New Battery Range & Pack Architecture [Announced at Battery Day]

[Sasmania]

Didn't read all 13 pages of replies, so it's probably been said, but Tesla has known about these new batteries BEFORE they announced the CyberTruck. Meaning they already were calculating the new batteries into the specs and pricing. Sure, they were probably low-balling just a bit to be safe, but I don't think we will see 50% + improvements on the specs given anytime soon.

Think about it, how could they have such amazing specs WITHOUT the new batteries?

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[shaneaus]

Trailer brakes are friction brakes. No regen.

Bums me out when towing with my hybrid pickup truck.

But, trailer brakes are vital to the stability and safety of a truck + trailer combination, so it's a necessary cost at this point.

Adding regen to a trailer is harder than it looks, due to the existence of a well-established tech stack with standardized interfaces, interchangeable trailers, and a large installed base of existing hardware. Adding regen/power to a trailer is certainly possible, but there's much more to it than many of the engineering-daydreamers (of which I am often one) are likely see on their first pass through the issues.

Exactly, which was why I was starting that when towing/hauling up/down steep grades the regen isn't as significant as related to how much power is used to ascend. And, that regen is more comparable when the truck is used as a passenger vehicle.

Makes one surprised that regen trailer brakes haven't been made yet. OH! That's right - the CT will be the first available vehicle for public purchase that they might really make a difference! :-/ LOL

 

[shaneaus]

Didn't read all 13 pages of replies, so it's probably been said, but Tesla has known about these new batteries BEFORE they announced the CyberTruck. Meaning they already were calculating the new batteries into the specs and pricing. Sure, they were probably low-balling just a bit to be safe, but I don't think we will see 50% + improvements on the specs given anytime soon.

Think about it, how could they have such amazing specs WITHOUT the new batteries?

Yes, sir. It's been said. But, not everyone is aware. So, never hurts to repeat it!

 

[ajdelange]

Exactly, which was why I was starting that when towing/hauling up/down steep grades the regen isn't as significant as related to how much power is used to ascend.

It isn't significant at all. There is no regen for the trailer. The truck could not handle it. All that potential energy is wasted in the trailers own brakes.

 

[shaneaus]

It isn't significant at all. There is no regen for the trailer. The truck could not handle it. All that potential energy is wasted in the trailers own brakes.

I understand. I don't think I'm communicating my intent to you at all! The regen of the TRUCK isn't as significant to the overall range BECAUSE of the additional power needed to move the trailer. That the trailer doesn't have regen braking is "duh" to me and understood.

I'm saying the same thing you are. Just not phrasing it in a way that you understand that is what I'm saying. So, no need to repeat yourself - we are in agreement.

 

[ajdelange]

Of course it takes a pretty steep grade for regen to be of any benefit (3% or more). Most of the value in regen is derived from the inertial load. You don't get that back either with a trailer. For grades less than 3% most of the invested potential energy is "recovered" in overcoming drag and rolling resistance in the sense that you don't have to take energy from the battery to supply those loads. The ultimate determinant of whether regen is of much use comes from looking at your power meter. If it is in and staying in the negative region for long periods of time then regen helps. But, as I said, unless the grade gets up around 4% that doesn't usually happen.

 

[ajdelange]

Just wanted to point out that if you are charging from home then having a super charger in your town is pointless. It will be cheaper to charge at home than at a super charger so when you sleep it’s being charged.

Yes. All excited that the new SC at the WaWa in the next town in open (with all V3's yet) and then realize that I'll never use it. Even though I get free charging it's just not worth the inconvenience relative to charging at home.

 

[Luke42]

It isn't significant at all. There is no regen for the trailer. The truck could not handle it. All that potential energy is wasted in the trailers own brakes.

Efficiency is one thing. The stability of the trailer is another.

With a heavy (or poorly balanced) trailer, the trailer brakes keep the combination stable when decelerating.

So, even if the truck's battery pack can absorb most of the deceleration energy, trailer brakes are still mandatory. Otherwise the tail wags the dog (the trailer shoves the truck around), which is dangerous.

 

[fritter63]

You're not getting an electric truck for two years. Two years ago was the first year there were Superchargers on hwy 101.

Small nitpick, we've had them here in Atascadero for a few years more than that. We were the halfway SC point between LA and SF for a long time.

Used to be if you saw a Tesla in our podunk little town, they were just passing through to charge.

 

[ajdelange]

And, most semi chargers will be along major highways ...

Yes! Exactly where they would be needed.

