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samroy92

samroy92

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We don't know the amps of the packs, C rating of the cells, or how much heat the packs can remove to keep them at that rating.

-Crissa
This is an extensive study on 4680 heat characteristics: https://iopscience.iop.org/article/10.1149/1945-7111/abd44f/pdf

They concluded:
With the larger cell format, the heterogeneity in current collection resulting from high ohmic losses along the length of the jelly-roll are exacerbated and must be addressed by the tabless design. When using the traditional end-tab design, the ohmic losses from the current collectors results in five times more energy being lost as waste heat, compared with the tabless case.

Five times less waste heat compared with tabbed, but 4680 is also 5x the volume too.

I hope I'm wrong and these cells can last 1 million miles charging at 6C rates. But I just don't see it. Maybe in a few years after some key milestones in the 4680 program. @Dids would kill me.
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Dids

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If you had 2 strings of 84 - for a total of 168:
  • You could then charge that system at 1000V - no problem.
  • Amps x Volts = Watts
  • 7.2A * 1000 * 2 strings = 14.4kW charging speed.
  • If you try to charge this battery pack at 1000kW (1 MW) - call your daddy, it's going to explode
  • Number of Volts don't matter.



I agree with you here - except the strings comment (strings don't matter, voltage does matter, what matters is power delivery to the cells). But play around with the 4680 specs and i'm happy to recalculate! Give me a 4680 cell spec and i'll run with it.
The number of strings matter and the number of cells in the string matter. The C rate is dictated by internal resistance. Two identical resistors in parallel have an equivalent resistance half the value of either resistor. In other words 2 strings cuts your internal resistance in half over 1 string.
 
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The number of strings matter and the number of cells in the string matter. The C rate is dictated by internal resistance. Two identical resistors in parallel have an equivalent resistance half the value of either resistor. In other words 2 strings cuts your internal resistance in half over 1 string.
So are are suggesting that every time you add another cell in parallel it can double its C-Rating? Strings don't matter - I am talking about the fundamental unit-level cell limitations
 

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This is an extensive study on 4680 heat characteristics: https://iopscience.iop.org/article/10.1149/1945-7111/abd44f/pdf

They concluded:
With the larger cell format, the heterogeneity in current collection resulting from high ohmic losses along the length of the jelly-roll are exacerbated and must be addressed by the tabless design. When using the traditional end-tab design, the ohmic losses from the current collectors results in five times more energy being lost as waste heat, compared with the tabless case.

Five times less waste heat compared with tabbed, but 4680 is also 5x the volume too.

I hope I'm wrong and these cells can last 1 million miles charging at 6C rates. But I just don't see it. Maybe in a few years after some key milestones in the 4680 program. @Dids would kill me.
You should probably read your source abstract before using it to prove my statement incorrect.

The paper numerically explores the electrochemical and thermal behaviour of a larger format 4680 cylindrical cell recently proposed by Tesla and explains the need to go “tabless.” An idealized spiral geometry is used for 2D simulations with the traditional tab-based current collection method and a new continuous current collection method compared.
It is merely a set of predictions. Did you mean to link to a different study where they took a thousand cells from a Model Y and cycled them a few thousand times?

-Crissa

PS, five times less doesn't mean one fifth, which is what 'five times more' would inverse to. It is very bad grammar I have been guilty of many times.
 
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I believe that standardization of battery technology will, and should, eventually come as the industry matures, as you put it. Gasoline octane rating/grades are standard. The auto industry has adapted their engines and the size of their gas tanks for example, to adapt.

Yes Tesla has resisted standardization in the past and may in the future given the idiosynchrities of their management.
This is a false narrative. Tesla created the NACS standard before CCS was even standardized. The Tesla charge standard was the first fast DC charging standard and the legacy auto groups pushing CCS are the ones who wanted to be different from Tesla. Tesla was making EV's using this standard and rolling out their Superchargers and didn't want to wait.

The Tesla (NACS) standard was engineered in a superior way to be more sleek, lighter and easier to handle and with the capability to carry more current. Legacy auto didn't want EV's to be easier to use or the charge handles to be sleek and modern because they wanted to keep selling gas cars for many decades. Many legacy auto companies claimed consumers didn't want EV's, that they couldn't sell them. If Tesla had aligned with people like that, they never would have made it.

