IBC Solar Cell Backside Layout for Doped Region Separation
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Solution Overview
Problem
Existing Interdigitated Back Contact (IBC) solar cells face challenges in efficiently separating boron-doped and phosphorus-doped regions, leading to reduced photoelectric conversion efficiency due to bipolar contact recombinations and complex manufacturing processes.
Innovation Solution
The design includes a substrate with staggered first and second regions separated by gap regions, with conductive layers of opposite conductivity types, and a line-pattern concave and convex texture structure on the back surface to prevent short circuits and enhance light trapping, along with passivation layers to reduce carrier recombinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography is used to form separated doped regions, then manufacturing precision is improved, but device complexity and manufacturing cost increase due to multiple mask lithography steps
Solution Approach 1:
The back surface is divided into first regions, second regions, and gap regions, with doped regions formed in alternating pattern. This segmentation allows clear separation of boron-doped and phosphorus-doped regions while simplifying the manufacturing process through direct patterning without multiple mask steps.
Solution Approach 2:
Different regions of the back surface are doped with different dopant types (boron or phosphorus) to create localized electrical properties. The first and second regions have opposite conductivity types, enabling selective charge carrier collection while maintaining simple manufacturing through direct doping in specific zones.
2Manufacturing precision
If ion implantation technology is used to form separated doped regions, then manufacturing precision is improved, but reliability deteriorates due to unstable doping
Solution Approach 1:
The doping process utilizes the substrate's own properties and simple direct doping methods rather than complex ion implantation. The alternating first and second regions are doped directly with boron or phosphorus, allowing the structure to self-establish stable doping profiles without requiring unstable ion implantation processes.
3Ease of manufacture
If doping paste printing is used to form doped regions, then ease of manufacture is improved, but manufacturing precision deteriorates due to excessive printing and cleaning steps
Solution Approach 1:
The back surface is segmented into alternating first and second regions that are directly doped with opposite polarity dopants. This segmentation enables precise separation of doped regions through simple printing or diffusion processes without requiring multiple printing and cleaning steps, achieving both ease of manufacture and high precision.
4Reliability
If gap regions are recessed toward substrate interior, then reliability is improved by preventing bipolar contact recombinations, but device complexity increases
Solution Approach 1:
Gap regions are extracted or recessed toward the substrate interior between the first and second doped regions. This extraction creates physical separation that prevents bipolar contact recombinations at the interface, improving reliability while the simple alternating pattern maintains manufacturing simplicity.
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 effectively separates the doped regions, reduces interface recombinations, increases light reflection and absorption, and enhances the photoelectric conversion efficiency of IBC solar cells by 0.07% to 0.15%.
Implementation Method 1
a line-pattern concave and convex texture structure is formed on the back surface corresponding to the boundary region
Implementation Method 2
enhances light reflection and absorption
Implementation Method 3
each gap region is provided between one first region and one second region adjacent to the first region by recessing toward an interior of the substrate
Data Source
AI summary
A solar cell including: a substrate having front and back surfaces, the back surface including first and second regions staggered and spaced from each other, and a gap region provided between one first region and one adjacent second region, a plurality of first pyramidal texture structure regions formed corresponding to a plurality of gap regions and a distance between a top and bottom thereof is 2-4 μm; a first conductive layer formed over the first region; a second conductive layer formed over the second region, the second conductive layer has a conductivity type opposite to the first conductive layer; a first electrode forming electrical contact with the first conductive layer; a second electrode forming electrical contact with the second conductive layer; and a boundary region between the gap region and the conductive layer(s) adjacent thereto, the boundary region including strip or line-patterned texture structures arranged at intervals.