Bipolar Front-Contact Solar Cell With Rear Junction and Split Contacts
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Solution Overview
Problem
Existing solar cell manufacturing processes face challenges in achieving high efficiency and low cost for front contact solar cells, particularly in maintaining aesthetic appeal while ensuring effective power generation.
Innovation Solution
A bipolar solar cell design featuring a backside junction with P-type and N-type doped polysilicon layers, where metal contacts are strategically placed on both sides to enhance electrical connectivity and radiation collection efficiency, utilizing a combination of chemical vapor deposition, thermal anneal, and antireflective coatings to improve performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal contacts are placed on the front side of the solar cell, then electrical connectivity is improved, but aesthetic appeal deteriorates
Solution Approach 1:
The solar cell is divided into front side and back side contact regions. The bipolar design segments the electrical contacts so that one contact is on the front side and the other is on the back side, allowing electrical connectivity to be maintained while improving aesthetic appeal by hiding one contact from the front view.
Solution Approach 2:
The contact configuration transitions from a single-plane (front side only or back side only) arrangement to a three-dimensional bipolar arrangement where contacts are distributed on both front and back surfaces of the solar cell, utilizing the third dimension (depth/thickness) to resolve the aesthetic conflict.
2Productivity
If conventional manufacturing processes are used, then manufacturing simplicity is maintained, but efficiency and cost-effectiveness deteriorate
Solution Approach 1:
The patent employs preliminary doping of polysilicon layers before they are deposited onto the solar cell substrate. This preliminary preparation of doped polysilicon layers streamlines the manufacturing process by pre-configuring the electrical properties needed for the bipolar contact structure, improving efficiency without significantly increasing overall process complexity.
Solution Approach 2:
The solar cell utilizes composite material structures including doped polysilicon layers combined with semiconductor substrates, and multiple metal contact layers with different properties. These composite structures enable enhanced electrical performance and radiation collection efficiency while maintaining manufacturability through established semiconductor processing techniques.
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
The solution results in a low-cost, high-efficiency front contact solar cell with improved solar radiation collection and reduced recombination, enabling competitive power generation with enhanced aesthetic appeal for residential applications.
Implementation Method 1
Solar radiation impinging on the solar cell creates electrons and holes that migrate to the diffusion regions, thereby creating voltage differentials between the diffusion regions
Implementation Method 2
utilizing a combination of chemical vapor deposition, thermal anneal, and antireflective coatings to improve performance
Implementation Method 3
utilizing a combination of chemical vapor deposition, thermal anneal, and antireflective coatings to improve performance
Implementation Method 4
utilizing a combination of chemical vapor deposition, thermal anneal, and antireflective coatings to improve performance
Data Source
AI summary
A bipolar solar cell includes a backside junction formed by a silicon substrate and a first doped layer of a first dopant type on the backside of the solar cell. A second doped layer of a second dopant type makes an electrical connection to the substrate from the front side of the solar cell. A first metal contact of a first electrical polarity electrically connects to the first doped layer on the backside of the solar cell, and a second metal contact of a second electrical polarity electrically connects to the second doped layer on the front side of the solar cell. An external electrical circuit may be electrically connected to the first and second metal contacts to be powered by the solar cell.