4 ms·

There is a fix for slow charging that is literally as fast as filling a tank but nobody wants to use it. (I assume it is the same reason that there are pages an

There is a fix for slow charging that is literally as fast as filling a tank but nobody wants to use it. (I assume it is the same reason that there are pages and pages of battery improvements that never make it to market.) https://en.wikipedia.org/wiki/Flow_battery https://en.wikipedia.org/wiki/Flow_battery

stcredzero 8y ago
In the case of flow batteries, don't a lot of them have poor power to weight figures? Those liquids are heavy, but aren't nearly as power dense as gasoline.
i80and 8y ago
Flow batteries, at least the kind that are commercially adoptable in the present/near-future (Vanadium redox), scale in capacity very easily. The downsides are twofold: * Poor power density * Relatively limited nominal power output These compromises are fine for stationary applications, but for vehicles, they'd be a riskier bet as far as I'm aware. (disclaimer: not a subject matter expert)
lolc 8y ago
The other fix would be swappable batteries. But it would require a huge engineering effort.
- dexen 8y ago
  >swappable batteries would require a huge engineering effort. Worked just fine back in 2013. The people's habits were the only obstacle: owners wanted to retain their own battery pack, instead of getting pre-owned one left by somebody else, in unknown condition. And/or drive over a weird contraption. [1] (loud music warning) https://www.youtube.com/watch?v=H5V0vL3nnHY https://www.youtube.com/watch?v=H5V0vL3nnHY
  - SketchySeaBeast 8y ago
    I wonder why it bothers people about battery packs, but not propane tanks. They seem to have equal chances of exploding.
    - mulmen 8y ago
      What if some jerk replaces half his cells with rocks then swaps the pack and you get it? You have to trust the charging station that you’re getting an equivalent pack in trade. Are incentives aligned to ensure that?
      - samatman 8y ago
        Gogoro has been quite successful with this model. The difference, of course, is that a scooter takes batteries small enough to swap by hand.
        mulmen 8y ago
        The Gogoro model is really cool and I would love to see it expand to cars. I’m just providing an example of why people might object to the idea.
    - michaelt 8y ago
      Propane technology has matured and stabilised; a 2019 propane tank is no better than a 2009 propane tank, it'll be the same size, supply the same amount of energy, and have the same connectors. A 2029 propane tank will, in all likelihood, be the same. The same cannot be said of EV battery technology. So why the Tesla demo video? According to [1] just doing the demo entitled them to $90 million of Californian "ZEV credits", and they never believed in or planned to roll out the technology. [1] https://www.quora.com/Whatever-happened-to-Tesla-battery-swapping-stations https://www.quora.com/Whatever-happened-to-Tesla-battery-swa... apologies for the Quora link
- bash-j 8y ago
  Why not fill up with loose cells? They are small, they roll. Couldn't they roll into a ribbed tray and then a rail on both sides clamps them in place and connects them? Or pulled in on a chain like a machine gun loading mechanism?
  - ovi256 8y ago
    This is an original idea that I haven't seen elsewhere. The big issue is that assembling loose cells into a battery pack is a hard enough operation. It must achieve good mechanical properties (the pack must be rigid enough), good electrical contact with the battery terminals (bad contact would ruin a pack, could start a fire as a bad contact could overheat) and good cooling (battery packs heat, so afaik all designs use liquid cooling, which needs very good thermal contact between the cells and the cooling assembly). Loose cells would essentially mean you're feeding the loose cells inside the pack and the pack has some robotic assembly arms that it uses to put the cells in the right places while it achieves the three objectives. With some different, taylor made cell design you could make this self-assembly easier, maybe even make it mechanically passive - have the cells orient vertically and slide into their places, and then they're locked. But the current cell design is definitely not chosen for this.
    - acct1771 8y ago
      tailor-made, unless we're talking golf, ha

stcredzero 8y ago

In the case of flow batteries, don't a lot of them have poor power to weight figures? Those liquids are heavy, but aren't nearly as power dense as gasoline.

i80and 8y ago

Flow batteries, at least the kind that are commercially adoptable in the present/near-future (Vanadium redox), scale in capacity very easily. The downsides are twofold: * Poor power density * Relatively limited nominal power output These compromises are fine for stationary applications, but for vehicles, they'd be a riskier bet as far as I'm aware. (disclaimer: not a subject matter expert)

lolc 8y ago

The other fix would be swappable batteries. But it would require a huge engineering effort.

dexen 8y ago
>swappable batteries would require a huge engineering effort. Worked just fine back in 2013. The people's habits were the only obstacle: owners wanted to retain their own battery pack, instead of getting pre-owned one left by somebody else, in unknown condition. And/or drive over a weird contraption. [1] (loud music warning) https://www.youtube.com/watch?v=H5V0vL3nnHY https://www.youtube.com/watch?v=H5V0vL3nnHY
- SketchySeaBeast 8y ago
  I wonder why it bothers people about battery packs, but not propane tanks. They seem to have equal chances of exploding.
  - mulmen 8y ago
    What if some jerk replaces half his cells with rocks then swaps the pack and you get it? You have to trust the charging station that you’re getting an equivalent pack in trade. Are incentives aligned to ensure that?
    - samatman 8y ago
      Gogoro has been quite successful with this model. The difference, of course, is that a scooter takes batteries small enough to swap by hand.
      - mulmen 8y ago
        The Gogoro model is really cool and I would love to see it expand to cars. I’m just providing an example of why people might object to the idea.
  - michaelt 8y ago
    Propane technology has matured and stabilised; a 2019 propane tank is no better than a 2009 propane tank, it'll be the same size, supply the same amount of energy, and have the same connectors. A 2029 propane tank will, in all likelihood, be the same. The same cannot be said of EV battery technology. So why the Tesla demo video? According to [1] just doing the demo entitled them to $90 million of Californian "ZEV credits", and they never believed in or planned to roll out the technology. [1] https://www.quora.com/Whatever-happened-to-Tesla-battery-swapping-stations https://www.quora.com/Whatever-happened-to-Tesla-battery-swa... apologies for the Quora link
bash-j 8y ago
Why not fill up with loose cells? They are small, they roll. Couldn't they roll into a ribbed tray and then a rail on both sides clamps them in place and connects them? Or pulled in on a chain like a machine gun loading mechanism?
- ovi256 8y ago
  This is an original idea that I haven't seen elsewhere. The big issue is that assembling loose cells into a battery pack is a hard enough operation. It must achieve good mechanical properties (the pack must be rigid enough), good electrical contact with the battery terminals (bad contact would ruin a pack, could start a fire as a bad contact could overheat) and good cooling (battery packs heat, so afaik all designs use liquid cooling, which needs very good thermal contact between the cells and the cooling assembly). Loose cells would essentially mean you're feeding the loose cells inside the pack and the pack has some robotic assembly arms that it uses to put the cells in the right places while it achieves the three objectives. With some different, taylor made cell design you could make this self-assembly easier, maybe even make it mechanically passive - have the cells orient vertically and slide into their places, and then they're locked. But the current cell design is definitely not chosen for this.
  - acct1771 8y ago
    tailor-made, unless we're talking golf, ha