Boeing is joining the global scramble for efficient batteries.

The aerospace giant's venture arm Boeing HorizonX Ventures has taken a minority stake in battery start-up Cuberg, Boeing said Monday.

Cuberg joins Boeing HorizonX Ventures' stable of investments that include Zunum Aero, an electric-and-hybrid plane startup whose investors also include airline JetBlue.

The terms of the deal were not disclosed, but Boeing spokeswoman Megan Hilfer said the investment was typical of Boeing HorizonX's minority equity investments "that span the single millions up to the low double-digit millions" of dollars.

While battery-powered flight is attractive, especially as fuel prices have recently surged to more than three-year highs, challenges abound.

"Currently, battery technology is still heavy," so you can't make it for a plane of current commercial aircraft size, Cuberg's co-founder and CEO Richard Wang told CNBC. "You need to take a leap to the next generation."

Berkeley, California-based Cuberg is developing a battery whose components are lighter and less flammable compared with current battery technology, Wang said. It hopes to test a prototype in late 2018.

"Cuberg's battery technology has some of the highest energy density we've seen in the marketplace, and its unique chemistries could prove to be a safe, stable solution for future electric air transportation," said Steve Nordlund, vice president of Boeing HorizonX.