Solar Photovoltaics being implemented at IIT Bombay and christened National Centre for Photovoltaic Research and Education (NCPRE) Phase II,
- The Ministry’s flagship project in solar photovoltaics being implemented at IIT Bombay and christened National Centre for Photovoltaic Research and Education (NCPRE) Phase II, had several major areas. The progress made in each of these areas is briefly described below.
- Education and Training: Various courses, workshops and training sessions have been organized to extend the knowledge gathered at NCPRE to people from academia and industry. Four familiarization workshops and two Hands-on training sessions were organized to familiarize other academia and promote their interaction with NCPRE investigators through the PUMP initiative which also saw submission of 67 new project proposals on PV.
- Crystalline Si Solar Cells: LIP set up established for 6 in x 6 in solar cells. Ni plating to be used as a barrier for Cu diffusion into Si. With all processes carried out at NCPRE, the champion cell on mono-Si wafers had an efficiency of 19.4% (VOC = 634 mV, ISC = 37.11 mA/cm2, FF = 81.2%). For mc-Si wafers, efforts are directed at reducing surface reflections through metal assisted chemical etching and additive-less alkaline texturing. PERC cell development saw further optimisation of sprayed Ai2O3 and joint development with industry a laser ablation process for dielectric films. For IBC solar cells, co-diffusion of B and P into silicon was studied with screen-printed diffusion source. For carrier selective contacts, an improved MoO3/n-Si solar cell with efficiency of 13.6% (active area efficiency of 15.24%) was demonstrated.
- Thin Film Materials and Devices: Multi-cation perovskite solar cells in n-i-p and p-i-n configurations have been fabricated with efficiencies 14.3% and ~17% respectively. Screen printed carbon based perovskite solar cells in order to reduce the cost and easiness in scaling up have been fabricated by two step drop cast method with efficiencies ~13.36% on 0.09cm2 and 5.9% over 4cm2 device area. A mini module of 10cm2 with ~4V open circuit voltage has been fabricated by interconnecting 2cm2 solar cells in series.
- Energy Storage: 20 Li-ion cells of 2.5 Ah capacity with LCO-graphite chemistry, having cycle life of more than 100 cycles has been successfully demonstrated. Along with this, a new chemistry C-LTO/LFP have been under investigation for long cycle life (10K). Also, a Prototype-Battery fabrication facility for demonstration of 7 Ah, 10 Ah stacked pouch cells, 2.5 Ah jelly rolled pouch cell and cylindrical cells has been established. The team has been also able to demonstrate an ultrahigh specific Na-ion full cell with a doped ammonium vanadium oxide (NVO) cathode against hydrogenated sodium titanium oxide (NTO) The cell is capable of retaining 94% capacity after 400 cycles, having a high energy density of 467 Wh/kg at a very high rate of 0.2 A/g
- Power Electronics: The power supply part of the high power inverter test setup has been completed. Five prototype, standalone 500 VA inverters for rural off-grid application have been fabricated and testing is carried out upto 125W power level. A 1 kVA inverter which can be operated in the presence or absence of grid is implemented and the detailed report along with BOM submitted to MNRE. A 2 HP BLDC motor which is driven from solar PV, and is used for surface mounted pumping application has been designed in-house. A 5 kVA solar PV based inverter with integrated 2.5 kW battery storage has been fabricated that can be operated in grid connected as well as in standalone mode.
- Module Reliability: Field Assessment of Reliability of PV Modules of Various Technologies in Different Climatic Zones of India in 2016, 2018 and 2020 covering 500-1200 modules is under process and report upto 2018 has been completed. IIT Bombay trying to develop the new test standards for PV modules, BOS and components based on the findings during the survey.
- The MNRE sponsored project on perovskite based thin film solar cells being implemented at IIT Bombay and showed 18% efficiency and sustained 1000 bending cycles. In another phase in the area of Flexible Perovskite Solar Cells and Intermediate Module with an target of Laminated Roll to Roll devices with >18% efficiency with T80>10000 hrs.
- In the on-going project on development of high efficiency solar cells using n-type Si wafers at the Meghnad Saha Institute of Technology (MSIT), Kolkata, base line solar cells have been fabricated on small (76 mm x 76 mm), n-type mono-Si wafers with champion efficiency of 16.8 %. The project has been continued to achieve 20-22% efficiency on 6 inch x 6 inch wafer.
- NISE has competed a R&D project with Surya Enertec, a Gurugram-based private company in developing Solar-powered Clean Drinking Water Systems suitable for various locations in the country. Five machines have been designed and fabricated. The controller and remote monitoring system have been developed and fabricated in-house. Third water purification machine of 500 LPH capacity is installed in a village: Khurampur, Distt Gurgaon. Fourth water purification machine of 200 LPH capacity is installed at Safdarjung Hospital Delhi. Fifth machine of 200 LPH capacity is installed at Civil Hospital, Gurgaon.
- The MNRE has sponsored the PERC cell project is being implemented jointly by BHEL-ASSCP and NISE and the facilty for primary reference is coming up at NPL, Delhi. In the PERC cell project, BHEL has the responsibility of cell processing while NISE has the responsibility of device simulation as well as complete characterization of solar cells. The process and the test equipment has been identified, the specification finalized and is under procurement.
- The MNRE has sanctioned new R&D projects entitled Design and Development of ‘High Efficiency Solar Water Pumping Systems implemented by NISE, Gurugram and Flexible Perovskite Solar Cells and Intermediate Module by IIT Bombay.