Battery Swapping is key for cold weather

There is so much frozen ice and mud under my EV right now. If I had a swappable battery, it would take a very long time to get it out and more time to make sure nothing nasty gets between the replacement battery and my car.

Getting carmakers to standardize on a swappable battery pack would seem to be a difficult task--how would they agree on a battery capacity? Owners of expensive EVs would have large-capacity batteries and owners of entry-level EVs would have batteries of lower capacity. Would a Bolt or a MINI have to provide space for the same battery used in a Ford Lightning or a Tesla Model S?

Then there's the potential for a swappable-battery EV owner to come out to their EV and find that catalytic-converter thieves have stepped up their game.

I believe battery technology will improve faster than a swappable battery standard could be realized.

 

I'm sure they could use car-wash technology to melt the ice coating the chassis and then blow the underside dry, but that would add time.

Those battery swaps you cite are for a single manufacturer's vehicles. Would each manufacturer have to maintain their own battery-swapping stations? Installing a universal DCFC charging station looks much easier than that.

Don't sell the ingenuity of thieves short--especially for unguarded high-ticket items.

 

It is easier to lease an EV than just lease a battery. Or in my case, pay a onetime fee until my EV goes to the salvage yard or next owner. Leasing a new EV means not only a better battery, battery management, and battery chemistry but also improved total vehicle systems. There are manufacturing saving too. For example, making the battery part of the vehicle crash structure:


This approach radically reduces the labor cost of making an EV. The battery pack and seats can be assembled on all sides without workers stumbling over each other. The empty hole in the bottom makes installation of interior wiring, HVAC, and safety equipment much easier than trying to noodle them through the doors:


No, I prefer my vehicles to be fully integrated from design, manufacturing, and operation. I buy them knowing it is a snapshot of EV technology the day it was made. So the battery swap approach has no appeal.

Bob Wilson

 

If Nio and the other Chinese companies end up ruling the EV world, perhaps their collaboration can create a single battery that fits all of their cars. However, I don't see Nio's swappable battery taking the EV world by storm the way Elon's NACS charging connector has. High-end and low-end EVs will always be using batteries of different capacities.

Swapping may be proven technology, but it's expensive technology. I'm ancient and remember when every gas station had attendants who filled your tank, checked your oil, and washed your windshield. Those attendants had to be paid by the gas station and so they're now history in most places.

Can a battery-swapping station be completely automated? Even if a battery-swapping station could be completely automated, compare the cost of such a station to the cost of a you-plug charging station. I can't see how the cost to the EV owner would be even close. If the battery-swapping station requires an attendant, the cost of swapping is even greater.

What is the benefit of battery-swapping stations being moveable? What the stations would need to be is numerous and ubiquitous. The argument that charging stations aren't numerous or ubiquitous enough right now does not suggest that battery-swapping stations solve that problem because battery-swapping stations cost more and require more maintenance than simple charging stations.

The idea that there would be cheaper-than-charging battery-swapping stations everywhere that would always have the single battery every EV is forced to use would be a difficult dream to realize. It would require an authoritarian govenment to enact and enforce, and not all authoritarians are pro-EV.

 

If we had human sized, battery modules in the 20 kG (~44 lbs) size that could be swappable by the owner, it might be interesting.

So around town, carry just enough for say 100 miles range and the rest in a benign for battery life state. Then when I want to do long distance travel, load up the car.

In effect, a human sized, set of batteries. They could line the outside of the EV also solving the battery fire problem with an emergency quick release.

After all, Nio has proven that power and coolant quick releases work great. Just make human sized batteries and the problem is solved.

Single, mechanically removable batteries are not appealing.

Bob Wilson

 

Battery swapping may be possible for smaller vehicles like scooters/motorcycles, but I don't see it as practical for large vehicles. If you think waiting for a charger is bad, think of how many swapping stations would be needed to service hundreds of thousands of large EVs traveling the highways and byways of North America. It's like visiting a Jiffy Lube, but doing it on a daily basis (or more if traveling cross-country!). Not to mention the enormous costs of maintaining inventory of replacement batteries at each of these locations. And @insightman's thievery concern is well-founded.

 

Not from one company, but only one standard capacity. Otherwise, the swapping stations will have to stock as many different capacity batteries as anyone might want? That makes the swapping-station model much more problematic. "Sorry, Mr. Tesla S, that Bolt just took our last battery with more than 60 kWh."

 

I agree. Battery swapping can work for scooters in counties where scooters are the primary means for transportation.

You might be able to make a case for cross country trucking and municipal busses if they can standardize on the size, connections, and software.

The capital costs are too high for these to be profitable in the USA. Heck, the current fast chargers are not likely profitable in most locations.

 

Let's take a look at a practical version of swappable batteries. I use 80VDC Greenworks batteries:

The extended run battery, 288 Wh, is on the left. The smaller 144 Wh batteries are on the right. But the right most one failed.

The problem is one or more cells have started corroding:

These are 18650 cells that I could buy on eBay for ~$40. Add to that a battery tab, spot welder, and a couple of hours and the 144 Wh battery would recturn to service.

Instead, I bought a new, 21700 cell, 288 Wh battery, $400, that is the same size as the original, small 144 Wh battery packs. Lighter than the large, extended run battery, it makes a lot of sense over several years of operation.

Fitting the 21700 cells in the same dimensions as the original 18650 cells is a neat trick. But 18650 cell chemistry has improved. The originals appear to be 2500 ma cells and I see 3000-3500 ma cells available. It makes more sense to let battery technology continue to improve and replace the failed 18650 with higher energy density, LiON cells within a year. So how does this relate to 'battery swapping?'

Notice the overhead of swappable battery packs. This adds weight and non-payload volume to the vehicle. These parasitic loads on the EV reduces their range and efficiency. They carry around extra structure. In contrast, the structural battery pack weights only as much as the minimum number of parts needed.

So I add swappable battery packs to hydrogen fool cells as another, dead-end technology. In PowerPoint or user forums, sounds GREAT. In real engineering, something less.

Bob Wilson