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Yeah I'm expecting a caveat like "they explode if they reach 40 degrees C" or "they degrade by 20% after 20 recharge cycles."

by api 7y ago

chris_overseas 7y ago
The article says their battery keeps 91% of initial capacity after 1,700 cycles at a rate of 2C, or 74% after 1,000 cycles at 5C, which sounds pretty reasonable given charge/discharge rates would likely be a lot lower than that in practice.
danans 7y ago
I do wonder what issues come from storing multiples of the same amount of energy in the same space, but I'm willing to wait and see. Anyways, beyond 400 miles or so, there's not so much value in longer range passenger EVs (obviously semi trucks for freight are a different use case). The real win if they can demonstrate this real-world will be the reduced weight or cost per mile of range.
- DennisP 7y ago
  Until chargers are as common as gas stations and charging takes five minutes, I'd see a lot of value in a battery that could get me through a road trip without ever needing to recharge.
  - michaelt 7y ago
    If you can drive 400 miles on a single five-minute break, you must have very fast car or a hell of a bladder :)
    - Skunkleton 7y ago
      What if I want to drive in 200 mile segments, but I want to stop places that are more interesting than electric charging stations?
      - deleted 7y ago
        [deleted]
    - toast0 7y ago
      Assuming you pee at the origin and the destination, and it's freeway driving, that's two rounds of three hours between the bathroom. As long as the weather is nice, and you don't overhydrate, that doesn't seem unreasonable.
    - quanticle 7y ago
      400 miles isn't that far. It's approximately the distance from Minneapolis, MN to Milwaukee, WI, which is a trip that I've done nonstop. It takes around 5.5 hours, which isn't too bad. Start around noon and arrive just a little before dinner. Minneapolis to Chicago is a bit longer (a little over 400 miles), and takes about 6 hours. For that I'd probably need to stop somewhere to eat.
  - toomuchtodo 7y ago
    You’re never more than about 100 miles from a Tesla Supercharger station in the US, and while charge times are roughly 20-30 minutes, it hasn’t been an issue for the ~20k miles we’ve driven traveling the US. Sure, it’s a bit longer than a 5 minute fill up, but between bathroom breaks, food, coffee, it’s not that much longer and we no longer have gas station trips when around town (charging our Teslas at home). Trade offs. Seems like the amount of folks who are waiting for 400 mile range EVs is exceedingly small.
    - rootusrootus 7y ago
      You get used to it, but it is fair to call it a significant time cost. When we take the Tesla, we stop halfway to grandma's house for 20-30 minutes, then we stop again on the way back. Sure, it's a convenient break for the kids to go pee, but it's only a 2.5 hour trip each way and in our F150 we'd do the whole thing without any fuel or pee stops and it'd be fine. So it costs a solid hour, or 20% more time.
- castratikron 7y ago
  Larger capacity batteries will also last longer because of fewer charge cycles.
- michaelt 7y ago
  > I do wonder what issues come from storing multiples of the same amount of energy in the same space If it makes you feel any better, gasoline stores 12,888.9 Wh/kg according to Wikipedia. So if you're worried energy density in car crashes, it's still much lower than the status quo.
  - ac29 7y ago
    The status quo is Lithium-ion batteries which have certainly been known to spontaneously combust or catch on fire. Gasoline, by contrast, is remarkably stable.
    - ecpottinger 7y ago
      You better not Google car fires if you want to hang onto that belief in the safety of ICE cars.
      - topkeks 7y ago
        Yeah, modern electric cars are at least an order of magnitude less likely to catch fire than internal combustion ones.
      - rootusrootus 7y ago
        Gasoline fires don't spontaneously restart, either. I've also never given much thought to parking my gasoline fueled vehicles inside my garage. When ICE cars do spontaneously ignite, it's never because of the gasoline. I do sometimes think about how prudent it is to park my Tesla underneath my kids' bedrooms every night while it starts charging unattended after everyone is asleep. I'm glad to have a smoke alarm in the garage.
        14 7y ago
        I am glad you have a smoke alarm in the garage I am now thinking how mine died in the garage and I sleep right above it. If it was me in your position I would make sure I used a linked fire alarm system where if one goes off they all go off. It will buy you precious extra seconds getting your kids out as fires can spread incredibly fast.
- m4rtink 7y ago
  Better capacity (but most importantly density) is important also for electric aircraft.
  - narrator 7y ago
    ... and slaughterbots unfortunately.
- ashtonkem 7y ago
  Faster charging arguably is more important than range at ~400mi. At that point I need a break, regardless of what the car could do.
- tzs 7y ago
  > Anyways, beyond 400 miles or so, there's not so much value in longer range passenger EVs (obviously semi trucks for freight are a different use case). If you could have a much longer range, then you could put up with more hassle to charge, which in turn could make some technologies feasible that would not be with lesser range. For an extreme example, if you can go long enough on one charge then it might be feasible to use a non-rechargeable battery and replace it when it is out. Believe it or not that has actually been considered. There is a company or two working on EVs using aluminum air batteries. Those are among the highest energy density available in batteries, comparable to gasoline. They are currently used in some military applications for aircraft and submarines. The claim I've seen is that you could do an EV with these that would have a 2000 km range using less battery weight than current lithium ion EVs use. As I said, these aren't rechargeable, so every ~1800 km you'd have to take it in for a battery swap. Presumably they would design these cars so that this would be a fairly easy operation. The dead battery would be sent back to the manufacturer for recycling. As the battery is used, the aluminum anodes become oxidized. The manufacturer can replace the anodes, and can extract the aluminum from the aluminum oxide and use that for making new anodes.
  - NotSammyHagar 7y ago
    There's lots of advantages of having more potential range. You can pull a trailer and still go a significant distance. How about driving in alaska? Sure, most people drive less than 30 or 40 miles a day. Having an ev has taught me you can never have too much range, at least in today's world.
- sho_hn 7y ago
  I'm curious about the real range requirements for EV freight trucks. At least in Europe, there's very strong regulations for mandatory rest periods for freight truck drivers. It seems to me you would basically design the system including the infrastructure so the trucks end up on a charger during those rest periods, and therefore don't need a very long range battery unless it improves the economics. I'm sure smarter and knowledgable people have done the numbers on this; I should go find a good source ...
greglindahl 7y ago
The usual caveats are things like "we can't build a car-sized one" or "we can't manufacture it cost-effectively" or "we thought we could improve it a lot but couldn't". New breakthrough every month! Shame that almost all of them don't pan out.

