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Inside the Tesla 100kWh Battery Pack
- ZeroGravitas 10y agoI wonder if anyone has estimated the impact of "simple" engineering changes on the progress of electric cars. I have seen things that extrapolate out battery progress, so if batteries become cheaper/lighter/more powerful in a similar way they have in the past then that has a big impact on EVs, dropping their price and/or increasing their range. But a lot of things seem fairly simple, if not obvious except with hindsight e.g. heated steering wheels and seats instead of air heating, heat pumps rather than resistive heating, puncture resistant tyres rather than carry a spare, led lighting, replacing side mirrors with cameras for lower drag etc. How much can straightforward, no new tech, improvements in all these areas actually help if you add them up?
- Hermel 10y ago> e.g. heated steering wheels and seats instead of air heating The next step could be microwave heating systems that directly heat your body. But I would probably not feel comfortable with that. https://www.wired.com/2008/01/pain-beam-centr/ https://www.wired.com/2008/01/pain-beam-centr/
- dzhiurgis 10y agoOr a Japanese invention - kotatsu.
- nannal 10y agoa blanket with a heater under it?
- ge96 10y agoI swear it works, let me show you. - No, no one will ever fund this
- mpg33 10y agothat seems like a terrible idea?
- espadrine 10y agoLet me see, people are already really upset by cellphone radiations, which are non-ionizing and therefore can only be harmful from the heat it generates. You would need marketing masterminds to sell this.
- delecti 10y agoAll it would take is one mommy blogger to make the connection that cell phone signals are already microwaves.
- greglindahl 10y agoThat is illegal in the US: there's a regulation that limits microwave power levels outside of an oven to little enough that it doesn't significantly heat anything.
- kpil 10y agoProbably good as microwaves behave very unpredictable in the complex fat-air-water boundaries in a body. It is hard to rule out that a focused reflection from the head accidentally heat up a part of the retina just a few degrees, which might blind someone.
- hawski 10y agoIf you would only keep bodies warm, wouldn't you constantly have steam coming out of your mouth in cold weather? Wouldn't you have steamy windows without heating or air conditioning? What about babies in baby seats?
- icebraining 10y agoPlug-in baby seats.
- jakozaur 10y agoMy guess there is quite a lot of this low-hanging fruit improvements. Electric cars its a young technology than can go through tons of incremental changes that will add up. E.g. compare gas cars over decades. There were tons of improvements that allow much better fuel efficiency.
- bluGill 10y ago>compare gas cars over decades. There were tons of improvements that allow much better fuel efficiency. Electric motors are old technology. Most of the improvements in electric motors have already been achieved, just like the internal combustion engine. Most of the things that original poster pointed to are improvements brought from gasoline cars (only the heat pump for heat is somewhat unique - gas engines have plenty of waste heat so they don't need that)
- greglindahl 10y agoAir conditioners are heat pumps.
- ZeroGravitas 10y agoThat's my point though, it's not that they invented new technology, they just sat down and said "heating is using X% of the battery, how can we lower that" and because it's an EV rather than an ICE car, different decisions would be made when picking from the existing range of off-the-shelf tech. There will be lots of these little decisions, and they'll probably add up, now that people are over the hump of "how can we build a modern EV" and just building incrementally better cars.
- projektfu 10y agoThis is the principle of the Chevy Bolt. Instead of hoping for a revolution, they went for lots of little optimizations.
- mschaef 10y ago> I wonder if anyone has estimated the impact of "simple" engineering changes on the progress of electric cars. Many years ago, I was browsing through an old Hot Rodding guide to Harley Davidson motorcycles. (Don't ask why.) One line from the book that made a lasting impression was a comment to the effect that real progress was more likely to be found in one hundred 1% improvements than one 100% improvement. As a practitioner and observer of engineering, this really resonates as something with a lot of truth. Even for seemingly transformative changes, they're backed with a long series of incremental refinements until they're actually useful. T
- RmDen 10y agosounds a lot like Kaizen
- jp555 10y agoCompounded growth is a powerful thing. 1% compounded 100 times = 270.48, which is way better than 100%! And it gets even better the more steps you go: 1% x 150 = 444.84 1% x 200 = 731.6 People lament the fact that batteries "only get better about 5% per year", but compounding that means they double in performance every ~14 years!
- nradov 10y agoTeam Sky won the Tour de France and Olympic medals through continuous aggregation of marginal gains. http://road.cc/content/feature/187025-12-ways-team-sky-develops-those-marginal-gains http://road.cc/content/feature/187025-12-ways-team-sky-devel...
