R2 / R3 battery pack photos from RJ

[captainjp]

^ exactly, and given the fact that the Chinese usually always "slightly exaggerate" cell output, they may indeed put out less than 119wH per cell. With that in mind, even if LG's cells do put put more energy than state of the art Chinese cells, you're not getting 10% (which would equate to an extra 12wH/cell) out of the LG cells.

Pretty sure LG is a Korean company
Edit. I misread your post

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[AirplaneDr]

I took a deep dive into the photos of the battery pack that have been posted with the goal of determining the R2 architecture voltage and capacity. Bottom line: I was unsuccessful, however I am very confident R2 will be 400V OR 800V. I think it did a bit better job at battery capacity

Here is my math. We know that there are 3 modules with 256 cells each in an 8 by 32 grid. The maximum voltage for each cell (NCM chemistry) is 4.25v. Working with multiples of 32 I came up with the following:

800v:
Each module is constructed in a 64s4p (64 cells in series in 4 parallel strings). 64 cells*4.25v=272v per module. 272v * 3 modules= 816v

400v:
Each module is constructed in a 32s8p (32 cells in series in 8 parallel strings). 32 cells*4.25v=136v per module. 136v * 3 modules= 408v

Battery pack capacity:
I was not able to find much detailed info on the 4695 LG cells that are slated for the R2. Spec sheets for other 4695 cells are all over the place for other 4695 cells. The Cybertruck 4680 NCM cell is listed as 91.5 Wh per cell. Using that data as a starting point and assuming 15% more capacity in the 4695 over the 4680 the math is pretty easy: 91.5 Wh*768 cells*1.15 = 80,812 Wh or 80.8 kWh.

To get 300 miles out of an 80.8 kWh pack efficiency would need to be ~ 3.7 mile per kWh which seems a bit optimistic for the R2.

 

[joggah]

What I wonder: Would it fit into a R3, or how much smaller will the R3 battery be?

 

[DuoRivian]

I took a deep dive into the photos of the battery pack that have been posted with the goal of determining the R2 architecture voltage and capacity. Bottom line: I was unsuccessful, however I am very confident R2 will be 400V OR 800V. I think it did a bit better job at battery capacity

Here is my math. We know that there are 3 modules with 256 cells each in an 8 by 32 grid. The maximum voltage for each cell (NCM chemistry) is 4.25v. Working with multiples of 32 I came up with the following:

800v:
Each module is constructed in a 64s4p (64 cells in series in 4 parallel strings). 64 cells*4.25v=272v per module. 272v * 3 modules= 816v

400v:
Each module is constructed in a 32s8p (32 cells in series in 8 parallel strings). 32 cells*4.25v=136v per module. 136v * 3 modules= 408v

Battery pack capacity:
I was not able to find much detailed info on the 4695 LG cells that are slated for the R2. Spec sheets for other 4695 cells are all over the place for other 4695 cells. The Cybertruck 4680 NCM cell is listed as 91.5 Wh per cell. Using that data as a starting point and assuming 15% more capacity in the 4695 over the 4680 the math is pretty easy: 91.5 Wh*768 cells*1.15 = 80,812 Wh or 80.8 kWh.

To get 300 miles out of an 80.8 kWh pack efficiency would need to be ~ 3.7 mile per kWh which seems a bit optimistic for the R2.

Thanks for the good investigative work. I thought I recalled from the initial showing that they were targeting around 270 and 330 miles which would then equate to around an 80 and 100kWh batteries with a reasonable 3.3-3.6 miles per kWh.

 

[Trandall]

What other packs are using the 4695 cells? And number of batteries doesn't mean anything at all. I would be happy with 1 battery cell if it was 100 kWh cell.

Haha... Rivian's new groundbreaking 3.7V electric drive architecture.

 

[Trandall]

So 1200 cycles fast charged and 2000 “normal” charged. I think I say the range was quoted as 300 miles? There is going to be a top and bottom buffer as well so driving the full range will be close to but not an actual full cycle, but lets ignore that.

So normal cycles gets you 600,000 miles, with a 90 mile commute (round trip?) you get 6,666 trips, 5 days a week 52 weeks a year gets you 25.6 years. A lot longer then most people keep a car.

If you exclusively fast charge it it is 360,000 miles. A mere 4000 trips. Or 15.38 years. Longer then most people keep a car, but not as long as a car tends to stay on the road.

Let’s see, your target is 8 years? Try not to trade the 90 mile commute for a 281 mile commute (or 168 if you are going to exclusively fast charge).

Note: this is envelope math, so not a guarantee, other factors may apply, bur from the cycle “limit” this isn’t a problem!

I believe I read that the the average age an automobile lasts in the US is only ~11.5 years in the U.S. obviously cars totaled in the first year or two skew the average down.
Automobiles used as daily drivers are almost invariably on their last leg if they even make it 15 years in upstate NY.

