Proof of Tesla's plan for battery swapping

[stopcrazypp]

Hence the problem with switching to numbers. Either you have 100% be standard charge, thus providing important psychological feedback to guide people's daily behavior (but then you confuse people who think in terms of absolute soc), or you have to train people to charge at 87% under normal circumstances (or, even worse, do what some people are suggesting, which is think about their own usage and charge accordingly - electric cars will never take off if people have to give it that level of thought).

Hence the suggestion that by making "100" correspond to what's currently range charge, Elon is telling people go ahead and range charge every day and don't worry about it.

From an interface perspective, I don't see why we can't have both a suggestion about charging lower for daily use AND also 100% corresponding to a full charge. That's why I mentioned the Leaf (which has a 80% and 100% charging mode), although that's still not perfect as it suggests 100% as default daily behavior as you say.

For the Model S specifically, have a mark at 80% or 90% that says "Standard Charge" and a mark at 100% that says "Range Charge" (or something similar depending on space in the interface) and then have the car preset to the "Standard Charge" mark. That preset will essentially be Tesla's suggestion for daily charging.

 

[brianman]

I don't see why anyone would have a problem with > 100% charge. Doesn't every car owner understand the concept of topping off?

"Topping off"

Ok, so you have a 15 gallon tank in your other car. You fill it to 110% so you leave 1.5 gallons on the ground by your tires?

The problem is that it's deficient math. I prefer non-deficient math when buying a technology-heavy product.

 

[jdevo2004]

I am positive the system they are going to implement will only be available in large cities. When you want to take a long distance trip, say from New York to LA and back you will leave your personal battery pack at the first swap station and pick up the latest, greatest, largest most advanced battery pack available for a weekly fee. You can then drive from city to city swapping or supercharging as needed for free. Once you return from LA to New York you just go to the original swapping station to get your own battery pack back. No one else is going to use your battery pack. It is that simple. Your warranty applies to your own battery pack, there is no way Tesla is going to let other people use it.

Tesla is smart to do this since then can sell the used battery packs after a year or two to people wanting to upgrade in 5-10 years. Remember that in a few years the batteries in current Teslas will be comparatively small.

 

[ohmslaw]

"Topping off"

Ok, so you have a 15 gallon tank in your other car. You fill it to 110% so you leave 1.5 gallons on the ground by your tires?

The problem is that it's deficient math. I prefer non-deficient math when buying a technology-heavy product.

Actually, it's not deficient math. This isn't like the case where you say "I'm giving 110% effort." In this case, it's just a choice of reference point.

You have to pick two reference points. The bottom one (0%) seems pretty uncontroversial. So the question is the top one. It's no different than how 100 degrees Farenheit was picked. You can say "100%" must mean "maximum state of charge," but I doubt even range charge really is the maximum SOC for the battery. And, for example, for the software-limited 40's, what does 100% refer to? It's all just arbitrary.

So the idea is that you pick reference points in order to encourage the right behavior by users of the machine.

In any event, it's all sort of off-topic. It doesn't look like 4.5 does some sort of tach-like "red line" above 80%, nor is there any evidence of any other mechanism to tell you that the proper daily setting is less than 100%. So right now, with the limited information we have, in combination with Elon's battery announcement, it may be that what Tesla is trying to do is encourage people to just go ahead an "range" charge starting in 4.5.

 

[CapitalistOppressor]

Yeah. I think some people are pretty confused or unaware of the dire straits they (not surprisingly) have found themselves in.

I haven't read this thread carefully and don't intend to either, but I highly doubt Tesla will adopt anything as elaborate and capital intensive as what Better Place has tried, at least not on a widespread basis. I could envision something like this at select locations (e.g. service centers) but not much beyond it. The capital and staffing costs look insane vs. deploying more Superchargers.

No. They dont. It's a far superior system and a much better match for Tesla's strategy in the next 10 years.

 

[NotTarts]

No. They dont. It's a far superior system and a much better match for Tesla's strategy in the next 10 years.

Far superior? I can't think of any advantage a battery swapping system would have over supercharging apart from turnover rate. And honestly, I don't think that alone is worth the large increases in capital and complexity, not when there's a possibility that charging could be reduced to 15 minutes in the future.

 

[cwerdna]

No. They dont. It's a far superior system and a much better match for Tesla's strategy in the next 10 years.

Seriously? Have you looked at how badly Better Place is doing?

