Flush with cash and fearing what it thought was peak oil production in the 1970s, Exxon funded a host of new ventures divisions geared to find alternatives to gas-powered powertrains. In the early 1970s, Exxon lured chemist M. Stanley Whittingham to develop what would become a prototype of a lithium-ion rechargeable battery.
Then, in the late 1970s, Exxon pioneered the concept of using an alternating-current (AC) motor as part of a gas-electric hybrid vehicle. The company retrofitted a Chrysler Cordova (yes, that's the model Ricardo Montalban used to hawk) with a powertrain that combined 10 Sears Die-Hard car batteries, an alternating current synthesizer (ACS), a 100-horsepower AC motor, and, yes, a four-cylinder 50-horsepower Volkswagen diesel engine. The result was a rather large two-door sedan that got an impressive 27 mpg. And while US automakers didn't see the potential in the early concept, in 1980 Exxon and Toyota began collaborating on a project that would involve retrofitting a Toyota Cressida with a hybrid engine. That car was completed in 1981, and may have been one of the seeds that eventually helped sprout the concept of the Toyota Prius.
Soon after rebuilding the Cressida, Exxon would get out of the advanced-powertrain-development business, as oil prices began to fall in the early 1980s, spurring cost-cutting measures. Cry no tears for the Exxon, though, as what's now known as ExxonMobil is the largest US oil company.