Toyota was the first major automaker to introduce a series production hybrid to its lineup nearly 25 years ago. The first-generation Toyota Prius, though not the most attractive-looking vehicle, was a game-changer on many levels. Interestingly enough, the automaker today is in no rush to change its entire lineup to pure battery electrics, a decision already made by General Motors and Ford of Europe, among others.

Toyota is still investing plenty of time and money into its solid-state battery program and it's been using lithium-ion batteries for popular models like the latest RAV4. But it still uses the old nickel-metal hydride battery, a chemistry nearly all other automakers long abandoned, if they ever even used it.

Automotive News reports that not only is Toyota sticking with nickel-metal batteries, but recent R&D efforts have proven very effective in giving it a new lease on life. Called the bipolar nickel-metal hydride battery, the updated configuration utilizes a new structural design that not only makes it more powerful but also more compact. It was a brilliant move on Toyota's part because the program required a significantly smaller investment instead of completely overhauling things for newer battery tech.

The new design is 1.5 times more powerful than before and allows for 1.4 times as many cells in the same space. Most customers are unaware of which kind of battery chemistry is used in their hybrids, and even fewer care.

Toyota answered the call. Nearly doubling their size helps keep vehicles like the Prius competitive for the next several years. Normally, nickel-metal hydride batteries have around a 40 percent lower energy density than lithium-ion batteries. Toyota hopes to introduce a new generation of lithium-ion batteries sometime in the second half of the decade, along with solid-state batteries. The downside with the latter is that they're likely to be more expensive at first. It'll take time to bring costs down.

But for now, the new bipolar nickel-hydride tech is here to stay as Toyota saw no reason to abandon a proven and reliable technology just because some perceived it as "old."