Tesla did the right thing, not to be idiosyncratic but to speed the adoption of EV's by making the charging equipment more compact and portable and affordable, as well as chopping costs off the charge port that every EV needs. And, perhaps most importantly, installing a nationwide network of fast DC Superchargers so EV's were viable to take on long, cross-country road trips. No other manufacturer has done this because they wanted to speed the adoption of EV's. American courts had to force VW to build a fast charging network as pennance for creating diesel cars that polluted 10 times as much as claimed. You know, Dieselgate. And it's a crappy charge network, VW made sure of it. Then they sold it off to another for profit company that cares more about ripping their customers off and leaving them in the lurch with out of order stations than serving them.

The CCS standard is a joke. To suggest that Elon went his own way to be idiosyncratic displays a real misunderstanding of the person who wisely resisted the stupid committee driven design of the CCS standard. Musk did it that way because he was fighting for the right to actually bring EV's to the people.

Legacy auto was just giving lip service to the idea of EV's so CARB would leave them alone. They purposefully tried to torpedo adoption of EV's to protect their ICE sales. This made big oil very pleased. The two industries have been in bed together for decades. Legacy auto recently realized they have to stop listening to big oil, it's time for a divorce to save their own asses. But they have little EV experience. Tesla can make better EV's more quickly and more cheaply so legacy auto still can't compete directly with Tesla. Legacy auto has become fat and lazy. And that's a problem because Tesla continues to grow production and reduce the cost to build which is the only way you can bring superior value to new car buyers.

GM is having the Federal Government pay LG to build them a battery factory. Tesla used their own money to build themselves a battery factory. GM is not sustainable except as a ward of the State.
 

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Battery swapping came at a time when it took 2 hours to charge.

I may be wrong, was it 1.5 hours to charge ?

Point is, it now takes 15 minutes. Or maybe 30.

The longer time goes on, the shorter the time needed to charge your battery.

A diminishing business case for battery swapping.
 

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So are are suggesting that every time you add another cell in parallel it can double its C-Rating? Strings don't matter - I am talking about the fundamental unit-level cell limitations
I know that you are, and no I am not saying that the c rate doubles. C rate is tied to the current measured in amps. The amperage that a cell can handle is due to it's internal resistance and heat discharge and heat tolerance etc. That makes c rate ambiguous and site specific.
But packs and cells are not the same thing and the 1MW+ charger is at the pack, not at the cell.
The reason you and I arrive at a different conclusion on 1000v and 1MW+ charging is that I imaging what it would take to reach those parameters and you imagine they are lying.
 
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The best part, I think, about megacharging is that it means literally only the pack and conditions is the limit to charging speed. Not the charger.

-Crissa
Fully agree
 


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The reason you and I arrive at a different conclusion on 1000v and 1MW+ charging is that I imaging what it would take to reach those parameters and you imagine they are lying.
I am not saying they are lying, I simply think people misunderstood what Elon said. I am backing up my hypothesis with real world data on Tesla's current cell charging characteristics + facts released about 4680 battery.

Agree to disagree. I don't think its helpful to hype up 1 MW charging speeds on CT when it is unlikely to happen and everyone is going to be disappointed.
 

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I am not saying they are lying, I simply think people misunderstood what Elon said. I am backing up my hypothesis with real world data on Tesla's current cell charging characteristics + facts released about 4680 battery.

Agree to disagree. I don't think its helpful to hype up 1 MW charging speeds on CT when it is unlikely to happen and everyone is going to be disappointed.
I think we’re all landing more or less on the same page here. If we get the expected battery chemistry improvements:
  • Cybertruck and he semi will be able to use v4 Superchargers to charge at up to 1 megawatt.
  • Cybertruck will likely not be capable of receiving that much juice or if it is, only for the very briefest time on the biggest battery pack.
  • V4 charging speeds on the Cybertruck will be much faster than on v3 chargers, but likely not 3-4x faster.
  • Likely result is charging sessions will be just a touch faster than most modern Teslas. We’ll be sucking in 50% more juice In 80% of the time.
Without the expected improvements, most of the above is still true, but both peak and average charging speeds will be significantly lower.

We don’t need megawatt charging for v4 charging on the Cybertruck to be king what we really need is average charging speed to be much higher and that is almost a lock in. It’s very likely the 500 mile Cybertruck is going to be by far the best road tripping EV on the market.
 

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Full charge in less than 10 minutes. Minga!
 

