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peskanov
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I will concede that there are fewer battery fires in other car brands, but I don't see that as significant. Yes, there is only 4 or 5 Hyundai Kona fires, 1 Taycan fire, 1 Panamera fire, 1 eGolf fire, 1 or 2 Fisker Karma fires,and the list goes on in that fashion... However, how is that significant? All these cars have sold a fraction of what Tesla sells. 8 Tesla fires versus all the cars sold in this list hardly seems worse. In the world of cheap electric motorcycles, fires are pretty common, and nearly all of the are pouch or prismatic. I can accept Nissan having a better track record in security (which imo is largely offset by the horrible tales of battery degradation; Nissan is hardly a good example of good EV engineering), but I am pretty sure this not due to cell format, but better electronics. In my experience (and yes, unfortunately I have first hand experience) a parked EV burns when overcharged. Any cell going north of 4.3V starts heating. Now, when you overcharge a pouch or a prismatic, it heats, swells, punctures and starts emitting gas at fast speed. If the cell is enclosed, the gas ignites very easily. I have seen this several times performing tests. A very similar process happens with prismatics, although they swell less dramatically and usually puffs less. Guess what? The only format which offers a [b]passive protection[/b] against overcharging is the cylindrical format. An overcharged cylindrical cell contains pressure to a limit, and then breaks electric contact using a pressure valve. This is called a CID. All of the cylindrical cells I have tested for overcharging did correctly break the circuit. The only way I have caused cylindrical cells to fire is puncturing them using a nail, and even then, only those rated for high discharge would catch fire.
Davemart, "Tesla leader in battery fires"? Lol, now it's obvious you are just trolling. There has been much more fires in pouch and prismatics than in cylindrical batteries. The number of fires in prismatics is less known, as the technology is mostly used in china, but still many reports exist on cars and buses burning. Prismatics are usually pretty thick, around 50 mmm. For thinner cells they usually choose pouch formats, and there are very few examples of them being cooled. The Chevy Bolt is one of them, and the (few) existing battery degradation graphs show faster aging than Tesla packs. I see your idea of Tesla engineering is that they don't know anything about batteries; I find this pretty fun.
Davemart, the secret sauce which provided excellent lifespan to Tesla batteries is perfectly known at this point: keeping the cells cool. Not just ambient temperature, but cool, south of 30 degrees Celsius which ages any Lithium cell fast. And this needs small cells to avoid heat pockets. Lithium-ion materials are not good heat conductors. This was told to me by a Tesla engineer himself, years ago, and I think is common knowledge by now. The other factor they were trying to avoid was electrode paste movement inside the cell. For example, in vertical pouch cells the paste tends to fall slowly to the bottom on each cycle. Cylindrical cells behave much better in that respect. So yes, of course they know bigger cells are cheaper to assemble, but robustness was the priority at it's obvious to me their bet payed off. Other early electric cars like the Leaf killed their battery in less than 8 years, I am bored of hearing bad reports about them. I wish they would have used the cylindrical format. The 2170 was Tesla's compromise between "can be cooled efectively" and "as big as possible". The reason of the bigger new format (4680) was explained yesterday: the tabless cell format they have created has less electric resistance, a lot less, therefore it produces less heat on charge or discharge. That allows a bigger cell to be kept cool as previous packs.
Davemart, I don't think the new 4680 format shown in the conference is "prismatic". They look pretty cylindrical to me. Tesla cylindrical, cooled cells have the best lifespan track record on the industry. All your talk around it is nonsense. BYD prismatics are comparable, but much heavier. The energy density of the new cell has not been clearly explained in the conference; maybe there is a tradeoff removing Cobalt. Maybe the energy density is really better, but at pack level that improvemente is reduced (due to the heavy cooling systems Tesla uses).
Back in 1996, a record of 604 km was established hypermiling a Solectria Sunrise. Using just a 25 kwh battery. That was a design which I would by in a blink, unfortunately it was to soon for EVs.
This little car is cool, but there is no info about the battery.
Severa interesting things here... The feature I like most is the motor, I hate the unnecesary use of neodimyum on electric cars. Unfortunately, only Reanult build EVs without it.
Nikola? A leader? What are these guy leading, vapourware? :D
That's a really nice chemistry. 400 wh/kg at cell level, all materials are abundant as far as I have read (it does not need litihum, cobalt or nickel). Lifespan is probably decent, like all Titanium based batteries. It's a pity all money goes to developing lithium batts.
You can reduce the pulsating torque of a SRM using several techs. like: - Different number of stator winding poles and rotor teeth. You need a high number of winding poles for this, so I guess that's what they are aiming for. - Skewing. - Wave shape modulation. My pet tech. is the flux switching motor, which is closely related to the SR motor. Its has the same troubles (vibration due to irregular torque) and the same fixes.
I don't think FC are cost effective in any of those cases. Ship engines are cost sensible, fuel intensive, and lifetime intensive. Existing FC can't compete in those specifications. Train engines are less cost sensible, but the rest applies. Current LiFePo4 and LTO are cost effective and have long lifespans, plus you save a lot in fuel using batteries. I believe ships should bet in LNG as a way of reducing pollution and enhancing energy independence as sustainability (biogas can easily be produced if needed by any country, at quantities large enough to support shipping operations).
