Nissan, which has been mass-producing electric cars for more than a decade, is seen as holding the upper hand in the alliance in electric-vehicle technology. TOKYO— Renault SA and Nissan Motor Co. said Monday they were discussing ways to reinforce their partnership, including the possibility of an investment by Nissan in Renault’s new electric-vehicle unit. The discussions over the possible Nissan investment are part of broader talks by the two auto makers over reorganizing their alliance, which dates back more than two decades, people with knowledge of the talks said last week.

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