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Posts Tagged ‘batteries

electric vehicles in Australia, a sad indictment

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Toyota Prius

I must say, as a lay person with very little previous understanding of how batteries, photovoltaics or even electricity works, I’m finding the ‘Fully Charged’ and other online videos quite addictive, if incomprehensible in parts, though one thing that’s easy enough to comprehend is that transitional, disruptive technologies that dispense with fossil fuels are being taken up worldwide at an accelerating rate, and that Australia is falling way behind in this, especially at a governmental level, with South Australia being something of an exception. Of course the variation everywhere is enormous – for example, currently, 42% of all new cars sold today in Norway are fully electric – not just hybrids. This compares to about 2% in Britain, according to Fully Charged, and I’d suspect that the percentage is even lower in Oz.

There’s so much to find out about and write about in this field it’s hard to know where to start, so I’m going to limit myself in this post to electric cars and the situation in Australia.

First, as very much a lower middle class individual I want to know about cost, both upfront and ongoing. Now as you may be aware, Australia has basically given up on making its own cars, but we do have some imports worth considering, though we don’t get subsidies for buying them as they do in many other countries, nor do we have that much in the way of supportive infrastructure. Cars range in price from the Tesla Model X SUV, starting from $165,000 (forget it, I hate SUVs anyway), down to the Toyota Prius C and the Honda Jazz, both hybrids, starting at around $23,000. There’s also a ludicrously expensive BMW plug-in hybrid available, as well as the Nissan Leaf, the biggest selling electric car worldwide by a massive margin according to Fully Charged, but probably permanently outside of my price range at $51,000 or so.

I could only afford a bottom of the range hybrid vehicle, so how do hybrids work, and can you run your hybrid mostly on electricity? It seems that for this I would want a (more expensive) plug-in hybrid, as this passage from the Union of Concerned Scientists (USA) points out:

The most advanced hybrids have larger batteries and can recharge their batteries from an outlet, allowing them to drive extended distances on electricity before switching to [petrol] or diesel. Known as “plug-in hybrids,” these cars can offer much-improved environmental performance and increased fuel savings by substituting grid electricity for [petrol].

I could go on about the plug-ins but there’s not much point because there aren’t any available here within my price range. Really, only the Prius, the Honda Jazz and a Toyota Camry Hybrid (just discovered) are possibilities for me. Looking at reviews of the Prius, I find a number of people think it’s ugly but I don’t see it, and I’ve always considered myself a person of taste and discernment, like everyone else. They do tend to agree that it’s very fuel efficient, though lacking in oomph. Fuck oomph, I say. I’m the sort who drives cars reluctantly, and prefers a nice gentle cycle around the suburbs. Extremely fuel efficient, breezy and cheap. I’m indifferent to racing cars and all that shite.

Nissan Leaf

I note that the Prius  has regenerative braking – what the Fully Charged folks call ‘regen’. In fact this is a feature of all EVs and hybrids. I have no idea wtf it is, so I’ll explore it here. The Union of Concerned Scientists again:

Regenerative braking converts some of the energy lost during braking into usable electricity, stored in the batteries.

Regenerative braking” is another fuel-saving feature. Conventional cars rely entirely on friction brakes to slow down, dissipating the vehicle’s kinetic energy as heat. Regenerative braking allows some of that energy to be captured, turned into electricity, and stored in the batteries. This stored electricity can later be used to run the motor and accelerate the vehicle.

Of course, this doesn’t tell us how the energy is captured and stored, but more of that later. Regenerative braking doesn’t bring the car to a stop by itself, or lock the wheels, so it must be used in conjunction with frictional braking.  This requires drivers to be aware of both braking systems and how they’re combined – sometimes problematic in certain scenarios.

The V useful site How Stuff Works has a full-on post on regen, which I’ll inadequately summarise here. Regen (in cars) is actually celebrating its fiftieth birthday this year, having been first introduced in the Amitron, a car produced by American Motors in 1967. It never went into full-scale production. In conventional braking, the brake pads apply pressure to the brake rotors to the slow the vehicle down. That expends a lot of energy (imagine a large vehicle moving at high speed), not only between the pads and the rotor, but between the wheels and the road. However, regen is a different system altogether. When you hit the brake pedal of an EV (with hand or foot), this system puts the electric motor into reverse, slowing the wheels. By running backwards the motor acts somehow as a generator of electricity, which is then fed into the EV batteries. Here’s how HSW puts it:

One of the more interesting properties of an electric motor is that, when it’s run in one direction, it converts electrical energy into mechanical energy that can be used to perform work (such as turning the wheels of a car), but when the motor is run in the opposite direction, a properly designed motor becomes an electric generator, converting mechanical energy into electrical energy.

