Model 3 To Have 50% Fewer Cells Than Model S

72 thoughts on “Model 3 To Have 50% Fewer Cells Than Model S”

• A 50% reduction in part count and assembly costs for the whole battery pack. Half the cooling channels, half the solder joints, half the connectors, … Half the capital equipment or twice the throughput on the same. On a per kWh basis, perhaps a 33% or 40% improvement in pack up charge over raw cell costs.

  • No soldering involved.. those are spot welded 😉

    • Thanks for the correction. Ok: “half the spot-welds, half the spot-welding capital equipment and associated depreciation, operations, and maintenance costs”…..

  • Even is these were 8 amp hour cells, BMW uses 92 amp hour now. If the M3 uses 4000 cells, BMW uses 400.

    • there is a balance. Too many cells, too much assembly. Too few, harder to cool.

      • Difficulty of cooling depends on the shape. It could be a problem to have a cylinder that is too large, because you cannot cool the centre. BMW uses flat packs so the cooling can be laid out differently.

        • Cylinders have space around them, and good surface are when they are packed. Tesla uses a square metal tube thermally bonded to the outside cylindrical cell case. Big prismatics large enough to power an EV require at most 100 in series or maybe twice that if two are in parallel. They are thick, have thick plastic packages and must have external pressure to prevent swelling. The last type, pouch, has some of prismatics problems as used. They are packed in a stack with pressure to avoid swelling like a stack of 8 X 11 papers only thicker and housed in a metal enclosure. Those are only a little bit easier to cool internally than prismatic. They could be if they had internal cooling between layers, but that’s a plumbing nightmare.
          In short, once the cooled cell, battery, or module volume increases, it becomes harder to cool the internal part of the cell, battery, or module. When you lose control of heat in a lithium battery, you risk degradation and thermal runaway. Read fire or dead pack.
          In all, it’s a good move not to make the pack too dense, and to allow even cooling everywhere in the pack. Hot spots also mean uneven charge/ discharge which limits performance.

        • Isn’t BMW using solid core cells that don’t swell?
          Just found that article.

          http://de.slideshare.net/mobile/DavidQuarles/bmw-i3-vs-tesla-battery

          I am just reading a lot about the Kreisel packs, they are cooked by liquid and are supposed to be the densest packs on the market.

        • They all swell. A picture of the i3 battery.
          http://c1cleantechnicacom.wpengine.netdna-cdn.com/files/2015/11/BMW-i3-battery-cell.jpg
          That’s either a pouch in its container or a special prismatic.

        • I just visited the Kreisel brothers site. Superb! Truly interesting custom projects by three engineer/ business brothers. Their vehicles appear to have Tesla range, and also include full size delivery vehicles and 7 passenger vans, and a fully electric porsche Panamera that really zips and has Model S range with an 85 kwh battery. Quite a find and could be the EV communities custom vehicle darlings.

        • They all swell. That metal enclosure is designed to contain it.

        • You can cool (and heat) flat packs. Batteries packs can be shaped long and thin, sort of like a pack of flat chewing-gums, where each gum is a battery cell. You can cool on the long narrow side wall. This way a limited cooling system is in contact with all cells. It is also not affected by any swelling.

          Swelling is absolute minimal for a correctly used battery. If a battery swells it is because it has been abused. If it swells it will occur in the thickness, so any swelling will not affect the packaging and cooling mentioned above.

        • Yes. Can is the word. Do they? Each pouch module is assembled in stacked layers and enclosed in a metal box. It’s required. Pouches have no mechanical constraining properties either to protect them or prevent swelling. That box en closure is mandatory. Pouches are stacked in the box, more than 2 means one is buries from the outside and cools less than the outside ones. That’s a problem. Could be one reason the Leaf under performs in hot climates.
          If the package is too thin, packing density and specific weight suffer, because it’s mostly package, not active cell in a flattish rectangular package. The ratio between volume and area is higher in a package like that. Theoretically, it’s cooling is better, but only if it’s surface is cooled uniformly. Tesla achieves the same thing by making its pack skateboard shaped, instead of making its cells flat. Then it can get more even cell cooling, because they are small and have metal enclosures. They have square metal coolant tubes that run the length of the pack like veins. That’s pretty optimal cooling, ideal for extending battery life.
          Take a look at ” A tale of three battery packs ” and stare at the pictures of the Leaf modules.