Yeah I'm expecting a caveat like "they explode if they reach 40 degrees C" or "they degrade by 20% after 20 recharge cycles."

by api 7y ago

Yeah I'm expecting a caveat like "they explode if they reach 40 degrees C" or "they degrade by 20% after 20 recharge cycles."

chris_overseas 7y ago

The article says their battery keeps 91% of initial capacity after 1,700 cycles at a rate of 2C, or 74% after 1,000 cycles at 5C, which sounds pretty reasonable given charge/discharge rates would likely be a lot lower than that in practice.

danans 7y ago

I do wonder what issues come from storing multiples of the same amount of energy in the same space, but I'm willing to wait and see. Anyways, beyond 400 miles or so, there's not so much value in longer range passenger EVs (obviously semi trucks for freight are a different use case). The real win if they can demonstrate this real-world will be the reduced weight or cost per mile of range.

DennisP 7y ago
Until chargers are as common as gas stations and charging takes five minutes, I'd see a lot of value in a battery that could get me through a road trip without ever needing to recharge.
- michaelt 7y ago
  If you can drive 400 miles on a single five-minute break, you must have very fast car or a hell of a bladder :)
  - Skunkleton 7y ago
    What if I want to drive in 200 mile segments, but I want to stop places that are more interesting than electric charging stations?
    - deleted 7y ago
      [deleted]
  - toast0 7y ago
    Assuming you pee at the origin and the destination, and it's freeway driving, that's two rounds of three hours between the bathroom. As long as the weather is nice, and you don't overhydrate, that doesn't seem unreasonable.
  - quanticle 7y ago
    400 miles isn't that far. It's approximately the distance from Minneapolis, MN to Milwaukee, WI, which is a trip that I've done nonstop. It takes around 5.5 hours, which isn't too bad. Start around noon and arrive just a little before dinner. Minneapolis to Chicago is a bit longer (a little over 400 miles), and takes about 6 hours. For that I'd probably need to stop somewhere to eat.
- toomuchtodo 7y ago
  You’re never more than about 100 miles from a Tesla Supercharger station in the US, and while charge times are roughly 20-30 minutes, it hasn’t been an issue for the ~20k miles we’ve driven traveling the US. Sure, it’s a bit longer than a 5 minute fill up, but between bathroom breaks, food, coffee, it’s not that much longer and we no longer have gas station trips when around town (charging our Teslas at home). Trade offs. Seems like the amount of folks who are waiting for 400 mile range EVs is exceedingly small.
  - rootusrootus 7y ago
    You get used to it, but it is fair to call it a significant time cost. When we take the Tesla, we stop halfway to grandma's house for 20-30 minutes, then we stop again on the way back. Sure, it's a convenient break for the kids to go pee, but it's only a 2.5 hour trip each way and in our F150 we'd do the whole thing without any fuel or pee stops and it'd be fine. So it costs a solid hour, or 20% more time.
castratikron 7y ago
Larger capacity batteries will also last longer because of fewer charge cycles.
michaelt 7y ago
> I do wonder what issues come from storing multiples of the same amount of energy in the same space If it makes you feel any better, gasoline stores 12,888.9 Wh/kg according to Wikipedia. So if you're worried energy density in car crashes, it's still much lower than the status quo.
- ac29 7y ago
  The status quo is Lithium-ion batteries which have certainly been known to spontaneously combust or catch on fire. Gasoline, by contrast, is remarkably stable.
  - ecpottinger 7y ago
    You better not Google car fires if you want to hang onto that belief in the safety of ICE cars.
