New Mercedes Electric will have a Pouch

[FrgMstr]

Mercedes is showing off what is going to be powering its new electric cars; the EQC lithium-ion battery. Trevor Long over at EFTM got a firsthand look at the technology while it was being shown off in Sweden. While Tesla has committed to a system centered around the commonplace 18650 battery form factor, which is still very different from what you would buy, Mercedes is going a very different route; the Pouch. 384 cells in a pouch format to be exact. Mercedes said it allowed it to provide greater power density. Just don't try to put your Mercedes in your checked luggage, as you would surely end up in a kangaroo court.


As always, there’s no way to quantify the life-span of an electric vehicle battery – it’s different for every user based on their driving and charging, however, the EQC battery is backed by an 8 year 160,000 km warranty, and Mercedes expects customers to get “much more” out of the battery. Batteries don’t just stop working – they degrade, so in reality, the EQC in 10 years from now will just have less range than it does on day one.

 

[DukenukemX]

I agree with Tesla's approach as I can find a 18650 battery fairly easily, where as what Mercedes is doing is probably going to cost a small fortune to replace it. Mercedes is ensuring that repairing their used cars is going to exceed the value of the car, and in 10 years those cars will cost less than a fraction of their original value because of this.

 

[nutzo]

As someone who doesn't put a lot of miles on my car, I'm more concerned about how many years the batteries will last under light use, as opposed to how many charge cycles they can take.

I've seen to many laptop batteries die after a few years, even though they are rarely used/charged.

If the battery only last 8-10 years, even if I'm only driving 4-5K/year, it would be cheaper to just drive an ICE.

 

[nutzo]

I agree with Tesla's approach as I can find a 18650 battery fairly easily, where as what Mercedes is doing is probably going to cost a small fortune to replace it. Mercedes is ensuring that repairing their used cars is going to exceed the value of the car, and in 10 years those cars will cost less than a fraction of their original value because of this.

Isn't that already true for many of their current cars?

 

[Teenk9]

I agree with Tesla's approach as I can find a 18650 battery fairly easily, where as what Mercedes is doing is probably going to cost a small fortune to replace it. Mercedes is ensuring that repairing their used cars is going to exceed the value of the car, and in 10 years those cars will cost less than a fraction of their original value because of this.

So par for the course with Mercedes Benz then. And BMW. And Audi, etc.

 

[vegeta535]

I agree with Tesla's approach as I can find a 18650 battery fairly easily, where as what Mercedes is doing is probably going to cost a small fortune to replace it. Mercedes is ensuring that repairing their used cars is going to exceed the value of the car, and in 10 years those cars will cost less than a fraction of their original value because of this.

So you think Tesla is any different? Tesla's are expensive to repair and also don't give access to anyone outside of Tesla the software and tools needed to work on them. So what if they use standard 18650 batteries. They proabably got proprietary connectors and circuits that keep you from using anything off the shelve.

 

[Riccochet]

So? Tesla's are expensive to repair and also don't give access to anyone outside of Tesla the software and tools needed to work on them. So what if they use standard 18650 batteries. They proabably got proprietary connectors and circuits that keep you from using anything off the shelve.

The cells are comprised of 18650's, but they still are configured with proprietary circuitry. It's not like you can run out to your local vape shop and buy some 18650's to replace in your Tesla.

 

[Rockenrooster]

I agree with Tesla's approach as I can find a 18650 battery fairly easily, where as what Mercedes is doing is probably going to cost a small fortune to replace it. Mercedes is ensuring that repairing their used cars is going to exceed the value of the car, and in 10 years those cars will cost less than a fraction of their original value because of this.

Yeah but Teslas have thousands of them.
Pouches probably would be lighter too.
It might even be cheaper to do pouch cells, if it's anything similar to Brushless RC cars. I can get a 3 cell 5000Mah 20C (100 Amp hour Discharge Rate!) 11.1v battery waaaaaaaaaaaaay cheaper than a equivalent 11.1v 5000Mah 18650 based battery, and that 18650 based battery would not be able to supply the current needed (50+ amps). I would need a 60 cell 18650 battery pack to provide the same discharge rate without blowing up!!! (100 Amp hours)

 

[Sufu]

Interesting concept, I just wonder how well it will scale (in mfg volume) compared to the standard 18650 format. Maybe Mercedes is really only planning in launching a paper, low volume only EV. Time will tell...

