Milestones:Commercialization and Industrialization of Photovoltaic Cells, 1959

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Commercialization and Industrialization of Photovoltaic Cells, 1959

Sharp Corporation pioneered the development and commercialization of photovoltaic (PV) cells for applications ranging from satellites to lighthouses to residential uses. From the beginning of research into monocrystal PV-cells in 1959, to the mass production of amorphous PV-cells in 1983, this work contributed greatly toward the industrialization of photovoltaic technologies and toward the mitigation of global warming.

 Location(s) of Milestone plaque(s):
(ⅰ) Solar System Group, SHARP Corporation
282-1 Hajikami, Katsuragi-shi, Nara, 639-2198 Japan
Phone: +81-745-65-1161, GPS: N 34.47574, E 135.741507
(ⅱ) Corporate Research and Development Group, SHARP Corporation
2613-1 Ichinomoto-cho, Tenri-shi, Nara, 632-8567 Japan
Phone: +81-743-65-1321, GPS: N 34.620162, E 135.843096
(ⅲ) Head Office, SHARP Corporation
22-22 Nagaike-cho, Abeno-ku, Osaka, 545-8522 Japan
Phone: +81-6-6621-1221, GPS: N34.621643, E 135.517143

 In 1954 three researchers at Bell Laboratories published the results of their discovery of the world’s first
practical ‘photovoltaic’ (henceforth abbreviated by ‘PV’) cell which was capable of converting sunlight into electricity, first at 4% and later at 6% conversion-efficiency[1]. In 1959 Sharp Corporation began R&D of silicon monocrystal PV-cells, with mass production starting in 1963[2], and commercialized a variety of mono/multi-crystalline PV-cells for everything
from satellites to lighthouses, and industrial applications to residential use[2]. The annual production capacity has
since grown to 500 MW with plans to double it to over 1GW by constructing additionally a new big plant in Sakai
City in Osaka Prefecture with the start of operations in fiscal 2009, and moreover the cumulative production
volume reached to 2GW at the end of 2007 for the first time in the world. It is estimated that the current world’s
cumulative production volume is 8GW, meaning that Sharp has produced a full one-quarter of that[3].

Sharp’s pioneering works of developing and commercializing PV-cells have been achieved mainly in the fields of consumer electronics, public facilities, space satellites, and industrial and residential applications.
Especially, untiring efforts of the project teams devoted to the development and implementation of PV-technologies
during the long period, ranging from the start of R&D of monocrystal PV-cells in 1959 to the mass production of
amorphous PV-cells in 1983, constructed the firm foundation for the industrialization of PV technologies, as
described in what follows.

Consumer Electronics
Since Sharp had been traditionally strong at consumer products, the commercialization of PV-cells was initiated in
the field of consumer electronics as follows.

World’s First Transistor Radio In 1961 Sharp succeeded in developing a prototype PV-cell,
which was installed in the world’s first transistor radio BX-381 operating on both PV-cell and battery.

Table Clock
In 1963 a project team headed by Dr. Kozabro Baba succeeded in mass production of PV-module S-224
which realized cell conversion-efficiency of 8.8%, with much smaller surface area than the conventional one. Using an improved version of this module S-224, Seiko developed the first PVinstalled table clock in 1966.

The World’s First PV-Installed Calculator and Watch
In 1976 Sharp developed a more efficient monocrystal silicon PV-module S-225, with cell conversion-efficiency of 10.0%, and installed the cell element of S-255 in calculator EL-8026[5], Seiko’s watch ‘Quarts’(see Fig. 3), and Citizen’s watch ‘Solar Cell’[6] for the fist time in the world. In addition, these modules S-224 and S-225 were also applied as power sources for consumer products, such as
(i) transceivers for Mt. Yalung-Kang (at a height of 8,505m in the Himalayas) Mountaineeing Party of
Kyoto University in 1973,
(ii) photometers and electronic shutters of cameras,
(iii) spinning trouble detectors, and
(iv) machinery for safety aid, etc.[7]
g.1.4) PV-installed Calculator Business
Sharp developed a new ‘ultra violet’ PV-cell on the basis of the cell of S-225 in 1979, which acted on
fluorescent light with much reduced surface area. This PV-cell contributed to the commercialization of a
series of wallet type PV-installed calculators, such as EL-826, EL-835, EL-838SE, EL-858, EL-867, EL-
325, EL-350, EL-355, EL-515, etc., in the early 1980s[8]. Thus, Sharp paved the way for a new business
field by introducing wallet type PV-installed calculators.

