Swapping is Coming [Discuss how it will be accomplished]

[ToddRLockwood]

Is it just me, or is that "microwave" space in the rear part of the frunk a little strange? Was that space really designed for additional cargo, or does it have another purpose yet to be identified? Perhaps the cargo net was a ruse, designed to throw us off the scent.

 

[Citizen-T]

Is it just me, or is that "microwave" space in the rear part of the frunk a little strange? Was that space really designed for additional cargo, or does it have another purpose yet to be identified? Perhaps the cargo net was a ruse, designed to throw us off the scent.

AWD is my bet.

 

[stopcrazypp]

The formulas are:

p = v * t + 2 (for the case where we store customer packs and return them)
p = v * c + 1 (for the case where any pack can be swapped for any other)

p = packs per station
v = visitors per min
t = average time before a customer returns to get their pack
c = average time it takes to charge a pack

I think the flaw in your model for the case of storing the owner's pack is that it assumes that every visitor to the station wants their pack stored, which will definitely not be the case (there will be plenty that are only in the middle of their trip). That's why your numbers grow so quickly for it.

So the formula there should be:
p = o * t + m * c
where
o = number of owners per minute that needs their pack stored
m = number of people per minute in the middle of their trip that don't need their pack stored
o+m = v the total visitors per minute in your original formula
(t and c means the same as in your original formulas)

Your formula for the case where every pack can be swapped is correct although you do not need to add the extra 1 (in steady state case). It's essentially the same formula Better place uses (which is charge time divided by swap time).

 

[markwj]

Is it just me, or is that "microwave" space in the rear part of the frunk a little strange? Was that space really designed for additional cargo, or does it have another purpose yet to be identified? Perhaps the cargo net was a ruse, designed to throw us off the scent.

The space is needed for the legs of the 8th vehicle occupant.

 

[Citizen-T]

I think the flaw in your model for the case of storing the owner's pack is that it assumes that every visitor to the station wants their pack stored, which will definitely not be the case (there will be plenty that are only in the middle of their trip). That's why your numbers grow so quickly for it.

So the formula there should be:
p = o * t + m * c
where
o = number of owners per minute that needs their pack stored
m = number of people per minute in the middle of their trip that don't need their pack stored
o+m = v the total visitors per minute in your original formula
(t and c means the same as in your original formulas)

Your formula for the case where every pack can be swapped is correct although you do not need to add the extra 1 (in steady state case). It's essentially the same formula Better place uses (which is charge time divided by swap time).

Good catch. I'll adjust. Want to take a shot at what percentage of users are mid trip?

Sent from my Nexus 7 using Tapatalk HD

 

[jeff_adams]

Is it just me, or is that "microwave" space in the rear part of the frunk a little strange? Was that space really designed for additional cargo, or does it have another purpose yet to be identified? Perhaps the cargo net was a ruse, designed to throw us off the scent.

I've convinced myself that Elon will reveal the usage for that space in his 5th announcement. If you look closely at it, you will notice a plastic sleeve that runs through the firewall and terminates near the back of the touchscreen. I believe that will be used as a conduit for cables and wires. I think they will show that they have developed a Metal Air battery that can fit there and "trickle charge" the main pack. You will be able to put some juice into the battery as you drive (extending your range). It also means you will never be stranded or Bordered if you will. You can drive up to that rural log cabin that has no electricity and still charge up the battery at night.

 

[stopcrazypp]

Good catch. I'll adjust. Want to take a shot at what percentage of users are mid trip?

Sent from my Nexus 7 using Tapatalk HD

Not sure. That would require a travel survey of Model S owners to see on average how many stops they make for a long trip (or alternatively how far the round trip length is).

But for the only two possible trips on the supercharger network right now (SF-LA, Boston-DC) it requires 5 stops for a round trip (2 in between, 1 at destination, 2 in between for return trip).

In the worst 1 visitor per minute case, this means 12 owners per hour needing a pack stored, 48 people in the middle of their trip (4x ratio) working out to 612 packs (576 for those needing pack stored, 36 for people in middle of trip).

There's another bound for this though. This implies there will be 576 owners starting trips in two days (288 per day) per station. That seems fairly high to me.

 

[copyhacker]

I've convinced myself that Elon will reveal the usage for that space in his 5th announcement.

Elon seems to have a fondness for hiding things in the frunk. In the Model S reveal, there was an extra person in there; for the Model X, it was the AWD announcement ("But there's something in the frunk you didn't expect").

It makes a lot of sense given the clues: charging, cross-country, already in place, faster than a fill-up, under your nose. But I have a hard time believing the technology is ready for prime time this soon. I'd love to be proven wrong.

