By Stephen Nellis

SAN FRANCISCO, Dec 3 (Reuters) - Shares of Aeva Technologies AEVA.O, a Silicon Valley-based maker of lidar units that help autonomous vehicles sense their surroundings, rose more than 18% in midday trading on Wednesday after the company announced an exclusive deal to supply a European maker of passenger vehicles.

Aeva did not name the automaker, but analysts at Morgan Stanley and Canaccord Genuity last month said in research notes they believe the customer is Mercedes-Benz MBGn.DE.

Aeva said in a press release the automaker will use its sensors, which can generate a 3D map of the world around a vehicle as well as detect how fast objects such as pedestrians are moving, for autonomous-driving functions in all of the automaker's combustion, electric and hybrid vehicles outside of China.

Aeva did not disclose a value for the deal and said it would provide more details early next year. At an analyst event earlier this year, Aeva executives said the partnership could be worth more than $1 billion in sales, though they did not give a time frame for those sales.

In a release on Wednesday, Aeva said its sensors would be used for what is known in the automotive industry as level 3 autonomy, where a vehicle can drive itself under limited conditions such as stop-and-go traffic or on certain kinds of highways.

“This OEM views lidar as essential to enabling safe level 3 automation, and their decision marks a pivotal moment as the passenger vehicle industry accelerates toward bringing level 3 capabilities to consumers worldwide," Aeva CEO Soroush Salehian said in a statement.

(Reporting by Stephen Nellis in San Francisco; Editing by Chris Reese)

((stephen.nellis@thomsonreuters.com))