From what I've watched and read... I just don't see Tesla installing chargers with higher charge capacity just for the CT.

Regarding splitting the batteries in a CT for faster charging - so far, that is all speculation with not even a rumor that might be the case.

From those who have been able to peek into a SC cabinet and the pictures they have posted the architecture is clearly, and it logically would be, modular. To increase the size you increase the number of modules. Similarly within the car the battery is modular. To increase its capacity you increase the number of modules. Another aspect to this is, of course, that how you connect the modules is significant. Connect them in series and you have higher voltage. Connect them in parallel and you have higher current.

The Teslas are 385 volt cars and the chargers are 385 V chargers and Tesla has a huge investment in them. Thus they will not be switching over to 800 V architecture any time soon. But other manufacturers are and EA is installing chargers capable of delivering 800V. This means they can pass more power to cars at less current. Rivian, for example, while it is a 400V architecture, can rearrange its batteries to charge from an 800 V supply thus enabling it to take on 300 kW charging power before taper cuts in. Assuming taper linearly decreases to 10% at 100% SoC starting at 40% SoC and that it consumes 450 Wh/mi it would have a 180 kWh battery. The implications of all this are that it can charge from 10% to 80% in 32.8 minutes thus taking on 0.7*400 = 280 miles for a rate of 512 mph.

Assuming the CT has the same basic consumption of 450 Wh/mi it's battery would have to be 225 kWh. Assuming the same taper that same 70% addition (10% SoC to 80%) from a 250 kWh charger (V3) would take 49.2 minutes but would add 0.7*500 = 350 miles for a rate of 426 miles per hour. If you are a motorist on a road trip you see 512 vs 426 mph in favor of the Rivian. If you are a working man who consumes 70% of his battery in running jobsite equipment, travel, towing a trailer, hauling stuff in the bed... and needs to replenish that you see 32.8 minutes vs 49.2 minutes. These days 50 minutes is not considered very good charging time when your competitor can claim 33. Further note that most of the SC terminals out there today are not V3's. They are V2's with peak power of 125 kW. The time to take on 70% would be double with one of them i.e. 98 minutes and the rate would halve to a paltry 213 miles per hour.

Thus Tesla has to increase charging rate. And they have to do it at 400V because they have all this investment in 400 V chargers. So how are they going to do that? Obviously by pumping more current into the car. The extra current is easy enough to get. Just put more modules in the charger cabinet. The trick is that the connector and cable are pretty much maxed out at the 625 amps they carry in a V3 charger now. The cables are liquid cooled. The obvious solution is more cables/connectors. If the vehicle can be connected to more than one of the current SC terminals at a time then the problem is solved. It is only necessary to make more terminals available to drivers. And, of course, the vehicle has to be able to accept more than one connector.

This is the solution they have taken with the Semi. These are seen from time to time charging at regular SuperCharger stations. The charging port on the Semi has four pairs of "pins" and a communications socket. These connect through a Semi connector to an interface box into which multiple SC hoses plug. There must be some sort of extension cords in use as well as clearly the hoses from multiple stalls would not reach a common point.

This is why I think there is a strong possibility that the CT will "double up" on SC stall use. For obvious reasons we would not want the CT to have a connector unique to it nor would we want to have to carry the adapter box. I would thus expect the truck to have two of the nomal Tesla charging connectors with the adapter box built into the vehicle. It would be necessary to carry an extension cable though.

One aspect of this which interesting to contemplate is as to what happens when you show up at a SC and grab two stalls. As most stalls out there are still V2's they can't be adjacent stalls. This leads me to believe that they will indeed put higher power chargers at stations but these are just the current chargers with twice as many modules and two hoses. Thus they could be used by any Tesla driver - not just CT drivers.

When Tesla can later convert the rest of the lineup to the new battery tech Tesla will begin converting the lower cap chargers - but, I don't see that happening for another 5-7 years.

The battery tech really has nothing to do with it. It takes a 255 kW charger that starts to taper at 40% SoC 49 minutes to add 70% SoC to a 225 kWh battery whether that battery is lead acid or lithium without a tab. Also no "conversion" is required. Just higher numbers of the current chargers (even of two of them are put in 1 cabinet).

Just no perceived need on EM's part - because, "we don't need more range." *sigh*

He was speaking of what my wife calls "comsumer cars" that is the one's that housewives take their kids to ballet lessons in. But he is banking on the trucks as a major source of revenue in the future. They don't need more range either. What they need is more kWh to enable them to do work other than moving people around. The extra range comes as icing (bad choice of words I suppose) on the cake when more kWh are installed. More kWh requires higher speed charging.

