R1T $69,000 starting price - opinions

ajdelange

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The electrodes are mostly science but the electrolyte seems to be mostly art i.e. the art of finding the right additive to control formation of the SEI layer, prevent dendrite formation, enhance ion mobility etc. Thus it is hard to predict breakthroughs. It's try a pinch of this and see what happens then try a pinch of that and see what happens and then try a pinch of this and that and see what happens. I liken it in my mind to coming up with the perfect recipe for beer. It takes tons of trial and error experimentation and years to do. With beer you know if you've been successful in a couple of months but one of the most important things about a battery is its longevity. Thus lots (really years) of cycle testing is going to be necessary to find a new electrolyte that gives good specific energy, is safe, can be managed at high and low temperature AND will last 8 years in an automobile without losing much capacity. Like the rest I am hopeful and confident that eventually battery technology will get there but I don't think it is going to be as quick as we'd like. I think increased demand will tend to raise battery costs perhaps faster than the battery scientists can invent means to lower them (of course these are coupled). Only time will tell.
 

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Fortunately, there may be some significant advances before we reach solid state nirvana several (or more?) years out. Graphene ball technology is nearer in the pipeline and will allow faster and fuller charging of Li-ion batteries without excessive dendrite formation. (Lucid Motors is teasing these features for its new Air sedan, so perhaps they may be the first to market with graphene ball technology in cars.) Tesla is reportedly exploring the use of super capacitors to augment acceleration and regeneration capture in order significantly to extend the range of the battery pack.
 

ajdelange

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You have to look at numbers. Here's an item made by Tesla (or actually by a company owned by Tesla). The system won't let me copy the URL so search Amazon for

Maxwell Durablue 16V 500F Super Capacitor Battery ultracapacitor 1900A Solar Power System Home Audio Power Amplifier
It is a 500F 16 V assembly and is thus capable of holding (500*16*16/2)/3600 = 17.7778 watt hours of energy. It would take 1000/17.7778 = 56 of them to hold just 1 % of the energy in a 100 kW battery pack. This would add 440 lbs and $15K (at retail) to the weight and cost of the car so extending the range 'appreciably' isn't in the cards at present day super capacitor specific energy ratings.

Now on the other hand if we regenerate at 75 kW (the top of the range on the dial) for 10 seconds that's only 750000/3600 = 208 Watt hours which is only 0.2% of the battery pack capacity but even so would take 12 of those units to store that much energy. Thus absorbing regen when the battery can't seems practical and that means a range extension in cold weather but not really an appreciable one. 208 Wh is about 2/3 of a mile's worth.
 

Hmp10

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It is my understanding that Tesla bought Maxwell mostly for its battery manufacturing technology, not its super capacitor products.

You're going to have to help me here with deciphering the technology, but I believe there are more advanced ultra capacitors on the market. For instance, Skeleton makes an 51V ultra capacitor for automotive applications that holds 63.9 watt hours of energy. (So three of them would hold almost 1% of the energy in a 100 kWh pack, if I'm doing the math right.)

https://www.skeletontech.com/hubfs/...70371e7c|121ac4f7-456e-4175-9c08-c55a68ebf86f

A capacitor array that held only 1% of the energy in a 100 kWh battery pack would still be of significant use in storing and releasing energy repeatedly from acceleration and regeneration cycles, wouldn't it? I ask because I like to do jack rabbit starts in my Tesla P90D, and it takes a prolonged burst of acceleration to register a 1% drop in battery charge on my dashboard indicator. If I could do this repeatedly during a drive using a capacitor array to assist acceleration and recapture regenerative braking energy more efficiently, it would seem that it would significantly reduce the draw on the main battery pack.
 

ajdelange

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It is my understanding that Tesla bought Maxwell mostly for its battery manufacturing technology, not its super capacitor products.
Could be but if you are interested in incorporating ultra caps in your design and you own a battery company that also happens to make capacitors...

