this post was submitted on 01 Mar 2024
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[–] MystikIncarnate@lemmy.ca 56 points 8 months ago (23 children)

So, I understand what Toyota is saying. I'm not sure I agree, but I get it.

Simply put, until we figure out a good solution to the battery problem, EVs are kind of at a dead end. They are about as good as they could be with current technology. There's a big push right now towards better energy storage tech, aka battery tech, for EVs and beyond (everything from cellular/mobile/device applications, to EVs, to "grid scale" storage).

The problem is basically twofold: first, limited energy storage. This is compounded by fairly slow charging... Second, current lithium tech used in EVs tends to be rather.... Flammable. Specifically, the most common chemistries are pyrophoric; aka, they burst into flames on contact with air. .... I'll emphasize that pyrophoric battery chemistries are commonly used in just about all consumer goods. This includes every Tesla, and every cellphone.

The only reason that your phone doesn't spontaneously combust in your hand is because the batteries are sealed so no air can get at the chemistry. The issue with Tesla's EVs is when one cell's seal fails, and it combusts, then the chances that adjacent cells will have their air seal compromised, dramatically increases. This can quickly lead to a chain reaction of failures.

Current research is ongoing into batteries. The golden battery for EVs will have, fast charging, high discharge capability (also known as the "C rate"), similar or better energy density to current cells, and longer charge/discharge cycle life. Since we're already comfortable giving pyrophoric batteries to the general public to carry around in their pockets, I don't think anyone is focused on eliminating that, but, if they can, while achieving the other goals, so much the better.

Other battery chemistries exist that are not pyrophoric, but they lack the energy density of their pyrophoric counterparts. One notable chemistry is LiFePO4, which, by sacrificing some energy density, you get much longer cycle life, and no pyrophoric materials.

Solid state batteries are being researched which should extend cycle life significantly if it can be achieved as a "commercially viable product" (which is corporate talk for something that can be mass produced). Thus far, while sold state batteries exist, they're either done in very small batches, and are very hard to produce, or, they simply don't have the same, or similar, energy density to the lithium/cobalt cells that currently dominate the market.

One alternative is hydrogen. Hydrogen fuel cell technology isn't perfect, with a loss of about 20-30% IIRC, from the energy in vs the energy out. The benefit to hydrogen is that it can be stored, highly compressed (a large volume of gas in a relatively small container), and it doesn't degrade or go bad, so it can be stored indefinitely, aka no significant loss over time. But hydrogen is a far more dangerous material than lithium/cobalt, and a tank rupture from a full tank of hydrogen in an EV, could create an explosion of significant size. It's far more dangerous than the pyrophoric batteries. For more information, see: Hindenburg.

Other alternatives exist, but generally are not being used in EVs for various reasons. Among these are RITEGs. An RITEG outputs a consistent and stable power flow indefinitely, even a relatively small unit could be used to power a vehicle, with a small buffer battery, for upwards of 40 years without needing to "refuel" so to speak. Possibly longer depending on the fuel used. The reason they're not considered is right in the name. The full name for an RITEG is "radio isotope thermal electric generator". Aka, nuclear. The unique thing about an RITEG is that the power output is dependent on the differential between the heating provided by the fuel, versus the temperature of the surrounding material (usually some sort of passive heatsink). They're very safe unless the seal is broken, in which case, you need Hazmat to clean up the mess. Their energy conversion is very very low. The power is stable, but only a small amount of wattage can be generated. It's constant, but it's a small amount. So the presence of a "buffer" battery for acceleration (and most driving) would be required, and often you can get more power from a small solar array, dependent on the weather. I like the idea of RITEGs, but more as a home generator type option, where you could bury one into the ground and dissipate the heat geothermally. No options exist for this and research into thermal electric tech has been stalled for many years. Nevertheless, I think it's awesome. The idea of having a mostly solid-state, base load generator in your back yard, seems like a really good idea, but nobody has done it, since IMO, the regulations would be a nightmare.