  • Higher performance batteries may require bulkier cooling if the energy efficiency doesn’t improve, so not as much reduction there. I also have to wonder if fewer cells means slower supercharging.

    Even if those disadvantages are real, the potential cost reductions you listed look like a fair tradeoff.

    • JB Straubel has talked about the “optimal” cell size for years, including thermal management and the whole package. The new ones are only 10% larger diameter so thermal characteristics are still in the same zone, (unlike the huge cells on the Dreamliner)

      • Sure, the form-factor might allow a slightly more efficient design for the cooling system, but the basic point I’m getting at is that for a (e.g.) a 45kW pack with 95% efficiency, the total amount of heat that system has to remove stays the same no matter what the cells look like. So more energy-dense batteries require bulkier cooling unless they also improve energy efficiency.

        On the other hand, Musk is obsessed with efficiency like any good engineer, so the point is probably moot.

        • Not necessarily bulkier. Kreisel allegedly has the most energy dense pack design on the market, both by weight and volume, using the same cells as Tesla.
          So there should be some room for Tesla to improve especially with optimised geometry.
          In fact I estimate a 20-25% improvement over weight and volume of the old pack design.
          Do your own estimate, we can check back on this thread when the car materializes 😉

          http://www.kreiselelectric.com/en/technology/battery-system/

        • They claim energy density around 245 Wh/kg. But not sure if it is for whole pack (I dont think so) or cells. If it is for cells, Elon already 2 years ago said that they have 260 Wh/kg.

        • The density of the Tesla 85kWh pack is 156Wh/kg from the data I see online?
          The density of the Kreisel E-Golf 168Wh/kg (same weight and size but double the kWh compared to the original VW pack).

          From the Kreisel Panamera Project:

          8,160 type 18650 cells provide a total capacity of 85 kWh and guarantee a range of 450 kilometres. The weight of the battery pack including the casing, BMS and electronics is 510 kg with a nominal voltage of 367 V (performance weight 6 kg/kWh and energy density 2.6 dm³/kWh).

          166Wh/kg complete with BMS.
          Can’t find the volume of the Tesla pack to compare that.

          I am not saying Tesla can’t built better packs. It only goes to show that their technological advantage is marginal and that even VW could license technology to built a long range EV today.
          I say that they don’t want to and that this is a pure strategical decision on their part.
          Audi took apart several Roadsters, S’s and apparently they also got their hands on an X in February already.
          Some are claiming they are still waiting for their solid state battery.
          I don’t know if it is a good choice to wait for faster charging and cheaper batteries.
          I’d rather see them put a 400km EPassat or Sharan for 40k€ out now.

        • Interesting. Obviously their power output for the same capacity is much lower if they can manage 5,6s from 0-100kmh with 7 gear transmission. But for Passats and Sharans of the world this is more than enough. What I could see is that max speed of DC charging is only around 70 KW (panamera electric) and I could not find anything about price/kwh.
          However you are right technology from third parties is on the level when with proper design and economies of scale VW can produce compelling family EV car in the 40k€ price range.
          I wouldnt say they dont want to. But in company like VW it is very hard to start with 200k/a EV project, which is build on completely new platform. Becuase if you will just put bateries in normal Passat result will be not compelling car.
          I think Model 3 will put enormous pressure on BMW, Mercedes, VW, GM, Toyota and now they will have to start moving.
          Porsche Emission will not be enough, but if they could put that technology in cheaper car made from ground as EV that would put VW in completely new situation and I hope that after introdution of Model 3 decision was made to go in that direction.

• My own clumsy amateur speculation leads me to say the pack will be 45 kwh and will achieve a 215 mile range. It is a combination of several factors including the .21 wind resistance, the weight of the vehicle and the increased efficiency of the battery that yields this improbably low estimate. As well, by simply reversing the mileage difference between the model S P 90 and the 70d so that we have mathematically produced a 50 kwh model S p50 we get 198 mile range. Therefore 45 kwh for the model 3 is likely.

