- cross-posted to:
- technology@lemmy.world
- cross-posted to:
- technology@lemmy.world
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China is so far ahead
For battery tech nerds like me, the battery is a more efficient lithium-iron battery, called Lithium Manganese Iron Phosphate or lmfp. It has a theoretical energy density of 525Wh/L, compared to normal lithium-iron theoretical density of 325Wh/L
For context jet fuel is around 9,720 Wh/L. However, energy density(energy per volume) is less important in aviation than specific energy(energy per mass) as weight is far more likely to be the limiting factor.
A standard lithium ion battery has 100-265 Wh/kg
The article claims 500 Wh/kg in this new battery.
Jet fuel has around 12,000 Wh/kg.
Though this is a major improvement in battery tech, batteries are unlikely to ever improve to the point to even approach the energy storage of liquid fuels.
Batteries cannot run commercial aviation as it currently exists. Battery planes will need to fly slower and shorter. There is no other way.
What’s the efficiency for turning jet fuel into mechanical work? I’d suspect the efficiency is somewhere around 45% for liquid fuel where it’s nearly 100% for electric. So you’re really trying to reach the equivalent of 5500 Wh/kg.
A factor in favour of jet fuel is that as the plane burns fuel if becomes lighter, thus consuming less fuel. Batteries stay the same weight. The difference between a full plane and an empty plane can be 18 metric tonnes. Super cheap operators tend to carry only a small extra margin of fuel over the amount technically necessary to make a trip, because it makes a real difference.
That means the energy density you need in this comparison isn’t really linear. If you’re doing Taylor Swift flights to the couch and back, you can save a lot of weight by having a minimal amount of fuel in the tank, but with an electric plane you’ll always have to have the full battery in case you need to go somewhere further away.
Energy density has been the number one most important factor since humans started using metal. Wood is good enough to smelt bronze, and with some refinement can get your iron, but not good enough for steel. Steel requires coal, and with some refinement steel is what our world is built on.
Fossil fuels allow cars, planes and more efficient trains and boats. Unless we somehow start utilizing uranium and transuranics electric airplanes are for grifters. Uranium and it’s derivatives are the only thing we have harnessed that even approaches the energy density of fossil fuels.
Trains don’t need to store the energy at all. Pantographs are a mature technology. High speed renewable long haul transportation is a technologically solved problem for all overland routes, it just requires infrastructure investment.
