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I have long wondered why battery swapping is a no-go. Just like with a propane tank (e.g. for backyard grilling) I just take the empty to a store and swap it f

I have long wondered why battery swapping is a no-go. Just like with a propane tank (e.g. for backyard grilling) I just take the empty to a store and swap it for a full. I don’t wait for them to fill it. My guess is that for engineering reasons this is a no-go because the carmaker needs to be able to cram battery into odd nooks and crannies of the car, so it isn’t practical to make them interchangeable. I did once hear of an idea to have ships use electric while in port, and have swappable batteries for this - but on a ship space is hardly a limiting factor. I know nothing about this though.

roumenguha 3y ago
There's at least one automaker (Nio) with battery swaps as part of their regularly offered services.
ylhert 3y ago
There are a number of reasons why battery swapping is not feasible in the real world, among them: - Batteries age differently from one another, so swapping would only be fair if you had a similarly aged battery that had a similar number of miles & charge cycles on it - Batteries need to be taken care of (like not using the last 10% at each limit of the battery). some people take really good care of their batteries, others don't. I would never want some random battery swapped into my car, as I've taken really good care of my car's battery - Batteries are structurally built into the vehicle, and making them easily removable would make a lot of the engineering more difficult - Batteries could become commoditized so that they fit in any car, but right now there are tons of different shaped & sized batteries, so it would be really hard to build the tooling to support all these different cars & battery types
cmrdporcupine 3y ago
The weight is crazy (Model 3 long range is ~1000lbs), so you need a serious facility to swap. They are relatively delicate, and flammable in a terrifying way, so you'd need to trust the facility more than e.g. your average oil & tire swap shop. From an engineering POV they need a coolant loop w/ a pump, a high voltage connect to the charger, and usually also a connection to a DC-DC converter for the 12v systems on the car. So if you make it modular/removable, you need a (standardized) answer for how to do all of this. The form factor of the battery is tied fairly strongly to the chassis generally, so if you force a standardization of it you limit manufacturer's options there. Finally, probably the most important, is ownership model. The battery is the most expensive part in the car, by far. It basically is the car. Who owns it? What's the revenue model? How does insurance handle it? Will consumers accept a situation where they're getting random batteries shoved in affecting the performance etc. of their car? It's just a whole thing. It's been attempted, and not succeeded is what I see. Now, what I don't understand is why this isn't the model for EV shipping trucks. In that case they already have a highly modular, heavy duty platform and they already have to check into frequent weigh stations, and the operator rarely owns the truck. I don't understand why the shipping industry wouldn't pursue a model where a standardized set of pre-charged batteries aren't sitting on automated forklifts at weigh stations ready for swap during weigh-ins, with the fleet owners paying a fee for that maintenance...
- massysett 3y ago
  The mechanical issues appear to me to be legitimate stumbling blocks. The ownership model is surmountable. Make the battery a service. I pay $xxx/month or $xxx/mile to Battery Exchange Corp. which replaces my battery each time I “fuel up”. Maybe I do this routinely, or maybe I typically charge at home and do an exchange only when on long road trips. As far as performance etc, surely the battery can track its health the way an iPhone measures battery health. Have specs for what a good battery is. But if Battery Exchange Corp. owns the battery, who cares? Corp. cares but it can figure this out, and maybe go after customers who destroy batteries (however this happens.) A typical car owner is interested in transportation. He’s not interested in owning a battery and he’s certainly not interested in sitting around for half an hour waiting for a battery to charge during a road trip. I’m not saying battery exchange would work, I just don’t think the ownership model is a difficult aspect of it.
cduzz 3y ago
Battery [edit changing to swapping]swapping is never going to work while people own the car and the battery. There will always be incentive to keep a battery that's healthy and dump a wonky battery back into the swapping pool. I've got a natural gas grill with a $20 tank. The tanks all have a "do not refill past this date" stamp on them to keep people from using 30 year old rusty tanks. New tanks typically have a stamp that's 10 or more years in the future. Some places swap the tanks rather than filling them. Whenever I took my tank to a "swap" place, the end-date is always closer to now than the one I gave them, to the point where you may start with a tank that's good to 2035 and if you swap it 8 times (over the course of 2 years) they'll refuse to take it because it will have expired.
- vel0city 3y ago
  > a natural gas grill with a $20 tank A natural gas grill with a tank? I don't think I've ever seen one. Are you sure its not propane?
  - cduzz 3y ago
    sorry yes -- propane. I guess natural gas is (mostly) methane? Bottle of compressed flammable gas.
    - vel0city 3y ago
      Yeah, bottling useful amounts of natural gas requires very high pressures or cryogenic storage facilities which require much more expensive bottles. They're pretty rare to see used for something like a grill. Meanwhile the phase change of propane from gas to liquid is a much lower pressure so its way easier to handle with far cheaper bottles.
vel0city 3y ago
A battery is practically the wear component of an EV drive train. Imagine if every time you got gas it also quickly swapped out your transmission and engine with someone else's who may or may not have abused the hell out of that drivetrain previously. You buy a new EV, you go do a battery swap, the battery you got dies in a month. Who replaces the battery? There's some talk about making battery leasing programs which could potentially be tied to battery swap stations, but I don't think I'd ever tie my refueling strategy to a $10k+ lease. Battery swapping is just very impractical when we can just recharge them. One of the big positives of battery swapping is reducing the load on the grid for those extremely high power draws in fast recharging, but if we just build up batteries at the charging site it can help smooth those demands out more evenly making it easier for the grid to handle in the same way. Either way you're going to need a cache of batteries extra on site at the charging site.