You're going to have to help me here with deciphering the technology, but I believe there are more advanced ultra capacitors on the market. For instance, Skeleton makes an 51V ultra capacitor for automotive applications that holds 63.9 watt hours of energy.
Ja, sure. It's a 177 F cap rated 51 V so its storage capacity is 177*51*51/2 = 230188 Joules which is indeed 63.9 watt hours. So far so good on the math.


So three of them would hold almost 1% of the energy in a 100 kWh pack, if I'm doing the math right.
Three of them would hold 191 Watt hours which is almost 200 % of the capacity of a 100 Watt hour battery but the X battery is 100 kiloWatt hours so that 191 Watt hours is only 0.191%


A capacitor array that held only 1% of the energy in a 100 kWh battery pack would still be of significant use in storing and releasing energy repeatedly from acceleration and regeneration cycles, wouldn't it?
Yes because 135 kW pulled for 10 seconds is only 375 Watt hours. This is where super/ultra capacitors do have a role in BEVs.

I ask because I like to do jack rabbit starts in my Tesla P90D, and it takes a prolonged burst of acceleration to register a 1% drop in battery charge on my dashboard indicator. If I could do this repeatedly during a drive using a capacitor array to assist acceleration and recapture regenerative braking energy more efficiently, it would seem that it would significantly reduce the draw on the main battery pack.
Clearly the more you "brake" the more benefit you get from regeneration. I find regeneration is necessary to get me from the rated 330 Wh/mi for my X down to the 300 Wh/mi I typically actually experience. That is certainly not efficiency I'd want to throw away but it isn't in absolute terms a whole lot of range extension.
 
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azjohnny

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It is my understanding that Tesla bought Maxwell mostly for its battery manufacturing technology, not its super capacitor products.
In a recent YT video involving Sandy Munro, Sandy was saying that he had heard Maxwell was close to perfecting a solid state battery before being acquired by Tesla. Tesla's battery day should be answer a lot of questions
 

Feathermerchant

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Problem with capacitor in a BEV. Energy stored in a capacitor is
E=½CV² where C is the capacitance and V is the capacitor voltage.
So to get the energy out, you must fully discharge the capacitor.
BEVs today commonly operate on a battery that is ~300V discharged to 400V charged.
How do you magically make the inverter (that drives the motor) work down to 0V?
One of the units mentioned above operates at 16V max. So do you install another inverter that works from 16V to 0V but that can output enough power and voltage to run the motor and switch between them?
 

ajdelange

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The real problem with capacitors (at this point in their evolution) is that their specific energy is small compared to batteries. Thus, as discussed in #138, you need about a quarter of a ton of them to hold 1 kWh.

The voltage problem really isn't much of a problem. For starters look at the stored energy which is proportional to the square of the voltage. If charging to some voltage fully charges the capacitor then discharge to 1/4 of that voltage recovers 15/16ths of the stored energy. Beyond that as the voltage does go down as the capacitor is discharged the capacitor bank would be connected to the main battery through a DC/DC converter.
 

delmi

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C'mon guys we are talking about vehicles which none of us have sat in let alone driven, and we are on about the environment, global warming and even "douchebags".
I am 89 years old and I thought my third Land Rover would be my last car but along came Rivian and captivated me, so I am buying my first pickup truck and I don't care what it costs. After Rivian has delivered about 10,000 units we can start talking about price, and extras and "is it worth it" and all of the other topics.
As for me I can hardly wait.
 

Kickaha

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I agree with Feather and delmi. If you need a cheap EV, go buy a Leaf - great cars for the price. I am buying the experience and features of Rivian. It will cost more and I accept that. You need to get what works for you and what you want. /shrug
 

Feathermerchant

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FWIW I have an F150 with a long bed. That's 8ft. It was full today and many Fridays when I pick up donated food from a neighborhood WalMart and take it to the food bank.
So I could really use a long bed. I expect that someone will make one eventually. In the mean time I have a reservation for a Cybertruck.
 
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