Technical Library

Latest Trends in Renewable Energy Technologies and Products


1. Introduction

Our company philosophy is to be contributing to a society with a brighter by creating valuable products that have the goal of protecting the environment. Nichicon is working to solve the serious environmental issue of global warming through the Nichicon Energy Control System Technology (NECST) Project. Initiated on March 15, 2010 under the direct control of President and COO Sachihiko Araki, the NECST project is aimed at achieving a stable supply of energy while still protecting the environment.

Since the Great East Japan Earthquake of March 2011, society has become all too aware of the compelling and pressing need to achieve a stable supply of energy while at the same time protecting the environment. That's why Nichicon is focusing on the following three areas under its NECST project.

(1) Expansion of renewable energy
(2) Intelligently controlled distributed power sources that make up smart grids
(3) Eco-cars like EVs (electric vehicles), and the supporting infrastructure

Let's look at the story of NECST products and the state-of-the-art technologies behind them.

2. Example of the Independent Distributed Power Sources that Make Up Smart Grids

In conventional power grids, large-scale power plants send electrical energy to various end points on the grid. There is a movement, however, toward decentralization of this system; namely, small-scale generators running on renewable energy such as solar power connected to points on the power grid in order to produce energy locally for local consumption. While this decentralization has advantages such as balancing energy supply and demand locally, and eliminating the transmission losses that occur over long-distance power lines in conventional power grids, it also makes control of the entire power grid more complicated.

This problem requires several solutions: the use of information technology to control the entire grid so that it acts as a smart grid; distributed power sources connected to various points of the grid operating 'intelligently' according to the state of the grid; and energy storage functions that allow an energy supply-demand balance at each point on the grid.

For more than eight years, Nichicon has been operating a solar power generation system installed on the roof of its head office that uses EDLCs (electric double-layer capacitors) as the storage device. It can be used to reduce peak load. Also, in an effort supported by Japan's New Energy and Industrial Technology Development Organization (NEDO), Nichicon has developed a lithium-ion battery storage system that stabilizes the fluctuating output of wind power generation. This system has been installed in a public relations facility (called the 'Solar power facility in Yamanashi Prefecture Public Relations') in Japan, where its combination of solar and stored power provides all the facility's electricity, as well as electricity for charging EVs.

This system is an energy-generation- and energy-storage-type energy management system (photo 1) that can store energy from small-scale hydropower sourcesas well as fuel cells. Displayed and operating in the aforementioned public relations facility, it has a 20-kW solar panel and a 1.5-kW hydropower source for input; a 32-kWh lithium-ion battery and a 3MJ EDLC for storage; and output capacity in the form of a 30-kW quick charger. Quick charging of Electric Vehicles takes place at an EV-charging stand outside the building. (Photo 2) shows the entire Komekurayama Mega-solar Power Plant in Yamanashi Prefecture, which houses the 'Solar power facility in Yamanashi Prefecture Public Relations' and Nichicon's energy-generation- and energy-storage-type energy management system. The system stores the power generated by renewable energy after converting the voltage level with a DC-DC converter; converts it to AC; and then supplies power to the building's load, while also providing direct current from the battery to the quick charger. The result is outstanding overall efficiency and energy savings. Since this system stores renewable energy, it can operate independently of the grid and thus be used as an emergency power source in the event of disasters and as an emergency quick charger. This holds promise for infrastructure in Japan, a country often beset by natural disasters and currently suffering from an energy shortage.

Photo 1:Energy-generation- and energy-storage-type energy management system

Photo 1: Energy-generation- and energy-storage-type energy management system

Photo 2: Komekurayama Mega-solar Power Plant in Yamanashi Prefecture, which runs on Nichicon’s energy-generation- and energy-storage-type energy management system
Photo 2: Komekurayama Mega-solar Power Plant in Yamanashi Prefecture, which runs on Nichiconís energy-generation- and energy-storage-type energy management system

3. Ultra-Compact Quick Chargers for EVs

Towards its goal of realizing a low-carbon society, Japan was the first country to develop EVs and install an EV charging infrastructure. A number of manufacturers in Japan and other countries are already offering products that use CHAdeMO, which an industry group in Japan is proposing as the international standard for quick EV chargers. So far, over 1,800 CHAdeMO-compatible quick chargers have been installed worldwide. Nichicon was the first company in the world to develop and manufacture OBCs (on board chargers), the devices that charge the lithium-ion batteries found inside EVs. Many of today's mass-produced EVs are equipped with Nichicon OBCs (photo 3).

Nichicon is also contributing to the spread of the charging infrastructure by applying its technology to a four-product lineup (10-, 20-, 30-, and 50-kW) of the world's smallest and lightest quick chargers for EVs (photo 4).

Because a single lithium-ion battery has a voltage of only 3.7V, a series connection of about 100 is required to obtain a high level of power, and such a connection requires a battery management system (BMS). Electrical charging and discharging of the lithium-ion batteries, whether they are used for on board chargers (OBCs) or quick chargers, requires communication with the BMS. The standard for this communication in Japan is the CHAdeMO standard.

