8 ms·
It may really be 10x, but you've mischaracterized what the paper is claiming a 10x breakthrough for. In fairness, the linked article is light on the specifics.
by rzwitserloot 6y ago
It may really be 10x, but you've mischaracterized what the paper is claiming a 10x breakthrough for. In fairness, the linked article is light on the specifics.
The claim is:
__This battery holds 10x more charge per kilo of material than previous attempts at STRUCTURAL (massless) battery materials__.
To be specific, this material holds only _ONE FIFTH_ the charge of what your smartphone's battery can hold per kilo of battery. No laws of thermodynamics is being broken and this is not at all about battery chemistry. It's all about the 'physics' of construction materials: About how this stuff is made in the factory and layered. The basic battery chemistry going on is not much different from what's been available for years - the interesting part is how this material encases it.
You can't make a car by building the chassis out of smartphone batteries. But the promise of this paper is that you CAN build the car chassis out of this battery, and even if this battery is only 20% as effective, a car chassis is rather large, and you needed it anyway, so every drop of power you can store in the chassis itself was effectively 'free' - hence the somewhat hyperbolous 'massless' terminology.
- vbezhenar 6y agoHopefully it'll be easy to repair. I'd hate to replace entire chassis because of light collision.
- gmueckl 6y agoIf your fender bender short-circuited your battery and ignited it, you might need a wee bit more than just a new chassis. (This is not a claim that the batteries described in the article are a fire hazard - I don't know)
- bbarnett 6y agoA mechanic working on a car, with enough juice to fry him, and no way to separate the battery from car? I guess a full discharge first. But what about your accident, and the jaws of life? Will they conduct? Will the wrenched apart car have conductive edges?
- shadowgovt 6y agoInterestingly, these are actual concerns that firefighters have regarding both Teslas and self-driving cars. The relevant companies put out explainers and training videos on how to do a rescue in these vehicles. In the Teslas, the power system is shunted through a single disconnect point... Cutting that line isolates the battery from the rest of the vehicle. In Waymo cars, firefighters needed to be made aware that high-power electrical conduit and liquid cooling channels go up through the pillars, which are usually empty of energized components or contain only low-power channels (for things like overhead lights).
- bmurphy1976 6y agoThat's interesting. I never considered this to be a problem but it makes sense. This could be quite challenging if every car manufacturer does something different, but I suspect over time just like with ICE cars they'll iterate towards some local optimum and things start to be very similar.
- omegaworks 6y ago>I suspect over time just like with ICE cars they'll iterate towards some local optimum and things start to be very similar. This doesn't happen organically. Manufacturers were happily iterating toward a different optimum before regulation forced their hands. https://www.nytimes.com/2015/11/27/automobiles/50-years-ago-unsafe-at-any-speed-shook-the-auto-world.html https://www.nytimes.com/2015/11/27/automobiles/50-years-ago-...
- bmurphy1976 6y agoThat's not really what I mean though. I'm well aware that without regulations short term incentives and optimization can lead to bad outcomes. What I mean is something along the lines convergent evolution where certain designs keep re-appearing because they just work better than the rest.
- elihu 6y ago
- elihu 6y agoIn the article, they say they're using a lithium iron phosphate chemistry. Those tend to be pretty safe. Or at least as safe as you can reasonably expect anything to be that can dump hundreds of amps across a closed circuit.
- Frost1x 6y agoMy thoughts exactly. Load bearing structures tend to be permanent or not frequently changed (on the order of decades). Now someone wants to place a battery in that structure? I hope they develop a mechanism that allows exchange of the battery and can bear load without the battery with some sort of mechanical movement that can shift the load to a more permanent structure (not that this is necessarily a good idea either but proposing an option). Or, perhaps the battery never needs changed, and by that I mean the life of the product lasts as long as it would with a replaceable battery. They can't just redefine the life of the product as the life of the battery to get around this (unless the life if the product was already defined by the life of the battery for a long time before).
- accountofme 6y agoHow about the structural problems with composites that occur with use ... Fractures from normal wear and tear (over years) in a composites will lead to catastrophic failure of the part
- ud_0 6y agoRepairability is guaranteed to be impossible if you have that level of integration, and I suspect that is a big part of the motivation behind adopting this.
- duckfang 6y agoIndeed. And having worked with a wide variety of batteries.... I would hate to see a 'load bearing battery under torsional stress'. Just ow.
- stainforth 6y agoExplosion?
- woah 6y agoIf you damage carbon fiber you generally won’t be repairing it. This doesn’t sound like it will be a very big limitation for similar use cases.
- hasmolo 6y agocarbon fiber repair is definitely a thing. i’ve had a few carbon bike frames break and had them repaired without any issues. there’s a few places that specialize in this
- Gravityloss 6y agoMany ultramodern carbon fiber processes don't use an autoclave so one might be able to do production grade repairs in-place.
- stjohnswarts 6y agoI would like a very simple electric car, simple motor(s), simple electronics to repair, no GPS or phone home necessary (I want to download on my time, send me a text/email/whatever about critical downloads). I want something easy and cheap to repair, have the simplicity of electric motors, and run 20 years with very little maintenance. I don't 30 computers running on my computer. I just want to get from A to B and it not cost me 80-100k for a decent electric vehicle. Tesla and others are overengineered for what they do and that complexity adds to failure rate and cost of ownership.