 

[EODetroit]

Except that the Tesla Model 3 uses 21700 form factor cells, not 18650. Considering they're making 3x as many Model 3s as S and X, and that multiplier will only increase over time, you can consider Tesla to be a 21700 size cell user instead of 18650.



Did Mercedes say how much cobalt per unit of energy storage its going to use? Tesla is basically going cobalt-free in the next few years, which is important (ethically) because cobalt is a conflict mineral and (financially) because cobalt's price is skyrocketing due to the Li Ion demand.

 

[M76]

As someone who doesn't put a lot of miles on my car, I'm more concerned about how many years the batteries will last under light use, as opposed to how many charge cycles they can take.

I've seen to many laptop batteries die after a few years, even though they are rarely used/charged.

If the battery only last 8-10 years, even if I'm only driving 4-5K/year, it would be cheaper to just drive an ICE.

Laptop batteries die because they sit most of the time on a charger, and most laptops don't give a shit about battery life. So they constantly keep topping up the battery which wears them almost as bad as complete discharge / recharge cycles. So if you use your car short range the best thing to do is to only charge it when the capacity goes close to empty. Or when you plan a longer trip. You don't go to the gas station to top up your car after every drive either.

 

[Rockenrooster]

Laptop batteries die because they sit most of the time on a charger, and most laptops don't give a shit about battery life. So they constantly keep topping up the battery which wears them almost as bad as complete discharge / recharge cycles. So if you use your car short range the best thing to do is to only charge it when the capacity goes close to empty. Or when you plan a longer trip. You don't go to the gas station to top up your car after every drive either.

While true for most laptops, I'm pretty sure Tesla knows this and has programmed the charging accordingly. I mean it's not like its impossible.

I have a MSI laptop (bought in 2014) that is actually "smart" about its battery charging (at least I think so), I get almost the same battery life as new even though it spends most of its life plugged in (Used as a low power server for ARK).

 

[M76]

While true for most laptops, I'm pretty sure Tesla knows this and has programmed the charging accordingly. I mean it's not like its impossible.

They can't because people except the car to be at full range when they take it off a charger. Tesla can't just arbitrarily decide to not charge the car until it's almost fully discharged.
What they can and probably do is hide some of the battery capacity from the end user, and have an overhead. So as the cells get weaker the car will still have the same usable range.

 

[velusip]

I thought the concern was with battery isolation, not energy density. I would prefer a car fire to a car bomb.

 

[aduljr]

Laptop batteries die because they sit most of the time on a charger, and most laptops don't give a shit about battery life. So they constantly keep topping up the battery which wears them almost as bad as complete discharge / recharge cycles. So if you use your car short range the best thing to do is to only charge it when the capacity goes close to empty. Or when you plan a longer trip. You don't go to the gas station to top up your car after every drive either.

Actually the best way to get the most life out of a battery and exceed 10 years is to simply keep the charge between 30% and 80%. Charging to 80% in a Tesla is easy as you can set it via the app or in the car when you plug it in. You really only fully charge to 100% when you go on road trips. And that doesn't mean its going to need to be replaced at 10 years either. You loose capacity gradually. There is a pretty good write up on this over here.

https://cleantechnica.com/2018/08/26/the-secret-life-of-an-ev-battery/

Some of the tips would work well for all lithium based batteries to get the most life out of them.

 

[clockdogg]

They can't because people except the car to be at full range when they take it off a charger. Tesla can't just arbitrarily decide to not charge the car until it's almost fully discharged.
What they can and probably do is hide some of the battery capacity from the end user, and have an overhead. So as the cells get weaker the car will still have the same usable range.

So...you're saying EV makers could be in league with the Flash memory 'spare capacity' cartel. I knew it!

