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Swapping is Coming [Discuss how it will be accomplished]
- Thread starter Citizen-T
- Start date
That's innacurate. From what we've been told previously, the battery easily detaches and is removable. Like a giant laptop cell.
stopcrazypp
Well-Known Member
This thread is starting to get less clear in terms of what people are thinking Tesla will do. There are a couple of distinct schemes that are NOT the same thing, but people are blurring the lines by speaking loosely in terms of leasing and owner batteries:
1) Owner enters a monthly battery lease contract with a monthly rate, does not own the battery, and the sale price of the car is reduced. This is what Renault and Better Place does.
2) Owner enters a per trip battery rental contract while using the battery swap network paying by hour or flat rate, still owns the battery (owner only rents a battery for the trip), and gets his/her own battery back at the end of the trip. This is what I am proposing and what Elon has suggested before.
3) Owner does a no contract battery swap paying per swap, still owns the battery, and does not get his/her original battery back at the end of the trip (but keeps whatever battery they swapped for). This is what I believe what Citizen-T is proposing in order to eliminate the need for an inventory of rental batteries.
1) Owner enters a monthly battery lease contract with a monthly rate, does not own the battery, and the sale price of the car is reduced. This is what Renault and Better Place does.
2) Owner enters a per trip battery rental contract while using the battery swap network paying by hour or flat rate, still owns the battery (owner only rents a battery for the trip), and gets his/her own battery back at the end of the trip. This is what I am proposing and what Elon has suggested before.
3) Owner does a no contract battery swap paying per swap, still owns the battery, and does not get his/her original battery back at the end of the trip (but keeps whatever battery they swapped for). This is what I believe what Citizen-T is proposing in order to eliminate the need for an inventory of rental batteries.
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Is this widely know, that the chassis structure around the battery has changed?
Look at the current/old styles of the "skateboard" models at Tesla stores, shown in this photo:
http://www.teslamotorsclub.com/show...ons-Corner-VA!?p=332526&viewfull=1#post332526
Seems the battery is now separated a bit more from the rest of the car, by these aluminum struts and beams in the "new" version. I wonder if this means the battery is even more easily decoupled for a swap from underneath? Or am I missing something here?
Look at the current/old styles of the "skateboard" models at Tesla stores, shown in this photo:
http://www.teslamotorsclub.com/show...ons-Corner-VA!?p=332526&viewfull=1#post332526
Seems the battery is now separated a bit more from the rest of the car, by these aluminum struts and beams in the "new" version. I wonder if this means the battery is even more easily decoupled for a swap from underneath? Or am I missing something here?
Why can't it just be as simple as swap one for another? The battery I currently have charges to a certain level and the one that it is swapped for will charge to that level or better. This appears to be the most cost effective method even if there is a fee for this service, which their might not be.
If the fear is that you'll get a battery that is worse than your current battery then that fear is unfounded with Elon at the helm.
If the fear is that you'll get a battery that is worse than your current battery then that fear is unfounded with Elon at the helm.
stopcrazypp
Well-Known Member
You can NOT guarantee that if using a scheme of owner swapping in their batteries. This is because say for example another person swapped in an owner battery with 85% permanent capacity left (this number can be arbitrarily low). That battery must be immediately used right away, so it'll start being charged. Then you come in 45 minutes later with your relatively new 95% capacity pack, and then you are given the 85% pack. Tesla can't guarantee you get a 95% capacity pack without holding on to the 85% capacity pack and if they do that the required packs will approach the rental scheme I am proposing (with the added complication of having to match the capacity of swapped packs).
Also if you come in with a presumably low SOC, Tesla actually can't immediately determine what condition your pack is in. Tesla can only find out after fulling charging it and looking at the kWh that is being stored.
The only thing Tesla may be able to guarantee is some kind of uniform lower baseline (near "end-of-life" which is 70%) like the 75-80% that most battery lease schemes use. They can't guarantee it'll be better than a pack you are swapping in at that moment, because of the uncertainty of the packs owners are swapping in.
Put simply because owners can swap their pack into the network, it's entirely possible that an entire station's packs are all owner packs of unknown condition.
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Causalien
Prime 8 ball Oracle
Here's how I think they will do it. I can see a type of leasing program similar to Solar city has with their customer base. Except you are contributing to the storage component of the solar power station that the super charger stations will be converted into. The lease battery act as a backup battery "leased" by you on the supercharger network if you ever need to use it in a pinch. You get to keep your own battery for your car without it being shared with other people, but while you take your "Leased" battery out, your own battery must replace its place in the super charger network. (but as a non swappable unit) If they hook up all solar city customer's solar panels to super charger networks, the problem of storing solar energy could be solved. You might even break even or make a profit if the whole SCTY panel + TSLA supercharger battery manage to make money contributing energy back to the grid.