Just so every one is clear: I have no special information or insider connections or even a crystal ball leading me to these conclusions. It just seems obvious to me that if you claim to be the leader in BEV tech, that your fastest charger is 250 kW, that you are building cars with batteries 200 kWh and more and that your competitors chargers are 350 kW, you had better up your chargers' capacities. Two V3 chargers can, and are, being combined to make one 500 kW charger today. Seems to me that's a better way to go than converting cars and chargers to 800 V. And I think we'll start to see this about the time the CT's and Semi's start to hit the road.

 

[ajdelange]

Regarding splitting the batteries in a CT for faster charging - so far, that is all speculation with not even a rumor that might be the case.

I did mean to comment on the "splitting" aspect. First, with the current crop of high voltage milliohm on resistance electronic switches it is pretty trivial to do it. Further to that if you do do it you now have two isolated packs each of which can be connected to its own charger both inside and outside the car. Outside (SC) this removes the need for a combiner box such as is used with the Semi. Each pack sees one terminal and each terminal sees one battery. That's the way it works in the current cars i.e. one terminal, one battery pack.

With respect to home charging it is the same story. If you have 2 HPWC each could charge one battery and, provided your total home charging capacity is 120 A, you could charge at twice the maxium rate (51.2 miles per hour as opposed to 25.6).

Should probably mention that Rivian has a patent application in for battery reconfiguration. They switch the two battery modules into a series configuration so the string can be charged from an 800 V charger (that's how they get 300 kW). As the Tesla mod would be separating two halves rather than reconfiguring them I don't see how that would violate the Rivian patent. But to be honest I don't see how the Rivian patent claims pass the "non obvious" test.

 

[ldjessee]

I do not live in California and I think there are a number of users who are NOT going to be wanting to tow something across the state or country, nor do I have such strict timelines that I cannot spend an extra 20 minutes every time I stop for me to put more energy back into the battery pack.

I do also see why some need that. That is the reason why manufacturers make trucks with different capabilities. If Tesla is serious, they will need to come out with a CyberTruck XL or Commercial Edition or something. It could have duallies, a second battery pack (or just bigger one), and all the other features that larger, more commercial trucks have.

Or maybe it will be a cut down Semi, as that would be closer to what many would want. Say $100k US, smaller cab, one axel in the back... Then others can manufacture backs for the truck.

Of course, they could just leave that for Ford, Dodge, and the others to fight over.

 

[Crissa]

Just wanted to point out that if you are charging from home then having a super charger in your town is pointless. It will be cheaper to charge at home than at a super charger so when you sleep it’s being charged.

It's not entirely pointless - it means you can charge effectively if your specific neighborhood is powerless; and it means people visiting you can charge effectively without sitting in your driveway ^-^

It's good for local businesses, too.

What you guys want isn't more battery capacity - you want faster charging. Bigger packs just means longer charge times.

-Crissa

PS, motorcycles all use the high-density, high-nickel-cobalt batteries. And they don't like being left at 0% for long; they start taking damage pretty immediately. If there's a mechanical failure, make sure to nurse your battery pack immediately.

 

[shaneaus]

Yes! Exactly where they would be needed.

I guess that all depends on the state you live in and where to work you need to do is located. Yes, that is exactly where Tesla should focus their efforts. But, I keep thinking of persons who work in rural areas. Granted, I live in Texas and like many of the mountain states there are large areas where there aren't many Interstate Highways nearby.

But, wow, you provided a lot of information to unpack! Thanks for that! The info about the SC's being modular is great! And, if they did integrate a switch/mechanism to reconfigure the batteries for faster charging and two chargers could be used at the same time that would be a game changer.

 

[ajdelange]

I guess that all depends on the state you live in and where to work you need to do is located. Yes, that is exactly where Tesla should focus their efforts. But, I keep thinking of persons who work in rural areas. Granted, I live in Texas and like many of the mountain states there are large areas where there aren't many Interstate Highways nearby.

Those places are not served by interstates and they are not served by many, if any, SuperChargers. And those SCs that do exist won't be getting the V3's until the main routes have them and they won't be getting double V3's until even later. Tesla will go first where it can serve most customers.

if they did integrate a switch/mechanism to reconfigure the batteries for faster charging and two chargers could be used at the same time that would be a game changer.

I think they really need one because at the moment they are behind in this.