You mean to tell me that it's cheaper to build a building w/mechanism like Better Place's (or an equivalent), keep the place staffed, keep a bunch of expensive battery packs on hand, have to charge them, etc. vs. building Superchargers that don't need any of this?

Think also about the physical footprint that would need to be covered/enclosed vs. Supercharger stations.

FWIW, there were a couple confused folks on the Electric Vehicle LinkedIn group who before the Supercharger announcements kept arguing that Elon was going to announce battery swapping, despite the rep at the Santana Row store saying it wouldn't be swapping. Well, those folks were wrong.

 

[SteveG3]

Another angle of speculation.

I think a SuperSwapper is likely the announcement, but what if it is not the heart of the plan.

They could announce SuperSwapper for SF to San Diego corridor as a study for a rollout.

With this they will clearly accomplish:

1. Selling more cars in CA given the added value of S-SWs. Given ZEV credits, no Model S is as profitable to Tesla as one delivered in CA. Will more than pay for 3 SuperSwapper stations.

2. They've been racing to add more and more SCs in CA with the very heavy usage. This allows them to get ahead of the demand issue with S-SWs that are 10X as fast as SCs... in and out quick, means lines go away.

3. Small scale makes storing owners batteries and filling S-SW system with batteries easier.

4. Small scale greatly reduces risk of potentially serious accidents rolling out a complex automated process with heavy equipment.

What it may accomplish without detection:

If Tesla's real aim for distance travel is a metal air range extender, they can work on this quietly with the other automakers off their scent. A small S-SW network in CA lets them test out the reliability, safety, and practicality of S-SWs in case metal air range extenders are not ready fast enough.

Why I think metal air may be the cloaked heart of the plan:

1. Look in the Frunk... nice spot for a range extender.

2. Much cheaper implementation. Stock M-A extenders at service centers and about 15 SuperCharger locations spread around the country. With a 1,000 mile range, you'd only need about 15 travel locations to cover the country. It would bring the station much more to the scale of a gas station. 2 or 3 attendants, a small building with stock, and 4 or 5 much simpler less expensive bays where a new range extender can be put in your Frunk if necessary en route (which will be rare given 1,000 mile range), and checked for proper installation by an attendant.

3. Much smoother during holidays. Service centers could stock metal air and the smaller cheaper equipment to put the extender in. Instead of showing up at a S-SW station at 11AM the day before Thanksgiving along with 30 other people, you pick a time weeks ahead to drop by service center and have extender put in.

4. More clearly complementary to SCs. a) you don't have an extender in your car, you need SC, b) you have extender in car: Say you're traveling 800 miles, you have options... if you are stopping to eat anyway SuperCharge, (incentive: using less of extender will lower the fee Tesla charges when you return extender at home service center). If you just want to zip through this SC location, drive by or if needed stop in for two minutes to put some water in the car for extender.

5. While storing your battery at the first SC on your way out and picking it up on return with S-SW model is realistic, going to the nearest service center on your own schedule to install and remove extender will almost always mean less effort, and always give you more flexibility.

While I think a full SuperSwapper rollout could work, I think buying time for metal air makes more sense to do.

 

[Kaivball]

In its end function but not in its complexity. You cannot compare a tank full of liquid to a highly complex 1,000 pound "tank" full of 8,000 batteries, thermal management tubes, sensors, high voltage lines, etc. Its also a structural member of the car. And then are they going to have a team of trained technicians at all of the 200 or so swap sites across the country just sitting there waiting for people 24 hrs a day. And then when they have battery problems with packs or need more of them at other sites, ship 1000 lb packs all over the place? No way. Not going to happen. I will not mess with this kind of integral component of the car every time I want to fill up!

I don't think the battery swapper proponents appreciate the complexity or liability involved here.

 

[cwerdna]

I don't think the battery swapper proponents appreciate the complexity or liability involved here.

Yep.

 

[WarpedOne]

I don't think the battery swapper proponents appreciate the complexity or liability involved here.

And the cost of the needed infrastructure for it not to be useless. Costs go way above the cost of a new factory.
It is peanuts demonstrating battery swapping at some existing Service Center, the problem is many orders of magnitude bigger if you want to offer every-day usable battery swapping across the country AND the world.
It * just * ain't * gonna * happen.
Do you really think future cars will have exact the same battery dimensions and kWh?
Do you really think they will setup swap centers near SS and stock all different batteries in enough quantities? Who will pay for this?

