SEOUL/MILAN—Stellantis and South Korea’s Samsung SDI Co., Ltd. have entered a preliminary agreement on a joint venture to produce electric vehicle (EV) battery cells and modules in the United States, the two companies said on Friday. The tie-up comes less than a week after the world’s fourth-largest automaker signed a similar agreement with South Korea’s LG Energy Solution (LGES), as it rolls out its $35 billion (30 billion euro) electrification plan. Automakers are investing billions of dollars to accelerate a transition to low-emission mobility and prepare for a progressive phase-out of internal combustion engines. Stellantis, which was formed in January via the merger of Italian-American automaker Fiat Chrysler and France’s PSA, earlier this year announced it would invest more than $35 billion (30 billion euros) through 2025 on electrifying its vehicle line-up. The two battery deals will support its goal to have EVs account for over 40 percent of its …