General Motors Co. has invested $300 million to upgrade and heavily automate its Detroit-Hamtramck plant ahead of this year's launch of the 2016 Cadillac CT6 luxury sedan, a company executive said Thursday.

The investment includes the construction of a new body shop equipped with 205 robots and designed to use such advanced manufacturing techniques as aluminum laser welding, Cadillac President Johan de Nysschen said in remarks prepared for the Washington Auto Show.

The CT6 is Cadillac's new flagship sedan and the first to employ a new naming scheme which, like many of Cadillac's luxury competitors, uses letters and numbers.

It will be slotted above the CTS and XTS sedans, and eventually will be joined by an even larger, more expensive model that will be called CT8 or CT9, de Nysschen, who last year left rival Infiniti for Cadillac, has said.

The Detroit-Hamtramck plant also has been upgraded in advance of production this summer of the redesigned 2016 Chevrolet Volt, which was unveiled last week at the Detroit Auto Show. The plant builds the ELR hybrid coupe, Cadillac's companion to the Volt sedan.