 

[aduljr]

They can't because people except the car to be at full range when they take it off a charger. Tesla can't just arbitrarily decide to not charge the car until it's almost fully discharged.
What they can and probably do is hide some of the battery capacity from the end user, and have an overhead. So as the cells get weaker the car will still have the same usable range.

So...you're saying EV makers could be in league with the Flash memory 'spare capacity' cartel. I knew it!

because truly draining a battery to 0% would cause to much damage to the cell. Telsa car ranges are based on usable storage capacity and not what the true capacity is on the batteries. Owners can take it a step further to extend the life even more with just a couple of habits.

 

[Sikkyu]

electric cars are the biggest planned obsolescence scam disguised as a virtual signal ever.

 

[Rockenrooster]

They can't because people except the car to be at full range when they take it off a charger. Tesla can't just arbitrarily decide to not charge the car until it's almost fully discharged.
What they can and probably do is hide some of the battery capacity from the end user, and have an overhead. So as the cells get weaker the car will still have the same usable range.

I wasn't talking about programming the charging to only start when near empty, that would be utterly stupid...
I remember reading somewhere that Teslas batteries don't charge to actual 100% capacity (4.25v per cell I think) and they "hide" some capacity from the customer for lifespan reasons (just like you suggest).

I don't know exactly how Tesla does it or Laptop manufactures do it, but the "don't leave it on the charger because it'll die sooner" and "Only charge your batteries when they reach zero to increase lifespan" is not true all the time.

 

[velusip]

electric cars are the biggest planned obsolescence scam disguised as a virtual signal ever.

Uh, well yes. But that may be looking beyond the point a bit. Electric cars are indeed virtue signaling platforms, and all tech is released incrementally for obsolescence purposes, but it's no worse than any other competitive platform. e.g. opposing piston engine is next. We'll see them roll out from all major vendors in the next 3-6 years. The fuel efficiency and power goes up, size and weight goes down. The concept is as old as the hills, but was "held back" to provide a longer profit curve. The same applies to batteries, DC motors, regenerative power systems, and DC to DC converters.

The more important problem with electric cars goes much deeper. They are a method to justify charging twice the local price for electricity as the demand goes way up. The more entrenched their "virtue", the more likely people will pay. And since electrical infrastructure is so tightly protected, it's not likely to ever change.

 

[M76]

I wasn't talking about programming the charging to only start when near empty, that would be utterly stupid...
I remember reading somewhere that Teslas batteries don't charge to actual 100% capacity (4.25v per cell I think) and they "hide" some capacity from the customer for lifespan reasons (just like you suggest).

I don't know exactly how Tesla does it or Laptop manufactures do it, but the "don't leave it on the charger because it'll die sooner" and "Only charge your batteries when they reach zero to increase lifespan" is not true all the time.

I didn't mean don't leave it on the charger because it will die, I meant don't charge it at all unless you need the capacity. You can spare a few charge cycles that way.

Of course you can't discharge the battery to zero, because there are failsafes for that too. When the car actually says it is fully discharged it still has charge left but it won't let you use it.

in theory these batteries are aged by discharge - charge cycles. So it should be better to only charge it when it reaches 20%, instead of charging it every day from 80% to 100%

 

[Wierdo]

As someone who doesn't put a lot of miles on my car, I'm more concerned about how many years the batteries will last under light use, as opposed to how many charge cycles they can take.

I've seen to many laptop batteries die after a few years, even though they are rarely used/charged.

If the battery only last 8-10 years, even if I'm only driving 4-5K/year, it would be cheaper to just drive an ICE.

They's supposed to last longer than most ICE cars, and by the time they need replacement the performance and prices will be vastly improved to boot.

Tesla batteries are thermally managed and you can expect some to easily pass half a million miles or over 20 years of normal usage.

Laptop batteries are not designed to last as long, nor cellphone batteries, that's a design decision.