Photo 3: On board charger

Photo 3: On board charger

  Photo 4: Ultra-compact Quick charger for EVs

Photo 4: Ultra-compact
Quick charger for EVs

4. EV Power Station for 2-Way Charging and Power Supply

Nichicon has developed a two-way charging and power supply system, the EV Power Station, which allows users to use the large capacity battery in an EV to send electricity to a home. Since it can power a home using a car battery, it is known as a V2H (Vehicle to Home) system (photo 5).

The EV Power Station can store inexpensive night-time electricity and shift it to the daytime for use in the home, thus contributing both to peak-time shifts and lower electricity costs. It can also fully charge the battery about twice as fast as is possible with a conventional 200-V Household energy source.

This system allows an average household to be completely energy self-sufficient while preventing reverse power flow to the grid. It also offers energy security and peace of mind: effectively using renewable energy by storing it when used in combination with a Household energy storage system, reducing peak load and thus helping overcome energy shortages, and acting as an emergency power source in natural disasters.

Photo 5: EV Power Station

Photo 5: EV Power Station

5. Household energy Storage Systems

Besides making it possible for families to maximize the electricity they sell through combination with solar power generation, Household energy storage systems (photo 6) reduce electricity bills by storing inexpensive night-time electricity for use in the daytime. They also act as a backup system in case of emergencies such as blackouts. Furthermore, combined use of solar power generation systems and Household energy storage systems produces energy locally for local consumption: this contributes to fewer CO2 emissions, reduces peak load during the heaviest electricity usage period in the daytime, and helps achieve locally balanced supply and demand of energy.

Technological advancements have allowed Nichicon to achieve a long-life design. Besides the large-capacity 7.2-kWh battery, whose stored electricity can be used by customers on a night-time electricity contract with their power company to meet their power needs during the high-cost daytime hours (under standard conditions of use), Nichicon's Household energy systems can be expanded with a 14.4-kW battery. And making use of Nichicon's electrical charging and discharging control technology built up through products like OBCs, the company has maximized the advantages of the lithium-ion battery. Furthermore, the system gives users energy security and peace of mind: it automatically switches to self-sustaining mode during a blackout to provide electricity from both solar power and stored electricity in the battery, and once the blackout is over it automatically switches back to normal operation.

Photo 6: Household energy storage system

Photo 6: Household energy storage system

6. Advanced Technologies Behind Environmentally Friendly Energy Products

Since its NECST project was launched, Nichicon has released a number of products that have been mentioned here. But behind these products, a major role has been played by the high-tech power sources for state-of-the-art equipment such as accelerators that Nichicon has been making for over 40 years. Accelerators cause particles such as electrons and protons to move at near the speed of light. The resulting phenomenon has numerous applications; for example, these accelerated electrons and protons are used to study the elementary particles that make up matter; or the intense radiant light from the accelerated electrons is used to observe the sub-atomic state of matter. These applications have contributed to developments in fields including semiconductors and pharmaceuticals. Accelerators require high-precision power sources, and in the 1990s Nichicon used its world-leading technology in this area to develop and commercialize a high-precision electrical charging and discharging power source essential for use on the production lines for lithium-ion batteries. The technology accumulated by the company in this area was also used in advancing the development of on board chargers and quick chargers.

To develop a way to cope with sudden voltage drops to the power grid, Nichicon worked with universities and the government, using the company's EDLCs to develop-in a surprisingly short time-a momentary voltage sag compensator that earned accolades for its compact size, light weight, long service life, and energy efficiency. The product won the Minister of Economy, Trade and Industry Prize. This evolved further when, with support from NEDO, Nichicon developed a lithium-ion-powered system that stabilizes the fluctuating output of wind power generation. In the process of such developments, Nichicon has built up advanced technologies for stabilizing the power grid through high-speed conversion between the grid and storage systems.

These and other technologies were behind the success of Nichicon's NECST project in rapidly developing a string of products using environmentally friendly energy. This is shown in the diagram below.

Diagram: Advanced technologies behind environmentally friendly energy products

Diagram: Advanced technologies behind environmentally friendly energy products


7. Conclusion

The NECST project's aim of "achieving a stable supply of energy while still protecting the environment" reflects a major problem the world faces in the 21st century-a problem whose solution Nichicon considers its mission. It is believed that we can achieve a power grid that is both flexible and efficient through a combination of (1) advanced control of power grids using smart grids, and (2) local production and consumption of energy through decentralization efforts such as distributed power sources equipped with storage functions for the effective use of renewable energy.

Through the state-of-the-art power electronics technologies it has built up through years of creating accelerator-related products, and through development of environment-related products driven by advanced grid-related technologies, Nichicon is contributing to a bright future in which people can enjoy the benefits that come with lower carbon emissions.


From the Dempa Shimbun, Feb. 7, 2013

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