Amorphous PV-cells by Roll-to-Roll Process
By introducing the roll-to-roll double-layer manufacturing process, as shown in Fig. 4, from Sharp-ECD
(Energy Conversion Devices) Solar Co., Ltd., established in June 1982 as a joint venture of Sharp and ECD Inc. (USA), Sharp began to produce amorphous PV-cells in 1983, which were installed in different consumer products, such as ‘card-calculators’, watches, etc. The annual production capacity of amorphous PV-cells soon grew to 1.5MW, which induced the commercialization of a sequence of cardcalculators EL-865, EL-875, EL-878, EL-900, etc.
It should be added that the mass production of amorphous silicon PV-cells also enabled Sharp to supply
thin and ‘printable’ card-calculators to other companies, which yielded a big boom of designed cardcalculators
in the mid and late 1980s[9].

Public Facilities
In the early 1960s NEC Corporation was the leading manufacturer in the area of PV-cells in Japan. In fact, as of 1961 NEC’s PV-cells had been installed in all of 6 wireless relay stations and 8 lighthouses in Japan. Thus Sharp made every effort to catch up technological skills of developing high efficiency PVcells. In 1963 a project team headed by Dr. Baba succeeded in developing PV-module S-224 which realized cell conversion-efficiency of 8.8% with much smaller surface area than the conventional one, and moreover satisfied the durability test of the Japan Coast Guard. Hence, the Japan Coast Guard adopted Sharp’s PV-arrays composed of this module as power sources for No.1 Tsurumi Light-Buoy of Fig. 5 in Yokohama Port in 1963[10] as well as for Ogami-Jima Lighthouse in Nagasaki Prefecture in 1966[11]. Following these successful PV installations of the Japan Coast Guard, other government agencies and public corporations began to employ Sharp’s PV-cells for different public facilities. Meanwhile, NEC changed the corporate policy to focus its R&D target principally on computer and communication, withdrawing from the R&D of PV-cells. Thus Sharp had attained by the mid 1970s the position as the Japan’s leading manufacturer of PV-cells. According to remarkable progress of cell conversion-efficiency as shown in Fig. 7[12], Sharp’s PV-cells have since been used exclusively for lighthouses/light-buoys, traffic/road management, river/dam control, meteorological observations, aviation safety control, broadcast/wireless relay stations, etc. In what follows, the main focus is on Sharp’s PV-cells used dedicatedly for such public facilities.

Light-Buoys and Wireless Relay Stations
In 1963 PV-module S-224 satisfied the durability test of the Japan Coast Guard[13], and was installed in the No.1 Tsurumi Light-Buoy of Fig.5 in Yokohama Port[10]. Although at that time Sharp had already provided PVcells
for 13 lighthouses and 21 light-buoys, this was the world’s first light-buoy floating on the sea[13]. Subsequently, the same type of PV-arrays were installed in a variety of public facilities, such as (i) light-buoys, not only in Japan
but also in Malacca Straits, (ii) wireless relay stations in Australia, Philippines, Africa, etc., and (iii) agricultural spray pumps in Indonesia, etc.[7,14].

Lighthouses and Radio/TV Relay Stations
In 1966 the Japan Coast Guard installed Sharp’s 225W PV-array constructed of module S-224, the world’s largest array at that time[3,15], in the Ogami-Jima Lighthouse, which was replaced by another array composed of new module
S-225 in 1976[14].

