1. Silicon CPVSilicon CPV
Silicon CPVSilicon CPV
Silicon CPV PlcSilicon CPV Plc
Renewable Energy Technology CompanyRenewable Energy Technology Company
2. Silicon CPV
A Brief Introduction to Silicon CPVA Brief Introduction to Silicon CPV
Silicon CPV is a British Company
with a Long History of
Research & Development
and Manufacturing facilities in UK
3. Silicon CPV
• Setting up of Akhter Group
• Field: Electronics, Semiconductor, IT
SILICON CPVSILICON CPV HistoryHistory
• Akhter Group starts R&D in Photovoltaics
• Silicon CPV Launches a Range of Light Weight Solar Street Lights
based on Very High Efficiency Solar Cells and High Efficiency LEDs
• Akhter Group spins off specialist R&D Company - Silicon CPV
• Silicon CPV Awarded Research Grant to Develop its Patented Very
High Efficiency Solar Cell by Technology Strategy Board UK
5. Silicon CPV
Silicon CPV’s R&D Facility in Harlow UKSilicon CPV’s R&D Facility in Harlow UK
Electro less Plating of Copper, Nickle and Silver on
P-Type and N-Type Silicon
Laser Grooving Facility for Silicon Wafers
4 Tube Diffusion Furness
Wet Chemistry Lab
Ion Implant Facilities
Scanning Electron Microscope
Solar Cell Characterisation Lab
6. Silicon CPV
Worldwide Patents & ResearchWorldwide Patents & Research
Silicon CPV has a Number of Worldwide
Patents in the Field of Photovoltaics
Silicon CPV has been Awarded Research
Grants by UK & Spanish Governments
Silicon CPV has done Collaborative R&D
work with many Universities
7. Silicon CPV
Current ProjectsCurrent Projects
High Efficiency Low Cost All Back Contact Silicon Solar Cell
– Target 24% Efficiency – “HELICS”
Novel Design Solar Street Lights
High Efficiency and Scalable Solar MPPT Charge Controller
Energy Management Controller for Integration of Scalable
Hybrid Power Plants – Grid, Solar, Wind, Diesel, Storage
Zig Bee Network based High Efficiency LED Lighting for
Optics for Solar Street Lights
Water Desalination and Filtration using Solar Energy
8. Silicon CPV
HELICS Solar CellHELICS Solar Cell
“HELICS” is Silicon CPV’s Patented “All Back Contact”
Solar Cell Device with Target Efficiency of 24%
Device is Produced Using Low Cost “Solar Grade”
Commercially available P-Type Silicon
Processing Steps are compatible with current
Volume Manufacturing Techniques
11. Silicon CPV
Silicon Cells can’t transform the whole
spectrum of sunlight into energy.
Economic limit is at 28% efficiency
Multi Junction Cells with several III/V
semiconductor layers can transform a
much higher percentage.
Concentrator TechnologyConcentrator Technology
12. Silicon CPV
• Multi Junction Cells
Uses Gallium Arsenide
(GaAs III-V) Cells
GaAs III-V Used in Space
High Cost Material
High Light > Energy
Efficiency in 2014
Can operate with Light at
Single Junction Monolithic
20. Silicon CPV
Silicon CPV - Solar Light TechnologySilicon CPV - Solar Light Technology
• Very High Efficiency “HELICS” Solar Cells
• Special Chemistry Long Life Lithium Batteries – 5 Years
• Maximum Power Point Tracking Controller - MPPT
• Proprietary LED drive Electronics that Achieves 180
Lumens per Watt
• High Power, High Efficiency LEDs
• Wireless Remote Monitoring and Control
• Computer controlled Energy Management System
• Specially Designed Optics to Direct Light on to Road
21. Silicon CPV
A Basic Solar Street Light StructureA Basic Solar Street Light Structure
22. Silicon CPV
Specifications of a Typical Solar LightSpecifications of a Typical Solar Light
• 120W LED Source
• 340W Photovoltaic Panel (2.5m² Area)
• 2x200Ah Batteries – Weight 130Kg
• Battery Life 2 Years
• Light out put 8,000 Lumens
• Actual Light on the Road area 6,000 Lumens
• Total Weight 220Kg
• Installation Requires Heavy Lifting Equipment
Most of the systems on, or entering, the market use crystalline silicon cells.With silicon supplies short, and prices high in the current climate, the ability to offer high output from a small quantity of silicon is extremely attractive.
