Category Archives: fuel

on the explosion of battery research – part two, a bitsy presentation

(this is reblogged from the new ussr illustrated, first published August 1 2017)

This EV battery managed to run for 1200 kilometres on a single charge at an average of around 51 mph

Ok, in order to make myself fractionally knowledgable about this sort of stuff I find myself watching videos made by motor-mouthed super-geeks who regularly do blokes-and-sheds experiments with wires and circuits and volt-makers and resistors and things that go spark in the night, and I feel I’m taking a peek at an alternative universe that I’m not sure whether to wish I was born into, but I’ll try anyway to report on it all without sounding too swamped or stupefied by the detail.

However, before I go on, I must say that, since my interest in this stuff stems ultimately from my interest in developing cleaner as well as more efficient energy, and replacing fossil fuel as a principal energy source, I want to voice my suspicions about the Australian federal government’s attitude towards clean and renewable energy. This morning I heard Scott Morrison, our nation’s Treasurer, repeating the same deliberately misleading comments made recently by Josh Frydenberg (the nation’s energy minister, for Christ’s sake) about the Tesla battery, which is designed to provide back-up power as part of a six-point SA government plan which the feds are well aware of but are unwilling to say anything positive about – or anything at all. Morrison, Frydenberg and that other trail-blazing intellectual, Barnaby Joyce, our Deputy Prime Minister, have all been totally derisory of the planned battery, and their pointlessly negative comments have thrown the spotlight on something I’ve not sufficiently noticed before. This government, since the election of just over a year ago, has not had anything positive to say about clean energy. In fact it has never said anything at all on the subject, by deliberate policy I suspect. We know that our PM isn’t as stupid on clean energy as his ministers, but he’s obviously constrained by his conservative colleagues. It’s as if, like those mythical ostriches, they’re hoping the whole world of renewables will go away if they pay no attention to it.

Anyway, rather than be demoralised by these unfortunates, let’s explore the world of solutions.

As a tribute to those can-do, DIY geeky types I need to share a great video which proves you can run an electric vehicle on a single charge for well over 1000ks – theirs made it to 1200ks – 748 miles in that dear old US currency – averaging around 51 mph. It’s well worth a watch, though with all the interest there are no doubt other claimants to the record distance for a single charge. Anyway, you can’t help but admire these guys. Tesla, as the video shows, are still trying to make it to 1000ks, but that’s on a regular, commercial basis of course.

In this video, basically an interview with battery researcher and materials scientist Professor Peter Bruce at Oxford University, the subject was batteries as storage systems. These are the batteries you find in your smart phones and other devices, and in electric vehicles (EVs). They’ll also be important in the renewable energy future, for grid storage. You can pump electricity into these batteries and, through a chemical process that I’m still trying to get my head around, you can store it for later use. As Prof Bruce points out, the lithium-ion battery revolutionised the field by more or less doubling the energy density of batteries and making much recent portable electronics technology possible. This energy density feature is key – the Li-ion batteries can store more energy per unit mass and volume. Of course energy density isn’t the only variable they’re working on. Speed of charge, length of time (and/or amount of activity) between charging, number of discharge-recharge cycles per battery, safety and cost are all vitally important, but when we look at EVs and grid storage you’re looking at much larger scale batteries that can’t be simply upgraded or replaced every few months. So Bruce sees this as an advantage, in that recycling and re-using will be more of a feature of the new electrified age. Also, as very much a  scientist, Bruce is interested in how the rather sudden focus on battery storage reveals gaps in our knowledge which we didn’t really know we had – and this is how knowledge often progresses, when we find we have an urgent problem to solve and we need to look at the basics, the underlying mechanisms. For example, the key to Li-ion batteries is the lithium compound used, and whether you can get more lithium ions out of particular compounds, and/or get them to move more quickly between the electrodes to discharge and recharge the battery. This requires analysis and understanding at the fundamental, atomistic level. Also, current Li-ion batteries for portable devices generally use cobalt in the compound, which is too expensive for large-scale batteries. Iron, manganese and silicates are being looked at as cheaper alternatives. This is all new research – and he makes no mention of the work done by Goodenough, Braga et al.

