For years, electric-vehicle investing meant one company: Tesla (TSLA -2.44%). Sure, Nissan had the Leaf and there were a few hybrids riding around, but Elon Musk's game-changing start-up was the only major player in the space.

That's changing. And fast. 

Here are three big developments you need to know about in the world of electric-vehicle stocks. 

A car speedometer's needle points to 250.

Image source: Getty Images.

1. It seems like there's a new one every month

It's true: We're on track to see nearly a dozen new electric-vehicle stocks make their market debuts in 2020.

Blame fuel cell-powered truck maker Nikola (NKLA 2.84%) for starting the craze, after it went public through a highly publicized reverse merger with special purpose acquisition corporation (SPAC) VectorIQ in June. Since then, we've seen the same reverse merger trick used by Lidar specialist Velodyne Lidar, Inc. (VLDR) and electric powertrain manufacturer Hyliion, with electric vehicle manufacturers Lordstown Motors, Fisker, and Canoo expected to follow suit before the end of the year. Chinese EV companies Li Auto and Xpeng also went public this year, through traditional U.S. IPOs.

With so many electric vehicle stocks hitting the market, investors need to look at the industry in a new way. A bet on Tesla in 2014 was a bet that the EV industry as a whole was viable. Now, even if the industry as a whole is successful, it's a near-certainty that at least one of these start-ups is going to flop. And with so much still in flux, it's not at all clear which one it will be.

2. Some of them have never built a car

When Tesla finally went public in 2010, it had already been manufacturing its flagship Roadster for two years. But many of the EV companies that are debuting this year have never built a production vehicle at all. At least, not yet.

Nikola is a prime example. Although it has built prototypes of its Nikola One, Nikola Two, and Nikola Tre semi trucks, it's never actually taken one of its vehicle designs through the production process, and in fact, doesn't even have a production facility built yet. Lordstown Motors has a facility in the former General Motors plant in Lordstown, Ohio, but it isn't expected to begin production of its first vehicle, the Endurance electric pickup, until 2021. Canoo's first vehicle, an all-electric minivan, won't debut until 2022.

It's risky to invest in a manufacturing company that's never, well, manufactured anything. Remember how even Tesla ran into snags trying to ramp up Model 3 production in 2019? And that was after it had already had more than a decade of successful car production under its belt. Don't underestimate the potential of manufacturing problems to derail these companies' timelines.

3. All car stocks are now electric car stocks

We've come a long way from the 1990s, when the big carmakers fought tooth and nail against offering electric vehicles as part of their product lineup. Today, every major automaker around the globe has at least one electric vehicle model currently for sale or in development. Many of these vehicles will hit the market in 2021 or 2022, if not sooner.

The battery-electric crossover SUV seems to be the most popular vehicle on offer, with Tesla's Models X and Y already available, to be joined by Ford's Mustang Mach E by the end of the year. Nissan's Ariya will debut in 2021, along with new crossover SUV offerings from AudiBMWVolkswagen, and others. Meanwhile, Subaru and Toyota are jointly developing a pair of electric SUVs.

Industry heavyweights aren't just developing their own cars, they're investing in smaller companies as well. For example, GM not only manufactures the Chevy Bolt, but owns a stake in Lordstown Motors and is also slated to invest in Nikola. Volkswagen is backing soon-to-go-public battery maker QuantumScape and is negotiating with Fisker regarding use of its technology in Fisker's Ocean SUV.

The surge in interest among legacy automakers, coupled with all of the new start-ups, is likely to have a profound impact on the industry as a whole.

A whole new world

By 2022, the global electric vehicle market will look profoundly different than it did just five years earlier. There will be new companies, new models, new technology, and -- most importantly -- new levels of competition among players in the space. 

Electric vehicle stock enthusiasts should expect that not all of their picks will be winners in this new world of EVs, and invest accordingly.