Anyways, the battery problem outlined here is what we're all waiting for... A commercially viable product that is on par with the current battery front runner, lithium/cobalt, for energy density, while having a much higher cycle life and a high "C rate".

[–] SeaJ@lemm.ee 35 points 8 months ago (4 children)

Hydrogen is NOT a viable option for consumer vehicles. Energy storage is not dense, it is barely more efficient than an ICE, and it is also very flammable because it is highly pressurized H and a large battery. They may be fine for commercial vehicles but there is not a market for them for consumers. That is why Shell is closing up its stations in CA and why Toyota is discounting the Mirai significantly while also giving lots of fuel up money and it is still not enough to do much for demand.

As for solid state batteries, they are already in some BYD vehicles and Toyota itself is claiming that their solid state battery that will offer 650 miles of range should be in cars by 2027.

As for current batteries, the limited storage is not a real issue in 99.5% of cases. Over 99% of trips are under 100 miles. There are quite a few EVs now that can get 300 miles which is more than enough for 99.9% of trips. The comparatively slow charge for fast charge stations is also not much of an issue since few people can drive that long without taking a half hour break (although several models can add 200 miles of range in 15 minutes). The current major hurdle for that charging is working stations that charge at a decent speed. And what about the 99.9% of times when you do not need fast charge? We need to make level 1 chargers significantly more available. The average American only goes a little over 30 miles per day and sits idle for 22-23 hours. If it can be charging for a large chunk of that time, even at level 1 speeds, you are looking at 70-90 miles added per day. We need to offer huge tax incentives to apartment owners to install them in parking spaces and incentives to either install smart panels or upgrade panels to 200A. Cities should also start putting slow chargers in their downtowns where people park.

The overall issues with EVs are largely not the batteries themselves, but the infrastructure surrounding them.

[–] MystikIncarnate@lemmy.ca 6 points 8 months ago (1 children)

I would agree the charging is a large issue. Apartments especially.

One problem you didn't mention is generation and the grid. The ability to transmit enough power down the grid if everyone were to go to EVs overnight, simply isn't there. The high voltage transmission lines are simply not up to the task right now; and that ignores if we can even currently generate that much power.

I don't recall mentioning range at all, but I would agree, range isn't much of a factor, fast charging is mainly a side benefit of high C rates, the main focus for C rate is the ability to get the power out of the pack when it is needed, so it can be used for the locomotion of the vehicle. Simply put, the amps needed to lug around several tons of metal, batteries and people, is significant, that's not even factoring in any hauling or towing. The ability to deliver that current directly from the battery on a consistent level is the key here. Current lithium/cobalt cells are more than capable of both charging and discharging quickly, though you can usually extend the life of the battery by primarily using lower C rates of charging, usually 0.5C provides the most benefit, lower doesn't increase longevity by enough to be worthwhile, and you get less and less benefit as you approach, then exceed 1C. Solid state batteries shouldn't have nearly the same trouble with this, as long as it's capable of 2 or 3C, it should be plenty for the application.

I disagree on the fuel cell comment regarding efficiency. ICE engines, last I checked, could only convert 20-25% of the energy in gasoline to motion, whereas fuel cells are capable of up to 60% conversion of the energy in the hydrogen to electricity, adjusting for losses in the motors and everything, you should be able to get around 50% energy conversion to locomotion. Fuel cells are getting to a point where they are running up against the physics of the issue and can't really make it any more efficient, ICE motors have been at that point for a while. There are small gains but a large percentage of the energy is converted into light+heat which is considered to be a waste product. There's also the matter of how to create the hydrogen, which, right now, there are not many good methods. The "most green" method is by water electrolysis, separating the oxygen from the hydrogen in water (H2O), which is a very inefficient process, more energy goes in than the resulting hydrogen has. If this is factored in then yes, you're correct that hydrogen fuel cells are not significantly more efficient, since the electricity to hydrogen to electricity conversion is the most lossy part of the whole system. There may be areas where we can enhance hydrogen production and get the numbers more on par with battery EVs, but I digress. As far as I know that is not a focus of current research.

