Plugging end-of-life EV batteries into the grid could ease renewables transition EV batteries could help meet short-term electricity grid storage demand by as early as 2030 in most parts of the world, scientists are claiming. Their study – which depends on new data and modeling – also found that end-of-life EV batteries could find a new purpose in helping smooth out domestic demand on an electricity grid …
like this. (For those allergic to links it's the Aptera, a lightweight, partially solar-powered car that's the most anticipated thing in the EV world since anything from Tesla.)
Yes, I inwardly groan every time I see the announcement of another over-sized, over-appointed electric EV, but it's what the market demands and if the major manufacturers don't sell them they won't be able to afford to make the sort of affordable EVs the world needs. (Or the Chinese will, because barring a war nothing will stop the flood of cheap Chinese EVs. People will be buying the on Ali Express.*)
*which you can do right now if you're prepared to lay down a few thousand for something that essentially a toy.)
Hmmm.
Did you miss the comment about potholes? In the dim, distant and impoverished past I owned a Reliant Robin (m/c licence) and it was great with potholes, it loved them and hit every one. This car looks like it would do the same.
Couple of small points 1) its not available and 2) between $26k & $45k for a Reliant Robin.
Cute, but not new. Essentially a pretty G-Whiz, with the same issues
No mention of pack size in kWh unfortunately, which I find intensely irritating as it prevents any checking of figures. It also raises my "snake oil" detector a notch.
> they won't be able to afford to make the sort of affordable EVs the world needs. (Or the Chinese will, because barring a war nothing will stop the flood of cheap Chinese EVs. People will be buying the on Ali Express.*)
Trouble with those cars is, they are not UK road legal. To be a UK road legal car, without ABS and a lot of other required safety features, it has to be of a different vehicle class entirely - the Citroën Ami, is classed as a light quadricycle. But like all of the damned cars from big manufacturers, it's a b*stard to repair long term. It's the same situation with ebikes in that regard, where the likes of Bosch, Shimao and others use proprietary comms to lock you into buying just their components and subsystems, and actively sabotage repairs by users/owner. In contrast, cheap, generic Chinese conversion kits and ebikes are easily repaired; components and subsystems can be swapped and adapted. The Chinese could easily manufacture a more user-repairable, fully enclosed light quadricycle like the Ami, legal to drive on British roads, but thus far none have AFAIK. The biggest hurt to the wallet within a few years of course, is the battery. A 14Kw/h battery could be made far more cheaply, if you make it yourself. I could convert a two seater tadpole recumbent to a UK legal pedelec quite easily, but the bodywork is a problem I'm still working on. My experience of towing heavy bike trailers up steep hills all summer using my 250W convereted folding bike, has informed me that lugging 100kg of body shell and extra suspension with that mid-drive kit, is no problem. It's deeply frustrating that electric cars are not user repairable.
Old lithium ion batteries differ in charged voltage, often widely - if the battery management systems of large groups of cells aren't very clever in how they charge, discharge and utilise individual cells, they'd create big unstoppable fires which burn uncontrollably for days... which for me begs the question, why can't very smart BMSs be created to utilise these old batteries in less demanding EVs, such as electric bicycles? 15A @36V is sufficient for say, a 250W Bafang BBS01B motor.
Don't hook up old cells to un-clever battery management systems.
As for why not reuse them in electric bicycles, that's because weight matters in a bicycle and using cells that are only 60% working or whatever is a lot of wasted weight. Most electric bicycles are still pedal powered at least some of the time by their owners, you might need to lift them up steps etc. and they already suffer a weight penalty. Why add to it?
> un-clever battery management systems.
Yes that's begging for a burned down home. Sodium-ion 21700 cells can't arrive soon enough!
>you might need to lift them up steps etc. and they already suffer a weight penalty. Why add to it?
