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Comment by osrec | Hacker News Reader

Swappable low cost sodium batteries are where I think cars may end up in the future.

Literally, pull into a swapping station, and have your battery swapped out for a charged one in a couple of minutes. Probably faster than fuelling up your car with petrol.

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This is kind of happening at scale in China right now (only some brands are pursuing it though): https://restofworld.org/2024/ev-battery-swapping-china/

It's an interesting trade off between swapping station cost and time to charge. I suspect charge times will decrease enough that it's not worth all the physical investment in swapping, it may already not be.

Swapping for regular cars is a dead end I think. But for trucks and such I imagine it makes a lot more sense. Much longer charging times vs a quick swap. Much easier to put battery in an easy-to-swap location. Fewer swapping stations needed before it makes sense to utilize it for transportation companies, ie team up with a company that has a few fixed large-volume routes to get going.

This either requires 1) Different swap stations for every brand of car or 2) a majority of car brands agreeing to use a common size, shape, and spec of battery pack across their vehicles.

Personally I don't see that becoming a reality anytime soon at least in the US.

I don't know why I feel this will be necessary for EVs to become mainstream. Batteries simply don't last long enough, and even if they do, they degrade over time. Making them easily swappable seems to be a reasonable solution to this.

I have a 5 year old EV with around 95% of its original battery capacity. I think battery degradation of newer EVs will not be the limiting factor in their lifetime or in transitioning from combustion vehicles.

Under 1% of EVs from 2016 or newer have had battery replacements.

https://www.recurrentauto.com/research/how-long-do-ev-batter...

Early EVs skewed that a bit by having poor thermal and charging management of their batteries. Newer chemistries and packs with active thermal management reduce the issues significantly.

Different chemistries also have varying lifetimes. LFP batteries trade a bit of energy density for greater resiliency to charge cycles over their lifetime.

Do you get the 95% number from the dashboard or from actual mileage that you’re able to drive? In my experience those two metrics can be very different, e.g. a vehicle with reported battery health of 80% getting just half of original range.

From the dashboard, and the Tesla BMS is fairly accurate as long as you allow it to calibrate at 100% charge occasionally.

I have also not seen a noticeable change in my range for actual long distance driving over those years, and I do occasionally stretch it to near its full range.

The biggest change was putting wider, higher-performance all season tires on after the factory eco tires were worn out. Still I mostly noticed that efficiency change by tracking my stats on trips. There wasn’t really a noticeable difference from the drivers seat.

I haven't been following this very closely, but it seems like it would be a positive development if EV manufacturers made batteries easily removable and interoperable. Swapping would necessitate this.

Sounds like a big step back from the car charges at home and is "always full" without ever "filling up", except on roadtrips, where it schedules periodic rest stops.

Doesn't preclude charging at home.

Just means "swap stations" instead of charging or gas stations.

The (major) challenge is what you do with 400-800kg of batteries and a bunch of different vehicle types from different manufacturers. Standardize the size/placement so a robot can do it? Break it down to smaller pack sizes so a human -- driver or attendant? -- can do it? Have each car manufacturer have their own set of stations?

Took everyone long enough to agree on a plug, would it be possible to agree on a swappable pack?

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