SEOUL, Oct 19 (Reuters) - South Korean battery maker Samsung SDI Co Ltd (006400.KS) and global automaker Stellantis NV (STLA.MI) have agreed to jointly produce electric vehicle (EV) batteries for the North American market, a person familiar with the matter said on Tuesday. Samsung SDI, an affiliate of South Korean tech giant Samsung Electronics (005930.KS), already has EV battery plants in South Korea, China and Hungary, which supply customers such as BMW (BMWG.DE) and Ford Motor (F.N). "The two companies (Samsung SDI and Stellantis) have struck a MOU (memorandum of understanding) to produce EV batteries for North America," the person with knowledge of the matter told Reuters. The source spoke of condition of anonymity because of the sensitivity of the matter. The person said the location of the battery joint venture is under review and will be announced later. In July, Reuters reported Samsung SDI may build a battery plant in the United States, citing a company source. read more South Korea"s Yonhap news agency earlier reported the two companies plan to build a factory in the United States, citing industry sources. Samsung SDI and Stellantis did not have immediate comment when reached by Reuters. Stellantis on Monday struck a preliminary deal with battery maker South Korea"s LG Energy Solution (LGES) to produce battery cells and modules for North America. In July, Reuters reported that Samsung SDI may build a battery plant in the United States, citing a company source. Shares of Samsung SDI were up 2.6% as of 0300 GMT, versus a 0.6% rise in the KOSPI (.KS11) benchmark index.