In any case it’s fascinating how new problems lead to new solutions. The two most touted and developed forms of renewable energy – solar and wind – both have this major problem of intermittence. In the meantime, battery storage, for portable devices and EVs, has become a big thing, and now new developments are heating up the materials science field in an electrifying way, which will in turn hot up the EV and clean energy markets.

The video ended by neatly connecting with the geeky DIY video in showing how dumped, abandoned laptop batteries and other batteries had plenty of capacity left in them – more than 60% in many cases, which is more than useful for energy storage, so they were being harvested by PhD students for use in small-scale energy storage systems for developing countries. Great for LED lighting, which requires little power. The students were using an algorithm to get each battery in the system to discharge at different rates (since they all had different capacities or charge left in them) so they could get maximum capacity out of the system as a whole. I think I actually understood that!

Okay – something very exciting! The video mentioned above is the first I’ve seen of a British series called ‘Fully Charged’, all about batteries, EVs and renewable energy. I plan to watch the series for my education and for the thrill of it all. But imagine my surprise when I started watching this one, still part of the series, made here in Adelaide! I won’t go into the content of that video, which was about flow batteries which can store solar energy rather than transferring it to the grid. I need to bone up more on that technology before commenting, and it’s probably a bit pricey for the likes of me anyway. What was immediately interesting to me was how quickly he (Robert Llewellyn, the narrator/interviewer) cottoned on to our federal government’s extreme negativity regarding renewables. Glad to have that back-up! I note too, by the way, that Australia has no direct incentives to buy EVs, of which there are few in the country – again all due to our troglodyte government. It’s frankly embarrassing.

So, there’s so much happening with battery technology and its applications that I might need to take some time off to absorb all the videos and docos and blogs and podcasts and development plans and government directives and projects and whatnot that are coming out all the time from the usual and some quite unusual places, not to mention our own local South Australian activities and the naysayers buzzing around them. Then again I may be moved to charge forward and report on some half-digested new development or announcement tomorrow, who knows….

References

They’re all in the links above, and I highly recommend the British ‘Fully Charged’ videos produced by Robert Llewellyn and Johnny Smith, and the USA ‘jehugarcia’ videos, which, like the Brit ones but in a different way, are a lot of fun as well as educational.

 

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anti-matter as rocket fuel?

easy peasy

easy peasy

This post is in response to a request, I’m delighted to report.

I remember learning first about anti-matter back in about 1980 or 81, when I first started reading science magazines, particularly Scientific American. I learned that matter and anti-matter were created in the big bang, but more matter was created than anti-matter. If not for that I suppose we wouldn’t be here, unless we could be made from anti-matter. I’m not sure where that would leave anti-theists, but let’s not get too confused. We’re here, and so is anti-matter. Presumably there are plenty of other universes consisting mostly of anti-matter, though whether that excludes life, or anti-life, I’ve no idea. Confusion again. If you’re curious about why there’s this lack of symmetry, check out baryogenesis, which will feed without satisfying your curiosity – just what the doctor ordered.

The next time I found myself thinking about anti-matter was in reading, again in Scientific American, about positron-emission tomography (PET), a technology for scanning the brain. As the name implies, it involves the emission of positrons, which are anti-electrons, to somehow provide a map of the brain. I was quite amazed to find, from this barely comprehensible concept, that anti-matter was far from being theoretical, that it could be manipulated and put into harness. But can it be used as energy, or as a form of fuel? Due to anti-matter’s antagonism to matter, I wondered if this was feasible, to which my 12-year-old patron replied with one word – magnets.