Maybe Elon intends to create a distributed utility, supplied by solar power and others. Assuming that there are battery storage facilities (basically batteries of batteries) with N batteries to supply a buffer for solar generated power with the ability to swap out up to N batteries of customers, which are actually returned after a long distance trip. Then that would actually achieve two goals in one fell swoop while reducing required resources to a minimum, or rather utilizing available resources to their maximum. Plus, the customer can feel good thinking "My battery is doing something good while I'm away". Which psychologically further increases the bond with green tech, IMHO. What do you think?
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ModelS8794
Member
I had the same notion, posted it upthread but didn't get any traction from the engineers and other smart thinkers here... I wonder if its feasible or whether the necessary capacity is even in the right order of magnitude to make sense for utility rate arbitrage/energy storage on the one hand and swapping on the other.
It feels like an elegant and novel implementation to me, if the numbers are in the right universe. Certainly Musk is well positioned to envision and execute something like this...
Wouldn't it be logical that the pack itself knows it's own condition?
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I would not call a temporary Li-air insert "battery swapping", but perhaps that's just my definition. Implementing swapping for a small number of cars (50,000) with different capacity packs (60 and 85 kWh), different conditions and infrequent use (esp. 85 kWh gets you quite the distance) has too many hairy implications. For a small 16 kWh swapping is more economical (more demand), but even that failed in the past.
If the Phinergy approach works as advertised (and I don't see why not), that - or something similar - looks like a *much more* promising direction.
What would the effect of a demo be on the short-term stock price?
Let's say each storage facility is supposed to deliver maximum 1 MWh capacity for distributed solar power storage. That's just 12 fully charged 85 kWh battery packs. Depending on swapping rate per hour, make it for instance 16 packs. Piece of cake for Tesla, $-wise. The storage facilities could even be designed for modular expansion, so that any number of additional capacity could be implemented in the future. Combine that with comfortable, automated travel planning in your car's computer and you're set for a trouble-free voyage.
Another question popping up: How would a swapping facility, as modeled above, fit into the furthering of battery capacity to, say, threefold over the course of the next years with Li-air? Would swapping actually be necessary, assuming a threefold increase in charging speed (or better) ? Maybe the swapper becomes a simple general means of reducing recharging overhead and waiting time?
ModelS8794
Member
I believe Tesla will be more interested in using battery tech advancement in the service of reducing cost, rather than increasing capacity. That would be particularly true if fast-recharge/swapping infrastructure develops at any rate at or greater than their initial Supercharger rollout announcement (150-200 mile density covering the US and Southern Canada within 5 years). If we start from the first principle "Musk's objective is to catalyze the worldwide adoption of sustainable transport" then solar installations with modular battery storage and fast charge/swapping seems to flow naturally from that principle. I think the Supercharger will eventually find its primary use in 50-60 KwH Gen3 and early release Model S cars like we have this year, and battery swap will find its primary audience in V2.0 and beyond Model S, Model X vehicles with 85-120 KWH capacity. If battery swap works and Tesla develops a full scale infrastructure, something approaching and certainly beyond 120kwh doesn't seem a necessary expense for the consumer.
thanks for sketching out the capacity numbers. I think, off of your suggested numbers here, that the bottleneck would be in real estate for 1-2Mwh of solar panels, not battery volumes. That bodes well for the rate arb/swapping thesis, since a large part of the battery usage in that case would be sucking low-rate energy out of the grid and storing it, rather than producing and storing high-rate midday solar production.
@ ModelS8794:
You're most probably right. Li-air could lead to 10 minutes instead of 30 minutes recharge time and reduce battery cost at least to 1/3 as well. This would achieve SCiB cells recharge speed but avoid the low capacity of SCiB. This sounds good. If they get the silicon-air cells to
work, they get rid of Lithium. That makes it even better. I'm thrilled.
Edit: Since oxygen and silicon are the most frequently occurring chemical elements in/on the Earth's crust, silicon-air batteries would be the greenest type of battery imaginable, IMHO, because there'd be practically no poisonous substances involved. It would give 5x Li-ion capacity, meaning 1500 miles or 2400 km on one charge.. insane. Finally some use for all that annoying sand
.
You're most probably right. Li-air could lead to 10 minutes instead of 30 minutes recharge time and reduce battery cost at least to 1/3 as well. This would achieve SCiB cells recharge speed but avoid the low capacity of SCiB. This sounds good. If they get the silicon-air cells to
work, they get rid of Lithium. That makes it even better. I'm thrilled.
