Abstract
Introduction
The economic situation and, in particular, the upward trend in the price of
fossil energies and political pressure on the markets induced in part by
public opinion and in part by geopolitical aims to loosen the ties of energy
dependence has meant that considerable budgets have been allocated over many
years to the development of alternative energy sources. The production of
photovoltaic electricity is one promising avenue among these various types of
"clean energies".
Three main technological avenues exist for the photovoltaic energy production
market: crystalline silicon cells (which represents in terms of patents nearly
3300 families since 1985), thin film cells (4300 families) and organic cells
(a little less than 1900 families). This study, which focuses on thin film
technology, represents the second part of a three-part analysis of the patent
environment in the photovoltaics field.
Thin films constitute second generation photovoltaics technology. In this
generation may be distinguished, in particular, amorphous silicon (a-Si),
copper indium diselenide (CIS) and cadmium telluride (Cd-Te), to cite only a
few.
At the moment, the maturity of thin film technology is lagging behind that of
crystalline silicon. In fact, not all of the technological, ecological and
economic stumbling blocks have been overcome yet and these cells, known as
second generation cells, still only account for a small part of the
photovoltaics market, namely around 10%, all technologies taken together. The
companies that have based their strategies on this type of cell have invested
heavily in research and development for more than 20 years to overcome these
hitches and to protect their technical solutions so as to profit from what are
assumed will be important spin-offs. In technological terms, the efficiency,
around 6-7% for amorphous silicon technology (up to 14% in the laboratory and
40% with concentrators developed in particular by BOEING' s subsidiary,
SPECTROLAB) and the deposition efficiency (slow or instead expensive) are the
two principal limitations. In environmental terms, the toxicity of certain
elements (cadmium) used in their manufacture also represents a brake to
intensive exploitation and numerous recycling solutions have been proposed.
Finally, in financial terms, this technology does not benefit as much from
strong synergies with pre-existing industry to promote it, unlike silicon
technology which relies on the semi-conductor industry and in particular the
producers of silicon.
However, photovoltaic thin film cells have several undeniable advantages
compared to crystalline silicon cells. Firstly, the process employed is very
different to that of first generation cells and enables on-line industrial
cell production, unlike silicon technology which requires the use of several
different manufacturing techniques (production of the ingot, slicing, doping,
etc.). Secondly, the production of this type of cell consumes less material
than first generation cells, since less semi-conductor is used.
These two factors suggest that the cost of thin film cells may well, in the
long run, be lower than that of cells based on crystalline silicon. Finally,
on account of their specific characteristics (such as the possibility of being
flexible and lighter or instead their high temperature resistance), they
enable the needs of new markets to be met, which may turn out to be important
in the future for building markets and in a sizeable chunk of specific niche
markets (such as the military market, with photovoltaic tents).
Rather than from considering the strong and weak points of the technology,
this study aims to establish a panorama of the industrial property in order to
provide a clearer insight into the issues and challenges at stake and to
position the different players involved in thin film technology in terms of
technological choices and patent filing strategies by providing a
complementary view to that provided by market studies. After an overall
analysis of the photovoltaics field, aimed at assessing the technological
weighting of each of the technologies involved (crystalline silicon, thin film
and organic), we will analyse in greater detail herein patents and patent
applications, filed between 1985 and mid 2007, that can be associated with
thin film technology.
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