 

[Mohonri]

Yeah but Teslas have thousands of them.
Pouches probably would be lighter too.
It might even be cheaper to do pouch cells, if it's anything similar to Brushless RC cars. I can get a 3 cell 5000Mah 20C (100 Amp hour Discharge Rate!) 11.1v battery waaaaaaaaaaaaay cheaper than a equivalent 11.1v 5000Mah 18650 based battery, and that 18650 based battery would not be able to supply the current needed (50+ amps). I would need a 60 cell 18650 battery pack to provide the same discharge rate without blowing up!!! (100 Amp hours)

There's an energy density question here as well, though. Cylindrical cells, while they do waste about 25% of the physical volume available, still have a higher density than lower-cost LiPo pouch cells. (why, yes, I've actually done the math!)

While true for most laptops, I'm pretty sure Tesla knows this and has programmed the charging accordingly. I mean it's not like its impossible.

I have a MSI laptop (bought in 2014) that is actually "smart" about its battery charging (at least I think so), I get almost the same battery life as new even though it spends most of its life plugged in (Used as a low power server for ARK).

Some phones do this as well, including my Sony Xperia. It charges up to about 80% overnight, thus allowing the battery to live longer. Priuses do this as well, although since they're hybrids, it's not super comparable.

 

[Spidey329]

I agree with Tesla's approach as I can find a 18650 battery fairly easily, where as what Mercedes is doing is probably going to cost a small fortune to replace it. Mercedes is ensuring that repairing their used cars is going to exceed the value of the car, and in 10 years those cars will cost less than a fraction of their original value because of this.

Exactly. The choice of 18650 batteries was to drive the cost down because those batteries were readily available (new models are supposed to have the new 2170 cell). Sure, you can save money by going with a custom pouch battery (less "shells" to add to the weight), but you also spend a lot more in manufacturing as it's not made at scale like a standardized cell.

 

[Rockenrooster]

There's an energy density question here as well, though. Cylindrical cells, while they do waste about 25% of the physical volume available, still have a higher density than lower-cost LiPo pouch cells. (why, yes, I've actually done the math!)\

What good is that energy density advantage if you can't use it in high discharge applications??? There is like zero market for 18650 based batteries for brushless RC cars.
Also, I think that 18650s are also heavier for their energy density..... so it offsets....

Tesla gets around the discharge rate limitation by using thousands of them (Special Design apparently too).
Can they not make even larger rectangular cells??? makes no sense....

I think that using pouch based batteries would allow better discharge rate just like in the RC world, and would allow for more current for electric motors for use like in semi truck, even faster EV cars, etc.

18650s make freaking awesome flashlight batteries though.... (I have like 30 18650s lol)

 

[Rockenrooster]

I didn't mean don't leave it on the charger because it will die, I meant don't charge it at all unless you need the capacity. You can spare a few charge cycles that way.

Of course you can't discharge the battery to zero, because there are failsafes for that too. When the car actually says it is fully discharged it still has charge left but it won't let you use it.

in theory these batteries are aged by discharge - charge cycles. So it should be better to only charge it when it reaches 20%, instead of charging it every day from 80% to 100%

Ok, but it sure sounded like it.

All Lithium battery cells need to cut off at 3.0v or else damage will occur and shorten the lifespan drastically, so it's basically mandatory to have special circuitry to account for that. Sure you can keep using the battery, but the battery will not like you lol!
I have my RC car cut off at 3.2v per cell, but if I wanted to I can turn that off.
Not to mention that the maximum power (Watts) lithium batteries can provide drop off a cliff at 3.0v or less.

 

[nutzo]

Laptop batteries die because they sit most of the time on a charger, and most laptops don't give a shit about battery life. So they constantly keep topping up the battery which wears them almost as bad as complete discharge / recharge cycles. So if you use your car short range the best thing to do is to only charge it when the capacity goes close to empty. Or when you plan a longer trip. You don't go to the gas station to top up your car after every drive either.

I've seen this on more than one laptop, and it's the lack of a charge that seems to do in the batteries.
I didn't keep these laptops on a charger, just the opposite.
Laptops sat for a month or two at a time, then charged when I needed to use it. Battery ended up

I have seen numerous Nimh batteries do the same thing. After being used several times, I put the on the shelf. When I need to use them after several months, some will no longer hold a charge. Even running them through the reconditioning cycle on my charger doesn't completely bring them back.

