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Sion Power has been working on this technology "since 1989". https://sionpower.com/about/ https://sionpower.com/about/ It still only lasts a couple of hundred

by jpm_sd 7y ago

Sion Power has been working on this technology "since 1989". https://sionpower.com/about/ https://sionpower.com/about/ It still only lasts a couple of hundred charge cycles before wearing out: https://advances.sciencemag.org/content/6/1/eaay2757 https://advances.sciencemag.org/content/6/1/eaay2757 "The cells are stable for more than 200 cycles..."

Retric 7y ago
200 charge cycles at 4x the storage = 800 lithium ion charge cycles. That’s easily competitive. Put another way if your getting 300 miles of range a current EV that’s 300 x4 x200 = 240,000 miles.
- ajuc 7y ago
  Only if you change your habits to maximize the lifetime of the batteries. For example avoid charging the car every night and instead charge it for a few nights after it's completely empty.
  - Retric 7y ago
    Most batteries handle partial charging better than full charging. But, assuming it’s an issue a hybrid design with say 150 miles of daily driving lithium ion and 150 x4 = 600 miles of extended range is another option.
    - ajuc 7y ago
      That's actually a good idea. I was thinking supercapacitors for fast acceleration/recuperation and batteries only rated for sustained driving at cruising speed. Should last much longer.
  - Enginerrrd 7y ago
    As I understand it, this is a terrible thing to do to lithium ion batteries. NiCad batteries were like that, but li-ion shouldn't be allowed to go below 20% if you're interested in longevity.
    - TheCraiggers 7y ago
      I thought this was basically a non-issue as the battery circuitry would kill power before it got past that point. Or does that just stop it from emptying completely?
      - audunw 7y ago
        I think it depends on the application where the circuitry cuts off. Almost all applications will have circuitry that cuts power before the cell dies completely. You even have individual 18650 cells that have such a circuit built in (for flash-lights and so on) But increased battery degradation starts way before you hit that limit. At least with cell phones, that tend to push battery cells pretty hard, you'll have pretty bad degradation when discharging to 0%. I think most EVs have a higher cut-off, and most people don't discharge EVs to near 0% anyway.
  - mumblemumble 7y ago
    To add to what others have said with some numbers: https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries https://batteryuniversity.com/learn/article/how_to_prolong_l... To distill it down to a single figure: If you drain the battery down to 40% capacity between recharges, you can expect it to take ~600 charge cycles for total capacity to drop by 30%. If you only drain it down to 90% between recharges, the number of cycles increases to ~6,000. The article doesn't specify, but I assume that's using a slow charge. I am guessing that with a fast charge, which is what is implemented in most consumer electronics, the difference would be even more stark.
  - NopeNotToday 7y ago
    Then divide the battery pack into two (or more) packs. The battery controller then uses one pack to exhaustion, then switches over to the other pack. Normal charging will only charge fully depleted packs. This would reduce maximum range. So add in a charging override for an occasional max distance drive.
  - audunw 7y ago
    What? No.. if you go from 80% to 60% back to 80%, that's not considered a full cycle. You seem to carry a misconception from an older battery chemistry (I don't remember which, but it was common in early cell phones), where it was supposedly better to discharge the battery completely before charging again. Most chemistries are not like that, as far as I know. In fact, with li-ion it's better to charge every night, if your EV battery has a good buffer, or you can configure it to charge to 80% except for days where you'll actually need 100%. Maintaining 99% for 200 cycles seem pretty good to me. Possibly better than Li-ion? It depends on how fast the battery degrades after that. But I'm pretty sure my EV lost its first 1% way before 200 cycles.
clutch89 7y ago
You misread that, it doesn't wear out after 200 cycles, it maintains 99% efficiency after 200 cycles.
- mhandley 7y ago
  Even if it did wear out after 200 cycles, you could still use it as part of a hybrid battery pack. Imagine 50% lithium ion, 50% lithium sulphur. If LiS has 4x the energy capacity of LiIon, you'd have 2.5 times the maximum range of a pure LiIon pack. But most of the time, you don't drive anywhere near the full range, so you discharge the LiIon pack first, and only dischange the LiS pack on those rare days when you need the extra range (or if you only very very rarely need the extra range, dischange the LiS half occasionally to avoid the LiIon half wearing out first).

