"The sale has not hurt the relationship with Tesla," Yuki Kusumi said at a press roundtable, when asked whether the sale indicated that their partnership was weakening.

In the year to March 31 Panasonic in sold its stake in Tesla for about 400 billion yen ($3.62 billion) to help to pay for the acquisition of U.S. supply chain software company Blue Yonder in a deal worth $7.1 billion.

Kusumi took over from Kazuhiro Tsuga in April and leads the conglomerate as it begins to profit from a decade-old partnership with Tesla that accounts for about 40% of earnings at Panasonic's automotive business.

The Japanese company this year established a test line in Japan to make a new battery cell that Tesla says will halve battery costs and help with a ramp-up in battery production.

Panasonic is also expanding its joint battery venture with Tesla in Nevada and also looking at building a lithium-ion battery business in Norway to tap European carmakers and reduce its reliance on the U.S. carmaker.

At the same time Tesla is diversifying its own battery supply chain, forging supply contracts with South Korea's LG Energy Solution, owned by LG Chem, and China's Contemporary Amperex Technology Co (CATL).

(Reporting by Tim Kelly; Editing by Mark Potter and David Goodman)