Along with the progress of global warming, the introduction of renewable energy sources such as solar and wind power has been promoted, and large-capacity energy storage batteries have become important as a measure to stabilize electric power systems. A redox flow battery (RFB) is one of such batteries. It is charged and discharged by redox reactions*1 of ions in an aqueous solution containing active materials*2. The RFB is suitable for large capacity storage and has excellent features such as long life and high safety. We began developing RFBs in 1985 and have delivered approximately 30 units. As a global trend, research and development have been actively promoted particularly in the United States, Europe, and China since around 2010, and recently, there have been many reports on new electrolytes using organic compounds. This paper introduces the development history of RFBs, the demonstration status of large capacity systems, and the recent development trends.

Recently, the demand for silicon photonics (SiPh) optical transceivers for data centers has been increasing rapidly. In order to address this situation, we have developed FlexBeamGuidE (FBGE) as an optical interconnection device indispensable for SiPh chips. The FBGE is an optical fiber array with a 90-degree bend, formed using state-of-the-art stress-free fiber bending technology. The developed FBGE is suitable for use in SiPh optical transceivers because of its compact nature with an overall height of less than 3.8 mm, low attenuation loss of less than 0.5 dB, and high reliability.

This paper describes a newly designed ultra-high-density (UHD) microduct optical cable to be installed into microducts with airblowing technique. The UHD microduct cable employs Freeform Ribbon, in which fibers meet and split out in turn in longitudinal and transverse directions, thus allowing high fiber density and mass fusion splicing. In order to enhance the blowing efficiency, we employed a thin and lightweight cable design and low friction jacket material. In addition, we have significantly increased fiber density owing to a bend-insensitive and thin optical fiber and Freeform Ribbon technology. We also evaluated the blowing performance in collaboration with Plumettaz S.A. to confirm the excellent blowing property of the developed cable.

There has been a strong demand for increasing data traffic resulting from the growth of advanced mobile terminals and the diversification of internet-based services. To address the needs, 100-Gbit/s optical transceivers have been used in optical communication systems. For further increase in data capacity, a new specification for 400-Gbit/s optical communications has been standardized, and optical transceivers applicable to it have been developed actively. We have developed a new compact receiver for 400-Gbit/s transmission based on the structure of our previous 100-Gbit/s receivers. This paper describes the design and typical characteristics of the new optical receiver.

Gallium nitride high electron mobility transistors (GaN HEMTs) are characterized by high power, high efficiency, and wideband operation. In recent years, they have gained market share for base station applications. GaN HEMTs are more advantageous for wideband applications than LDMOSs and, therefore, expected to contribute to the establishment of high-power multi-band base stations. This paper presents a packaged GaN HEMT device with internal matching circuits. A high-power wideband asymmetric Doherty amplifier using the devices are also described. The transistor has a pair of 180 W GaN dies. The internal matching circuit is designed with a high-dielectric substrate so that it can be mounted in a compact package while maintaining the wideband characteristics. The asymmetric Doherty amplifier is fabricated using three transistors to cover B1 and B3 LTE bands. It achieves an output power of 59.2 dB and drain efficiency of more than 50% at 8-dB power back-off in the 1.8-2.2 GHz range.

For the next-generation power systems, a mechanism called Virtual Power Plant (VPP) is expected to be deployed, where distributed energy resources are aggregated and remotely controlled by a resource server so that it operates like a virtual power plant. Sumitomo Electric Industries, Ltd. has developed what is called a resource aggregation server, s EMSA server, which plays a core role in this mechanism. Sumitomo Electric has been working to develop VPP systems and extend energy resources in order to enter a new electric power market that will be created after 2020. This paper presents the features of sEMSA server and its verified performance in pilot projects for VPP operation and photovoltaic power generation control.

Copper conductors cross-linked polyethylene insulated wires are widely used for overhead distribution lines in Japan. On the other hand, a trend can be seen in the shift from copper conductors to aluminum conductors because aluminum is light and moderately priced. For the replacement, however, the increased diameter of insulated wires is inevitable due to the difference of conductivity between aluminum and copper. This causes an increase in wind pressure on wires, occasionally requiring rebuilding supporting structures (for example poles). Under such a circumstance, we have developed a low wind-pressure aluminum insulated wire with an original grooved surface. This helps reduce the wind pressure at a wind velocity of both 28 m/s and 40 m/s. Featuring competent electrical performance and workability for connection and other wiring work, the wire has been applied to actual distribution lines.

The “System UPS” is an energy solution system that achieves both peak shaving and business continuity plan (as a countermeasure for instantaneous voltage drop and blackout). It combines battery energy storage systems with emergency generators on the consumer side. Aiming to present a solution that offers new customer value as part of our SPSS (Smart Power Supply System) business, we are conducting verification at Maebashi Factory of Nissin Electric Co., Ltd. We report on the development progress and demonstration results of the System UPS.