- mikeash 10y agoTesla's original major innovation in this area was realizing that, if batteries are expensive, then the way to make an electric car people want to buy is to make it really expensive and really good, rather than trying to cut costs everywhere and ending up with something moderately expensive that sucked. They don't really eke out efficiency the way you describe. They have heated seats standard and use aluminum body panels to cut weight, but it's still a big, heavy car. They're among the least efficient EVs out there. Tesla doesn't use a heat pump for cabin heating. Heated seats cut down on heating energy a little bit, but speaking from my own experience, I'd say they let me drop the cabin temperature by only 2-4 degrees (F). Energy consumption from lighting is insignificant (Tesla didn't start using LEDs until recently, I have halogen bulbs), and the weight saved from not carrying a spare tire is pretty minor. I believe they omitted it manly to have more cargo space. The main reason they go so far is because the batteries are several times larger than anyone else's (save the Bolt). Certainly it helps. Tesla keeps pushing to replace side mirrors with cameras, as you mention, which would add maybe 3% to range. On the other hand, the Model 3 will have a steel body, since apparently cost matters more than weight there. Batteries seem to be far and away the most productive area of improvement.
- seesomesense 10y agotldr: "Basically they crammed a couple more rows of cells into the module."
- DiabloD3 10y agoBetween that and the ever so sliiightly higher capacity cells they already adopted, I can't see them getting any more performance out of the existing tech. That, and 100kwh for a Model S battery is pretty damned good, could probably set a 650+ mile record under special handling (current record is 550 miles on a 85D).
- dkbrk 10y agoOut of the existing tech, no. But within a couple of years the Model S will probably transition to the new 2170 cell [0]. I belive production has already started at the Gigafactory, though the Model 3 will probably have priority. It may require some dimensional changes to the Model S though, as the cells are longer. So it may not be compatible with the existing versions of the Model S. [0]: https://electrek.co/2016/11/02/tesla-panasonic-2170-battery-cell-highest-energy-density-cell-world-cheapest-elon-musk/ https://electrek.co/2016/11/02/tesla-panasonic-2170-battery-...
- StavrosK 10y agoApparently the new ones are worse, according to this comment? https://news.ycombinator.com/item?id=13481067 https://news.ycombinator.com/item?id=13481067
- DiabloD3 10y agoThat comment, I think, is going to have to do side by side comparisons of the relevant figures from the manufacturer specification sheets. Not only that, there are different grades. A 18650 is a size and voltage specification. As in, it's like calling a battery a AA or AAA: any AA or AAA fits into a device and makes it run, but some AAs and AAAs last a lot longer than other batteries in flat out runtime, or survive usage in abusive devices, or in extreme weather conditions, or so forth. There are low grade 18650s just as there are high grade 18650s. Maximum capacity isn't the only way to measure a battery, but also it's maximum discharge rate and thermal characteristics under load; as in, larger capacity isn't always better in some use cases. It sounds like he saw one specification sheet of the new upcoming product, and generalized it to every battery in that size. A quick Google Search (tm) did not yield any useful statements on such. I personally assume that the grade of battery used in the Model 3 battery packs is going to be similar to the lowest grade used in the Model S, but with lower available engine torque to compensate for the smaller overall battery pack size.
- Fifer82 10y agoIs it really just an array of 18650s? Seems primitive??
- AmVess 10y agoConcept and execution are two different animals.
- olex 10y agoMusk has stated several times that this rather simplistic architecture works best for them. Tesla has evaluated other cell and pack designs, and still maintains that cylindrical cells are optimal. The Model 3 pack will use newer 2170 cells, same cylindrical format but larger, produced at the Gigafactory.
- owenversteeg 10y ago18650s are pretty much the only way to get decent energy densities and allow for high power output. What a lot of people don't know - which I find fascinating - is that discharge rates on batteries are set mostly by how much heat the battery can dissipate safely, and not as much by the cell chemistry itself. Looking at a random 18650, it may be able to (in theory) put out 200 watts, but the cell would be permanently damaged by the intense heat produced. As a result, if you build an enormous single cell battery, even though it seems futuristic, it'll be horrible at distributing heat. A Tesla pack that was consolidated into one cell would basically be an enormous furnace at any reasonable discharge rate, and they'd have to discharge it at a very low rate in order to prevent it from permanent damage and/or fire. If there's one thing to call "primitive", it would be the new low cost 21700 battery cells Tesla is producing; these have shockingly low power and energy densities, and disappointing cycle limits. They are cheap though, and that seems to be why Tesla's making them: for lower cost vehicles.
- bryanlarsen 10y agoDoesn't the number just refer to the size? 18mm x 65 mm vs 21mm x 70mm? Density and all other specs vary from manufacturer to manufacturer and model to model, AFAICT. Or do we have more information about the 21700 that Tesla's producing or am I just wrong?
- yazinsai 10y agoDoes anyone know how they get around faulty individual cells taking out the whole group?
