No matter how much battery technology improves, charging an electric vehicle will never be as fast as filling up a tank of gas. The laws of thermodynamics simply won’t allow it, not even for Elon Musk and Tesla.
The rate of energy transfer can only get so fast — for car batteries, that means a minimum of around 10 minutes charging time. If you try and go faster, the charging becomes too inefficient and generates a high level of heat, which means lost energy.
“There are fundamental limits as to how fast one could ever charge a battery pack,” Venkat Viswanathan, assistant mechanical engineering professor at Carnegie Mellon University, tells Inverse. “We can never get to the 30 second or two minute time frame you have for fuel filling.”
But, Viswanathan says, that is no reason to be pessimistic about the future of electric vehicle traveling. Yes, even on long distance trips.
The infrastructure problem accompanying the technology problem
Tesla’s supercharger network is the fastest, most advanced network in the United States. But it isn’t everywhere and it only works with Teslas.
Owning an electric vehicle is “very much like having a cell phone that you can only charge at the office or in coffee shops,” Tesla owner Will Schenk writes on the Tesla blog. “Kind of weird, takes a little bit of planning, but it can work.”
When the relatively low-priced Tesla Model 3 comes out and more people are able to utilize the Supercharger infrastructure, that planning will have to be based around approximately 215 miles per charge. The number of Superchargers (and regular chargers that are just as capable, if slower) is growing every year, but areas of the Midwest still have long, range-anxiety producing stretches.
Completely charging a battery takes over an hour. That’s a lot of time to give up every 200 or so miles, and before many people feel comfortable investing in an electric vehicle, they need to know they can go the distance.
People will still have to stick to urban streets for that lower priced, smaller battery Model S in the short term.
“I think the breakthrough in charging technology will probably start after the adoption of electric vehicle increases a little bit, or after we have bigger batteries,” Mehrnaz Ghamami, assistant professor of engineering at Michigan State University, tells Inverse.
Battery swapping: speed vs. reliability
Tesla looked into a battery swap program in the early days of the company. By 2013, it only took 90 seconds, or about half the time it takes to fill a tank of gas, to swap a battery out of a Model S. Despite the progress, the program was largely abandoned by 2015.
That’s because batteries, in a sense, have a memory of how it was used and what conditions it experienced in the past.
“Say I used a battery for 10,000 miles and another person used their battery for 10,000 miles and we do a battery swap,” Viswanathan says. “One would think they’re indistinguishable, but they’re not.”
A battery exposed to cold weather, hot weather, and heavy stop-and-go traffic will have more degradation than a battery in temperate California. A 90-second swap could result in you paying for a less efficient battery.
The best use for a battery swap, says Ghamami, is for an electric ride-share fleet. So battery swap is a good idea if Lyft and GM’s plan to eliminate car ownership entirely with a fleet of autonomous electric Chevy Bolts works out. If not, an extensive Supercharger infrastructure or some future technology is more likely to be the answer to range anxiety.
Wireless charging: The long term solution
Plugging in is a modern inconvenience. Sure, it’s what you might call a first world problem, but when wireless charging advances enough it could change the entire way that cities are designed.
Wireless charging will never be as fast or as efficient as plugging into a Supercharger. More energy is lost in the transfer from charger to car. Ubiquitous wireless chargers could mean never needing to intentionally charge though.
Plugless, one of the foremost companies working on wireless electric vehicle charging, has successfully worked with a variety of companies from Google to Hertz rental service. Once the technology advances enough, it’s not hard to imagine having something like Plugless under every parking spot in town. Going to the local vape outlet isn’t just running errands, it’s getting your car ready for the next trip you take.
Eventually, chargers could even be put in roads to charge electric vehicles while they drive. As with Superchargers, infrastructure is just as important as the technology. How it will be paid for, which lanes will be dedicated, and how it will affect traffic conditions all have to be taken into account. It’s no small task for future generations if that path is taken.
For now, electric vehicle owners will have to calm their range anxiety with proper trip planning and avoiding places without public chargers. Electric vehicles are just on the edge of what is possible.
“We are not quite there,” Viswanathan says, “but all of the right factors are in place for us to be able to set up an infrastructure to make long distance trips more seamless.”