  • 44 kWh has already been speculated in the media.

    • Well, well, well. Perhaps I am not so clumsy after all.

    • Interesting stats, especially as the 2016 Leaf is 30kwh for 107 miles – https://en.wikipedia.org/wiki/Nissan_Leaf

      Tesla special sauce must be very special indeed.

      • The Leaf has a relatively poor Cd of 0.30 or 0.28 in improved models. It measured at 0.30 by car mags. Frontal area is not so small, either. They all matter.
        http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test-fifth-place-nissan-leaf-page-2

        • Thanks for the clarification.

        • eveee has designed EVs. a good guy to go to for technical tips. 😀

        • Aw shucks. Mostly electrical and batteries. The mechanical guys dealt with suspension, steering, and such. A lot of work and people goes into making one car. Part of the fun is figuring out how to make an efficient vehicle. EVs are really nice. You can measure the current and voltage at any speed and estimate the load. Easier to measure drag than an ICE. its just whatever current and voltage you measure.

        • The hideously ugly front lights were designed to direct air around the mirrors. The sooner the regulators get off their asses and allow cameras to replace the mirrors the better.

  • Therefore 45 kwh for the model 3 is likely.

    Wow, that’s the lowest estimate I’ve seen yet, but your numbers check out. Extrapolating, that would mean a 65kWh pack would yield a 310 mile range. Using the $190 per kWh price that we’ve heard, that means an upgraded pack would cost Tesla $3800. Musk has said that he expects the average price paid for a Model 3 to be $42k, so one has to wonder if that will be the price for a 310 mile version.

    • I suggest there will be three models. 45, 55, and 65 kwh. Because as the weight increases there is a slight drop in miles per kwh, the top model will just hit 300 miles. Along with the larger battery though, will have to come space loss. They will make up for this with luxury additions and slightly higher acceleration to bring the top price up to $50,000.

      • It’s counter-intuitive, but there’s no space loss with a larger battery. Tesla installs blank cells in their lower spec’d battery packs. The battery “skateboard” is always the same physical size.

        Also, I’d be surprised if they go with 3 battery size offerings as you’ve described. 10kWh is not a lot of delineation to justify extra manufacturing complexity and an extra SKU. Conventional speculation is more along the lines of two pack options — 50/75 kWh (or thereabouts).

        • For the model S they need 20 kwh differentiation to make significant mileage changes. At the level of the model 3 a 10 kwh battery increase makes close to 50 mile range difference.

        • They tend to sneak in the battery advances and announce the battery upgrades after the fact. The standard battery just keeps increasing. But the size doesn’t. 😉

        • I’ve been disappointed in that standard battery size increases have been accompanied by a price increase. I would like to see periodic 5kWh increases WITHOUT a price increase. This should be doable given improving price/performance. We don’t pay more for this year’s basic PC than we did last year despite better performance and storage capacity.

        • I guess we need some real competition for that. Nissans 192 mile range increase for extra money and the Bolt for 40k with optional slower charging DCFC for 40k are not helping that. I think I will take my chances with a used Leaf, they’re cheap, or just buy a 3. They make the competition look dated already.

        • I have a 2011 Volt now which I have been very happy with. I bought it as a CPO vehicle with 30k miles and in 2 years now has 61k miles. I do want to go full electric but don’t feel the time is right for me yet. My wife drives a Prius with 151k miles and her car will soon be passed down to my stepson as his first car. When that happens she will likely get the Volt and I will be commuting on a gasoline motorcycle or my electric bicycle. I often need the cargo capacity of a car though and will start looking for another used plug in. I’ve toyed with the idea of a LEAF ($7k – $9k) but in my hot climate it is hard to get past the expected battery degradation. I’ve toyed with the idea of a Prius V ($13k), Camry Hybrid ($15k), Fusion Energi ($15k) or CMax Energi ($12k) but it is hard to go backwards from the feeling of driving on “true” electric power as in the Volt. As such I will likely get a second used Volt, ’13 models can be found for about $12k, then sell my ’11 Volt when Model 3 CPOs become available ($25k for one with a few upgrades?) around 2021 or so. Reliability on Model 3s will have to be better overall than S or X however for me to consider them. I would like to see them at least at average level on Consumer Reports scale.

