While lithium-ion cells have powered all but a handful of plug-in electric cars since 2008, carmakers have looked further down the road toward solid-state battery cells with an eye toward launching them sometime during the 2020s.

On Monday, BMW Group and Solid Power announced that the two companies would partner in an effort to develop Solid Power's solid-state battery systems for future long-range electric cars.

The goal, the companies said in a press release, is to develop those cells to provide the output, durability, and safety required for use in "high-performance electric vehicles" of the future.

DON'T MISS: 2022 Toyota electric car to use solid-state batteries: report

Solid Power was established in 2012 as a spinout from solid-state battery research conducted at the University of Colorado at Boulder.

It hopes to use that technology to develop battery packs and systems for devices from portable electronics to aircraft, satellites, and of course electric cars.

The partnership with the internal battery R&D group within BMW should enable cell and pack development to proceed with significant feedback from an experienced automaker.

2019 BMW i8 Roadster, 2017 Los Angeles Auto Show

2019 BMW i8 Roadster, 2017 Los Angeles Auto Show

No financial details of any investment were given in Monday's release, which was light on the specifics of the actual cooperation.

BMW is the furthest advanced of the three German automakers in electric vehicles, with its technically advanced i3 battery-electric model in production since 2013.

READ THIS: Solid-State Batteries Already Powering Electric Cars: BlueCars, In Fact

The Colorado company's solid-state battery cell substitutes a proprietary, inorganic material for the liquid electrolyte used in today's lithium-ion cells of all formats.

That technology, the companies said, has "great potential" for longer driving range in a battery with extended shelf life that can safely withstand high temperatures due to its higher energy density and lack of volatile or flammable components.

2016 BMW X5 xDrive 40e, Hudson Valley, NY, Dec 2015

2016 BMW X5 xDrive 40e, Hudson Valley, NY, Dec 2015

“Since the company’s inception," said Doug Campbell, founder and CEO of Solid Power, "[our] team has worked to develop and scale a competitive solid-state battery, paying special attention to safety, performance, and cost."

“Collaborating with BMW is further validation that solid-state battery innovations will continue to improve electric vehicles," he continued. "We’re looking forward to working with BMW on pushing the limits on developments around ... batteries.”

CHECK OUT: Fisker still aims at solid-state electric-car batteries, as patents attest

Solid Power says it expects to double its employment over the next three years, centered on a new research and development facility in Louisville, Colorado.

While many automakers are involved in advanced research into solid-state battery cells, analysts don't expect vehicles using such cells to hit the road before the early to mid-2020s.

_______________________________________

Follow GreenCarReports on Facebook and Twitter.