IBC Solar Cell Back-Surface 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 recombination.
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
Solution Approach 1:
The back surface is divided into first regions, second regions, and gap regions, with doped regions formed in a staggered arrangement. This segmentation allows precise spatial separation of boron-doped and phosphorus-doped regions without requiring complex photolithography masks, as the pattern is defined by the physical layout of regions on the back surface.
Solution Approach 2:
The patent transitions from planar doping patterns to a three-dimensional configuration where doped regions are separated by gap regions that recess into the substrate. This vertical dimensionality change enables better separation and control of doped regions without increasing lateral process complexity.
2Manufacturing precision
If ion implantation technology is used to form separated doped regions, then manufacturing precision is improved, but reliability deteriorates due to doping instability
Solution Approach 1:
The substrate is pre-configured with first regions, second regions, and gap regions before doping. This preliminary structural preparation ensures that subsequent doping processes occur in predetermined locations with stable and reproducible results, eliminating the instability associated with ion implantation alignment.
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 patent extracts and eliminates the excessive printing and cleaning steps from the doping process. By using in-situ doping methods that directly form doped regions in the predetermined first and second regions, the process achieves both simplicity and precision without the need for multiple printing and cleaning cycles.
4Manufacturing precision
If gap regions are recessed toward the interior of the substrate, then separation of doped regions is improved, but device complexity increases
Solution Approach 1:
The gap regions are selectively recessed only in specific locations between the first and second regions, rather than uniformly across the entire back surface. This localized structural modification achieves the necessary separation precision while minimizing the increase in overall device complexity.
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 improves 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
the IBS solar cell has a higher short-circuit current and thus a higher photoelectric conversion efficiency
Data Source
Figure 1-1~1-2
Figure 1-3~2
Figure 3~5
AI summary
A solar cell including: a substrate having front and back surfaces, the back surface includes first, second and gap regions, the first and second regions are staggered and spaced from each other in a first direction, and each gap region is provided between one first region and one second region adjacent thereto by recessing toward interior of the substrate; 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 first and/or second conductive layer adjacent thereto, and a line-pattern concave and convex texture structure is formed on the back surface corresponding to the boundary region.