| General > General Technical Chat |
| “Battery EV” vs “Hydrogen Fuel cell EV” |
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| ejeffrey:
--- Quote from: Rick Law on November 12, 2021, 06:17:49 am ---I miscalculated once and ran out of gas. I walked to the gas station with a 2 gallon jug, filled it, and walked back to my car. That 2 gallons would take me 50+ miles, within the distance to the next gas station. AAA (USA's largest motor club for road side assistance) would have come with a gallon or two of gas if I was members and called for assistance. I think AAA (or the likes) has the capacity to carry a fuel cell should they decide to do so. They usually come in a small pick-up with other equipment, some including a generator for starter-battery and jumping. I doubt they would be able to come with large enough a generator to charge up your car for another 20 to 50 miles in short duration. In USA mid-west States, finding a common gas station in the middle of night (1am to 6am) can be iffy within 50 miles. I doubt charging stations will be more available than common gas stations any time soon. I think the lack of an easily portable energy source is a huge disadvantage. In that context, fuel cell at least have some hope, EV's that is plug-in charging only has much less hope... --- End quote --- This is a disadvantage but I think it is relatively minor. Running out of gas on roads in the US is extremely rare these days. It is absolutely not something we should be optimizing for in passenger vehicles. The easiest solution and the one that most people will probably use is just towing. Certainly that is what would happen today. Tow the car to a service station or the nearest place with a power outlet / charger. Yes, that means you have to dispatch a tow truck rather than just a guy in a pickup truck, but it's really no big deal. AAA dispatches plenty of tow trucks for other breakdowns already. If it were a common problem it wouldn't be hard to fit roadside assistance trucks with 10 kWhr batteries they can give you enough charge to get where you are going. The charge part will take a bit longer than dumping a couple gallons of gas in the tank, but still less than the amount of time you waited for assistance. I doubt mobile chargers like this will catch on, but as EVs get a larger market share maybe? |
| nctnico:
--- Quote from: Faringdon on November 12, 2021, 06:31:30 pm ---Thanks, its difficult to find articles accurately detailing what is the cold weather performance of hydrogen cars. (filling time, drive-ability in cold weather, etc) ...woops, just seen your article, ..ok...it looks like cold weather refilling for HEV's is now solved (?)...and it can be done just as fats as at say 20 degc ambient? --- End quote --- Technology is progressing fast. Articles over 2 or 3 years old are likely to be outdated already. --- Quote ---Google also doesnt give stats for percentage of BEV batteries that get "rogue" cell. If this is too high, it will be a major downer for BEVs. --- End quote --- That is not a real problem in today's EV batteries. Typically cells are tested / matched before they are used to assemble a battery. On top of that modern EVs are optimised to maximise battery life by using active cooling / heating systems and limiting charge / discharge currents. But still there is a chance a battery pack goes bad which easely could lead to a car being scrap because the cost of a replacement pack is higher compared to the value of the vehicle. This largely depends on how the packs are constructed. Some manufacturers use modular packs in which it is possible to swap out a small number of cells which greatly reduces the cost of repairing a battery pack. --- Quote ---And for those out-of-service-life BEV batteries that get used for the grid storage systems.....what's the rate (total stats) at which they get "rogue" cell?....i bet its high. --- End quote --- IMHO that is a pipe dream. A Li-ion cell shows exponential wear so using it for grid storage gives a very poor capacity to weight ratio and you'll also need to match used cells and somehow keep quality constant with a supply of cells which vary in quality and chemistry. On top of that you need to disassemble the packs in a way you can recover the cells in a usefull state; in most packs the cells are welded to nickel strips / plates. Recycling to recover the raw materials is a much saner approach. |
| rstofer:
--- Quote from: nctnico on November 12, 2021, 07:01:40 pm ---IMHO that is a pipe dream. A Li-ion cell shows exponential wear so using it for grid storage gives a very poor capacity to weight ratio and you'll also need to match used cells and somehow keep quality constant with a supply of cells which vary in quality and chemistry. On top of that you need to disassemble the packs in a way you can recover the cells in a usefull state; in most packs the cells are welded to nickel strips / plates. Recycling to recover the raw materials is a much saner approach. --- End quote --- And yet Australia has a huge battery storage system - 150 MW/194 MWh We need a bunch of those systems in California. https://en.wikipedia.org/wiki/Hornsdale_Power_Reserve It's my understanding that the Lithium is still valuable in depleted cells. That's important because we're not knee deep in Lithium. |
| nctnico:
--- Quote from: rstofer on November 12, 2021, 07:22:24 pm --- --- Quote from: nctnico on November 12, 2021, 07:01:40 pm ---IMHO that is a pipe dream. A Li-ion cell shows exponential wear so using it for grid storage gives a very poor capacity to weight ratio and you'll also need to match used cells and somehow keep quality constant with a supply of cells which vary in quality and chemistry. On top of that you need to disassemble the packs in a way you can recover the cells in a usefull state; in most packs the cells are welded to nickel strips / plates. Recycling to recover the raw materials is a much saner approach. --- End quote --- And yet Australia has a huge battery storage system - 150 MW/194 MWh --- End quote --- But those systems are using new cells. Not used ones from EVs. Faringdon was asking about using used cells from EVs for grid storage. |
| ejeffrey:
When talking about recycling or reuse, its important to remember that the rate of sale of new EVs completely dwarfs the number going off the road due to age. The oldest Tesla model S is less than 10 years old and most of them are still going strong unless they have been wrecked. There are older EVs than that but non that sold in large volumes and of course the number of cars Tesla is producing now is way more than back then too. Aside from some cars like the early Nissan Leafs that had undersized and passively cooled battery packs that died quickly, there just aren't a lot of EV batteries available to recycle or reuse. So there isn't a huge commercial incentive to improve that technology. In another 10 years there will be a lot more available EOL batteries and a lot more incentive use them efficiently, but it will take at least another decade after that before recycled materials can be a significant fraction of new battery production. |
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