Ford and Samsung showed off a prototype for a lithium-ion battery that could finally spell the death of ye ol' lead acid brick for good. And it's about damned time.

At the same event in San Francisco where the wraps came off the , Ford and Samsung SDI – the tech giant's battery/green arm – gave us the first taste of a new automotive-grade battery that would make lead-acid batteries obsolete.

What you're looking at is a Ford Fusion. It looks like perfectly average, mid-sized sedan on first…

While lithium-ion batteries power everything from smartphones to Teslas to Ford's range of hybrids, they haven't replaced the traditional 12-volt battery under your hood. The reason, according to Mike O'Sullivan from SDI, is because lead-acid chemistry remains reliable and cheap. But that's changing.

The lithium-ion pack that Ford wants to use is 40 percent lighter than its lead-acid counterpart, saving about 12 pounds overall. That's not much, but combined with the other weight saving technologies shown in the Ford Lightweight Concept, it adds up.

Unfortunately, neither Ford nor Samsung would say when we'll see the lead-acid battery replaced with the lithium-ion pack, but it's likely to happen within the next few years as automakers test the load limits and longevity of the new cells.

But the lead-acid battery isn't completely off the table. Ford also took the opportunity to detail its efforts to combine a lithium-ion battery with a lead-acid unit to bring regenerative braking capabilities to non-hybrid cars.

The system works in conjunction with the start-stop system for the engine, keeping power flowing to the accessories when stopped in traffic. By capturing the energy lost to braking, Ford will port the same tech on its hybrids to traditional ICE vehicles, boosting fuel economy and efficiency without the weight penalties of a full hybrid system.