I don't get why the train industry is waiting so much to use modern batteries instead of expensive overhead lines... Batteries slightly bigger than this one are perfect for railroads. LiFePo4 or LTO chemistries will give you >10 year of constant operation and unlimited power. Exchanging batteries in the route end points should be trivial for the rail industry. And the "fuel" cost would be so low, charging the batteries at valley hours... That would make much more sense than electrifying ships, which is probably one of the most difficult applications for batteries.
What a pity, it seems BYD is going ternary lithium. I was hoping they would keep using LiFePo4 and I could buy one of their cars in my country in the future...No nickel, no Cobalt, that's what I understand as sustainable. Also, LiFePo4 is finally getting cheap and competitive in China. You can already ~$120/kwh in many products.
These guys are promising $150/kwh now, and $85 in 2020. I wish them well, but that's not cheaper than current li-ion ($100/kwh). Who knows what the cost of li-ion will be in 2020! This is highly reminiscent of many solar technologies which have died recently, because traditional silicon cells kept going down in cost fast.
Heterojunction cells are about 22% efficient, just a bit more than monocrystalline cells (which are dead cheap by now). And the voltage problem the claim have solved, is just silly. In nealy all uses, cells (electrochemical, solar or otherwise) are operated in series, and balanced if needed. There is no real advantage on coupling directly the solar cell with the electrolyzer to gain a few marginal points in efficiency. If you go "parallel" like these guys are doing, you end up needing huge copper bars for conductors. Plus, any change in solar radiation lowers the voltage & the model stops working. Much better to use a DC-DC device, which are 95% efficient today. The only new (to me) information I get from this article is that PEM electrolyzers are very efficient, about 65%. Cool, but it seems these devices have their own problems which remain to be solved (mostly related to lifetime). Seems like poor research to me.
Does "Cryogenic fluid" means they are using liquid air or nitrogen? If that's the case, how do you compute the efficiency? Producing liquid nitrogen is an energy-intensive proccess. I think this 60% efficiency does not account for energy spent in producing the cryogenic fluid.
These trucks have no traction battery. They don't charge from the wire. When the electric contact is lost, the diesel engine kicks in instantly Trolleybuses used to have big problems when electric contact was lost, but that's not the case for these trucks.
Sublime, I think you misread the article. It says: "specific energy of 152 Wh/kg". Barely better than LiFePo4, but half the energy density of modern Li-ion. Also, we don't know the chemistry, wyth all the components. Maybe nickel or manganese is used too...Lithium cells are usually complex beasts. BTW, manganese is really cheap an abundant. Nickel and cobalt are problematic, though.
What's the point of this chemistry? - It has low energy density. - No mention to power density. - Has a long life, but no longer than LiFepo4, currently used in China. - Good safety; ok, but current Li-ion systems are very safe too. - It has low voltage, not a good thing. So what's the point? Price maybe?
This is how the future of batteries looks like... - Common and dirt cheap materials: carbon, sulfur...and probably sodium will replace lithium. Hopefully copper will find a replacement too, because we don't have much. - Complex and precise microstructures. - Energy densities around 1 kwh/kg. - Probably having some self-repair capabilities? Li-ion is changing lot's of old technologies today. Tomorrow's batteries will change everything, including flight transport. But how could those organic-like system be mass produced? I have the feeling that genetically modified bacteria (or even viruses) could be the fastest way to reach this point. Put these things in a soup and teach them to build complex microscopic structures. As bacteria reproduce themselves, the technology becomes some kind of "software development". You only have to provide the original egg with the genetic code. Once you have the basic hw tools, development could grow really fast.
I understand with torque vectoring systems you can balance the torque as you wish, which seems a bit better than having two motors. But it looks quite complex mechanically. I read Tesla (but have no official confirmation) brakes the inside wheel to allow more torque to be transferred to the outside wheel when needed.
Maybe there is a fear of tires exploding due to malfunction or something similar... About differentials: I read in several places that Tesla and other car engineering firms prefer differential because you can use the full torque of your motor on curves. With two motors, the one closer to the internal part of the curve should not use full torque. I think this concept is interesting (electric torque vectoring): http://www.greencarcongress.com/2014/10/20141015-visom.html
$4000 for 4 kwh of used li-ion? Ok, I will buy a new one instead, is cheaper!
Engineer-Poet, the EV1 only had 1 motor, plus differential. There is one gadget in the EV1 that would be nice to have today: automatic tire inflation. Every wheel had a device which kept tire pressure at the optimum level. That saves a lot of energy, as many people use their cars with under inflated tires.
500 cycles is not referred to capacity under 80%. They just mentioned the cell was tested for 500 cycles and capacity loss was ok. There is also the question of how much cycles do yo need. That depends on battery capacity; 500 cycles on a 60 kwh battery means more than 100k miles. This technology is fascinating, but does not seem fit for production (3d graphene?). We need to develop nanoengineering to mass produce this kind of devices. But at least we get a glimpse about what is possible using common chemistries, when you can order the molecules at your will. :)