- lj3 10y agoMy guess would be strict quality controls on each individual battery combined with a sophisticated battery management system. I've long thought that one of the reasons Tesla built their own battery factory is so they can be absolutely assured of the consistency of the batteries. If the charge rate, discharge rate or internal resistance of an individual battery varies from the others over time, that's when battery packs tend to catch fire. Well, one of the reasons battery packs tend to catch fire, anyway.
- cesarb 10y agoFuses and active cooling. Each module has six groups connected in series, and each group has dozens of cells connected in parallel, each cell with its own tiny fuse (see the pictures in the article). If one cell shorts, the fuse removes it from the group, while the rest of the cells in the group is enough to keep it working. And the active cooling removes the heat released from a failing cell, so it won't overheat its neighbors.
- dzhiurgis 10y agoIf you managed to find ~50kg motors & wheels and strap them directly to this battery pack, you could do 0-60 in 1 second.
- hunterwerlla 10y agoI know this is a joke but you really couldn't, traction (friction) plays a huge role in 0-60 times and something so light would not have that much traction.
- ge96 10y agoI wonder if there is any potential danger to having a public Bitcoin wallet string. I don't know if you can "receive bad money" for example. I don't know.
- EdHominem 10y agoYes and no. "Coins" aren't a thing, so there's nothing to be tainted, per-se. However, yes - if an address that ordered a murder sends you a lot of btc, expect someone to come by and discuss it. Also, the waters are muddied now (intentionally), in a similar way to how every piece of American cash is rumored to have traces of cocaine on it. The theory is that the more this implicates everyone, the less it implicates anyone.
- ge96 10y agoI briefly searched on it, the one thing they mentioned was the possibility of being able to link exchanges to other unknown people because you're now known if your website says who you are and you have a key right there. But they also said to use other ones for each transaction. I don't know. Anyway thanks for the info. Bitcoin is a bit volatile for me but I appreciate it's capability and would like to have some in the future. I'm also broke/in a lot of debt so any concept of savings... Anyway I'm trying to "spread out my money" so to speak for a safety net. I don't know.
- EdHominem 10y agoIf you're in debt, you need to pay off your highest-interest creditor first, and then on to the next one. When you have spare money, you can hedge bets on investing it. But, Bitcoin is not an investment. First, nothing you don't understand is ever an investment for you. If you don't know mining and I do, I'm investing by buying shares in a mine whereas you're gambling by doing it. (For instance, if you don't know, and really understand, why bitcoin tends to be used in a manner where you empty the balance from one address, sending some to the intended recipient, and the leftovers to yourself at a new address, then you're not ready to invest.) Second, it functions as a store of wealth not capital. Its gains are partly from other currencies devaluing around it, not it being used to create more goods the way buying a piece of capital (shares in a manufacturing company) would. That said, if you do any gambling (lottery tickets) you might as well put that into bitcoin, you at least might get something back.
- Shivetya 10y agohttps://teslamotorsclub.com/tmc/threads/my-take-on-the-new-100kwh-pack.76065/ https://teslamotorsclub.com/tmc/threads/my-take-on-the-new-1... The above has some better details but the one I cannot find is weight of the pack, assumptions put it near 1300lbs. Weight is the one area batteries suffer compared to other alternatives and it needs to be addressed because weight is one area car makers are trying real hard to solve.
- ethagknight 10y agoCan anyone explain (or hazard a guess) why Tesla uses cylindrical cells verses the 'scalloped potatoes' approach of Apple's newer laptops?
- lykron 10y agoCheaper to buy standardized cells at scale, due to production capacity?
- lsaferite 10y agoWith the giga-factory coming online I wonder if that will change the equation in favor of flat cells instead.
- MR4D 10y agoMy understanding is that the sheer size of Tesla's battery pack is too large to take a layered approach - at least across the whole size. That forces the designers to go with a segmented approach, in which case the cylindrical is tried and true. From a safety perspective, it also has many more years of data/research behind it. It would be more tolerant to defects. Trying to create small sheets that are then rolled up is easier than creating big sheets, just like smaller silicon processors have better production rates than ones of equal complexity but larger surface area.
- URSpider94 10y agoFlat cells are great if you're trying to build a flat product, where z space is much more critical than x and y. However, flat cells have an unfavorable effect on specific capacity (both weight and volume) since you need two flat sheets to package the display top and bottom, sandwiching a relatively thin active cell, instead of a single cylindrical package wrapped around a larger volume.
- neolefty 10y agoIn another comment [1] in this thread, owenversteeg says that Tesla batteries are not space-constrained, but rather weight-constrained, and that the cylindrical shape is only suboptimal in its space efficiency, not any other important design parameters. [1] https://news.ycombinator.com/item?id=13482273 https://news.ycombinator.com/item?id=13482273