Asahi Shimbun (apparently one of Japan's five national newspaper's) wrote,
"Panasonic is expected to sign a contract this month to help Tesla construct a plant and produce batteries for its vehicles.
Initial operations at the plant are scheduled to commence in 2017 and become fully operational by 2020. The facility will produce batteries for 500,000 vehicles annually."
I take this with a sizable grain of salt. In the next paragraph they also suggest Panasonic's investment would be something like $200 million ("likely investing more than 20 billion yen"). This seemingly very low investment might reflect Panasonic's past comments that they want to make their Gigafactory investment in stages over time. Or it may reflect that the article may not be particularly reliable.
Panasonic to build factory, produce batteries for Tesla Motors - AJW by The Asahi Shimbun
"Panasonic is expected to sign a contract this month to help Tesla construct a plant and produce batteries for its vehicles.
Initial operations at the plant are scheduled to commence in 2017 and become fully operational by 2020. The facility will produce batteries for 500,000 vehicles annually."
I take this with a sizable grain of salt. In the next paragraph they also suggest Panasonic's investment would be something like $200 million ("likely investing more than 20 billion yen"). This seemingly very low investment might reflect Panasonic's past comments that they want to make their Gigafactory investment in stages over time. Or it may reflect that the article may not be particularly reliable.
Panasonic to build factory, produce batteries for Tesla Motors - AJW by The Asahi Shimbun