Partners and International Organizations
(English)
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Leclanché S.A., Lausanne (CH), DSM (NL), Energy
Center of the Netherlands (NL), University of Uppsala (S), Pricer AB (S), The Swedish Institute of Production Engineering
Research (S), Industria Plastica Monregalese (I)
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Abstract
(English)
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In close collaboration with Leclanché S.A., the Swiss Polytechnical Federal Institute, Lausanne, the Energy Center of the Netherlands, Petten, DSM Netherlands, Geleen, the University of Uppsala, Pricer AB Uppsala, the Swedish Institute for Production Engineering and Research, Mölndal and Industria Plastica Monregalese, Mondovi, the core topics of a research programme on dye sensitized nanocrystalline solar cells for indoor applications have been finished . The aim of this collaboration, to set up a concise proposal for a pilot production line for small, low-power PV modules, has been pursued, which finally led to a concise proposal for a pilot production facility.
A standardized 'hardware' for long-term stability tests, industrial feasibility studies and an engineering study on the layout and the material flux of a pilot production have been built up in the pilot laboratory at Leclanché S.A. and in collaboration with our project partners.
During the reported project period, a standardized design and production methods for a serially interconnected module have been worked out. This design defines a generic product line, i.e. modules which vary from minimally 30 x 50 mm to 100 x 100 mm overall size and which could serve from 200 uA at 0.5 V up to 10 mA at 5 V, at luminosities between 100 and 1000 Lux, preferentially at about 250 Lux of diffuse daylight.
Stability tests of primary test cells and complete modules have proven the compatibility between the chosen materials, i.e. the type of electrolyte, sensitizer and sealing material Our experience from this development programme has shown, that it takes extensive efforts to transfer low-scale results to machine-produced modules. The main conclusion at the end of this project is, that the only way to evaluate the Dye PV technique is to produce modules by using industrial-scale methods and. installations. We now understand, that failures and partial degradation of the electrical characteristics of laboratory batches were due to inadequate production methods, which in most cases did not allow the necessary control of environmental factors like humidity or adsorption of undesirable airborne impurities into the electroactive interfaces. Stability tests under simulated environmental stress, like temperature and humidity cycling allow to extrapolate a minimal device lifetime of at least 18 months, with 8 type approval standard comparable to analogous battery products.
The concentration on material design, production technology and life time testing led to significant changes of the basic configuration for photo-electrochemical devices, compared to the original description of the license holder EPFL. Due to the necessity of a cost-effective design, the original sandwich-type configuration had to be changed to a structurally simplified version, the so-called 'monolithic technique', which allows the use of only one transparent conducting sybstrate. This technique regroups the functional eletroactive interfaces into a production-friendly configuration. Consequently, the composition of the electroactive nanocrystalline ceramic materials have been drastically changed and reformulated, with regard to standard formulations used at the beginning of our activities.
A production technology which allows the use of industrially available, metal-polymer composite sealing materials, has been studied and developed up to precise mechanical tool elements and to the simulation of the material flux in a virtual continuous production line. The engineering key elements for these studies have been realized or are currently under construction at Leclanché and other partners in the project, SQ that a logistic structure for the future industrialization now exists In the form of tested mechanical tools and production equipment Most of the collaborations built up during the project will be maintained beyond the project duration, to maintain the necessary infrastructure for this Innovative technology.
The accelerated and quantitative ageing tests revealed in all cases, that the stability of our photoelectrochemical devices under low-light conditions depends entirely on the quality of the sealing principle and that the lifetime of serially interconnected modules under typical indoor conditions is most probably not depending on photochemical degradation of sensitizer or electrolyte. This led to the decision, to focus the industrial R+D programme on the optimization of the sealing technology Itself. The result of this strategy is now the design of a fully automated in-line production sequence for the complete photo-electrochemical device, with the option to have an electronic control or adaptation interface integrated into the sealing structure, This provides PV modules for low-power applications and leads, in combination with integrated batteries or capacitors to new product ideas for industrial exploitation.
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