 

[CapitalistOppressor]

Elon seems to have a fondness for hiding things in the frunk. In the Model S reveal, there was an extra person in there; for the Model X, it was the AWD announcement ("But there's something in the frunk you didn't expect").

It makes a lot of sense given the clues: charging, cross-country, already in place, faster than a fill-up, under your nose. But I have a hard time believing the technology is ready for prime time this soon. I'd love to be proven wrong.

This.

Honestly, if Elon announced this it likely would be an awesome thing or else they wouldn't be doing it. But until he actually announces something like this I don't see why folks keep expecting it. If you are going to swap a battery, why add one to the car instead of just swapping the battery that has already been designed to be swapped?

To have any range, these aluminum batteries will have to be fairly heavy, which reduces the efficiency of the car, and seriously impedes its handling characteristics while potentially compromising safety as well. In addition, the thread discussing this option is listing a requirement that in order to reduce the weight of the battery, they should just use a smaller water tank, and have the drivers stop every 130 miles to add water and remove the toxic waste from the battery. Really??

This all seems to be based on the hybrid battery patent that Tesla filed, but Tesla prides itself on its engineering, and I seriously doubt they would compromise their car by adding a kludgey toxic waste tank to their frunk. The crash safety issues alone boggle the mind. If they ever do something like this it will be a well engineered solution that will enhance the performance of the car, as opposed to compromising it.

 

[jerry33]

IMPORTANT WARNING: None of the following are meant be a snarky comments, if they come across that way, apologies in advance -- J3

Honestly, if Elon announced this it likely would be an awesome thing or else they wouldn't be doing it. But until he actually announces something like this I don't see why folks keep expecting it. If you are going to swap a battery, why add one to the car instead of just swapping the battery that has already been designed to be swapped?

Because no one wants to see Tesla go down the tubes like Better Place, so everyone is trying to come up with a more practical solution. Of course, Elon may pull a rabbit out of his hat, but if so, no one has figured out how he's going to do it.

To have any range, these aluminum batteries will have to be fairly heavy, which reduces the efficiency of the car, and seriously impedes its handling characteristics

It's like adding an additional small person. I don't see the big deal here--we're driving on roads at sensible speeds, not racetracks.

while potentially compromising safety as well.

I guess putting a suitcase in the frunk would compromise safety as well.

In addition, the thread discussing this option is listing a requirement that in order to reduce the weight of the battery, they should just use a smaller water tank, and have the drivers stop every 130 miles to add water and remove the toxic waste from the battery. Really??

I doubt that is how it will work. If water is to be added, it's added once after the module is installed, but if I was designing it, I would opt for four, six, or eight small sealed easy to handle modules that just snap in, rather than one large module.

This all seems to be based on the hybrid battery patent that Tesla filed, but Tesla prides itself on its engineering, and I seriously doubt they would compromise their car by adding a kludgey toxic waste tank to their frunk. The crash safety issues alone boggle the mind. If they ever do something like this it will be a well engineered solution that will enhance the performance of the car, as opposed to compromising it.

It's less kludgy than keeping a bunch of expensive batteries around in very expensive swap stations that will cost a fortune to operate and will be very slow rolling out (think decades). Being in the back of the frunk is unlikely to cause a problem in a crash because the crumple zone is mostly in front of that area. I agree that you won't be stopping for water every 130 miles, no one would design like that. I haven't seen any information on how toxic a battery like this would be. It's 100% sure to be less toxic than the 12V battery--probably far less toxic--plus lead-acid batteries have been in the front of cars for years, usually on the side where they are less protected than the frunk microwave area.

You're probably correct that's it's just going to be a swap of the existing battery, but that's not even remotely exciting to me as I doubt that I'll live to see any installed where they might be of some use. Heck, I'll be lucky to see Superchargers on the routes I normally drive during my lifetime

 

[Citizen-T]

In order to put the metal air battery patents in the right context you need to understand how the patent system works (or how it fails to work). I work for a company where we are incentivized to get patents. We are encouraged to patent everything and anything that we can think of, especially stuff for our competitor's products. If something is not worth patenting, we publish it.

It's a game of chess. We try to think ahead enough moves and beat our competitors to the patent office. That way we can insure that worst case, our competitors can't patent their next product or killer feature because we've already published it. And, best case, we have a bigger trove of patents that we can use to get favorable licensing agreements when one of us decides the other is infringing on something (which happens constantly).

This is why I laugh every time I see a news story about how Apple just patented a technology that can read your mind, and "experts" predict that this is a hint at what we can expect in the next iPhone. No matter how many times these technologies fail to manifest themselves, they keep claiming they can predict a product by watching the patents. It's nonsense.

