Nissan and Renault on Monday unveiled details of their redesigned alliance, with the Japanese car maker committing to buy a stake of up to 15% in Renault’s electric vehicles unit Ampere.

The alliance junior partner Mitsubishi Motors will also consider investing in Ampere, the companies said in a statement.

“Nissan’s intention is to invest up to 15% in Ampere, Renault Group’s EV & Software entity in Europe, with the aim to become a strategic investor,” the statement said ahead of a presentation in London.

The companies had already announced that under the deal to revive their 24-year old alliance the French carmaker would reduce its stake in its Japanese partner to 15% from around 43% now.

Renault will transfer 28.4% of Nissan shares into a French trust, making the two more equal partners in the alliance.

Sources close to the matter said the agreement aimed to make the alliance freer and more balanced for the next 15 years. The partnership will produce synergies from joint projects in Europe, India and Latin America, and the companies will work together in Renault’s flagship EV business, electronics and solid-state batteries.

Renault will have full flexibility to sell the Nissan shares held in the trust but “it has no obligation to sell the shares within a specific pre-determined period of time,” the statement on Monday said.

When it does sell, “Nissan would benefit from a right of first offer, to its or the benefit of a designated third party.”