R&D ACTIVITIES AT -BHEL,GURGAON IN SOLAR PV at the DST-EPSRC Workshop on Solar Energy Research (22 nd 23 rd April, 2009) by Dr.R.K. Bhogra, Addl. General Manager & Head Email: cpdrkb@bhel.co.in Dr.A.K. Saxena, Dy. General Manager Email: aksaxena@bhel.co.in Amorphous Silicon Solar Cell Plant (), BHEL, Gurgaon
PRESENTATION PROFILE 1. FACILITIES AT -BHEL 2. R&D ACHIEVEMENTS OF 3. ONGOING R&D ACTIVITIES 4. NEW R&D PROJECTS PLANNED
FACILITIES AT -BHEL PROCESS FACILITIES FOR DEVELOPMENT OF CRYSTALLINE SILICON SOLAR CELLS PROCESS FACILITIES FOR DEVELOPMENT OF a-si and OTHER THIN FILM SOLAR CELL MODULES TESTING & CHARACTERISATION FACILITIES PRODUCTS AND SYSTEMS DEVPT. AND TESTING LAB.
Facilities established for crystalline Si solar cell Process development 1. Cleaning /Saw damage removal/ Texturisation 2. Diffusion 3. Edge isolation 4. Anti Reflection Coating 5. Printing of contacts 6. Firing of contacts 7. Moduling and framing
Wet Chemical Texturisation Station
High temperature diffusion furnace
Anti reflection coating facility
Automatic push rod for firing of contacts
PROCESS FACILITIES FOR AMORPHOUS SILICON AND OTHER THIN FILM SOLAR CELLS TCO Deposition using APCVD Laser scriber for TCO layer a-si Deposition using PECVD Metallisation using DC sputtering ITO Deposition using DC sputtering Screen printer
TRANSPARENT CONDUCTING OXIDE (TCO) PROCESS FACILITY
PECVD SYSTEM FOR a-si/ito deposition
Testing and Characterization Facilities 1. Ellipsometer 2. UV-Vis. Spectrophotometer 3. Metallurgical Microscope 4. Minority carrier life time tester 5. Diffused reflectance measurement set up 6. Solar cell tester 7. CV / GV analyzer 8. OES
ELLIPSOMETER Important Features Tabletop model, using non-destructive and non-contact method Configuration: Source-Polarizer- Compensator- Analyzer-Detector, sample holder, manual goniometer Arrangement for sample alignment: Auto collimating telescope for sample tilt and height adjustment. Wavelength of laser beam: 632.8 nm Parameters to be measured: Refractive Index (n), Extinction coefficient (k) and Thickness (t) Accuracy of measurement: Refractive index: ±0.001 Thickness: ± 1A Sample size: Maximum 6 x 6 silicon wafer
UV-VIS Spectro photometer Function To measure absorbance, transmittance and specular and diffused reflectance of bulk and thin film solar cell materials Featuress: Band width: Variable: 0.1 to 4 nm Wavelength range: 200-1100 nm Wavelength accuracy: ±0.1nm Wavelength reproducibility: ±0.1nm Photometric reproducibility: ±0.002Abs
Metallurgical microscope Features Upright, Bright/Dark Field, polarizing attachment, Plan achromatic objectives, Wide field eyepieces, Reflected light illuminator. Total magnification: 100x to 2000x in Bright field and 100x to 800x in Dark field Sample stage: 150 mm x 150 mm with provision for X, Y and Z movement Fine Focus adjustment: With least count of 1 µm Camera: High resolution,video capture
Minority carrier Lifetime Measurement setup Features: Function: Measures the lifetime of the charge carriers in the base material/wafer of the solar cells Features: Monitors the quality of processed wafers/ solar cells at different fabrication stages starting with initial inspection Suitable for single or multicrystalline silicon wafers/ solar cell Provides a contactless, implied-iv curve at any stage of a solar cell fabrication process Wafer size, standard Configuration: 38-200 mm diameter Wafer thickness range: 10-2000 µm Lifetimes from 100 ns to 10ms Effective Lifetime (s) 1.0E-04 5.0E-05 0.0E+00 1.0E+1 2 1.0E+1 3 1.0E+1 4 1.0E+1 5 Carrier Density (cm-3) 1.0E+1 6