- Afton 6y agoAren't you describing a Nissan Leaf? I can't really speak to the repairability, because even though I've had it 2 years, I haven't had to do anything but charge it. Oh, once I had to put more air in the tires. Great little car, with about a 70 mile range on my 2017 model.
- waiseristy 6y agoYou're not going to get around the 5-10 computers required for basic 21st century automotive safety. But, the rest of what you are describing is the status-quo for quite a few Chinese 'budget' brands. I'm betting once EVs start making their way into fleets, you'll find your 300k mile, low maintenance, minimal electronics American/German brand.
- elihu 6y agoOne way to get what you're asking for is to do a conversion (or pay someone else to do it, or buy one that someone is selling). I'm in the middle of converting a Mazda RX-8. Just got the motor/clutch/transmission assembly (mostly) in place last weekend. It's kind of fun, but it's also a lot of work. It seems like a tremendously inefficient way to get the car I want: electric, no phone-home or over-the-air update capability, ability to control how everything works, easy to fix, manual transmission, modern safety features. I thought about buying a Model 3, but decided it was a lot of money for something that wasn't quite what I want. 200+ mile range would have been nice though; it's hard to get that in a conversion without making it unreasonably heavy.
- mattrick 6y agoI'm wondering if these batteries will maintain their capacity over time. I think part of the appeal of traditional battery packs is you can replace them as they wear out and hold less charge. If they do degrade, hopefully a chassis/ battery replacement won't be too expensive.
- reader_mode 6y agoI've seen estimates that put modern battery at the expected age/mileages comparable to ICE expected lifetimes - at 300-500k miles you usually replace the car anyway, especially modern ones with so much electronics inside, those will probably get outdated way faster
- pjc50 6y agoCars? Probably not. Drones? Military drones or aircraft? (The paper mentions ARL) Quite possibly. What this promises is that anywhere you would have a strut or panel made from carbon fiber as a load-bearing element, you can have it store some energy for you as well.
- deleted 6y ago[deleted]
- erikerikson 6y ago> Cars? Probably not. Why not cars?
- ajuc 6y agoBecause structure makes up a small percent of an electric car mass and batteries make up a big percent of electric car mass. Let's say that it's 10% for structure and 30% for batteries. If you decrease energy density of batteries several times now they take up let's say 90% of the car mass and the only thing you saved was 10% :)
- framecowbird 6y ago10% for structure might be an underestimate. I did a Google and it suggested 25% for suspension and chassis and another 25% for body. Obviously that includes more than what you could make a battery, but I reckon it’s more than 10%. Also, even if it’s only 10% weight you are saving, that sounds pretty good to me!
- deleted 6y ago[deleted]
- Pokepokalypse 6y agoWhen the battery needs replacement, what do you do? You toss the car in a landfill and stamp out a new one in the factory. So probably better for drones and things that have a short lifetime anyway.
- 6y ago
- mromanuk 6y agoEven more interesting for aviation industry.
- westurner 6y ago> You can't make a car by building the chassis out of smartphone batteries They're called Structural batteries (or [micro]structural super/ultracapacitors) "Carmakers want to ditch battery packs, use auto bodies for energy storage" (2020,) https://arstechnica.com/cars/2020/11/carmakers-want-to-ditch-battery-packs-use-auto-bodies-for-energy-storage/?amp=1 https://arstechnica.com/cars/2020/11/carmakers-want-to-ditch...
- ctdonath 6y agoNote that Tesla Cybertruck is using battery pack as a structural element.
- geocrasher 6y agoThe battery pack yes. The batteries? I would guess not.
- ctdonath 6y agoIt’s a step in that direction others haven’t made yet.
- znpy 6y agoYou comment is more useful than the article, just so you know.
- UncleOxidant 6y agoHaving the chassis of the car be the battery seems problematic. Once the battery is worn out the whole car must be disposed of.
- rini17 6y agoWhat about bicycles?
- Justsignedup 6y agoLeads to a lot of potential if the support structure is also the battery. Even as you said, if you have to still have more of it, you don't add weight to store a charge, and if you already need a lot of structure, you're fine. Having said that, the car chasis is not juuuust about holding up a roof and the humans inside. You also have to handle impact stresses, you don't want it discharging on the poor inhabitants as the car is being hit, etc. This sounds like a step, out of many, the the direction of lighter cars or aircraft that are electrically powered. It also doesn't have to be the only tech. If we can eliminate say 20% of the battery weight by making the frunk/trunk casings out of this material, some other inner parts of the car, we can use it as part of the solution.
- mcswell 6y agoI'm not understanding, perhaps you can enlighten me. The article says "The battery has an energy density of 24 Wh/kg, meaning approximately 20 percent capacity compared to comparable lithium-ion batteries currently available." But the article goes on to say, "since the weight of the vehicles can be greatly reduced." If you need 5x the weight of this kind of battery than if you used Li Ion battery, and a Li Ion battery constitutes 1/3 the mass of a car (at a guess), how is there any savings? Seems like the result will be even heavier than current EVs.