Back-Contact Solar Cell Rear Layout Without Front Shadowing
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Solution Overview
Problem
Conventional crystalline silicon solar cells face efficiency limitations due to shadowing effects from front electrodes, and the fabrication process of back contact solar cells is complex and costly, requiring photolithography.
Innovation Solution
A fabrication method for back contact solar cells that uses a laser method to form patterns for p-type and n-type semiconductor regions on the rear surface, omitting the need for photolithography and simplifying the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If front electrodes are formed on the light-receiving face to extract current, then electrical conductivity is improved, but shadowing increases reducing light absorption efficiency
Solution Approach 1:
The patent inverts the conventional electrode placement by moving all electrodes to the rear surface of the solar cell instead of the front light-receiving face. This inversion eliminates shadowing on the front surface while maintaining electrical conductivity through properly designed rear contact structures including metal fingers and grid patterns.
2Manufacturing precision
If photolithography process is used to form patterns for p-type and n-type regions, then manufacturing precision is improved, but device complexity and fabrication cost increase
Solution Approach 1:
The patent replaces the complex photolithography mechanical system with a simpler laser-based direct writing system. The laser method uses optical focusing and computer-controlled movement to directly write patterns without requiring photoresist coating, exposure, development, and mask alignment processes, thereby reducing fabrication complexity while maintaining precision.
Solution Approach 2:
The patent extracts and removes the photolithography process step entirely from the fabrication sequence. By using laser direct writing to form patterns, the multi-step photolithography process (photoresist application, exposure, development, masking) is eliminated, simplifying the overall manufacturing process while achieving the same pattern formation objective.
3Manufacturing precision
If conventional fabrication process is used with multiple steps, then manufacturing precision is maintained, but productivity and fabrication efficiency decrease
Solution Approach 1:
The patent merges multiple separate fabrication steps into integrated processes. The laser system combines pattern writing, sintering, and heating functions in a single tool and process sequence, eliminating the need for separate equipment and process steps, thereby improving productivity while maintaining precision through controlled parameter optimization.
Solution Approach 2:
The patent implements continuous fabrication processes where the laser beam continuously writes patterns and sinters materials without interruption. The computer-controlled laser system maintains continuous operation with optimized scanning speeds and power levels, eliminating idle times between steps and maximizing fabrication efficiency while preserving manufacturing precision through real-time parameter control.
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 method enhances solar cell efficiency by minimizing shadowing and reducing recombination of electron-hole pairs through rear surface passivation, while also simplifying the fabrication process and reducing costs.
Implementation Method 1
removing the oxide layer by irradiating laser light to the oxide layer formed on the rear surface of the substrate at predetermined intervals to form a pattern of the different conductive type semiconductor regions
Implementation Method 2
The solar cell, which is a device converting light energy into electrical energy using a photovoltaic effect
Data Source
AI summary
The present invention discloses a back contact solar cell. The back contact solar cell includes a semiconductor substrate having a front surface and a rear surface; a first conductive type semiconductor region having a first conductive type and a second conductive type semiconductor region having a second conductive type at an interval on the rear surface of the semiconductor substrate. Furthermore, the rear surface of the semiconductor substrate has a texturing structure at the interval between the first conductive type semiconductor region and the second conductive type semiconductor region.