        • Good for you. Are used Volts really that cheap? Sounds like another good buy. We all will feel better when there are more EV choices and used ones. The Hyundai PHEV and Volvo C90 are going like hot cakes. Somebody needs to make more plug in SUVs and smaller wagons. you think? 🙂

        • I suspect is charging what it thinks the market will bear. Since their GPM is already almost the highest in the industry Tesla is not trying to sell their S (and X) for the least money possible, but to use them as revenue bringers. That extra income helps build the larger corporation needed to produce more affordable, lower margin EVs.

  • Model S 60 208 miles range, weight 4323 lbs.
    I expect base Model 3 to have 55kWh battery. M3 will be more from steel and only 400-500 lbs less than MS.
    every 200-220 lbs will reduce the consumption with 1.5-2%
    better aero/drag coef. will reduce 5-10%
    55kWh battery pack has 50kWh usable energy if can do 215 miles that’s 145 MPGe.
    That low energy consumption will not be easy.
    I expect M3 to has and 80kWh battery version with his wheel base and taller cells but I need bigger pack with which will can have 300+ miles range

    • The model S 90 D 2016 upgraded mileage is 302 miles hwy. The Model S 70 D 2016 has 255 miles hwy. These are the new EPA numbers. So notice that the 90 gets 3.35 miles kwh, and the 70 gets 3.64 miles per kwh. A theoretical model S 50D would get about 3.95 miles per kwh, total 197.5 miles. The model 3 is AWD as are these other higher mileage cars. The weight difference of the new more efficient battery pack plus the 20% reduction in volume and the aerodynamic of .21 will result in 4.77 miles per kwh Hwy. 215 mile range on 45 kwh battery. The weight reduction could be a full 800 pounds or around 3500 lbs.

      • M3 will be from steel instead of aluminium. That’s why 20% reduction in volume doesn’t mean same reduction in weight of MS.
        Who said that the base version of M3 will be AWD?
        I expect total 17-20% less consumption than S60 or S70D
        or 4.3 miles/kWh * 50 usable kWh = 215 miles

        • You may be right. But we are definitely in the ballpark.

        • Apparently someone took a magnet to the Mod 3 unveiling and reported the body was largely aluminum.

        • But on prototype car.

        • Good point.

          But there’s the report that Tesla installed aluminum stamping equipment with a much higher output capacity than would be needed for 200,000 Model S/X per year.

        • Wow! People are so bright, that was clever. Somebody should have figured out how to weigh the car!

  • “Therefore 45 kwh for the model 3 is likely.”

    Probably not. 50-55kWh is more likely. 55kWh x 95% usable = 52 kWh/ 215 miles = 242 wh/mi. Model S 85 got around 290 Wh/mi EPA, (available usable capacity of 77kWH).

    • Usable energy in Model S batteries is 88-90%.
      The record range with S85D was with 76.5kWh used energy which is 89%. I’ve never seen more.

      • People on TMC have reported up to 78 or 79kWh reading from the CAN bus I believe. From analysis the 85kWh packs weren’t really 85kWh, but closer to 82kWh actual. 60kWh packs were slightly over 60kWh, around 61kWh.

    • I base it not on theoretical discharge percentages but on epa rated mileage on the Tesla website. That already includes discharge losses.

      Those of course are hwy speeds. Imagine the distances at 30mph!

      • The EPA is a combined cycle test, not just highway speeds. I’m taking the EPA number of 265 miles and using the 77kWh max that is actually available in a new Model S to come up with 290Wh/mi. Range at 30mph is irrelevant. Bottom line, you won’t get the distance Tesla has stated, i.e. EPA 215 miles or more, from a 45kWh pack in the Model 3.