 

[nutzo]

They's supposed to last longer than most ICE cars, and by the time they need replacement the performance and prices will be vastly improved to boot.
Tesla batteries are thermally managed and you can expect some to easily pass half a million miles or over 20 years of normal usage.

Guess we'll have to wait 10-15 year to see if they really last that long.

 

[Rockenrooster]

I've seen this on more than one laptop, and it's the lack of a charge that seems to do in the batteries.
I didn't keep these laptops on a charger, just the opposite.
Laptops sat for a month or two at a time, then charged when I needed to use it. Battery ended up

I have seen numerous Nimh batteries do the same thing. After being used several times, I put the on the shelf. When I need to use them after several months, some will no longer hold a charge. Even running them through the reconditioning cycle on my charger doesn't completely bring them back.

If only batteries could be perfect lol

 

[Wierdo]

Guess we'll have to wait 10-15 year to see if they really last that long.

We already have some numbers based on current drivers, with different scenarios broken down, maybe one of them would fit your specific case.

But the general trend is something like this:

https://electrek.co/2016/11/01/tesla-battery-degradation/

 

[HammerSandwich]

I can get a 3 cell 5000Mah 20C (100 Amp hour Discharge Rate!) 11.1v battery waaaaaaaaaaaaay cheaper than a equivalent 11.1v 5000Mah 18650 based battery, and that 18650 based battery would not be able to supply the current needed (50+ amps).

18650s would need a 3s2p setup to provide 5Ah @ 11+V, but you'd actually end up with ~6Ah. And recent, high-rate 18650s can get very close to 50A discharge in 2p config. What do size & weight look like for the equivalent 3-cell?

What good is that energy density advantage if you can't use it in high discharge applications??? There is like zero market for 18650 based batteries for brushless RC cars.

You already mentioned flashlights, so... Runtime. A pocket-rocket flashlight's fun for 10 minutes of showing off*, but something that can provide 500 lumens for 2 hours is more useful for Getting Shit Done. Same divide exists between an RC car & a Tesla.

 

[Mohonri]

Also, I think that 18650s are also heavier for their energy density..... so it offsets....
...
Can they not make even larger rectangular cells??? makes no sense....

I think that using pouch based batteries would allow better discharge rate just like in the RC world, and would allow for more current for electric motors for use like in semi truck, even faster EV cars, etc.

I don't know about the volumetric energy density between 18650 and pouch batteries, so I'll assume you're right. I guess it's a matter of whether you run out of room for the batteries before you run out of weight allowance.

I don't think that current capacity is really a concern right now--a few thousand 18650's are more than enough to deliver the current needed.

 

[Ocellaris]

I agree with Tesla's approach as I can find a 18650 battery fairly easily, where as what Mercedes is doing is probably going to cost a small fortune to replace it. Mercedes is ensuring that repairing their used cars is going to exceed the value of the car, and in 10 years those cars will cost less than a fraction of their original value because of this.

Have you ever look at what you need to do to replace a Tesla battery? It ain’t simple or the the faint of heart. The hole battery pack has a permanent cover sealing the top.

And the Tesla pack comes in modules, you can’t just replace one cell like this is an 18650 in a toy.

 

[Jedi2155]

Battery engineer here with a Model 3 Performance on order.

Couple of points regarding Tesla's decision to use 18650/2170 vs. pouch cells.

• Cylindrical cells have much better manufacturing tolerances compared to pouch cells. Its much easier to control the defects versus pouch which makes them ideal for lower cost mass manufacturing.
• Energy density, pouch cells are more energy dense than from a volumetric perspective than cylindrical cells BUT they typically use a safe and less energy dense chemistry due to the high risk of fire/danger of thermal runaway.
• Battery pack design: Tesla decided to use a more dangerous chemistry but with higher energy density and reliable design for their battery pack design. Their logic is sound, sure you could have a failed dangerous failed cell, but if you able to contain that failure, it doesn't matter as opposed to large pouch cell failure you have some serious issues and hard to stop that fire from spreading to adjacent cells.
• Maximum battery output is a function of their overall capacity. Assume 1 to 10C of output (varies based on duration of the output and thermal limitations), so say for a 75 KWh battery pack, thats 75 kW (100 hp) to 750 kW (1000 HP).

