Is Musk lying on maximum battery capacity?

[R.S]

Well, Elon is scheduled to actually speak, much like the first reveal. I'm hoping we'll get more from his talking points than from the dopey, redundant reporters' questions.

Let me correct my comment:

On the topic of supercharging:
Elon:"And it can use the super charger network!"
*clap-clap-clap*
[Next topic, organic leather]
Journalist [after the event] "So it will be able to use a supercharger network to refill it's batteries?"
Elon:"Yes, every Model 3 will be able to use the Tesla-Superchargers, but there will be a small fee to charge"
Journalist:"Cheaper than refilling a gas car?"
Elon:"Yes"

I can guarantee you that is what's going to happen. At least at the after event interviews. Lot's of very basic questions from badly prepared journalists. The only hope is Elon telling us, at the event, that it will take xx long to recharge to xx-miles/xx%. But I am not sure if that's going to happen.

 

[SageBrush]

S/X 75 kWh pack charges i 90-100 kW range before taper. There is no reason why 75kWh 3 pack should not charge in 80-90 kW range, so 55 kWh pack i~65 kW that's way above Bolt's with its maximum 48 kW and retarded taper algorithm

In fact, there is a physical reason: the 2170 cells have a reduced surface area to volume for heat dissipation.

Welcome to the conversation

 

[ModelNforNerd]

Let me correct my comment:

On the topic of supercharging:
Elon:"And it can use the super charger network!"
*clap-clap-clap*
[Next topic, organic leather]
Journalist [after the event] "So it will be able to use a supercharger network to refill it's batteries?"
Elon:"Yes, every Model 3 will be able to use the Tesla-Superchargers, but there will be a small fee to charge"
Journalist:"Cheaper than refilling a gas car?"
Elon:"Yes"

I can guarantee you that is what's going to happen. At least at the after event interviews. Lot's of very basic questions from badly prepared journalists. The only hope is Elon telling us, at the event, that it will take xx long to recharge to xx-miles/xx%. But I am not sure if that's going to happen.

My hope is that the webpage will update and go live as soon as he's finished talking, so it's all laid out right there on the screen.


IDEALLY, the Design Studio would go up, but I'm not going to hold my breath on that just yet.

For now, I'd be happy if the current info page was updated with solid numbers.

 

[R.S]

My hope is that the webpage will update and go live as soon as he's finished talking, so it's all laid out right there on the screen.


IDEALLY, the Design Studio would go up, but I'm not going to hold my breath on that just yet.

For now, I'd be happy if the current info page was updated with solid numbers.

You want more information? I thought those 6 vague points should be enough...

 

[ModelNforNerd]

You want more information? I thought those 6 vague points should be enough...
View attachment 236607

What do this, the Bible, and the Constitution have in common?


They are easily the 3 most misinterpreted works whose underlying messages are manipulated to fit an agenda. LOL

 

[Zaphod]

What do this, the Bible, and the Constitution have in common?


They are easily the 3 most misinterpreted works whose underlying messages are manipulated to fit an agenda. LOL

I think you could add all religious books to that list, not just the Bible...

 

[ModelNforNerd]

I think you could add all religious books to that list, not just the Bible...

fair enough. but you get the point. it is all things to all people....until the one truth is revealed on the 28th.

 

[SageBrush]

The Chevy Spark and Hyundai Ioniq both have peak charging rates well above 2C. Anybody know what trade-off was involved ?
I presume energy density but I don't know.

Perhaps the Model 3 will do the same and it explains the 75 kWh maximum capacity.

 

[scaesare]

In fact, there is a physical reason: the 2170 cells have a reduced surface area to volume for heat dissipation.

Welcome to the conversation

OK, before this becomes "fact", based on that hackernews thread, this is not a forgone conclusion.

There are a number of factors here that don't make the assumption that a new pack comprised of 2170 cells will necessarily be heat limited to a greater extent than one comprised of 18650s:

- The exothermic reaction of the cell chemistry itself. This is a function of the chemical makeup of the electrolyte and the cathode and anode materials. Changes in chemistry can reduce this factor. (or increase it, but that's not a likely design goal)

-The internal resistance of the cell. This generates heat as current is passed. This is often not constant (e.g. in the current Tesla cells the IR drops as they heat up). This ohmic heating factor is dependent on several aspects of cell design such as anode and cathode structure, later thicknesses, chemistry, etc. New designs can have less IR than old.

- The cooling mechanism within the pack. The current pack uses a glycol coolant loop that is looped through an active chilling unit. This has a specific coefficient of heat removal. We already know Tesla has a patent on new mechanism utilizing heat-pipes which incorporate phase-change cooling. This may provide grater cooling coefficient at the cell itself.

- The cell surface area contact patch. Currently the coolant loop is only in contact with a fraction of the 18650 wall surface area. If I had to guess, it's less than 30%. Different pack designs could allow for greater contact patch area corresponding to the larger cells.


One or more of the factors above renders direct comparison of what a new pack comprised of new cells to the old pack comprised of old cells a guessing game at best.

 

[Guy V]

The model 3 is likely modular and there might be more "other stuff" in the pack that comes out of the gigafactory. I agree that there seems to be more room available than just space for 75kWh, but the design of the car is likely quite different than the model S.

I'm curious to see if they made the model 3 a little too good. The impression of the 3 and the S side by side in the showroom will be interesting.

Not "too good". Like any other product they have open-ended opportunity to configure mods and options on the same platform. There is absolutely nothing fake or lying about it. They rework their costs, technology and margins across models to offer competitive choices to customers along with good profit margins.

 

[SageBrush]

OK, before this becomes "fact", based on that hackernews thread, this is not a forgone conclusion.