by jpm_sd 7y ago

Retric 7y ago

200 charge cycles at 4x the storage = 800 lithium ion charge cycles. That’s easily competitive. Put another way if your getting 300 miles of range a current EV that’s 300 x4 x200 = 240,000 miles.

ajuc 7y ago
Only if you change your habits to maximize the lifetime of the batteries. For example avoid charging the car every night and instead charge it for a few nights after it's completely empty.
- Retric 7y ago
  Most batteries handle partial charging better than full charging. But, assuming it’s an issue a hybrid design with say 150 miles of daily driving lithium ion and 150 x4 = 600 miles of extended range is another option.
  - ajuc 7y ago
    That's actually a good idea. I was thinking supercapacitors for fast acceleration/recuperation and batteries only rated for sustained driving at cruising speed. Should last much longer.
- Enginerrrd 7y ago
  As I understand it, this is a terrible thing to do to lithium ion batteries. NiCad batteries were like that, but li-ion shouldn't be allowed to go below 20% if you're interested in longevity.
  - TheCraiggers 7y ago
    I thought this was basically a non-issue as the battery circuitry would kill power before it got past that point. Or does that just stop it from emptying completely?
    - audunw 7y ago
      I think it depends on the application where the circuitry cuts off. Almost all applications will have circuitry that cuts power before the cell dies completely. You even have individual 18650 cells that have such a circuit built in (for flash-lights and so on) But increased battery degradation starts way before you hit that limit. At least with cell phones, that tend to push battery cells pretty hard, you'll have pretty bad degradation when discharging to 0%. I think most EVs have a higher cut-off, and most people don't discharge EVs to near 0% anyway.
- mumblemumble 7y ago
  To add to what others have said with some numbers: https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries https://batteryuniversity.com/learn/article/how_to_prolong_l... To distill it down to a single figure: If you drain the battery down to 40% capacity between recharges, you can expect it to take ~600 charge cycles for total capacity to drop by 30%. If you only drain it down to 90% between recharges, the number of cycles increases to ~6,000. The article doesn't specify, but I assume that's using a slow charge. I am guessing that with a fast charge, which is what is implemented in most consumer electronics, the difference would be even more stark.
- NopeNotToday 7y ago
  Then divide the battery pack into two (or more) packs. The battery controller then uses one pack to exhaustion, then switches over to the other pack. Normal charging will only charge fully depleted packs. This would reduce maximum range. So add in a charging override for an occasional max distance drive.
- audunw 7y ago
  What? No.. if you go from 80% to 60% back to 80%, that's not considered a full cycle. You seem to carry a misconception from an older battery chemistry (I don't remember which, but it was common in early cell phones), where it was supposedly better to discharge the battery completely before charging again. Most chemistries are not like that, as far as I know. In fact, with li-ion it's better to charge every night, if your EV battery has a good buffer, or you can configure it to charge to 80% except for days where you'll actually need 100%. Maintaining 99% for 200 cycles seem pretty good to me. Possibly better than Li-ion? It depends on how fast the battery degrades after that. But I'm pretty sure my EV lost its first 1% way before 200 cycles.

clutch89 7y ago

You misread that, it doesn't wear out after 200 cycles, it maintains 99% efficiency after 200 cycles.

mhandley 7y ago
Even if it did wear out after 200 cycles, you could still use it as part of a hybrid battery pack. Imagine 50% lithium ion, 50% lithium sulphur. If LiS has 4x the energy capacity of LiIon, you'd have 2.5 times the maximum range of a pure LiIon pack. But most of the time, you don't drive anywhere near the full range, so you discharge the LiIon pack first, and only dischange the LiS pack on those rare days when you need the extra range (or if you only very very rarely need the extra range, dischange the LiS half occasionally to avoid the LiIon half wearing out first).