Metal Air Range Extenders (MARE) on the other hand *could* work, across the globe, in current and future Tesla vehicles and vehicles from other manufacturers.
As every vehicle will still have its own primary battery designed to meet its daily needs, MARE modules could stay unchanged (except for kWh) for long time. They could be easily sold at existing gas stations ...

 

[Yggdrasill]

Why I think metal air may be the cloaked heart of the plan:

1. Look in the Frunk... nice spot for a range extender.

2. Much cheaper implementation. Stock M-A extenders at service centers and about 15 SuperCharger locations spread around the country. With a 1,000 mile range, you'd only need about 15 travel locations to cover the country. It would bring the station much more to the scale of a gas station. 2 or 3 attendants, a small building with stock, and 4 or 5 much simpler less expensive bays where a new range extender can be put in your Frunk if necessary en route (which will be rare given 1,000 mile range), and checked for proper installation by an attendant.

3. Much smoother during holidays. Service centers could stock metal air and the smaller cheaper equipment to put the extender in. Instead of showing up at a S-SW station at 11AM the day before Thanksgiving along with 30 other people, you pick a time weeks ahead to drop by service center and have extender put in.

4. More clearly complementary to SCs. a) you don't have an extender in your car, you need SC, b) you have extender in car: Say you're traveling 800 miles, you have options... if you are stopping to eat anyway SuperCharge, (incentive: using less of extender will lower the fee Tesla charges when you return extender at home service center). If you just want to zip through this SC location, drive by or if needed stop in for two minutes to put some water in the car for extender.

5. While storing your battery at the first SC on your way out and picking it up on return with S-SW model is realistic, going to the nearest service center on your own schedule to install and remove extender will almost always mean less effort, and always give you more flexibility.

While I think a full SuperSwapper rollout could work, I think buying time for metal air makes more sense to do.

Using the frunk is mostly unworkable, though, it can't hold enough weight and volume.

Aluminium-air has an energy density of 2 kWh/kg at best, and a Model S would need around 400 kWh to travel 1000 miles. That means that for the remaining 315 kWh you need to stuff 157 kg or 350 lb into the frunk. That amount of mass at the front would leave the car fairly unbalanced, the crumple zone would be gone, and the remaining allowable payload would be reduced substantially.

Here at least, it seems like the total allowable weight is 2590 kg (5700 lb), and the curb weight is 2108 kg (4640 lb) without driver. That means the allowable payload is 482 kg (1060 lb). Losing 157 kg means all occupants and luggage would need to weigh less than 325 kg (715 lb). With 2 occupants weighing 75 kg (165 lb) each, and 3 occupants weighing 40 kg each (88 lb), that would leave 55 kg for luggage, or 11 kg (24 lb) per person. Putting 7 people in the car would be out of the question, as would putting 5 adults in it be.

 

[SteveG3]

Using the frunk is mostly unworkable, though, it can't hold enough weight and volume.

Aluminium-air has an energy density of 2 kWh/kg at best, and a Model S would need around 400 kWh to travel 1000 miles. That means that for the remaining 315 kWh you need to stuff 157 kg or 350 lb into the frunk. That amount of mass at the front would leave the car fairly unbalanced, the crumple zone would be gone, and the remaining allowable payload would be reduced substantially.

Here at least, it seems like the total allowable weight is 2590 kg (5700 lb), and the curb weight is 2108 kg (4640 lb) without driver. That means the allowable payload is 482 kg (1060 lb). Losing 157 kg means all occupants and luggage would need to weigh less than 325 kg (715 lb). With 2 occupants weighing 75 kg (165 lb) each, and 3 occupants weighing 40 kg each (88 lb), that would leave 55 kg for luggage, or 11 kg (24 lb) per person. Putting 7 people in the car would be out of the question, as would putting 5 adults in it be.

What I've read in past (link below) Phinergy said 8 kWh/kg, so we're talking about 100 pounds... no major impact on the car, cubby whole low and as close to center of car as you'll find with easy access (other than in cabin itself).

Phinergy's metal-air battery could eliminate EV range anxiety

 

[Yggdrasill]

What I've read in past (link below) Phinergy said 8 kWh/kg, so we're talking about 100 pounds... no major impact on the car, cubby whole low and as close to center of car as you'll find with easy access (other than in cabin itself).

Phinergy's metal-air battery could eliminate EV range anxiety

The aluminium itself has around 8 kWh/kg, but the aluminium is only one part of the battery, you also need water, all sorts of electronics, structural elements, etc. On the battery pack level, you're talking about more like 1.5-2 kWh/kg.