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Yes, I think that's right. The charge curves of the various EV's at fast chargers limits the rate after one hits 80% or some other level, to protect the battery. The 15-18 minutes is usually at a 350k fast charger up to 80% (as with the Hyundai 10%-80% 18 minute fast charging spec) but read Hyundai's caveat about performance and durability!
--------------------------------------------------
Level 3: DC fast chargers are widely accessible and also stationed in populated areas around the country and interstate exits. These charging stations feed a direct current (DC) to your battery for a more immediate boost. Fast chargers are great for road trips and long-haul drives. However, Hyundai states battery performance and durability can deteriorate if DC chargers are used constantly. For good battery health, plan to use a Level 2 AC connection as your primary charging method. This bet practice will help keep your high-voltage battery in “optimal condition.”

Fast Charging

The Hyundai Ioniq 5 is one of the fastest charging electric vehicles on the market today, boasting an 800-volt charging capability. It can go from 10% to 80% state of charge in as little as 18 minutes when connected to a 350-volt DC fast charger. If you’re especially short on time, you can still boost the battery by 62 miles in roughly five minutes using a high-voltage fast charger.

Charging speed and time estimates will vary depending on multiple factors, including the outdoor temperature, current battery levels, vehicle settings, and more.

https://www.kbb.com/car-advice/ioniq-5-charging/#DC
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To have the 250 miles in 15 minutes (fast charge without battery damage) means batteries may have to get considerably larger, which means until battery production ramps up, the EV's are going to stay expensive.

Ample says they can battery swap in as little as 10 minutes, NIO says 3 minutes.
And without the risk of battery deterioration or the cost of battery replacement.

Personally, I rather use fast charging on a battery swapping company's battery than one I own and will have to replace (at great cost) if fast charging causes significant deterioration.

Battery tech should improve over time and could become rapid without risk of damage eventually. Still it's hard to say when. In the mean time a variety of options, including swapping, will remain viable.

I have never used fast-DC charging with my Leaf even though I could with CHAdeMO - it would take maybe 30 minutes for 80% from 10% they say. But my Leaf was bought for local tripping of no more than 100 miles round trip, commuting, etc.

Reading about the potential problems with fast charging and battery degradation, esp. with an air-cooled battery like on the Leaf, over the years was anther reason I avoided it. The potential damage may have been over stated however, time will tell.

Yesterday I got word from Ford I could order a Lightning. But OMG the price really went up from the original reservation in May 2021. The Pro version which was originally $39k is now starting at $56k, a $17k increase, and they aren't even available it seems, sold out for model year 2023.

So the next higher model, the XLT, starts at $63,474 but really over $65k due to transportation charge of nearly $2k. And with the options I would want (bed liner and cab liner and an upgrade that adds things like heated steering wheel, etc.) it comes in at $71k.

Tesla Cybertruck Cybertruck 1000V Architecture + V4 Supercharging Confirmed!! ⚡️ "It's Going to be Used for Cybertruck Too" - Elon Musk choose your model


I am having trouble getting my head around a $71k pickup truck. Yes I could swing it, but can I justify it?

Sticker shock. Can you say "bait and switch?"

---the action (generally illegal) of advertising goods which are an apparent bargain, with the intention of substituting inferior OR MORE EXPENSIVE goods---

Or "price gouging?"

--- Price gouging is a pejorative term used to describe the situation when a seller increases the prices of goods, services, or commodities to a level much higher than is considered reasonable or fair. Usually, this event occurs after a demand or supply shock. ---

Will the Cybertruck have the same enormous price increase over the 2019 reservation price - probably. Will the Chevy Silverado EV's advertised starting price ($39k) experience the same price inflation - probably.

And how long will I have to wait for either the Cybertruck of the Silverado?

In the Ford Lightning forum there a a good number of people deciding not to go forward due to the enormous price increase and the unavailability of the cheaper model. At least they are saying that.

Add to that, if one opts for the extended range battery, the federal tax credit disappears since it goes over the $80k limit even before any options are added!

Tesla Cybertruck Cybertruck 1000V Architecture + V4 Supercharging Confirmed!! ⚡️ "It's Going to be Used for Cybertruck Too" - Elon Musk extended range battery


A $17,500 price jump for the ext range battery?! That only adds an estimated 70 miles of range?!
Forget about it!

One reason (battery cost) that for the near future, I think the Ample battery swapping could succeed.

AMPLE: https://www.forbes.com/sites/ianpal...reduce-oil-and-gas-emissions/?sh=52736e44518a

NIO: https://www.nio.com/nio-power
 
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@Dids @Crissa new video from The Limiting Factor released 30 minutes ago:



Confirming my priors here, Jordan see's a peak 612kW on a 168kWh Cybertruck - with 700kW if CT has 200kWh pack. Really simple C-Rate limitations for battery longevity. We will not see 1MW charging on the CT.
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