 

[theonetruestripes]

I believe I read that the the average age an automobile lasts in the US is only ~11.5 years in the U.S. obviously cars totaled in the first year or two skew the average down.
Automobiles used as daily drivers are almost invariably on their last leg if they even make it 15 years in upstate NY.

That is one way to look at it. The US vehicle fleet has roughly a 20 year turnover. Most vehicles don’t make it past 20 years. Most. My neighbor across the street has a 90 year old Chrysler (I think — I’m sure about the age, it is a 1930s car, not 100% on the brand because it doen’t have any modern logos!).

So there are outliers. NY can be rough on cars, what with all the salt.

I expect even with batteries that “only” go 300 cycles you can see some battery EVs that last as long as some of the gas car outliers. Tesla has already had some 900k mile cars on the original battery packs, I don’t see why other brands can’t hit the same kind of lifetimes. Or exceed them (as long as the battery cooling is well designed! Or the whole BMS.)

 

[Trandall]

That is one way to look at it. The US vehicle fleet has roughly a 20 year turnover. Most vehicles don’t make it past 20 years. Most. My neighbor across the street has a 90 year old Chrysler (I think — I’m sure about the age, it is a 1930s car, not 100% on the brand because it doen’t have any modern logos!).

So there are outliers. NY can be rough on cars, what with all the salt.

I expect even with batteries that “only” go 300 cycles you can see some battery EVs that last as long as some of the gas car outliers. Tesla has already had some 900k mile cars on the original battery packs, I don’t see why other brands can’t hit the same kind of lifetimes. Or exceed them (as long as the battery cooling is well designed! Or the whole BMS.)

I agree, Tesla allows comparatively high C-rate and maximum temperature of the battery packs compared to Rivian and many other EV's and they still are holding up.

One of the biggest concerns I hear from non-EV drivers is battery longevity, but it doesn't seem to be warranted. It's funny that the opposite may end up being true... What do we do with thousands of generally good EV batteries when the rest of the car is worn out.

 

[theonetruestripes]

What do we do with thousands of generally good EV batteries when the rest of the car is worn out.

In theory Reuse them as stationary location batteries because the storage per pound and per unit volume matters a lot less forcells sitting in a garage guarding against a blackout, and/or making solar overproduction more valuable. Or recycling them into new batteries.

Normally when asked how we are going to solver the “recycling problem” I point out we are stuck at the first step having enough worn out batteries in need of replacing.

About the only batteries to be found in abundance are early Nissan Leaf batteries, and they ration too much value as “test for bad cells, replace them from other packs, and resell for a few thousand bucks to people that have been quoted $20k or more for a new pack and are overjoyed to pay $4k for a refurbished one”

 

[HaveBlue]

You just described what the R2 platform is. Lol

Not sure who Fast Company is but this is the Rivian skateboard for the R1:

It is believed that Ford used the skateboard for it's early test mules before they parted ways:

The R2/R3 is less of a skateboard and more Unibody:

 

[Alchemy]

2,000 cycles x 300 miles = 600,000 miles. Unless you have a seriously long commute you will be fine for 8 years. (A cycle is 1 complete charge and discharge. A 50% - 80% charge / discharge = 30% of a cycle).

I do not think that is the correct way to calculate the time life of the battery. We all know that we do not drive a full 300 miles before we recharge the battery.

It all depends on what a "recharge cycle" means. If you only add 100 miles of its range during a charge, does that mean you have only used 1/3 of a recharge cycle and doing that 3 times would only count as one charge cycle? Or are the chemical effects on the battery similar to a full charge? a half charge? My guess is that it has more of an impact just 100 miles out of your mythical 600,000 miles. We all know that long range trips are made of hopping from charger to charger with numerous partial charges (at best a 20% to 80% charge). Also, if you travel a longer distance to work, you are going to be topping off your battery at home. This toping off the battery would be at least every other night, if not every night for those that want to play it safe (very easy to plug and take advantage of lower rates at night and have a full car incase you have a change of plans).

The extreme case of heavy charges every night (2000 cycles)/(365 days/yrs) = 5.5 years Of course, that is not realistic, but neither is your 600,000 miles.

 

[TexasBob]

I do not think that is the correct way to calculate the time life of the battery. We all know that we do not drive a full 300 miles before we recharge the battery.

It all depends on what a "recharge cycle" means. If you only add 100 miles of its range during a charge, does that mean you have only used 1/3 of a recharge cycle and doing that 3 times would only count as one charge cycle?

Yes, that is what it means. Going 80% - 60% each day for a week would be one cycle.

However, as I am sure you know, in addition to cycle degradation, there is also time-based degradation (aging). The aging degradation is the more significant of the two and is accelerated when you hold a battery (esp NMC) at a high state of charge. Cycling is not really an issue on large batteries as you will still have 80% capacity after several hundred thousand miles if you were to run, say, 500 miles a day. That is why we see reports of EV taxis with 400k miles and more.

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