Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
Check out the new SourceForge HTML5 internet speed test! No Flash necessary and runs on all devices. ×

Comment Re: Why does the ESA have a worse record of landin (Score 1) 89

QA is the problem. They refuse to do majorly expensive testing on earth to check all subsystems. They really need to fire a 'mars test' system into space and test it landing here. In general, the same system that will land on Mars will land on earth, though not the other way around. Btw, this is exactly what America nasa and new space does. Prior to sending red dragon, they will make it land on earth first from helicopters, then aircrafts, finally a test space shot.

Comment Re:I say BS (Score 2) 146

the improvements have been minor in battery tech... the main improvement has been in lowering energy use in the chips (shrinking mainly)

Flatly contradicted by comparing old batteries with new, amp hours vs. volume and mass. For the past couple decades, batteries have doubled in energy density once every 8 years or so. Do you perchance have an old cell phone lying around at home? Check out its amp-hour rating and see how big/heavy it is compared to the amp hour rating and size/mass of your current cell phone's battery.

and the article say's nothing about 10x, so yes this is bullshit..

No, it is not. The maximum theoretical energy density of li-air is about 10x that of the maximum theoretical for LCO/graphite li-ion.

The problem is chemistry, no matter how much you want to believe it's possible to make a battery that is anywhere near as energy dense as gasoline, the chemistry say's no!!

Once again, false. The maximum gravimetric energy density for li-air is comparable to gasoline (12kWh/kg vs. 13kWh/kg) in the charged state, and significantly better in the discharged state. Now, you don't ever achieve the maximum for a particular chemistry, or even close to it. But then again, for a given amount of EV range, you don't have to, as electric drivetrains are 3-5x more efficient than ICE drivetrains.

Of course, neither of these are actual impediments to EV adoption; nobody gives a rat's arse whether a battery pack is physically larger or heavier than a gas tank (partially or completely offset by the reduced drivetrain mass). The real impediment is price. That said, if cost per unit mass/volume remains the same and energy density improves, then cost per watt hour improves as well.

Comment Re:I say BS (Score 1) 146

Wow, unreferenced rant someone added at the bottom - clearly you've got me there!

Try googling those quotes. The first one is only people quoting Wikipedia. The second one, I downloaded the paper and the conclusion says just the opposite ("A huge interest expressed by the scientific community in the development of Li-air battery is the demand of modern automotive industry. We have identified four major areas. If properly addressed, this technology may enter the commercial phase in the near future." (immediately after going into a wide range of papers on dealing with each of these four topics))

Comment Re:I say BS (Score 5, Informative) 146


And I'm telling you that lithium-ion batteries are not a "single tech", that they've dramatically improved in power and energy density (both volumetric and gravimetric) over time. And if you doubt this, I repeat: go find and older lithium-ion battery and compare it to a new one.

As for li-air, yes, the maximum energy density of li-air is about 10x of the maximum of li-ion. Namely because it works by direct oxidation rather than intercalation, so you don't need the mass of the matrix into which the ions get intercalated. It is not a "magical tech". It exists. Like all technologies in all fields, however, you have to reach production specs. This means not only maintaining a combination of safety, reliability, longevity, efficiency, temperature range, power density (charge and discharge) and energy density, but also affordability in mass production. And to be able to guarantee that you can do all of these things to a high enough level for investors to take the risk.

As with all technologies, you start out with promise in one or two fields, but serious problems in many others that you have to deal with. With time you refine them, until all of refined to a state where the product is commercialized. Li-air has actually been advancing quite well. In the early days one of its biggest problems were efficiency and longevity, but they've made huge strides in both in recent years. Lithium sulfur still looks nearer term, but commercialization of Li-air appears to have gone from "possible" to "quite probable".

Comment Re:Halfway There (Score 2) 384

Right. Out of the 330 million people in the US (not counting the broader market, there's "nobody" who wants a gun that can't be accidentally picked up and used by their young children or an intruder. Literally "nobody". Yeah, totally believe you.

They have a niche. You want to prevent them from filling it.

Slashdot Top Deals

The confusion of a staff member is measured by the length of his memos. -- New York Times, Jan. 20, 1981