Exotic alloys, such as nickel alloys, cobalt alloys, and titanium alloys, are widely used for equipment and parts in the aircraft and auto industries due to their superior heat and corrosion resistance. There has been a growing demand for the machining tools for these alloys. When machined, exotic alloy work materials are likely to adhere to the edges of cutting tools, resulting in a sudden fracture of the tools. These tools have a significantly shorter life than those used for general steel. Thus, demand is high for cutting tools with stable performance and long tool life. The newly developed grades, AC5015S and AC5025S, are characterized by improved wear and fracture resistance with a state-of-the-art physical vapor deposition coating and special cemented carbide. These materials help reduce tool replacement frequency and tool consumption by extending tool life, thus contributing to the reduction of machining costs.

In recent years, the quality level required for diamond dies has risen along with an improvement in the precision of wire materials such as semiconductor bonding wires and medical wires. Requirements are increasing for wire characteristics, particularly wear resistance and properties to maintain roundness and wire surface roughness. In order to meet the needs, we have developed the BLPCD die using a nano-polycrystalline diamond (Sumidia binderless) developed by Sumitomo Electric Industries, Ltd. as its core material. This paper reports the performance evaluation results.

Extrusion tools made of refractory metals, such as molybdenum (Mo) and tungsten, are used in increasingly severe environments. Nevertheless, these tools are required to have superior mechanical properties, long life, and excellent reliability. We have developed a new Mo alloy “MSB” for hot extrusion dies used in plastic working, by using a dispersed Mo-base intermetallic compound. The MSB exhibited superior mechanical properties compared with conventional Mo alloys at temperatures below 1000°C. In addition, by adding a titanium alloy to the MSB, we have developed another alloy “T-MSB” that has high mechanical properties at high temperatures. In the hot extrusion of brass, dies made of these Mo alloys had 2.5 times longer tool life than conventional Mo dies.

In the development and production of compound semiconductor devices, atomic-scale structural analysis is required to evaluate their performance and characteristics. For the analysis, scanning transmission electron microscopy (STEM) is indispensable. However, it is necessary to control the sample thickness to around 100 nm using a focused ion beam (FIB) milling system, and the required number of samples could not be prepared quickly even by highly skilled engineers. In order to solve this problem, we have improved the processing capacity by automating the FIB milling process. Since a wide variety of devices are being developed and manufactured in our company, it is necessary to prepare various kinds of samples according to the analysis objectives of each device. Therefore, we identified the automation conditions for each sample, and by combining the established automation functions we constructed a system that can deal with a large number of samples expeditiously. The higher throughput enables us to repeat the device fabrication and evaluation in the shorter turnaround time, accelerating the development of devices and improvement of the quality.

With the recent tightening of fuel consumption/emission control regulations, Zero-Emission Vehicle regulations, and other environmental regulations, the use of electrified vehicles (electric vehicles, plug-in hybrid vehicles, hybrid electric vehicles) is expanding. A motorized vehicle is equipped with a battery pack for powering electric motors. In the battery pack, multiple battery modules are connected to each other to produce high-voltage, highcapacity power. In the battery module, the electrodes of multiple laminated battery cells are electrically connected in series or parallel by the bus bars of a battery wiring module. A control unit is connected to the battery modules via the wires of the battery wiring module to monitor the voltage of each battery cell .

The OPTHERMO fiber-optic distributed temperature sensing system is a product of Sumitomo Electric Industries, Ltd. and is one of the component technologies used in infrastructure monitoring and maintenance systems. There are currently two models in the OPTHERMO lineup: the FTR3000 (a short distance model at an accessible price) and the FTR3000X (a long-distance and high-performance model at a higher price). By limiting its functions, the FTR3000 has offered the most reasonable price in Japan among equivalent products. However, it is 10 years since FTR3000 was introduced to the market, and therefore it was time for the product to be updated with functional enhancements and other changes. We have now developed a successor model, the FTS3500, which offers better performance while still maintaining the lowest price in Japan.

Recently, automobile-related industries are required to protect the global environment by improving the fuel economy of vehicles. To meet the requirement, vehicle manufacturers are increasing the use of aluminum alloy and other nonferrous metal parts to reduce vehicle weight, in parallel with an increase in the production of hybrid vehicles, electric vehicles, and fuel cell vehicles. To increase the productivity of these nonferrous metal parts by improving machining efficiency, cutting tools are required to be easy to handle and feature highly effective chip evacuation, thereby reducing machining time and nonmachining time. In light of the situation, demand for lighter-weight cutting tools suitable for compact machining equipment is also increasing recently to improve the productivity per unit area of machining equipment. To meet such demand, Sumitomo Electric Industries, Ltd. has developed a polycrystalline sintered diamond (PCD) cutter, ALNEX (ANX series) , for high-efficiency aluminum alloy machining application.

A milling cutter is a cutting tool with a cutting edge on the end face or side face. Various kinds of parts are machined by revolving this cutter. Cutting tools equipped with indexable inserts are widely used today for face milling, shouldering, side milling, slot milling, contouring, ramping, helical milling, and various other types of cutting. On the other hand, in the field of machining, the accuracy and quality required of parts are becoming stricter year by year. Accordingly, cutting tools are required to provide increasingly enhanced performance in order to be able to cut the surfaces of parts to the required roughness and quality. To realize parts of reduced weight, the quantity of parts made by machining low-rigidity thin-walled workpieces and intricately shaped difficult-to-clamp materials is increasing. As a result, the demand for cutting tools with sharper edges is increasing.