In recent years, energy consumption has continued to increase. Realization of peak-shift management of electric power is in demand where economic nighttime power or renewable energy is stored to cover the more expensive on-peak electric power. However, the introduction of such management is not active because there is no storage device that can meet the needs.

Capacitor expected for use as a storage device

 The study of batteries has always been a cutting-edge field through the ages, which includes the proactive introduction of new materials and technologies in a continuous attempt to improve performance. However, even the improved types of cutting-edge rechargeable batteries for use with peak-shift management of electric power are dependent on electrochemical reactions for reasons that include longer charging time, low instantaneous power, and shorter service life. On the other hand, capacitors where the operating principle is ion transfer without a chemical reaction have the features of shorter charging time, higher output density, and hard-to-deteriorate performance. Therefore, they are expected to be the next-generation power storage device.

Aiming for increased energy density with nanostructured electrode

The term “energy density” implies the amount of electric power per unit weight or per volume, and the energy density of a capacitor is around one-twelfth that of a versatile rechargeable lead battery. Facing this problem, NamoSummit has been working to develop a new type of capacitor following selection as the Innovative Technology Creation Promotion Project (MAFF) through collaborations with Tokyo University, Shinshu University, and Taiyo Yuden Co., Ltd. The electrostatic capacitance can be increased by controlling the electrode structure at the nano level and enlarging the specific surface area of that electrode. The key is the isolation and dispersion technology of nanomaterials developed by Fugetu Bunshi, associate professor of Tokyo University. It is not possible to realize structure control at the nano level without the technology to uniformly disperse nanomaterials that are likely to randomly agglutinate. A capacitor with large capacitance and high energy density will be developed by using electrodes with a larger specific surface area wherein organic nanomaterials and nonorganic nanomaterials that are isolated and dispersed are hybridized and highly laminated.

Utilizing the capacitor for energy-saving in the cold chain

In the present agriculture, forestry, and fisheries field, transportation of low-temperature controlled fresh foods is implemented through the dissemination of cold chains. For the current condition where freshness, taste, and safety are maintained by using vast amounts of energy, the introduction of a capacitor with large capacitance will enable dramatic power savings in the freezing and refrigeration processes. If energy density about three times the conventional capacitors can be realized, continuous operation of refrigerator-freezers for several hours becomes possible, and such capacitors are expected for use with cold chains. I wish for the new-type capacitor that will be further enhanced with the nanomaterials control technology. (Report/Takashi Okazaki)

Published in the December 2015 Issue of Professional Journal EngGARAGE