There's no denying most electric vehicle (EV) stocks have been lackluster performers of late -- the movement simply hasn't caught on as it was expected to just a few years back. Indeed, sales trends and feedback suggest consumers are actually losing interest in EVs, citing range and charging concerns. And those worries aren't invalid.

This doesn't mean EV-related companies are a bust, however. There's still a very bright future ahead. Bloomberg predicts sales of EVs will grow at an average yearly pace of 21% over the next four years, reaching annualized sales of 30 million cars en route to 73 million vehicles in 2040. The recent headwind is mostly just the result of fading euphoria before the industry clears the last of its marketability hurdles.

With that as the backdrop, here's a rundown of three underestimated EV stocks that could go parabolic at some point in the foreseeable future. It's no coincidence that all three companies are developing solutions that will allow EVs to live up to their initial expectations.

1. QuantumScape

If you're familiar with the technology of EVs at all, then you likely know the lithium-based batteries they require are a stumbling block. They degrade over time and must be replaced every few years. Those replacement batteries are not cheap, priced anywhere from $5,000 to $20,000 apiece. They're also difficult and expensive to recycle (and not every part of these lithium batteries can be reused).

What if, however, EV batteries' biggest drawbacks were overcome? Enter QuantumScape (QS -3.09%).

In simplest terms, QuantumScape makes better lithium-based batteries. Using a proprietary technology, it has designed a ceramic solid-state lithium battery that not only doesn't require anodes, but remains 95% efficient (in terms of energy-storage capacity) for far longer than the typical EV batteries currently in use do. Perhaps most notably, QuantumScape's solid-state batteries offer markedly more driving range on a single charge.

A bit of due diligence on QuantumScape raises a red flag. That is, it hasn't yet reported any revenue. Dig deeper, though. It's coming. The company only began delivering prototype batteries for EV manufacturers to start tinkering with in March of this year, and these prototypes still aren't the final version of the QSE-5 battery it intends to make en masse once the technology is finalized.

Interest in its batteries is firming up, though. In July Volkswagen's battery company PowerCo entered an agreement allowing the carmaker to manufacture EV batteries based on QuantumScape's impressive tech. Other automobile makers are also likely eyeing this proprietary technology, since it has the potential to make their EVs more marketable as well.

The point is, QuantumScape's first-ever revenue is on the horizon. That's the sort of milestone that could light a fire under any stock.

2. Plug Power

While a better lithium-based battery could certainly give the EV industry a much-needed boost, that's not the only way to power an automobile (aside from the current conventional, pollution-creating combustion engine). Hydrogen fuel cells can generate direct electric current that spins an electric motor too. In fact, a company called Plug Power (PLUG) has already proven the idea works in automobiles.

The science is simple enough. A fuel cell's cathode and anode chemically split a hydrogen molecule into positively and negatively charged protons and electrons, essentially becoming a battery in and of itself. And the only output from this process is heat and water.

This idea's biggest hurdle to date has arguably been the world's lack of understanding of it. Most everyone knows how well-proven combustion engines work, and battery-powered EVs are simple enough. But using hydrogen to create electricity? That's a bit of a leap. There's also the not-so-small issue of raw hydrogen not being readily available everywhere vehicles are driven.

As is always the case, though, time takes care of smart ideas. A few dozen consumer-facing hydrogen refueling stations are now up and running (mostly in California) plus many more private ones for bus and delivery-truck fleet operators.

So far Plug Power's focus has been on everything but passenger vehicles. Large trucks and buses, industrial robotics, and aerial drones are where it's making its biggest impact. It also provides stationary fuel cell systems that can power buildings, data centers, and factories in a pinch, or even on a permanent basis now that hydrogen is available -- and in some cases cheaper than more mainstream methods of procuring electricity.

Wherever this technology's growth awaits, Plug Power stands ready.

As for investors, they should know that this company's revenue has been inconsistent. The company is also habitually unprofitable, with losses growing rather than shrinking. Plug Power may be at a fiscal turning point, though. Analysts are calling for a strong reversal of this year's top-line lull, putting the company on a sustained path toward profitability. As is the case with QuantumScape, simply being on the right fiscal trajectory could be enough to reignite the stock following its three-year lull.

This might help: As of the latest look, analysts' consensus price target of $4.06 per share is nearly twice Plug Power stock's present price.

3. Nikola

And if you're looking for practical, commercial uses of hydrogen fuel cells as a power source for conventional vehicles, look no further than Nikola (NKLA 0.88%).

You won't be driving a Nikola vehicle anytime soon. In fact, you probably won't be driving one at all. The company's production is limited to class-8 trucks; you know them better as "big rigs" (the tractor part of a tractor-semitrailer). While the company makes a purely battery-powered rechargeable truck, following problems with these battery-powered haulers that forced a sweeping recall, it's becoming clearer to the company -- as well as its customers -- that fuel cell-powered electric vehicles are actually the more cost-effective and reliable option. To this end, Nikola delivered 72 of these tractors in the second quarter of this year, up 80% from Q1's figure.

The tech lends itself to this sort of heavy-duty industrial usage, anyway.

While hydrogen fuel cells are a proven means of generating clean electricity, they're still not quite practical for the mass market, which of course requires lots of refueling infrastructure. (For perspective, there are nearly 200,000 gas stations in the U.S. alone.)

Class-8 truck fleet operators don't necessarily need such a widely available network of refueling options, however. They often manage their own, allowing their drivers to fuel up at warehouses or dispatch centers rather than getting them tied up in traffic. Nikola is supporting the paradigm shift on this end of the business as well, launching a venture called Hyla early this year to offer refueling solutions for its hydrogen-powered class-8 rigs.

Like Plug Power and QuantumScape, Nikola is presently unprofitable. Founder Trevor Milton brought legal trouble to the table as well but is no longer involved with the company.

Look forward rather than backward, though. This company's top line is projected to grow more than 200% this year and then repeat the feat next year as fleet owners clamor for its long-awaited solution. This will at least drive the company toward profitability.

That will still only scratch the surface of its opportunity, however. Roughly a quarter of a million of these big trucks are sold every year in the U.S. alone. More and more of them are zero-emissions vehicles that comply with continually rising emissions standards.