Battery EVs are upwards of 90% efficient or better in most cases, even factoring in all the losses from getting the power into the pack and out of the pack. BEVs are simply more efficient overall. There's no disputing that. ICE vehicles are usually dead last no matter how you look at it.

For charging, foregoing the grid issues, which need to be addressed regardless, every EV owning citizen should have access to a charger at their residence, or at least the option for one. Homeowners can easily buy and install (or have installed) a charger for their own personal use, condos and apartments are the main targets since the parking areas are usually managed by the property owner or condo authority, so installing a charger is a bit more of a problem. That definitely needs to be addressed.

[–] SeaJ@lemm.ee 6 points 8 months ago* (last edited 8 months ago) (1 children)

The grid issues are not really that significant. You are correct that we would not be able to do it if things changed immediately. We would need another 800-1000 GW of power generation (an extra 15-20%). But it is not going to happen overnight. Cars last a pretty damn long time. Even if we hit 100% of new cars being B/PH EV in 2035, only about 13% of cars on the road will be EV at that point. It would take another couple of decades for those to be phased out. So this is more problem over the span of three to four decades to increase our grid capacity by 15-20% which is absolutely doable. It can actually result in a more stable grid if vehicle to grid becomes anything close to the norm.

I brought up range and charging speeds because that is what most people worry about. That is almost certainly due to their current mindset from using ICE vehicles where they go to a station to charge. But yes, that was more generalized info and not geared towards your points.

ICE vehicles are about 25-30% energy efficient. FCEV vehicles are a little under 40% while BEVs are about 80% efficient. . So FCEVs are slightly more energy efficient than ICE but a far cry from a BEV.

I did forget one other issue with BEVs that needs to be fixed: they are insanely heavy. That can take quite a toll on roads. This can be solved a couple of ways. The easiest way would be by not buying fucking massive SUVs and trucks that are not needed for the vast majority of trips. A commuter car used to be a thing. Speaking of commute, that brings us to number two. A commuter car does not need 300 miles of range. Small cars with 100-150 mile range are absolutely fine for 99% of trips. The last way would be to use solid state batteries since they can be much lighter for the same range.

But switching to EV will not get us even close to where we need to be for emissions because whole they may produce 80% fewer emissions over the vehicle's lifespan, consumer vehicles only make up less than a third of emissions. Public transportation and biking infrastructure could be massively improved and help a hell of a lot more. Then we need to work on trucking, flight, and energy production.

[–] MystikIncarnate@lemmy.ca 1 points 8 months ago (1 children)

You're forgetting that we also need to work on global shipping. It's a massive contributor to global emissions.

This is bluntly the place where I think we need fuel cells. Yes, they're less efficient, but they can produce a significant amount of power for a significant amount of time given how much space is usually allocated on shipping vessels for the engine and fuel reserves.

I'm not talking about your mom and dad's little motor boat, I'm talking about freight liners. They run basically 24/7 while on the water and consume more fuel daily than your average coal rolling F350 owner would in a year.

Since it would be done in a more controlled commercial context, safeguards can be put in place that other vehicles wouldn't be able to have. Regular inspections of the safety equipment and testing of the storage and energy systems would be almost trivial to implement.

Honestly, I understand why this isn't in the news, but why isn't anyone else talking about this?

[–] SeaJ@lemm.ee 3 points 8 months ago

Global shipping is probably not talked about much because it is extremely tough to push any standards. It took forever to get an agreement to stop using the horribly toxic sludge they used to use in international waters. You are right though. It is 100% something that needs to be focused on and fuel cells would help a fuckton in that area. Sure they are not as energy efficient as BEVs but they are a ton better than the garbage fuel cargo ships currently use.

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