The executive, Kim Hong-gyeong, said "weakness" in some batteries for Note 7 had been confirmed, adding that the exact cause of the Note 7 issue is being analysed.
Samsung SDI later said in a statement that Samsung Electronics would announce the results of the probe, without giving a timeframe.
Analysts have said Samsung SDI supplied about 60 percent of the batteries for the Note 7.
Another SDI executive said the issue was limited to batteries for the Note 7 and the company was preparing to supply batteries to a new Samsung phone model due for release early next year as planned.
After the Note 7 fires, SDI checked the safety of other products with major customers, but has found no defects, he said.
Samsung SDI also announced plans to buy back shares worth nearly 300 billion won $263 million).