The physicist Hans Georg Dehmelt received a Nobel Prize for his role in the development of ion traps, devices which capture particles of different kinds and charges, including antiparticles, within magnetic and electrical fields, so clearly my patron was onto something and it’s not just science-fiction (as I initially thought). It’s obvious from a glance through the physics of this field – using ion traps to analyse the properties and behaviour of charged subatomic particles – that it’s incredibly arcane and complex, but also of immense importance for our understanding of the basic stuff of the universe. I won’t be able to do more here than scratch the surface, if there is a surface.

The idea is that antimatter might be used some time in the future as rocket fuel for space travel – though considering the energy released by matter-antimatter annihilation, it could also have domestic use as a source of electricity. To make this possible we’d have to find some way of isolating and storing it. And what kind of antimatter would be best for this purpose? The sources I’m reading mostly take antiprotons and also anti-electrons (positrons) as examples. The potential is enormous because the energy density of proton-antiproton annihilation is very many times that of equivalent fission reactions. However, experts say that the enormous cost of creating antimatter for terrestrial purposes is prohibitive at the moment. Better to think of it for rocket propulsion because only a tiny amount would be required.

Three types of antimatter rocket have already been proposed: one that uses matter-antimatter annihilation directly as a form of propulsion; another that uses the annihilation to heat an intermediate material, such as a fluid, and a third that generates electricity from the annihilation, to feed an electric spacecraft propulsion system. Wikipedia puts it this way:

The propulsion concepts that employ these mechanisms generally fall into four categories: solid core, gaseous core, plasma core, and beamed core configurations. The alternatives to direct antimatter annihilation propulsion offer the possibility of feasible vehicles with, in some cases, vastly smaller amounts of antimatter but require a lot more matter propellant. Then there are hybrid solutions using antimatter to catalyze fission/fusion reactions for propulsion.

A direct or pure anti-matter rocket may use antiproton annihilation or positron annihilation. Antiproton annihilation produces charged and uncharged pions, or pi mesons – unstable particles consisting of a pair of quarks – as well as neutrinos and gamma rays (high energy photons). The ‘pion rocket’ channels this released energy by means of a magnetic nozzle, but because of the complex mix of energy products, not all of which can be harnessed, the technology currently lacks energy efficiency. Positron annihilation, on the other hand, only produces gamma rays. To use gamma rays as a form of propulsive energy has proved problematic, though it’s known that photon energy can be partially transferred to electrons under certain conditions. This is called Compton scattering, and was an early proof of the particulate nature of light. Recent research has found that intense laser beams can produce positrons when fired at high atomic number elements such as gold. This could produce energy on an ongoing basis, eliminating the need for storage.

The more indirect types are called thermal antimatter rockets. As mentioned, these are divided into solid, gaseous and plasma core systems. It would be beyond my capacity to explain these technologies, but the finding so far is that, though plasma and gas systems may have some operational advantages over a solid system, the solid core concept is much more energy efficient, due to the shorter mean free path between energy-generating impacts.

It’s fairly clear even from my minuscule research on the subject that antimatter rocketry and fuel are in their early, speculative stages, though already involving mind-numbing mathematical formulae. The major difficulties are antimatter creation and, where necessary, storage. Current estimates around the technology are that it would take 10 grams of antimatter to get to Mars in a month. So far, storage, involving freezing of antihydrogen pellets (cooled and bound antiprotons and positrons) and maintaining them in ion traps, has only been achieved at the level of single atoms. Upscaling such a system is theoretically possible, though at this stage prohibitively expensive – requiring a storage system billions of times larger than what has so far been achieved.  There are many other problems with the technology too, including high levels of waste heat and extreme radiation. There are relativistic problems too, as the products of annihilation move at relativistic velocities.

All in all, it’s clear that antimatter rockets are not going to be with us for a long time, if ever, but I suspect that the technical issues involved and the solutions that might be nutted out will fascinate physicists and mathematicians for decades to come.