I still don’t get it. Anyway, apparently this type of braking system works best in city conditions where you’re stopping and going all the time. The whole system requires complex electronic circuitry which decides when to switch to reverse, and which of the two braking systems to use at any particular time. The best system does this automatically. In a review of a Smart Electric Drive car (I don’t know what that means – is ‘Smart’ a brand name? – is an electric drive different from an electric car??) on Fully Charged, the test driver described its radar-based regen, which connects with the GPS to anticipate, say, a long downhill part of the journey, and in consequence to adjust the regen for maximum efficiency. Ultimately, all this will be handled effectively in fully autonomous vehicles. Can’t wait to borrow one!

Smart Electric Drive, a cute two-seater

I’m still learning all this geeky stuff – never thought I’d be spending an arvo watching cars being test driven and  reviewed.  But these are EVs – don’t I sound the expert – and so the new technologies and their implications for the environment and our future make them much more interesting than the noise and gas-guzzling stink and the macho idiocy I’ve always associated with the infernal combustion engine.

What I have learned, apart from the importance of battery size (in kwh), people’s obsession with range and charge speed, and a little about charging devices, is that there’s real movement in Europe and Britain towards EVs, not to mention storage technology and microgrids and other clean energy developments, which makes me all the more frustrated to live in a country, so naturally endowed to take advantage of clean energy, whose federal government is asleep at the wheel on these matters, when it’s not being defensively scornful about all things renewable. Hopefully I’ll be able to report on positive local initiatives in this area in future, in spite of government inertia.

 

Written by stewart henderson

August 15, 2017 at 9:51 am

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

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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.

 

Written by stewart henderson

August 1, 2017 at 9:26 pm

on the explosion of battery research – part one, some basic electrical concepts, and something about solid state batteries…

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just another type of battery technology not mentioned in this post

Okay I was going to write about gas prices in my next post but I’ve been side-tracked by the subject of batteries. Truth to tell, I’ve become mildly addicted to battery videos. So much seems to be happening in this field that it’s definitely affecting my neurotransmission.

Last post, I gave a brief overview of how lithium ion batteries work in general, and I made mention of the variety of materials used. What I’ve been learning over the past few days is that there’s an explosion of research into these materials as teams around the world compete to develop the next generation of batteries, sometimes called super-batteries just for added exhilaration. The key factors in the hunt for improvements are energy density (more energy for less volume), safety and cost.

To take an example, in this video describing one company’s production of lithium-ion batteries for electric and hybrid vehicles, four elements are mentioned – lithium, for the anode, a metallic oxide for the cathode, a dry solid polymer electrolyte and a metallic current collector. This is confusing. In other videos the current collectors are made from two different metals but there’s no mention of this here. Also in other videos, such as this one, the anode is made from layered graphite and the cathode is made from a lithium-based metallic oxide. More importantly, I was shocked to hear of the electrolyte material as I thought that solid electrolytes were still at the experimental stage. I’m on a steep and jagged learning curve. Fact is, I’ve had a mental block about electricity since high school science classes, and when I watch geeky home-made videos talking of volts, amps and watts I have no trouble thinking of Alessandro Volta, James Watt and André-Marie Ampère, but I have no idea of what these units actually measure. So I’m going to begin by explaining some basic concepts for my own sake.

Amps

Metals are different from other materials in that electrons, those negatively-charged sub-atomic particles that buzz around the nucleus, are able to move between atoms. The best metals in this regard, such as copper, are described as conductors. However, like-charged electrons repel each other so if you apply a force which pushes electrons in a particular direction, they will displace other electrons, creating a near-lightspeed flow which we call an electrical current. An amp is simply a measure of electron flow in a current, 1 ampere being 6.24 x 10¹8 (that’s the power of eighteen) per second. Two amps is twice that, and so on. This useful video provides info on a spectrum of currents, from the tiny ones in our mobile phone antennae to the very powerful ones in bolts of lightning. We use batteries to create this above-mentioned force. Connecting a battery to, say, a copper wire attached to a light bulb causes the current to flow to the bulb – a transfer of energy. Inserting a switch cuts off and reconnects the circuit. Fuses work in a similar way. Fuses are rated at a particular ampage, and if the current is too high, the fuse will melt, breaking the circuit. The battery’s negative electrode, or anode, drives the current, repelling electrons and creating a cascade effect through the wire, though I’m still not sure how that happens (perhaps I’ll find out when I look at voltage or something).

