An Interview with Koichi “Ichi” Kono

by ABT staff members
Jo Chesworth and
Brenda Geary-Bucek

Mr. Kono and ABT’s Jo Chesworth meet at Tonen’s poster.

At the Advanced Automotive Battery Conference we had the pleasure of meeting Koichi “Ichi” Kono, inventor of the micro porous polyolefin film used for Tonen Chemical Co. Ltd.’s lithium-ion battery (LIB) separators.

In 1979, Prof. Pennings reported gel spinning and super drawing of ultra-high molecular weight polyethylene to obtain high modulus/high strength oriented filaments. This triggered Kono’s research after he joined Tonen Chemical as a researcher late in 1980.

On a snowy day in 1984, Kono obtained a thin and strong film by bi-axially orienting a gel of specific polyolefins. He rushed into the scanning electron microscopy lab and later that night found a large number of micro pores in the film. He remembers jumping for joy on a snowy road in the moonlight – this was the world’s first bi-axially oriented micro porous film.

In 1989, Kono filed a U.S. patent for commercially available micro porous film (MPF). Tonen separator products have been protected by this patent and more than 200 others. In 1991, polyethylene MPF was used in the world’s first commercial rechargeable lithium-ion batteries as a separator that affects capacity, power and safety.

Recently, Kono has focused on the development of a new generation of heat-resistant improved separators for HEV/EV applications. He explained that the separator insulates cathode and anode electrodes electrically, while allowing ready ion transport through micro pores. If a cell becomes too hot from abuse, the polymer separators melt to close micro pores and shut down the cell circuit ionically.

In April, ExxonMobil Chemical Co. honored Kono and three of his colleagues with its Outstanding Patent Award and Kono and six other colleagues with its Global Technology Award for their accomplishments. The outcome was presented at the AABC in Long Beach in May.