 

[nutzo]

We already have some numbers based on current drivers, with different scenarios broken down, maybe one of them would fit your specific case.

But the general trend is something like this:
View attachment 101438

https://electrek.co/2016/11/01/tesla-battery-degradation/

That is a chart based on miles, not years.
I haven't seen anything about battery degradation over time.
If anything, it appears heavy use of the battery (fast charging), results in less degradation (at least as far as how much of a charge the battery will hold).
Based on the results shown in other charts at the site, it would appear that a lightly used car/battery would degrade faster.

 

[Flogger23m]

Isn't that already true for many of their current cars?

Pretty much. You can find 4 year old cars for 35K or so when the sold for around 60K. The higher end the car, the bigger the price drop in general.

All electric cars will be more expensive. Being affordable isn't the point for electric vehicles. In time it may very well be so, but not within 15 or so years.

 

[Luke Wells]

There are several downsides to using a pouch over a hard case cell design:

*Water ingress can be an issue if you are designing a cell for >3 years of use.
*The pouch foil is not as resistive as the way the tabs are insulating in a cylindrical design. Having control over this is a challenge. This leads to cell balancing issues.
*Gas generation is unavoidable. Without a rigid wall, swelling is an issue. This leads to non-homogeneous current densities and then accelerated degradation.

I would not want an automotive pack designed with pouch cells. If you want to see a cell that is designed to last, look at what is used for medical devices (pace makers etc.) They don't use pouch foil for a reason.

The German's are FAR behind in lithium ion technology and far too arrogant to understand that. They are far ahead in marketing though. They may have some short term success but they are going to be flooded with warranty returns!

-Lithium Ion Battery Scientist in Germany (Coming from Lithium Ion industry research in the US)

 

[Rockenrooster]

Battery engineer here with a Model 3 Performance on order.

Couple of points regarding Tesla's decision to use 18650/2170 vs. pouch cells.

• Cylindrical cells have much better manufacturing tolerances compared to pouch cells. Its much easier to control the defects versus pouch which makes them ideal for lower cost mass manufacturing.
• Energy density, pouch cells are more energy dense than from a volumetric perspective than cylindrical cells BUT they typically use a safe and less energy dense chemistry due to the high risk of fire/danger of thermal runaway.
• Battery pack design: Tesla decided to use a more dangerous chemistry but with higher energy density and reliable design for their battery pack design. Their logic is sound, sure you could have a failed dangerous failed cell, but if you able to contain that failure, it doesn't matter as opposed to large pouch cell failure you have some serious issues and hard to stop that fire from spreading to adjacent cells.
• Maximum battery output is a function of their overall capacity. Assume 1 to 10C of output (varies based on duration of the output and thermal limitations), so say for a 75 KWh battery pack, thats 75 kW (100 hp) to 750 kW (1000 HP).

There are several downsides to using a pouch over a hard case cell design:

*Water ingress can be an issue if you are designing a cell for >3 years of use.
*The pouch foil is not as resistive as the way the tabs are insulating in a cylindrical design. Having control over this is a challenge. This leads to cell balancing issues.
*Gas generation is unavoidable. Without a rigid wall, swelling is an issue. This leads to non-homogeneous current densities and then accelerated degradation.

I would not want an automotive pack designed with pouch cells. If you want to see a cell that is designed to last, look at what is used for medical devices (pace makers etc.) They don't use pouch foil for a reason.

The German's are FAR behind in lithium ion technology and far too arrogant to understand that. They are far ahead in marketing though. They may have some short term success but they are going to be flooded with warranty returns!

-Lithium Ion Battery Scientist in Germany (Coming from Lithium Ion industry research in the US)

Now all this makes sense. Thanks for your input. The only thing that doesn't make sense is you said 18650s are can be cheaper to make due to defect rate but the opposite seems to be true, at least in smaller packs (less than 10000mah).
Pouch cells seem to be more radical in performance for their size and I have seen more puffed pouch cells than 18650s lol. Way harder to destroy a 18650 lol, but when they do pop, ooooh boy.