        • Ah, I see! You do not accept the Tesla range numbers, whereas I do. I do not have a Tesla and cannot speak from personal experience. I am speaking strictly from the stated numbers. They said 215 mile range per charge. Now, what do they think will produce that.

        • I’m not sure what you mean. I am using Tesla’s range numbers, they said 215 miles per charge, at least, maybe more. To get that they’ll need more than a 45kWh pack. It’s that simple.

        • Well, I like your confidence. Indeed we will see. Alas, I think it will be quite some time before Tesla settles the matter for us.

        • Math and physics already settled it.

        • You must be a theoretical physicist. They need to have their theories proven by experimental physicists!

        • It’s already been proven by existing vehicles and testing. The Model 3 won’t be magic, it’s going to be constrained by well known parameters. With the vehicle Tesla has shown there is no way to get the range they mentioned with the pack size you propose.

• There’s a host of stuff close by to progress things – utilising more kinetic energy, radically improving the management of statistical variance and internal resistance etc. This is all a journey that has ‘just begun’…

• This article led me to price out 18650 cells. I found prices all over the place. Any idea what the best source is when buying less than 10?

  • depends on quality and reputability of manufacturer and the distributor(s) of those cells.
    The manufacturer makes them in batches.. I don’t know details, but for sure you can get them on a pallet only with boxes that have 50 or more each from the fab.
    If you buy 10 they have gone through the hands and warehouses of 2-3 different people/companies and it’s hard to tell how they got them and what you get and what it’s history is.

    Best advise I can give for 10 cells is to get a brand name like Panasonic and a popular premade pack that comes like that from the manufacturer (series or parallel, so the cells match in their abilities) and those from a high volume seller/distributor so you can get current buyer reports and also have a big chance to get fresh stock.

    PS:
    I bought some a while back online.. today (didn’t check) I would expect you get 10 brand name cells at current tech energy density in a pack from the fab for about $60-80 from a high volume seller. Depending on after sales service and locality you might need to add another 20 bucks.

  • ebay? Alibaba (http://www.alibaba.com/)

  • Buy a couple laptop or radio-controlled car batteries and break them up yourself.

    Everything else is a total crapshoot at this point. The consumer market for loose cells is still a wild west.

    • So very very true.

    • Oh, and do not buy powertool packs. Lowes wants $169 for a 2Ah 80V pack, That’s $1056.25/kWh! Before sales tax, at that.

      Seems there could be a good business opportunity there for a while though, in making “compatible” packs for power tools.

  • $12 for 2 on Amazon.

    Buy 7100 of them and you can build your own supercar. 🙂

    http://www.amazon.com/Panasonic-NCR18650B-3400mAh-Rechargeable-Battery-Green/dp/B00DHXY72O/

    • on aliexpress it says 3.57 for 2

  • This is the forum for you Ivor – http://budgetlightforum.com/forum – a rollercoaster ride through the world of cells and torches.

    And here is the sub forum for rechargeable reviews inc 18650’s – http://budgetlightforum.com/forum/batteries/rechargeable/reviews

    The reviews have more graphs than you can shake a stick at.

    This is my second favourite forum ever 🙂

• The 3D model at the launch showed 8 modules not 14… so start there.

• It has been discussed that the Model 3 will start at $35,000 and go as high as $60,000 depending on the options. I presume one of those options will be bigger batteries for more range. I would like to know just how long of a range Tesla intends. Will a 300 mile be available? Would that eat into “S” sales? (I know that “S” sales have actually increased since the unveiling of the Model 3, but I think that is because when people thought it was going to take two years and more to get a “3” that they decided to get an “S” instead. Now it may be interesting to see if that continues after the two year “pull up”.)

• I’ll go with a 55kWh Pack and 345kg battery weight.

  • I have to lower the weight. The 55.7kWh pack from Kreisel using 18650 cells was already 330kg including BMS and electronics…
    ~15-20% weight reduction on top of that for the Tesla pack with the new form factor cells.

    55kWh and 260g-290kg.

    I am taking bets…
    Jenny – 55kWh/285kg

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