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 inefficiencies due to complex manufacturing processes for separating boron-doped and phosphorus-doped regions, leading to bipolar contact recombinations and reduced photoelectric conversion efficiency.
Innovation Solution
A solar cell design with staggered first and second regions on the back surface, featuring pyramidal texture structures and boundary regions with line-patterned textures to enhance light reflection and separation of conductive layers, along with passivation layers to reduce 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
Solution Approach 1:
The patent extracts and removes the complex photolithography process by introducing a laser slotting technique that directly creates separation grooves in the semiconductor substrate. This extraction eliminates the need for multiple mask lithography steps while maintaining precise separation of boron-doped and phosphorus-doped regions, thereby reducing device complexity and manufacturing cost without sacrificing separation precision.
Solution Approach 2:
The patent replaces the mechanical/chemical photolithography system with a laser-based system. The laser slotting process uses optical energy to ablate material and create precise separation grooves, substituting the complex sequence of photolithography steps (mask alignment, exposure, development) with a more direct laser processing approach that reduces overall process complexity while achieving comparable or superior precision.
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 patent extracts the unstable ion implantation doping process and replaces it with a more reliable in-diffusion method. By removing the ion implantation step that causes doping instability, the patent achieves both precise separation through laser slotting and stable, uniform doping concentrations through thermal diffusion, thereby improving reliability without compromising manufacturing precision.
Solution Approach 2:
The patent changes the doping method from ion implantation to thermal in-diffusion, altering the physical and chemical parameters of the doping process. This parameter change results in more stable and controllable doping concentrations, improving reliability, while the laser slotting technique maintains precise spatial separation of the doped regions.
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 removes the excessive printing and cleaning steps associated with doping paste printing by implementing a laser slotting followed by in-diffusion process. This extraction eliminates the need for multiple printing passes and extensive cleaning operations, maintaining ease of manufacture while significantly improving the precision of doped region separation through direct laser patterning.
Solution Approach 2:
The patent replaces the mechanical doping paste printing system with a laser-based slotting and thermal diffusion system. This substitution eliminates the precision limitations inherent in paste printing (such as paste spread, alignment tolerance, and cleaning residue) while maintaining process simplicity, thereby achieving both ease of manufacture and high manufacturing precision.
4Power
If IBC solar cell structure is used, then photoelectric conversion efficiency is improved, but harmful factors increase due to bipolar contact recombinations
Solution Approach 1:
The patent applies segmentation by introducing physical separation grooves (laser slots) that divide and isolate the boron-doped and phosphorus-doped regions on the back surface of the solar cell. This segmentation prevents direct contact between oppositely doped regions, thereby eliminating bipolar contact recombinations and the associated harmful factors, while preserving the IBC structure's high photoelectric conversion efficiency.
Solution Approach 2:
The patent introduces an intermediary structure (the laser-created separation groove filled with dielectric material or void space) between the boron-doped and phosphorus-doped regions. This intermediary acts as a barrier that prevents charge carrier recombination between opposite polarity contacts, eliminating the harmful recombination losses while allowing both doped regions to maintain their functionality for high efficiency photoelectric conversion.
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
Improves photoelectric conversion efficiency by 0.07% to 0.15% through effective separation of conductive layers and enhanced light utilization, reducing interface recombinations and increasing light absorption.
Implementation Method 1
boundary region includes strip or line patterned texture structures arranged at intervals and configured to increase reflection of incident light on the back surface of the substrate
Implementation Method 2
first pyramidal texture structure regions are formed on the back surface corresponding to the gap regions
Implementation Method 3
An Interdigitated Back Contact (IBC) solar cell has a light receiving surface with no electrode arranged thereon, while positive and negative electrodes are arranged in an interdigitated manner on a backlight surface of the solar cell
Data Source
AI summary
A solar cell including: 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 adjacent first and second regions, first pyramidal texture structure regions are formed corresponding to gap regions and distance between top and bottom thereof is 2-4 μm; first conductive layer formed over the first region; second conductive layer formed over the second region, the second conductive layer has conductivity type opposite to the first conductive layer; first electrode forming electrical contact with the first conductive layer; second electrode forming electrical contact with the second conductive layer; and boundary region between the gap region and the first and/or second conductive layer adjacent thereto, and the boundary region includes strip or line patterned texture structures arranged at intervals.