The truth is, we can patent something up to a year after we release it. So, if we are going to market with something new and exciting, WE DON'T PATENT IT until we've already shipped.

So, if Tesla is anything like any other company in the U.S. It is almost certain that these patents do not predict this announcement. Sorry to disappoint.

 

[stopcrazypp]

I'd like to also add that the patent in question talks about rechargeable metal-air batteries, not the non-rechargeable aluminum-air ones that have recently been in the news.

See the section: [0033] Charging Characteristics
http://www.faqs.org/patents/app/20120041625

 

[CapitalistOppressor]

IMPORTANT WARNING: None of the following are meant be a snarky comments, if they come across that way, apologies in advance -- J3

Nothing snarky about that at all. Just direct argument. I'd only take offense if someone called me a name, lol.

As to the rest, the estimates I have read on the threads here indicate that an aluminum air battery large enough to eliminate the need for extensive swapping would be far larger than a small person.

However, I know nothing about the technology, so I could easily be wrong here. Most comments talking about small batteries seem to indicate some kind of cartridges, which is battery swapping, with a need for a large inventory and all the rest. Plus you need to do large scale refurbishment since every battery is single use.

In regards to toxicity, some forms of alumina hydroxide are an antacid which is medically prescribed. So maybe non-toxic. But it is also unlikely that you can just dump it into the nearest drain. If anything, I'd assume you would want to recycle it.

Regardless, if cartridges were planned, there would be something more than a wire guide to the back of the dashboard. There would be heavy duty attachment points/clips that would allow for fast swapping. The pictures I've seen of stripped out frunks showed nothing like that, though in fairness I was not looking. Still, I'd expect there to be clear evidence besides a nook that doesn't have seem to have the required structural attachment points.

 

[jerry33]

Regardless, if cartridges were planned, there would be something more than a wire guide to the back of the dashboard. There would be heavy duty attachment points/clips that would allow for fast swapping. The pictures I've seen of stripped out frunks showed nothing like that, though in fairness I was not looking. Still, I'd expect there to be clear evidence besides a nook that doesn't have seem to have the required structural attachment points.

My assumption would be that there would be a modification required ($1500) to allow this kind of charging when they would put in the heavy duty attachments. Maybe they would even be free for those who purchased the 4+4 plan (Well, I can always dream

 

[Citizen-T]

My assumption would be that there would be a modification required ($1500) to allow this kind of charging when they would put in the heavy duty attachments. Maybe they would even be free for those who purchased the 4+4 plan (Well, I can always dream

Wouldn't fit with the idea the "under your nose" comment, and OFF TOPIC FOR THIS THREAD. =)

 

[Aphysician]

This should have a seperate thread. I believe this is the most logical answer I've heard. Think about these applications of a "trickle charger" mounted in the frunk cubby.


*No more Brodering. You always have spare power with you if you run into bad weather or detours. Worse case, you have to pull over for a while to charge up enough.


*You get home late with little charge only to discover power outage at home. No problem, you let the Air Metal run while you sleep and you have a charged up car in the morning.


*You go to the lake to fish. No power outlet, no problem again. Camp all weekend and drive back on a full charge.


*Extended distance travel. Turn on the Air Metal once the battery is down 10% and trickle charge as you drive. Can't do this with an ICE!


What I like about this solution:


You don't need swapping stations. You would simply go to existing service centers or have a Ranger come install it. It would be rated on "hours of charge", not how many miles you could drive. Software would keep track and you would know when it's time to replace. Because it's not designed to put out enough power to "drive" the car, it can be light enough to not cause weight or storage issues.

