Back-Contact Solar Cell Recessed Isolation for Better Passivation
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Solution Overview
Problem
Conventional interdigitated back contact solar cells face issues with insufficient isolation between differently doped regions, leading to increased short-circuit possibilities and reduced power conversion efficiency due to poor passivation effects on the non-illuminated side.
Innovation Solution
The implementation of recessed structures on the sides of doped regions near isolation regions in back contact solar cells, along with a passivation layer, enhances isolation and passivation performance by increasing contact area and reducing recombination rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the isolation region is made narrower to accommodate smaller cell sizes, then the cell size is reduced, but the insulation protection is insufficient and short circuit possibility increases
Solution Approach 1:
The patent introduces recessed structures that extend into the isolation region from both the P-type and N-type doped regions. This creates a three-dimensional isolation structure where the recessed portions form a protective cavity that enhances insulation without increasing the planar footprint, thus maintaining small cell size while improving reliability.
Solution Approach 2:
The recessed structures are nested within the isolation region, creating a hierarchical structure where the isolation region contains recessed structures from both adjacent doped regions. This nested configuration maximizes the isolation effectiveness within the limited space, preventing carrier diffusion and short circuits while maintaining compact cell dimensions.
2Loss of energy
If a surface passivation layer is formed on the non-illuminated side to reduce carrier recombination, then power conversion efficiency is improved, but the passivation effect is poor due to direct contact with metal electrodes
Solution Approach 1:
The patent segments the passivation structure by introducing recessed structures that create distinct zones: the recessed portions are filled with passivation material while the metal electrodes are positioned in the protruding portions. This segmentation allows the passivation layer to effectively cover the recessed areas where carriers accumulate, reducing recombination without direct electrode contact.
Solution Approach 2:
The recessed structures act as intermediaries between the metal electrodes and the passivation layer. The passivation material fills the recessed structures, creating an intermediary zone that prevents direct contact between the passivation layer and metal electrodes, thereby maintaining effective passivation while avoiding the harmful direct contact that would compromise passivation quality.
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
Improved isolation and passivation lead to enhanced power conversion efficiency and reduced short-circuit risks, optimizing carrier collection and transmission.
Implementation Method 1
a surface passivation layer is usually formed on one side of the non-illuminated side of the interdigitated back contact cell to reduce the recombination rate of the carriers
Implementation Method 2
The present disclosure relates to the technical field of solar cell, and particularly relates to a back contact solar cell
Data Source
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AI summary
The present disclosure provides a back contact solar cell, including P-type doped regions, N-type doped regions, and isolation regions, wherein the P-type doped region and the N-type doped region are alternately disposed on a non-illuminated side of an N-type silicon substrate, and the isolation region located between the P-type doped region and the N-type doped region, wherein the side of the P-type doped region close to the isolation region is provided with n1 recessed structures, the side of the N-type doped region close to the isolation region is provided with n2 recessed structures, and n1>n2.