1. Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, Roskilde 4000, Denmark
2. Venture Business Laboratory, Nagoya University, C3-1, Chikusa-ku, Nagoya 464-8603, Japan
3. Department of Electrical Engineering and Computer Science, Nagoya University, C3-1, Chikusa-ku, Nagoya 464-8603, Japan