    - topkeks 7y ago
      Yeah, modern electric cars are at least an order of magnitude less likely to catch fire than internal combustion ones.
    - rootusrootus 7y ago
      Gasoline fires don't spontaneously restart, either. I've also never given much thought to parking my gasoline fueled vehicles inside my garage. When ICE cars do spontaneously ignite, it's never because of the gasoline. I do sometimes think about how prudent it is to park my Tesla underneath my kids' bedrooms every night while it starts charging unattended after everyone is asleep. I'm glad to have a smoke alarm in the garage.
      - 14 7y ago
        I am glad you have a smoke alarm in the garage I am now thinking how mine died in the garage and I sleep right above it. If it was me in your position I would make sure I used a linked fire alarm system where if one goes off they all go off. It will buy you precious extra seconds getting your kids out as fires can spread incredibly fast.
m4rtink 7y ago
Better capacity (but most importantly density) is important also for electric aircraft.
- narrator 7y ago
  ... and slaughterbots unfortunately.
ashtonkem 7y ago
Faster charging arguably is more important than range at ~400mi. At that point I need a break, regardless of what the car could do.
tzs 7y ago
> Anyways, beyond 400 miles or so, there's not so much value in longer range passenger EVs (obviously semi trucks for freight are a different use case). If you could have a much longer range, then you could put up with more hassle to charge, which in turn could make some technologies feasible that would not be with lesser range. For an extreme example, if you can go long enough on one charge then it might be feasible to use a non-rechargeable battery and replace it when it is out. Believe it or not that has actually been considered. There is a company or two working on EVs using aluminum air batteries. Those are among the highest energy density available in batteries, comparable to gasoline. They are currently used in some military applications for aircraft and submarines. The claim I've seen is that you could do an EV with these that would have a 2000 km range using less battery weight than current lithium ion EVs use. As I said, these aren't rechargeable, so every ~1800 km you'd have to take it in for a battery swap. Presumably they would design these cars so that this would be a fairly easy operation. The dead battery would be sent back to the manufacturer for recycling. As the battery is used, the aluminum anodes become oxidized. The manufacturer can replace the anodes, and can extract the aluminum from the aluminum oxide and use that for making new anodes.
- NotSammyHagar 7y ago
  There's lots of advantages of having more potential range. You can pull a trailer and still go a significant distance. How about driving in alaska? Sure, most people drive less than 30 or 40 miles a day. Having an ev has taught me you can never have too much range, at least in today's world.
sho_hn 7y ago
I'm curious about the real range requirements for EV freight trucks. At least in Europe, there's very strong regulations for mandatory rest periods for freight truck drivers. It seems to me you would basically design the system including the infrastructure so the trucks end up on a charger during those rest periods, and therefore don't need a very long range battery unless it improves the economics. I'm sure smarter and knowledgable people have done the numbers on this; I should go find a good source ...

greglindahl 7y ago

The usual caveats are things like "we can't build a car-sized one" or "we can't manufacture it cost-effectively" or "we thought we could improve it a lot but couldn't". New breakthrough every month! Shame that almost all of them don't pan out.