The batteries are detachable - I remove mine and place it in my rucksack, before runing along with my rolling folded bike along a train platform to board. Ebike weight doesn't matter all that much in practice - I've been towing a 15.5kg Homcom folding bike trailer with a 78kg cargo + myself (78kg) + 22.4kg bike (with battery and motor etc.) up steep hills all summer (Bafang BBS01B converted Dahon Helios P8 folding bike [manufactured in April 2006]), so an extra 20kg without trailer + cargo isn't going to make much difference. My battery pack is 19.2ah containing LG MH1 cells, personally I wouldn't mind if it was 20% heavier, if it was made using cheapo used cells, managed safely by a very smart BMS... sadly such don't exist for ebike batteries, to safely utilise "Second life" lithium-ion cells.
Rack mount end of life EV batteries in containers which include a battery management system. There is going to be an absolute shit ton of end of life EV batteries with plenty of usable charge left in them.
Container infrastructure is ubiquitous and global so transporting them is a non issue.
They could be attached to electric trains to extend range in locations without overhead cables.
Located in electricity substations to deal with peak demands thereby obviating the need for an expensive substation and local grid upgrade.
Located in charging stations to smooth charging capacity.
Used as power sources in place of fossil fuel generation for construction, events, festivals and suchlike temporary events. I recall hearing of a dutch company planning something like this on a rental basis.
Containers could be built for specific battery types which may make the BMS easier to manage. So long as the output is standardised they could then be chained.
Containers come in a range of standardised sizes.
One of the reasons why there’s not a lot of recycling when the batteries are completely exhausted is because there aren’t large numbers of fully exhausted batteries available yet. Clearly this is set to ramp up in the coming years.
@DenTheMan
Using used laptop cells is asking for trouble, with any common BMS. New cells vary in high discharge capability, and usually the battery packs which burst into flames use cheap Chinese cells, which have high internal resistance, are of highly variable chemistry (often within the same pack) and overheat when individual cells are stressed at high discharge rate... which is less of a problem if the battery pack is large, where individual cells are less stressed, but then high internal resistance means a hotter pack than say using say Molicel P28A. Many cheap Chinese escooter battery packs are only capable of discharging 7A safely, but the controllers are set to draw 15A to 25A... which is why they feature most often in the news. On a pedelec, high currents are drawn briefly (if throttles aren't used, which are illegal in the UK anyway) because of pedal assistance, so it's less of a issue using chep Chinese battery packs on those.
A few years ago I had a go at designing a BMS to balance four large cells - using (essentially) an Arduino as the brains.
It turns out to be quite a hard job to do well. I read a lot of whitepapers (google "Quasi-Resonant LC Converter cell balancing" for my favoured design), tested a few prototypes - almost all revolved around sucking charge out of cell A into a capacitor, then pushing it back into cell B. As the cells are hooked up in series you need to be able to switch a "floating" capacitor across a single cell to charge, then switch both sides of it to a another cell with a lower voltage to discharge. Switching had to be controlled very carefully - the two cells are in series with eachother, so at completely different ground voltages. Also, you're talking about very small voltage differences so switching losses really started to add up unless you used a clever design (like the QRLC)
It all got quite complicated, and that was with just four cells. Balancing across N for large versions of N would require more than one capacitor, and with N cells and M capacitors you've got a proper wiring headache. I don't know how they do it in cars - I'd love to find out. In the end I gave up with the conclusion this is a lot harder than it looks.
For reference, one of the best documented, if not most efficient options available for DIY was this http://cleanpowerauto.com/files/HousePower%20BMS.pdf. As I recall this one balanced by simply bleeding charge out of the highest cells into a fat resistor until they were all equal.
Batteries are balanced during charging with shunt regulators or linear regulators. It sounds inefficient but there's not much to do. I have an old 95 Wh pack and the balancer chip doesn't even get warm.
I don't think there's any discharge balancing other than putting lots of cells in parallel to average out capacity. Except Honda. They made every cell a single point of failure in their early hybrids.
Ah thanks, that's very interesting. My use case was charging from solar, so I wanted to scavenge every last coulomb (a yacht battery). But when you're charging from the grid I suppose it makes a lot of sense just to dump excess with linear regulators.