Concentrating PV also offers the option of shifting away from crystalline silicon to use the very high-efficiency, nonsilicon cells. Such cells have mostly been developed primarily for space applications.These multi-junction III-V cells (which use elements from columns 3 and 5 of the periodic table, typically gallium and arsenide) are prohibitively expensive for extensive use in large flat panel arrays.
Concentrator systems however, because they require smaller and fewer cells, can afford the higher cost of multi-junction cells and yet still be manufactured at lower dollar-per-watt cost than flat plate modules.
Concentrix Solar uses multi-junction III-V cells.
Target market is large-scale photovoltaic power plants consisting of multiple PV arrays.
Developing Multi Junction Technology
Although the gallium indium phosphide (GaInP)/GaAs tandem cell has achieved an efficiency of 30% and is now commercially available for space applications, the cells have not yet been integrated into a concentrator system.
Source: U.S. Department of Energy Photovoltaics Program.
Triple Junction technology
GaAs (Gallium (III) Arsenide) is a compound of gallium and arsenic which is an important semiconductor in solar cells. GaAs heterostructure solar cells have been around since the 1980s, and their efficiency has been improving ever since. Triple-junction solar cells based on GaAs with germanium and indium gallium phosphide were developed as the basis of a triple junction solar cell which held a record efficiency of over 32% and can operate also with light as concentrated as 2,000 suns. Triple Junction solar cells began with AM0 efficiencies of approximately 24% in 2000, 26% in 2002, 28% in 2005, and in 2007 have evolved to over 30% AM0 production efficiency, currently in qualification. In 2007, two companies in the United States, Emcore Photovoltaic and Spectrolab, produce 95% of the world&apos;s 28% efficient solar cells.
A key high efficiency feature of the of the buried contact solar cell is that the metal is buried in a laser-formed groove inside the silicon solar cell. This allows for a large metal height-to-width aspect ratio.
A large metal contact aspect ratio in turn allows a large volume of metal to be used in the contact finger, without having a wide strip of metal on the top surface.
Therefore, a high metal aspect ratio allows a large number of closely spaced metal fingers, while still retaining a high transparency.
For example, on a large area device, a screen printed solar cell may have shading losses as high as 10 to 15%,
while in a buried contact structure, the shading losses will only be 2 to 3%.
These lower shading losses allow low reflection and therefore higher short-circuit currents.
In addition to good reflection properties, the buried contact technology also allows low parasitic resistance losses due to its high metal aspect ratio, its fine finger spacing and its plated metal for the contacts.
The emitter resistance is reduced in a buried contact solar cell since a narrower finger spacing dramatically reduces the emitter resistance losses. The metal grid resistance is also low since the finger resistance is reduced by the large volume of metal in the grooves and by the use of copper, which has a lower resistivity than the metal paste used in screen printing. As well, the contact resistance of a buried contact solar cell is lower than that in screen printed solar cells due to the formation of a nickel silicide at the semiconductor-metal interface and the large metal-silicon contact area. Overall, these reduced resistive losses allow large area solar cells with high FFs.
When compared to a screen-printed cell, the metalization scheme of a buried contact solar cell also improves the cell&apos;s emitter. To minimise resistive losses, the emitter region of a screen-printed solar cell is very heavily doped and results in a &quot;dead&quot; layer at the surface of the solar cell. Since emitter losses are low in a buried contact structure, the emitter doping can be optimized for high open-circuit voltages and short-circuit currents. Furthermore, a buried contact structure includes a self-aligned, selective emitter, which thereby reduces the contact recombination and also contributes to high open-circuit voltages.
The efficiency advantages of buried contact technology provide significant cost and performance benefits. In terms of $/W, the cost of a buried contact solar cell is the same as a screen-printed solar cell (Jordan, Nagle). However, due to the inclusion of certain area-related costs as well as fixed costs in a PV system, a higher efficiency solar cell technology results in lower cost electricity. An additional advantage of buried contact technology is that it can be used for concentrator systems (Wohlgemuth, Narayanan).
The prismatic lens is made of an array of square refractive prisms.
Every square prism deflects, on the squared solar cell, the solar beam incident on its flat surface.
In this way a good spot uniformity on the photovoltaic cell has been obtained