There are a number of factors here that don't make the assumption that a new pack comprised of 2170 cells will necessarily be heat limited to a greater extent than one comprised of 18650s:

- The exothermic reaction of the cell chemistry itself. This is a function of the chemical makeup of the electrolyte and the cathode and anode materials. Changes in chemistry can reduce this factor. (or increase it, but that's not a likely design goal)

-The internal resistance of the cell. This generates heat as current is passed. This is often not constant (e.g. in the current Tesla cells the IR drops as they heat up). This ohmic heating factor is dependent on several aspects of cell design such as anode and cathode structure, later thicknesses, chemistry, etc. New designs can have less IR than old.

- The cooling mechanism within the pack. The current pack uses a glycol coolant loop that is looped through an active chilling unit. This has a specific coefficient of heat removal. We already know Tesla has a patent on new mechanism utilizing heat-pipes which incorporate phase-change cooling. This may provide grater cooling coefficient at the cell itself.

- The cell surface area contact patch. Currently the coolant loop is only in contact with a fraction of the 18650 wall surface area. If I had to guess, it's less than 30%. Different pack designs could allow for greater contact patch area corresponding to the larger cells.


One or more of the factors above renders direct comparison of what a new pack comprised of new cells to the old pack comprised of old cells a guessing game at best.

The reduced surface area to volume is a fact.
You are pointing out that many other variables play into the final C rate, and you are most certainly right.

Regarding the contact patch, I thought the cells are encased in goo ?

 

[Guy V]

Not sure S and X really qualify as "affordable".

Well, people are buying them by the 10s of thousands

 

[Guy V]

Elon explains it here: Elon Musk Comments On Minimum Range For Electric Cars

So I could interpret "200 miles usable range" as "240 miles EPA range". So, someone may have to recalculate their predictions

... so now the question is what Elon was talking about with his "215+ miles range", was he still talking about 215+ miles usable range? (215*1.2=258)
Or was he talking about 215+ miles EPA range? No-one can say that 240 miles EPA range is not within "215+ miles EPA range"

But no, I do not expect a battery with 55kWh *total* energy to deliver 240 EPA miles, but if we are talking about 55kWh(+) *usable* energy it may be more realistic. And no, I do not think he *really* was planing on 240+ EPA miles, but something close like maybe 230+ miles EPA range. A battery with 55kWh(+) *usable* energy may be labeled as "55" or "60" just as a battery with 70kWh(+) usable energy (and therefore about 75kWh total capacity) may be labeled as "70" or "75".

There's a common trick that Tesla hasn't resorted to yet but with the technology they have built in most certainly could any time they feel the need: Eco Mode

 

[electracity]

Not "too good". Like any other product they have open-ended opportunity to configure mods and options on the same platform. There is absolutely nothing fake or lying about it. They rework their costs, technology and margins across models to offer competitive choices to customers along with good profit margins.

I wasn't suggesting they were lying. I was suggesting that an optimal model 3 might have been a somewhat smaller and less expensive car.

 

[Guy V]

Depends where you are located. Here in the Midwest I experience the full 0-60 mph far more often than just 0-30 mph.

I'm not about to admit how often that happens where it shouldn't

 

[Guy V]

I wasn't suggesting they were lying. I was suggesting that an optimal model 3 might have been a somewhat smaller and less expensive car.

But far more limiting in where they can easily take the platform over time. Elon is always thinking many steps ahead.

I predicted 75 and 100 for the S a long time ago because that hit some great market sweet spots (like 300+ range) and figured Elon's engineers would work it out. Even so I didn't anticipate that the low end would match the performance of the original premium priced Performance editions. They are amazing and given a little room to grow in the base version I have no doubt they will do more wonders.

 

[scaesare]

The reduced surface area to volume is a fact.

True, but the post you rebutted with a "physical reason" for was when @transpondster stated: "There is no reason why 75kWh 3 pack should not charge in 80-90 kW range"

In fact we do not know if cell surface area will cause the new packs to charge slower than the rates suggested.

You are pointing out that many other variables play into the final C rate, and you are most certainly right.

Regarding the contact patch, I thought the cells are encased in goo ?

Although Tesla has a patent for coating the cells in an intumescent coating, that's not been implemented on any of the packs inspected this far.

The cooling loop is in in contact with a portion of the bare cell casing via a thermally conductive membrane.

 

[SageBrush]

True, but the post you rebutted with a "physical reason" for was when @transpondster stated: "There is no reason why 75kWh 3 pack should not charge in 80-90 kW range"

Right -- that would be a reason for reduced charging rates.

If may be offset by other changes, or it may be additive. All we know for sure right now is that the 2170 cells start with a heat dissipation design disadvantage; that I think fair to say was taken on to lower cost.

The other variables you mention are not published yet but we do know that the 2170 cells are not planned for the Model X or S so trade-offs must remain. Take some combination of C rate, weight and or volume as likely explanations.

 

[transpondster]

True, but the post you rebutted with a "physical reason" for was when @transpondster stated: "There is no reason why 75kWh 3 pack should not charge in 80-90 kW range"

In fact we do not know if cell surface area will cause the new packs to charge slower than the rates suggested.



Although Tesla has a patent for coating the cells in an intumescent coating, that's not been implemented on any of the packs inspected this far.

The cooling loop is in in contact with a portion of the bare cell casing via a thermally conductive membrane.

and I reduced charge rate by 10% compared to S/X 75 because of surface/volume difference (I didn't try to calculate precisely, but should be close)

 

[scaesare]

and I reduced charge rate by 10% compared to S/X 75 because of surface/volume difference (I didn't try to calculate precisely, but should be close)

Right. The new cells could actually charge at a higher C-rate for all we know...