roumenguha 3y ago

There's at least one automaker (Nio) with battery swaps as part of their regularly offered services.

ylhert 3y ago

There are a number of reasons why battery swapping is not feasible in the real world, among them: - Batteries age differently from one another, so swapping would only be fair if you had a similarly aged battery that had a similar number of miles & charge cycles on it - Batteries need to be taken care of (like not using the last 10% at each limit of the battery). some people take really good care of their batteries, others don't. I would never want some random battery swapped into my car, as I've taken really good care of my car's battery - Batteries are structurally built into the vehicle, and making them easily removable would make a lot of the engineering more difficult - Batteries could become commoditized so that they fit in any car, but right now there are tons of different shaped & sized batteries, so it would be really hard to build the tooling to support all these different cars & battery types

cmrdporcupine 3y ago

The weight is crazy (Model 3 long range is ~1000lbs), so you need a serious facility to swap. They are relatively delicate, and flammable in a terrifying way, so you'd need to trust the facility more than e.g. your average oil & tire swap shop. From an engineering POV they need a coolant loop w/ a pump, a high voltage connect to the charger, and usually also a connection to a DC-DC converter for the 12v systems on the car. So if you make it modular/removable, you need a (standardized) answer for how to do all of this. The form factor of the battery is tied fairly strongly to the chassis generally, so if you force a standardization of it you limit manufacturer's options there. Finally, probably the most important, is ownership model. The battery is the most expensive part in the car, by far. It basically is the car. Who owns it? What's the revenue model? How does insurance handle it? Will consumers accept a situation where they're getting random batteries shoved in affecting the performance etc. of their car? It's just a whole thing. It's been attempted, and not succeeded is what I see. Now, what I don't understand is why this isn't the model for EV shipping trucks. In that case they already have a highly modular, heavy duty platform and they already have to check into frequent weigh stations, and the operator rarely owns the truck. I don't understand why the shipping industry wouldn't pursue a model where a standardized set of pre-charged batteries aren't sitting on automated forklifts at weigh stations ready for swap during weigh-ins, with the fleet owners paying a fee for that maintenance...

massysett 3y ago
The mechanical issues appear to me to be legitimate stumbling blocks. The ownership model is surmountable. Make the battery a service. I pay $xxx/month or $xxx/mile to Battery Exchange Corp. which replaces my battery each time I “fuel up”. Maybe I do this routinely, or maybe I typically charge at home and do an exchange only when on long road trips. As far as performance etc, surely the battery can track its health the way an iPhone measures battery health. Have specs for what a good battery is. But if Battery Exchange Corp. owns the battery, who cares? Corp. cares but it can figure this out, and maybe go after customers who destroy batteries (however this happens.) A typical car owner is interested in transportation. He’s not interested in owning a battery and he’s certainly not interested in sitting around for half an hour waiting for a battery to charge during a road trip. I’m not saying battery exchange would work, I just don’t think the ownership model is a difficult aspect of it.

cduzz 3y ago

Battery [edit changing to swapping]swapping is never going to work while people own the car and the battery. There will always be incentive to keep a battery that's healthy and dump a wonky battery back into the swapping pool. I've got a natural gas grill with a $20 tank. The tanks all have a "do not refill past this date" stamp on them to keep people from using 30 year old rusty tanks. New tanks typically have a stamp that's 10 or more years in the future. Some places swap the tanks rather than filling them. Whenever I took my tank to a "swap" place, the end-date is always closer to now than the one I gave them, to the point where you may start with a tank that's good to 2035 and if you swap it 8 times (over the course of 2 years) they'll refuse to take it because it will have expired.

vel0city 3y ago
> a natural gas grill with a $20 tank A natural gas grill with a tank? I don't think I've ever seen one. Are you sure its not propane?
- cduzz 3y ago
  sorry yes -- propane. I guess natural gas is (mostly) methane? Bottle of compressed flammable gas.
  - vel0city 3y ago
    Yeah, bottling useful amounts of natural gas requires very high pressures or cryogenic storage facilities which require much more expensive bottles. They're pretty rare to see used for something like a grill. Meanwhile the phase change of propane from gas to liquid is a much lower pressure so its way easier to handle with far cheaper bottles.

vel0city 3y ago

A battery is practically the wear component of an EV drive train. Imagine if every time you got gas it also quickly swapped out your transmission and engine with someone else's who may or may not have abused the hell out of that drivetrain previously. You buy a new EV, you go do a battery swap, the battery you got dies in a month. Who replaces the battery? There's some talk about making battery leasing programs which could potentially be tied to battery swap stations, but I don't think I'd ever tie my refueling strategy to a $10k+ lease. Battery swapping is just very impractical when we can just recharge them. One of the big positives of battery swapping is reducing the load on the grid for those extremely high power draws in fast recharging, but if we just build up batteries at the charging site it can help smooth those demands out more evenly making it easier for the grid to handle in the same way. Either way you're going to need a cache of batteries extra on site at the charging site.