PALO ALTO, California (Reuters) - A joint venture between U.S. electric pickup and SUV maker Rivian and Volkswagen is in talks with other automakers about supplying their software and electrical architecture, a senior Rivian executive said on Thursday.

The German automaker agreed in November to invest $5.8 billion in the joint venture, which will integrate advanced electrical infrastructure and Rivian's software technology for both companies' future electric vehicles.

While a joint venture will give Rivian higher volumes to negotiate better supplier deals and reduce costs, seen as critical amid a slowdown in EV demand, Volkswagen and potentially other traditional automakers will get quick and easy access to technology and software they have struggled to build for years.

"I'd say that many other OEMs are knocking on our door," Rivian Chief Software Officer Wassym Bensaid said in an interview, referring to Original Equipment Manufacturers, a phrase used to describe vehicle makers.

Bensaid, who is also co-CEO of the joint venture, declined to provide names of the interested automakers and details on what stage the talks were at.

Rivian's architecture requires fewer electronic control units and significantly less wiring, reducing vehicle weight and simplifying manufacturing. The technology is core to building cars with software that could be updated over the air like a smartphone - what the industry calls "software-defined vehicles", an area where established automakers are still running behind.

"There is demand," said Bensaid, adding that the priority until 2027 was to roll out the R2, Rivian's smaller, less-expensive SUV and to integrate the technology in other Volkswagen brands. "Obviously other OEMs are talking to us and we're trying to figure out how to support that in the future."

"Any other OEM who wants to make a leap from a technology standpoint, the joint venture today becomes one of the key partners with whom they can make that collaboration," he said.

The venture is likely to become the platform of choice in the Western world apart from Tesla, Canaccord Genuity analysts said in a note. The joint venture also helps alleviate "a significant chunk of the capital concern" for Rivian, the analysts said.