Edit: Since oxygen and silicon are the most frequently occurring chemical elements in/on the Earth's crust, silicon-air batteries would be the greenest type of battery imaginable, IMHO, because there'd be practically no poisonous substances involved. It would give 5x Li-ion capacity, meaning 1500 miles or 2400 km on one charge.. insane. Finally some use for all that annoying sand
.
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Well, that's just a modification of the Better Place model, with the addition that you get your battery back. The problem is that you're limiting the ability to serve customers. Image a car rental lot where the renter is always dropping off their existing car, which takes up a space and can't be rented out. Not good.
The best you could do for customers is no-contract battery swapping, seeded with "Tesla" packs where the customer receives, in order of preference: their pack, a Tesla pack, the first-swapped owner pack.
But, let's think in numbers. Let's say $3M per swap station. Let's say you can arbitrage at an average rate of $0.10/kWh (allowing for extremes during peaks and low numbers at other times) for about 6 hours per day. So you get $0.60/kW/day. So just using this arbitrage your station would need 5 million kWdays to recover the original investment.
Let's then say 10 packs with each one discharging at 50kW giving you 500kW output. Then for each day, it's 1/4 days outputting giving you 125kWdays each day, meaning it would take you 109 years to recover the original investment using arbitrage.
(Feel free to correct my numbers, they're just guesses).
So you'd probably want a lot more batteries per swapping station, and then cover additional costs like maintenance and battery replacement by charging the customer. But, every dollar you charge them makes their BEV more expensive.
For general use, I think swapping would have to be something to use as a supplement to Supercharging in areas with high BEV penetration, to overcome congestion.
For specialized use, it might be economically viable for high-mileage taxi fleets, where a BEV can drastically lower per-mile fuel and maintenance costs and a swap station would reduce dead charging time.
So, instead I think you want to focus on
The problems you list are only there on the surface. I'm convinced that any expenditures concerning the swapping system are already priced into the cost of a battery pack, the car and whatnot. I'm pretty sure they're using mixed calculation to achieve that goal . Add to that the usual writing off, and it will work out alright.
. Add to that the usual writing off, and it will work out alright.
stopcrazypp
Well-Known Member
Yes, you can log the information on memory in the pack, but that information can also be modified (there's probably no law similar to anti-odometer fraud to protect battery packs). On the other hand, there's no way to cheat fully charging the pack (as you can monitor the amount of energy going in and the SOC). To be extra safe, if you do a full cycle it'll tell you how much you can get out too.
But even if you had the condition information on the pack, that doesn't change the fact that to guarantee x-amount of capacity you have to hold on to packs that are lower capacity. This would increase the number of packs needed compared to just giving you whatever pack is available at the time.
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Car rental and battery rental is not directly comparable. For one, batteries can be stacked and it takes about 10 batteries to take up the volume of a car (plus you can stack even higher).
And you can't just use an arbitrary $3M for a station and then try to make the arbitrage pay for the station. Better Place might be over optimistic, but they estimate $500k for a station. This is a fixed cost that would apply not matter what scheme you use (no-contract or rental or monthly lease).
You essentially have to figure out the costs of the rental battery and storage area. Tesla charges a retail price of $400/kWh, which means a retail cost of $34k for a pack (such a cost should be able to cover storage area costs too as I imagine the cost to Tesla per pack is way lower than this). Such a pack can provide a conservative ~850 equivalent cycles or ~73MWh of discharge until 70% (pack can of course still be used for load leveling below this number, but it'll have to be removed from the swap network), giving about $7.3k assuming $0.10/kWh (will take 243 days of cycling at 50kW for 6 hours given the 300kWh/day/pack in your math). In the rental scheme, these equivalent cycles will be put on the owner's pack.
The rest of the battery cost ($34k-$7k=$27k) will have to be made up with rental fees, which work out to $32 per cycle ($40 per cycle assuming no load leveling). This price can easily be covered by a $50-100/day fee as I propose (2-3 swaps per day can be covered). Then the pack can continue to be used for load leveling after it degrades to below 70% capacity (Tesla estimates $12k value for the pack if you assume this kind of use, which would drop the per cycle cost down to $14).
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ChadS
Last tank of gas: March 2009
No, they haven't offered it yet. I have been figuring they want to wait until after the next two announcements because they might, as you note, include some material information.
Then again, maybe they just are focusing on other things with a nearer time horizon.
Then again, maybe they just are focusing on other things with a nearer time horizon.
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