed on a surface of the doped conductive layer facing away from the substrate; and a plurality of electrodes spaced apart from each other, extending in a second direction and passing through the passivation layer to contact the doped conductive layer, at least two first heavily doped regions contacting a same electrode.