These modules S-224 and S-225 continued to be installed widely in public facilities[12,16], such as
(i) lighthouses throughout Japan; i.e. 159W Tsushima-Kuroshima Lighthouse, 590W Kousaki Lighthouse,
546W Shimotsu-Okinoshima Lighthouse, 576W Eboshi Lighthouse, 660W Koshiki-Jima
Lighthouse, 590.4W Tsushima Lighthouse, etc., constructed in the late 1960s through the 1970s,
(ii) NHK’s radio/TV-broadcasting relay stations (see Fig. 9) in Wakayama, Hiroshima, Hyogo, and
Yamanashi Prefectures,
(iii) unmanned lighthouses in Malacca Straits (see Fig. 10), etc., and
(iv) unmanned signals on a South Africa railroad (see Fig. 11), etc.

Sharp has since provided PV-arrays for more than 10,000 public facilities, including 8,000 wireless/
broadcasting relay stations and telemeters, and 1,900 lighthouses/buoys, among which the Ogami-Jima
Lighthouse and the Kousaki Lighthouse, both in Nagasaki Prefecture, had 225W and 590W PV-arrays,
the world’s largest as of 1966 and 1974, respectively. Especially, it should be added that through Sharp’s
long-term installation of PV-arrays in lighthouses, the Japan’s last resident lighthouse, the Meshima Lighthouse[17] in
Nagasaki Prefecture, became unmanned on November 12, 2006.

Public Facilities for Road Management, Meteorological & River/Dam Observation, and Aeronautical Safety
Following PV installations by the Japan Coast Guard, other government offices/agencies and public corporations, such as the Civil Aviation Bureau, the Japan Highway Public Corp., the Japan Meteorological Agency, NHK, electric power companies, etc., employed Sharp’s PV-cells for a wide range of public facilities, such as

(a) aeronautical safety,
(b) road & navigation management,
(c) meteorological and river/dam observation, and
(d) agricultural and environment use, etc.

In addition, Sharp by itself commercialized PV-installed consumer products, such as road lamps, road signs, road information boards, delineators, raised markers, curb markers, beacon lights, lighting systems, battery chargers for farming and grazing, etc.[12] Specifically, in 1981 modules of S-270A series, i.e. S-270A, S-271A, S-272A, and S-274A, were developed, in which 36 pieces of elements, each with 4 inch diameter, were processed to mold form, as
shown in Fig. 12[16]. These PV-modules were very light in weight, and could be installed in elevated places without difficulties. Moreover, they had high reliability even under severe ambient conditions encountered in mountains, deserts, and frigid areas. Thus, modules of S-270A series were installed in a variety of public facilities as follows[16]:
(i) Aeronautical Safety: PV-installed systems for aviation safety control, aircraft warning light, beacon
light, aeronautical ground light, airway beacon, aeronautical radio, etc.,
(ii) Road & Navigation Management: PV-installed systems for road lighting, road sign, road information board, delineator, raised marker, curb marker, highway emergency phone, railroad crossing signal, etc.
(iii) Meteorological and River Observation: PV-installed telemeters for rainfall and snowfall observation, water-level control of river and dam, etc., and
(iv) Agricultural and Environmental Use: PV-installed water-pumping systems for irrigation and drainage, PV-installed electric fencing systems for stock farming, PV-installed solar green housing systems, etc.

Space Satellites
In 1967 another project team headed by Mr. Akio Suzuki began to develop PV-cells dedicatedly for installation in space satellites, and made untiring efforts to construct the manufacturing facilities to satisfy the prescribed tests of NASDA (National Space Development Agency of Japan) concerning (i) withstanding radiation environment, (ii) heat cycle, and (iii) high-temperature and high-humidity storage. Consequently, in 1972 NASDA authorized Sharp as the Japan’s first official manufacturer to supply PVcells, and even after NASDA and ISAS (Institute of Space and Astronautical Science of Japan) were unified into JAXA (Japan Aerospace Exploration Agency), JAXA has still authorized Sharp as the sole
manufacturer of the PV-cells of satellite use. Sharp has since manufactured PV-cells monopolistically for 50 Japanese satellites, and has also provided PV-cells for 110 foreign satellites. In what follows, PV-cells produced by the end of 1983 dedicatedly for satellite use were outlined.

NASDA’s Authorization
In 1967 the project team began to set up the manufacturing process for radiation proof silicon PV-cells of satellite use, until in 1972 Sharp’s PV-cells were authorized as official parts of NASDA’s satellites. In 1974