I privately suspect that a lot of the improvements in EV range over the last few years have come from improvements in BMS tech rather than the batteries themselves or the motors. A friend has a Porsche Taycan and confirms he really has seen it charge at the listed 350kW. Even with an 800V pack that is an astonishing 430 amps to distribute - you'll only get close to that rate when the pack is fairly depleted, but the engineering blows me away.
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@Androgynous Cupboard
That's very interesting information, and a good post.
Marvellous... the Battery Management System needs a Capacitor And/Or Resistor Management Subystem, plus a Temperature Management System, plus oodles of wires and tubes. Sounds heavy, but even a ebike battery ten times the weight, made using "Second life" lithium-ion battery cells, isn't really much of an issue in use, from my experience at least, towing very heavy trailers up steep hills, using UK legal 250W pedelecs.
Who funded this study? I'm all for being green and reusing batteries when possible, but the jaded cynic inside me smells this study as a possible way to spin the environmental impact of failed lithium batteries.
Once the car companies can throw them over the fence to the utility company, it's their problem now.
As a utility company, I wouldn't be excited to manage arrays of thousands of cells of dubious heritage and lifespan. I'd prefer them to be recycled and create new cells with a predictable lifecycle before I put them into service.
I suppose it all boils down to how manageable each pack is and if the price was low enough to offset the extra cost of the management layer.
It's not a new idea – it's happening right now. The study just quantifies the effects of it becoming mainstream.
As for management – battery management systems are known tech. As pointed out above, you should never connect up a li-ion battery without one. And they just work. Provided you don't buy something of unknown provenance (and why should you, it's not as if we can't track these things) your used batteries can be just as safe as new ones.
Regarding the provenance of the cells... sure, we would be able to know what batch they were built on and when they were put into service, but it would be impossible to know which ones were heavily discharged, spent years in freezing/desert climates, overly discharged, underwater in a flood, etc.
Re-purposing worn out EV batteries for home energy storage has been talked about for several years now. Using vehicle batteries for stabilizing the grid goes back to at least 1999, when a paper by Alex Brooks of Aero-Environment was first publishd on AeroEnvironment's website.
One problem with the concept of re-using batteries removed from vehicles is re-creating the vehicle's infrastructure that supports the battery, e.g. physical support, cooling, electrical connections. Having to do a bunch of one-off projects to fit random battery packs into a utility scale energy storage facility would ruin the economics. The work around is to accept only one or two types of vehicle batteries for a given facility.
Batteries are hazardous, require materials which are very polluting to produce, capacity drops with discharge/charge cycles and need to be recycled. This is not a sustainable future.
If one wants to "store" electricity, use hydrogen instead
In other words, energy companies can't be arsed to build enough generating capacity and storage themselves, and governments can't be arsed to force them or do it themselves. So the public has to suck it up in the form of accepting inconveniences imposed upon them. When you can wash and dry your clothes. When you can charge your car. When you can do anything else the state deems "energy intensive".
And say we all have to use our cars to prop up the grid. What happens when everyone then needs to use their car? No power because the grid has sucked it dry. So now all those cars have to go back on charge, drawing a massive load from the grid and causing instabilities elsewhere in the system. Except they probably can't because they're being demand-side managed.
Absolutely. Terrible. Idea.
I've said it before and I'll say it again. This is not progress to a better, more energy secure and more relaxed society. This is a massive leap toward energy insecurity, artificial energy scarcity, increased public anxiety and a more controlling state.
Your body seems to contradict your title.
What we need is better pricing to the consumer, so (for example) when there is excess wind or solar generation the price comes right down.
I.e. instead of being an average for 3 months at a time, it tracks the wholesale spot price.
Then, combined with intelligent plugs, you can automate the demand side. For example, you set your tumble dryer to only run when leccy < 10p/unit.
This puts the consumer firmly in control of their own bills, is fair, and will help a lot to balance demand.
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