Volts

So, yes, volts are what push electrons around in an electric current. So a voltage source, such as a battery or an adjustable power supply, as in this video, produces a measurable force which applied to a conductor creates a current measurable in amps. The video also points out that voltage can be used as a signal, representing data – a whole other realm of technology. So to understand how voltage does what it does, we need to know what it is. It’s the product of a chemical reaction inside the battery, and it’s defined technically as a difference in electrical potential energy, per unit of charge, between two points. Potential energy is defined as ‘the potential to do work’, and that’s what a battery has. Energy – the ability to do work – is a scientific concept, which we measure in joules. A battery has electrical potential energy, as result of the chemical reactions going on inside it (or the potential chemical reactions? I’m not sure). A unit of charge is called a coulomb. One amp of current is equal to one coulomb of charge flowing per second. This is where it starts to get like electrickery for me, so I’ll quote directly from the video:

When we talk about electrical potential energy per unit of charge, we mean that a certain number of joules of energy are being transferred for every unit of charge that flows.

So apparently, with a 1.5 volt battery (and I note that’s your standard AA and AAA batteries), for every coulomb of charge that flows, 1.5 joules of energy are transferred. That is, 1.5 joules of chemical energy are being converted to electrical potential energy (I’m writing this but I don’t really get it). This is called ‘voltage’. So for every coulomb’s worth of electrons flowing, 1.5 joules of energy are produced and carried to the light bulb (or whatever), in that case producing light and heat. So the key is, one volt equals one joule per coulomb, four volts equals 4 joules per coulomb… Now, it’s a multiplication thing. In the adjustable power supply shown in the video, one volt (or joule per coulomb) produced 1.8 amps of current (1.8 coulombs per second). For every coulomb, a joule of energy is transferred, so in this case 1 x 1.8 joules of energy are being transferred every second. If the voltage is pushed up to two (2 joules per coulomb), it produces around 2 amps of current, so that’s 2 x 2 joules per second. Get it? So a 1.5 volt battery indicates that there’s a difference in electrical potential energy of 1.5 volts between the negative and positive terminals of the battery.

Watts

A watt is a unit of power, and it’s measured in joules per second. One watt equals one joule per second. So in the previous example, if 2 volts of pressure creates 2 amps of current, the result is that four watts of power are produced (voltage x current = power). So to produce a certain quantity of power, you can vary the voltage and the current, as long as the multiplied result is the same. For example, highly efficient LED lighting can draw more power from less voltage, and produces more light per watt (incandescent bulbs waste more energy in heat).

Ohms and Ohm’s law

The flow of electrons, the current, through a wire, may sometimes be too much to power a device safely, so we need a way to control the flow. We use resistors for this. In fact everything, including highly conductive copper, has resistance. The atoms in the copper vibrate slightly, hindering the flow and producing heat. Metals just happen to have less resistance than other materials. Resistance is measured in ohms (Ω). Less than one Ω would be a very low resistance. A mega-ohm (1 million Ω) would mean a very poor conductor. Using resistors with particular resistance values allows you to control the current flow. The mathematical relations between resistance, voltage and current are expressed in Ohm’s law, V = I x R, or R = V/I, or I = V/R (I being the current in amps). Thus, if you have a voltage (V) of 10, and you want to limit the current (I) to 10 milli-amps (10mA, or .01A), you would require a value for R of 1,000Ω. You can, of course, buy resistors of various values if you want to experiment with electrical circuitry, or for other reasons.

That’s enough about electricity in general for now, though I intend to continue to educate myself little by little on this vital subject. Let’s return now to the lithium-ion battery, which has so revolutionised modern technology. Its co-inventor, John Goodenough, in his nineties, has led a team which has apparently produced a new battery that is a great improvement on ole dendrite-ridden lithium-ion shite. These dendrites appear when the Li-ion batteries are charged too quickly. They’re strandy things that make their way through the liquid electrolyte and can cause a short-circuit. Goodenough has been working with Helena Braga, who has developed a solid glass electrolyte which has eliminated the dendrite problem. Further, they’ve replaced or at least modified the lithium metal oxide and the porous carbon electrodes with readily available sodium, and apparently they’re using much the same material for the cathode as the anode, which doesn’t make sense to many experts. Yet apparently it works, due to the use of glass, and only needs to be scaled up by industry, according to Braga. It promises to be cheaper, safer, faster-charging, more temperature-resistant and more energy dense than anything that has gone before. We’ll have to wait a while, though, to see what peer reviewers think, and how industry responds.

Now, I’ve just heard something about super-capacitors, which I suppose I’ll have to follow up on. And I’m betting there’re more surprises lurking in labs around the world…

 

 

Written by stewart henderson

July 29, 2017 at 4:00 pm