 

[SteveG3]

Yggdrasill, I'm not a battery engineer, but it sounds a bit surprising to me that in one of these packs the aluminum itself would be only 25% of the weight. Water, other components... it just doesn't seem like they'd weigh hundreds of pounds.

Granted the pack for the small car Phinergy used in the video required only half as much aluminum, but the way their employees handle the pack at the start of the video, it doesn't seem anywhere near 200 pounds.

Do you have a point of reference for this?

 

[Yggdrasill]

Yggdrasill, yes, water, other components would add some weight, perhaps 50 pounds, but admittedly I am not a battery scientist... perhaps one will chime in here.

I see you calculated the weight of the pack ignoring the non aluminum components in your first post and now your putting them in as 75% of the weight of the pack... which just happens to bring the pack weight to the weight in your original conclusion

I calculated using the figure 2 kWh/kg on the battery pack level.

Here's one study saying the current batteries achieve 1300 Wh/kg and future batteries can achieve 2000 Wh/kg. http://www.sciencedirect.com/science/article/pii/S0378775302003701

The study is from 2002, so I assumed they have achieved closer to 2000 Wh/kg by now.

- - - Updated - - -

Granted the pack for the small car Phinergy used in the video required only half as much aluminum, but the way their employees handle the pack at the start of the video, it doesn't seem anywhere near 200 pounds.

I am at work, so I can't watch the video, but here's a few things to keep in mind:

- Are they lifting the entire battery pack, or merely some parts of it?
- Is it filled with water and aluminium?
- How strong are they?

Basically, any video won't give the full picture. Until Phinergy releases information about the energy density and power to weight ratio of their batteries, I'll assume they haven't had a major breakthrough. (I haven't seen them claim so either.)

 

[WarpedOne]

The aluminium itself has around 8 kWh/kg, but the aluminium is only one part of the battery, you also need water, all sorts of electronics, structural elements, etc. On the battery pack level, you're talking about more like 1.5-2 kWh/kg.

There is *NO* need to include water tank into the MARE modul.
It would contain only Aluminum sheets with 8kWh/kg and supporting components. Water tank should be external and not big enough to burn through a new MARE modul.
One would need additional stops to tank water (if there isn't any rain and AC condenser doesn't remove enough water from air).

 

[aronth5]

If Elon was tossing out a battery swap trial balloon looking for feedback he certainly was successful:smile:

 

[SteveG3]

I am at work, so I can't watch the video, but here's a few things to keep in mind:

- Are they lifting the entire battery pack, or merely some parts of it?
- Is it filled with water and aluminium?
- How strong are they?

Basically, any video won't give the full picture. Until Phinergy releases information about the energy density and power to weight ratio of their batteries, I'll assume they haven't had a major breakthrough. (I haven't seen them claim so either.)

Thanks for link Yggdrasill certainly consistant with the numbers you used, and you're right a video is certainly nothing conclusive (fwiw, it looks to be entire pack from the design of the compartment in the car they put it in, they don't look like they are handling 200 pounds, but yes, your point is valid, this is nothing conclusive looking at a video).

So, if today the best that can be done is 2 kWh/kg that article was projecting at the time, it seems right about on the border of making sense... i.e. a 200 pound range extender offering 500 extra miles for long distance.

As to best results with pack weight in 2013 perhaps someone knows more about current developments/Phinergy.

- - - Updated - - -

yes indeed aronth! perhaps crowd sourcing us for business strategy as well!

 

[Yggdrasill]

Well, like I was saying in the similar thread in the "Tesla Motors" subforum, I am not entirely dismissive of aluminium-air batteries in the Model S. I just think that if we are talking about aluminium-air batteries, it makes a lot more sense to swap out the Model S battery pack with a long range aluminium-air battery pack. It could contain 10-20 kWh of regular li-ion and 400 kWh of aluminium-air, without weighing more than the current 85 kWh battery pack.

You simply drive into a battery swap station, they remove your battery pack for storage and transportation to any other battery swap station you desire, then they put in a 410 kWh battery pack and you're ready to go. 1000 miles later you pull into a different battery swap station, they replace your battery pack with one that's fully charged, and refill the depleted one with aluminium and water for the next customer. When you arrive at your destination, you return the al-air battery and get your battery pack back. (If the destination is far from where you handed off your battery pack, you wait a couple of days until they ship it to your nearest battery swap station or tesla service center, and collect it. While you wait, you make due with the 40 miles of range on the regular li-ion and any remaining range on the aluminium-air.)