Yoshio Nishi, a former operating officer and senior managing director of Sony
Yoshio Nishi, a former operating officer and senior managing director of Sony
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The capacity and the market of Li-ion secondary batteries have been rapidly growing since they were put into practical use in the early 1990s. And now their applications are expected to expand in the fields of mobile devices, electric vehicles, green batteries and so forth.

We interviewed Yoshio Nishi, who engaged in the development of Li-ion secondary batteries from the research phase for many years as an operating officer and senior managing director of Sony, about the current situation, problems and future development directions of Li-ion batteries. (Interviewer: Hideo Ampo, Senior Editorial Staff)

How do you think applications of Li-ion secondary batteries have been expanding?

Nishi: In the 1990s, when Li-ion batteries were introduced, the target applications were audio-video equipment like home video cameras and MD players. But such applications required only a small amount of production, and I did not expect at all that those batteries would become mainstream.

However, It was not long before notebook PCs started to use Li-ion secondary batteries and boosted the demand for them. I heard it was trigged by a PC maker's advertisement that highlighted the capability of using a notebook PC during a five-hour flight from New York to Los Angeles without charging the battery. From the spread period to the prosperity period, what enlarged the market most were notebook PCs, followed by mobile phones.

Furthermore, in the 2000s, Li-ion batteries began to be adopted by digital still cameras, power tools and game consoles. And, from now on, considering the demands of an approaching low-carbon society, they will be widely used for hybrid vehicles, electric vehicles and stationary power supply systems for both home and industrial uses.

The energy density of Li-ion batteries and security measures for them have since been steadily enhanced by technological developments. And they contributed to the expansion of the market.

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