@ jefffadams and @ alpha


A add-on battery in the frunk seems to be the most logical idea. It has many advantages in addition to the one you already highlighted
- Tesla's approach to problem-solving is a very simplistic. They will not propose anything which makes the whole thing complex and then adds cost. The longer and complex the battery swapping is, the costlier it becomes. Just imagine lots of people waiting for battery swap, more people leads to more infrastructure and again hidden costs.
- People will have ownership of their battery. The whole idea of swapping with someone else's battery will not take hold. As mentioned in the post. The only way it can work is that used batteries will be swapped to the next vehicle, to keep inventories low and decrease costs related to storage. If your batteries are swapped then there is no point in owning battery and Tesla will need to refund current owners.
- If Tesla decides on main battery pack swap then leasing is the only way to go. It can make Model S even more affordable. Now how to please people who bought the battery pack, no leasing costs and no swapping costs. Charge others who lease the battery, lets say 2000 $/year for 60 kWh and 4000 $/year 85 kWh for a 6 year lease. This way you can have lower upfront costs and be flexible if life situation changes. Just agree to higher battery lease if you move and 60 kWh doesnt suit you. I still think swapping main battery is a cumbersome an unlikely idea, I like my odds with a frunk add-on.
- There is another post on forums,where owners have discussed how quickly the pack can be changed. It seems it is quite an extensive operation taking certainly more than 15 minutes, even if it is automated the time to mount the car needs to be factored in, as the cost of installing robotic machine. The add-on battery is just put in the frunk and you drive away. How easy would that be.
- They need to offer this solution to every Model S owner, irrespective of current battery size. Storing different capacity packs will again lead to increase in inventory. How about one size fits all add-on battery? No matter what your current capacity is, come and have the add-on installed and drive away. This will ensure that 85 kWh don't feel cheated by 60 kWh owners getting 85 kWh in swapping.
- They can have these add-on battery charged overnight, esp when electric rates are lower and they will be ready to go. These can be charged by solar too. Elon owns solar-city and deploying more solar panels to charge add-on batteries can only be good for that company. I think it is brilliant to use your current company to jumpstart your next big thing.
- Tesla needs to be sure, which battery tech is for future. There is lot of noise in battery tech and everyday you hear that some new battery tech will give these many miles. Point is, that battery tech is still very young and in rapid R&D phase. It would be foolish to bet big on any tech at this time and integrating that tech in large battery packs for swapping. Take the next tech, have it ready for smaller add-on packs and you can test the tech in the field. If something better comes along, then use that technology in add-on packs. This way Tesla can test many different techs at the same-time without actually integrating it in large battery packs.
- Tesla owners need freedom to roam anywhere. The battery needs to be such that it can be swapped at any service center. Somebody gave a good analogy with red-box. That's exactly the approach Tesla needs. Pick up a battery at one service station, keep it as long as you need it, return to any service center on your way. Your original battery is always on your car, no need to go back to the same service station to get your pack back.
- How should they charge? There has to be an uniform fee structure without any significant difference between 60 kWh and 85 kWh owners. Both should be equally eligible for such facility. The new gen add-on batteries will be expensive, so you only lease it for a minimum charge. Tesla can charge for the juice in the pack, free to them if they use solar to charge. Basically, the application needs to be widespread and still cheaper than buying a tank full off gas (lease cost + charge costs) for it to succeed.
- This can also earn extra revenues for the company, as supercharging is free. However offering add-on packs will reduce congestion on superchargers and will reward drivers who are willing to wait a bit, but still offer convenience to drivers who are in hurry. Ultimately everybody wins.


Hope you all like the reason. Feel free to comment. Waiting for all announcements to be over quickly. The suspense is toomuch to take.

 

[Yggdrasill]

I'd like to also add that the patent in question talks about rechargeable metal-air batteries, not the non-rechargeable aluminum-air ones that have recently been in the news.

See the section: [0033] Charging Characteristics
http://www.faqs.org/patents/app/20120041625

True. It doesn't exclude the possibility of Tesla going to Phinergy (or someone) and licencing their technology, however.

The potential frunk battery would be nice in some circumstances, but it wouldn't be quicker than filling gas. If you assume a 50 kg (110 lb) battery, the most I would expect to be pactical to put into the frunk, that's around 100 kWh. You'd still need to stop every 250 miles or so, replace 12.5 kg of aluminium and refill water. An operation that probably takes longer than filling gas, and you still need to do it twice as often as one would need to fill gas.

 

[jeff_adams]

@Aphysician

The frunk battery is just a much more elegant solution. I get the arguments that it may not be ready for prime time, but this is Elon we are talking about. If anyone could find a way, it's him.

If they were planning on doing battery swapping of the main packs, why not have owners just lease the batteries in the first place? Why wait until now to announce it?

I think Tesla had to wait until they believed the tech was ready for the frunk battery. Maybe the Broder incident pissed Elon off enough that he pushed up development of it. Whatever solution they plan on "demonstrating", I'm sure it will be impressive

 

[WarpedOne]

@Aphysician: you add nice spin to the swapping idea.
Now lets lay out what battery tech is out there already with high Wh/kg? Poor cycle life and low power are not a problem.
The best lithium batteries are around 300Wh/kg, 20lbs modules could hold ~3kWh (no thermal management, full DOD cycle, no recharging in car).

5 such modules would add about 15kWh or about 50 mile of range. IMHO this is still not enough to bother.

 

[stopcrazypp]

True. It doesn't exclude the possibility of Tesla going to Phinergy (or someone) and licencing their technology, however.

Sure it doesn't exclude it, but at the same time it completely shoots down the suggestion that the patent somehow supports that claim. Right now there is zero evidence that Tesla is doing anything with Phinergy or aluminum-air. Seems like this is mostly people's wishful thinking.

In contrast, swapping of the main pack has been a claim Tesla made since the beginning.