Tesla Motors Inc. may get batteries for its energy unit from Samsung SDI Co., Elon Musk, chief executive officer of the electric-car company, said on Twitter. After reports emerged over the past week that Samsung’s batteries might supply Tesla’s electric vehicles, Musk tweeted that Panasonic Corp., a longtime investor in the youngest publicly held U.S. automaker, will be the exclusive provider of batteries for the upcoming Model 3 small car, as it is for the Model S large sedan and Model X sport utility vehicle. Asked on Wednesday if Samsung might supply Tesla Energy, Musk replied “yes.” Samsung SDI shares rose as much as 4.1 percent to 113,500 won in Seoul following the report. Panasonic shares, which had climbed in the past two days, declined 2.7 percent on Thursday. Samsung SDI declined to comment. “We can neither provide further confirmation or comment on this issue,” the company said. Tesla Energy is the business unit that provides stationary batteries for homes, known as the Powerwall, and for businesses and utilities, known as the Powerpack. In the first quarter, it delivered more than 2,500 Powerwalls and almost 100 Powerpacks in North America, Asia, Europe and Africa, Tesla said last month. Tesla and Panasonic have a strong partnership. The Japanese electronics maker invested $30 million in Tesla in 2010 - now worth more than $300 million - and the two companies have a supply agreement for 1.8 billion cells through 2017, for both the Model S and the Model X. For the Model 3 - a more affordable electric car that promises a range of at least 215 miles (346 kilometers) per charge and start at $35,000 - the companies are jointly developing a new, slightly larger cylindrical battery cell than those used in the S and X. Panasonic is also an investor in Tesla’s gigafactory east of Reno, Nevada. A May report by the Nevada Governor’s Office of Economic Development noted that as of the end of the first quarter, Panasonic had 52 employees working at the gigafactory. By Dana Hull/Bloomberg