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People always underestimate batteries, even though we're in the middle of a battery technology revolution at this very moment. In 5 years, people will laugh at

by nardi 12y ago

People always underestimate batteries, even though we're in the middle of a battery technology revolution at this very moment. In 5 years, people will laugh at the idea of using compressed air instead of just storing electrons. I imagine battery energy density will have doubled by then.

deleted 12y ago
[deleted]
throwaway2048 12y ago
amazing battery tech has been around the corner for a long time now, yet energy density hasn't changed significantly since the introduction of lithium ion.
dredmorbius 12y ago
Battery technology is fundamentally limited by chemistry. The best available battery techs (generally metal-air designs which consume the anode) offer about 1/10 the energy storage density of liquid hydrocarbon fuels. The best of these, lithium-air, offers a theoretical maximum of 11140 wH/kg (40 MJ/kg), excluding oxygen weight, which is actually close to that of gasoline, diesel, or fuel-oil (~46 MJ/kg). But at practically attainable levels for rechargeable designs, you're down to 9 MJ/kg, and on a gross energy-density basis, while sufficient for some uses, including a fair number of ground-transport uses, but with some significant operational and technical constraints imposed by the battery's own operation. You also have the further disadvantage of having to carry around the full weight of the battery even when its energy content has been exhausted (fuels by comparison are burned off). For other uses, particularly large bulk-good transport (ground or sea), or practical heavier-than-air craft, it's simply not good enough. And that's the best possible designs. For more viable designs -- LiON or even hypothetical graphene / carbon nanotube batteries, you're looking at vastly lower storage densities -- 0.36–0.875 MJ/kg for LiON. The prospect of synthesizing hydrocarbons using electrical energy from renewable or sustainable sources strikes me as a highly probable future path, though I'm partial to the US Navy's fuel-from-seawater proposals, given the much higher (140x) concentrations of CO2 available in dissolved and bound (carbonate, bicarbonate) form. For more: http://redd.it/22k71x http://redd.it/22k71x For discussion of energy storage see generally Wikipedia: https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemical_cell https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemi... https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density
- nardi 12y ago
  I'm well aware of the current limitations of battery technology. Nanotechnology processes are poised to destroy the existing best energy densities. [1] [1] http://en.m.wikipedia.org/wiki/Nanobatteries http://en.m.wikipedia.org/wiki/Nanobatteries
  - nardi 12y ago
    I felt bad for leaving such a horrible reference, so here are a few better ones: http://techland.time.com/2013/05/23/amprius-begins-shipping-a-better-smartphone-battery/ http://techland.time.com/2013/05/23/amprius-begins-shipping-... http://en.wikipedia.org/wiki/Nanowire_battery http://en.wikipedia.org/wiki/Nanowire_battery
  - dredmorbius 12y ago
    Your nanobattery reference cites a capacity of 580 WH/liter energy storage density. This compares with 10,690 WH/l for liquid hydrocarbons (scaling a barrel of oil equivalent to liters and converting to watt hours). That's roughly 5% the energy storage density of liquid fuels.

by nardi 12y ago

deleted 12y ago

[deleted]

throwaway2048 12y ago

amazing battery tech has been around the corner for a long time now, yet energy density hasn't changed significantly since the introduction of lithium ion.

dredmorbius 12y ago

Battery technology is fundamentally limited by chemistry. The best available battery techs (generally metal-air designs which consume the anode) offer about 1/10 the energy storage density of liquid hydrocarbon fuels. The best of these, lithium-air, offers a theoretical maximum of 11140 wH/kg (40 MJ/kg), excluding oxygen weight, which is actually close to that of gasoline, diesel, or fuel-oil (~46 MJ/kg). But at practically attainable levels for rechargeable designs, you're down to 9 MJ/kg, and on a gross energy-density basis, while sufficient for some uses, including a fair number of ground-transport uses, but with some significant operational and technical constraints imposed by the battery's own operation. You also have the further disadvantage of having to carry around the full weight of the battery even when its energy content has been exhausted (fuels by comparison are burned off). For other uses, particularly large bulk-good transport (ground or sea), or practical heavier-than-air craft, it's simply not good enough. And that's the best possible designs. For more viable designs -- LiON or even hypothetical graphene / carbon nanotube batteries, you're looking at vastly lower storage densities -- 0.36–0.875 MJ/kg for LiON. The prospect of synthesizing hydrocarbons using electrical energy from renewable or sustainable sources strikes me as a highly probable future path, though I'm partial to the US Navy's fuel-from-seawater proposals, given the much higher (140x) concentrations of CO2 available in dissolved and bound (carbonate, bicarbonate) form. For more: http://redd.it/22k71x http://redd.it/22k71x For discussion of energy storage see generally Wikipedia: https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemical_cell https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemi... https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density

nardi 12y ago
I'm well aware of the current limitations of battery technology. Nanotechnology processes are poised to destroy the existing best energy densities. [1] [1] http://en.m.wikipedia.org/wiki/Nanobatteries http://en.m.wikipedia.org/wiki/Nanobatteries
- nardi 12y ago
  I felt bad for leaving such a horrible reference, so here are a few better ones: http://techland.time.com/2013/05/23/amprius-begins-shipping-a-better-smartphone-battery/ http://techland.time.com/2013/05/23/amprius-begins-shipping-... http://en.wikipedia.org/wiki/Nanowire_battery http://en.wikipedia.org/wiki/Nanowire_battery
- dredmorbius 12y ago
  Your nanobattery reference cites a capacity of 580 WH/liter energy storage density. This compares with 10,690 WH/l for liquid hydrocarbons (scaling a barrel of oil equivalent to liters and converting to watt hours). That's roughly 5% the energy storage density of liquid fuels.