Diffused reflectance measurement setup Measures diffused reflectance of full size (5 6 sq.) silicon wafers Non-destructively p
Solar cell measurement setup Function: p Provides Information on Performance & Reliability of mc-si & c-si solar cells Features: Measures dark and light I-V characteristics of large area solar cells developed indigenously (at very low cost) Accommodates solar cell up to 150 mm X 150 mm Pneumatically operated probe holders for uniform contact on solar cell 4 - probe (2 for current and 2 for voltage) measurements for higher accuracy Constant chuck temperature within ± 1 C with illumination on Maximum Range of Cell measured: Current 10A and Voltage: 1 Volt
CV/ GV Analyzer at Low Temperatures (10 K) For characterisation of the interface between a-si & crystalline Cryostat (10 K to 300 K) Optical Windows Optical Windows Signal Source & Lock In Amplifier IEEE 488 Protocol IEEE 488 Protocol Data Acquisition System
Optical Emission Spectrometer (OES) For plasma diagnostics Optical Windows
Significant Achievements including R&D capabilities developed at BHEL-, Gurgaon Development of single junction (1 x1 ) and double junction (1 x3 ) a-si solar PV modules Establishment of process facilities for amorphous silicon (a-si) and crystalline silicon (c-si) solar cell development including TCO and Clean Room facility Up gradation of Testing & Characterization (T&C) facilities for development of solar cells Establishment of Solar Product Development and Testing Laboratory (including PCB facility and laminator up gradation for BIPV) Development of Solar PV-Grid-DG Hybrid system for Rural Electrification and BIPV
Developed large area (1 x3 ) a-si double junction modules ve CONTACT BHEL SERIAL # H24B22 01-03-2004 19:44:55 ve CONTACT n a-si METAL (Al) Sun = 100mW/cm 2 Temp = 26 DEG C Voc = 24.52 V Isc = 1.38 A P max = 19.71 W Vmp = 18.48 V Imp = 1.07 A FF = 0.58 Rs = 2.78 OHMS Rsh = 216 OHMS Eff = 7.8 % (cell) Eff = 7 % (module) + ve CONTACT i a-si p a-si n a-si i a-si p a-si TCO GLASS + ve CONTACT VOLTS LIGHT RAYS
a-si double junction modules processed at BHEL- Street Light Powered by Double Junction a-si Modules 15 sets performing satisfactorily from dusk to dawn for the last 6 years
Significant Achievements including R&D capabilities developed at, Gurgaon contd. View of BIPV room at BHEL-, Gurgaon
ONGOING R&D ACTIVITIES AT -BHEL DEVPT. OF HIGH EFF. PASSIVATED INTERFACE HETEROJUNCTION SOLAR CELLS PLASMA BASED REACTIVE ION ETCHING (RIE) PROCESS FOR TEXTURISATION OF mc-si WAFERS DEVPT. OF ACID TEXTRURISATION PROCESS FOR mc-si WAFERS DEVPT.OF a-si/µc-si DOUBLE JUNCTION SOALR CELL MODULES CONCENTRATOR PV SYSTEMS BUILDING INTEGRATED PHOTOVOLTAICS (BIPV) DEVPT. OF PRODUCTS AND SYSTEMS (HYBRID CONTROLLER, LOAD PRIORITY SYSTEMS, MODULE CLEANING SYSTEMS, SOLAR MOBILE PHONE CHARGER, LAPTOP CHRGER etc.)
Reactive Ion Etching (RIE) process for texturization of multicrystalline silicon wafers View of Reactive Ion Etching (RIE) process facility commissioned at
PROPOSED NEW PROJECTS (THROUGH NETWORKING WITH ACADEMIA / R&D INSTITUTIONS IN INDIA & ABROAD) DEVELOPMENT OF a-si/ µc-si TANDEM JUNCTION SOLAR CELL MODULES (HIGH RATE AND UNIFORMITY IN DEPOSITION) LASER FIRED CONTACT SILICON SOLAR CELLS (Eff.~18%) (PROCESS OPTIMISATION) DEVELOPMENT OF CIGS THIN FILM SOLAR CELL MODULES (PROCESS TECHNOLGY DEVELOPMENT) DEVLOPMENT OF Dye-Sensitised Solar Cells (DSSC) (USING NANO PARTICLES) DEVELOPMENT OF REAR CONTACT SOLAR CELLS (PROCESS TECHNOLGY DEVELOPMENT)