18650s would need a 3s2p setup to provide 5Ah @ 11+V, but you'd actually end up with ~6Ah. And recent, high-rate 18650s can get very close to 50A discharge in 2p config. What do size & weight look like for the equivalent 3-cell?

I had a 4000mah battery rated for 10C constant for my RC car so like 40Amps. That thing would get warm/hot after 10-15 min and died within a year lol.
I since have gotten 2 5000mah 20C (100amps constant) batteries for $25 each and they still work pretty good after 4 years, and stay cool to the touch! Brushless motors can draw absurd amounts of peak power and I'm pretty sure a 3s2p 18650 pack rated for 50amps would not last very long in mine. I have enough 18650s to make one but then again, they are cheap ones pulled from laptop cells and not the highest end Panasonic cells. Building a nice pack with the best Panasonic cells would be expensive and not really worth it.

I'm not an electrical engineer or anything, but I love messing with electronics and understanding them...

 

[Wierdo]

That is a chart based on miles, not years.
I haven't seen anything about battery degradation over time.
If anything, it appears heavy use of the battery (fast charging), results in less degradation (at least as far as how much of a charge the battery will hold).
Based on the results shown in other charts at the site, it would appear that a lightly used car/battery would degrade faster.

I think balance is key here, overdoing it with high current charging is not a good idea either, the thermal management certainly helps takes care of it so that - if you have to - you can operate it that way, but it's still better to charge at home than regularly hit superchargers.

The ideal scenario is also keeping the battery between 20 and 80 percent charge - which you can easily manage in the UI.

So for normal driving you drive with 80 percent full, and then for long distance trips you may decide to bump it up to 90 or 100 percent to help skip a supercharger on the way if you absolutely must for some reason. The software does something similar to wear leveling in SSDs.

Now having said that, we're talking an estimated minimum of half a million miles to 80 percent, that's the degradation level that triggers warranty claims. It's not like the battery just up and dies after that point, just becomes less convenient due to the range loss.

Tesla's warranty is 8 years and 100-120k miles for the model 3. Their Model S/X cars get unlimited miles warranty for 8 years, so they have confidence in the battery not needing replacement in most cases for that long at the minimum, you'd be unlucky to hit 90 percent during that time, let alone the 80 percent.

Pretty much. You can find 4 year old cars for 35K or so when the sold for around 60K. The higher end the car, the bigger the price drop in general.

All electric cars will be more expensive. Being affordable isn't the point for electric vehicles. In time it may very well be so, but not within 15 or so years.

I think the estimate of when EVs reach cost parity with ICE is around 2025. It's gonna take a few years, but not that far down the road (hopefully not).

Tesla even claims they're aiming to reach those targets in 2020, so there's rapid progress being made thanks for mass production and ongoing refinements.

https://insideevs.com/tesla-cheapest-battery-pack-costs/

Elon Musk said in June that the target for battery cell cost in 2018 is $100/kWh, and $100/kWh on the pack-level within two years.

BNEF’s research revealed that other suppliers offered cells for $120/kWh in 2017, but to reach $100/kWh on the pack-level is in general not expected for the industry until 2025.

 

[Luke Wells]

Now all this makes sense. Thanks for your input. The only thing that doesn't make sense is you said 18650s are can be cheaper to make due to defect rate but the opposite seems to be true

It depends on the type of pouch cell. You can 'wind' the electrodes into what is referred to as a jelly-roll. You can also cut dozens of electrodes and weld them all together in what is referred to as a stacked design. The later has the benefit of having higher energy density (marginally) and better rate capability. However the stacking process has a much higher scrap rate (you need to make more cuts and do more process touches). The stacked design also has a drastically lower throughput because of the additional touches.

In lithium ion, the name of the game is $/KWh. Any hit in throughput is a hit in $/KWh. Knowing what I know about Germany, Mercedes will make stacked pouch cells.