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Used EV Batteries Could Power Tomorrow's Solar Farms (ieee.org)
155 points by headalgorithm 4 months ago | hide | past | favorite | 80 comments

There's no shortage of uses for 'used' ev batteries that outlasted the vehicles they were in. They are quite a valuable commodity already. There's all sorts of things you can do with a good quality battery that is still good for a few tens of kwh of storage.

But even when they are still in the car they can be off use to the grid and provide many GW of on demand buffers for both energy shortages and over supply.

There recently have been negative energy rates where electricity producers preferred to not shut down expensive to restart plants and instead ended up incentivizing people to charge their car batteries.

This doesn't even have to be a huge amount of energy per car. Even a single kwh of capacity per day would quickly add up if there's millions of vehicles plugged into the grid.

The same technology can allow the same users to power their house for several days using just a single car and allow them to leverage their own solar panels, get payed to soak up excess grid energy (e.g. at night when wind mills continue producing), deal with grid outages, resell their own solar excess when demand is high, etc.

With million mile batteries, people'll be less concerned about breaking their batteries; especially if they get to spend less on electricity. With leased battery business models, this could be simply part of the deal.

This is becoming more and more common in the UK: https://www.energy-stats.uk/octopus-agile-london/ (these are retail prices anyone in the UK with a smart meter can take advantage of).

Basically high wind production with sunlight results in negative pricing. The difference between the 4-8pm "peak" is very high between the rest of the day too.

There is an enormous business opportunity here. Prices are going from -3p/kWh to 25p in the same 24 hours nearly weekly.

I wish there were home appliances that could take advantage of this excess supply of electricity. Since 2003 I have been hearing about the concept of the smart grid and yet nothing seems to have particularly materialized.

It's 2020, I wish there was a way for me to somehow schedule my washing machines and dishwasher to run easily other the internet at times of negative energy. Heck why isn't this possibility grid controlled yet? Having a large surplus of consumer appliances controlled by the grid could be a greener easier solution than relying on batteries.

Alas, I still can't even control my washing machine over the internet. If I could, the appliance is expensive and using proprietary 'dumb' apps.

I think that it's unlikely that exposing individual consumers to such highly variable pricing will induce much change in consumer behavior. It's just so much to think about, with absolutely tiny potential cost benefit for the consumer.

However, high prices are unbounded, and I think that it's easier to respond to those signals than to respond to a signal from low selectivity prices.

In California (and maybe other places?), companies like OhmConnect are facilitating demand response. A third party bundles together lots of homes' potential drops in demand, then sells that drop in demand back to the utility when they would otherwise use expensive and highly polluting leaker plants.

This gets around several market challenges: 1) consumers don't trust utilities and won't believe that they are acting in their best interest. 2) OhmConnect can advertise the environmental benefits to consumers, something that utilities are loathe to do, and 3) it lessens management load on the utilities, who are not used to dealing with data challenges like that, 4) a third party is much more likely to be able to experiment with UX (eg gamificaion) than a staid, highly-regulated utility company.

Even for businesses the focus is usually on cutting demand at times of high prices, not the converse.

The contract looks something like "You pay 10% less per kWh, but in return we get to turn off the power to this part of your warehouse for up to one hour per day". It works for places that have, say, big industrial freezers - set the thermostat half a degree lower and the outages aren't a problem.

I think this will get better as more heating is done electrically. A hot water tank, or a house, stores a surprising amount of energy and the heater has a few degrees of wiggle room to intelligently decide when to activate. I think the amounts of energy used for heating are large enough that end-consumers will care about price differences.

Also cooling -> lots of energy -> cool your house 16C instead of 17C.

> I think that it's unlikely that exposing individual consumers to such highly variable pricing will induce much change in consumer behavior. It's just so much to think about, with absolutely tiny potential cost benefit for the consumer.

Let me present a counter case: Latvia. Quite a few people choosing a dynamic hourly rate for their electricity with pricing set based on spot market rates. Lots of ordinary people living hand to mouth on tiny wages. They do care about a few euros difference at the end of the month. It makes a real difference to them.

I am not looking forward to having my neighbors starting their noisy washing machines at 03:30 am.

My dishwasher can control me over the internet. I can give it access to my Wifi. Then it will talk to https://www.home-connect.com/ . I can then install an app so it can tell me to buy more dishwasher tabs for it. Not going to happen.

I would like to root my dishwasher.

If the peak is predictable, there's no need for networking. The appliance equivalent of a light-timer (or a little robot that presses "start") is all that is requisite.

Both peaks and lows are not that predictable or regular. A storm at night will drive prices down because of wind turbines. That can be predicted days in advance but it requires access to weather forecasts.

Certain events such a sport games or TV shows could drive the price up. That could be predicted but requires more than a timer.

For a heat pump from air the efficiency depends a lot on the outside temperature. So the best time to run it might not be when electricity is cheapest.

If it it's not super predictable, stuff like X10 has been around for a while.

Having used one of these used LifePo4 batteries for my van build, https://www.techdirectclub.com/lifepo4-lfp-battery-24-volts-... I'm pretty impressed how much bang for buck I can get compared to traditional lead acid batteries. In future build's I'll resort to just using singular Nissan Leaf battery cells, give more configurability + easy to replace just a dysfunctional cell.

I see a lot of useful tools on van and boat sites, around managing non traditional batteries and interfacing them with solar panels + engine alternators. Off to a cleaner and decoupled from grid future! Micro grids everywhere.

Careful with Leaf batteries, they used air for cooling instead of water which means that most cells show significant capacity loss after a few years.

Climate and usage dependent.

And it's not even a matter of air vs water, is between being actively thermal managed or not.

This is why the first/second generation Leaf batteries sell for REALLY cheap from used battery dealers. They're generally in poor condition. As compared to harvesting used 18650 cells in the 2500mAh range capacity from other 'used' sources, and building a DIY powerwall that way.

Indeed! More than getting ripped off on capacity, I'm super scared of using large capacity lithium batteries in general. Having seen small samsung phones blow up, I'm a little scared and have a lot of fuses and cut off switches.

To be fair, there is no real contest between a good LiFePO4 cell and some Samsung battery as thermal runaway on the former is near impossible in normal conditions.

IIRC, this is highly dependent on the climate in which they were operated. A battery used in Phoenix may have much bigger problems than one from Pacifica.

LFP is rumored to be part of Tesla battery investor day, where the LFP will be used for cheap / standard range cars at $80/kwhr at PACK level, and NMC for higher performance / longer range.

And allegedly LFP is improving density further based on some chinese rumors about CATL's advances in LFP for next year's batteries.

But there's so many rumors...

That is my guess. If you treat a LFP battery well you can probably get 4000 cycles out of it. If one cycle is 250 mi then there's your 1M.

Downsides are lower energy density and higher internal resistance, so it's probably not the battery they would want in one of those super fast Roadsters with the huge range.

Just took a look at the battery listing you provided. I have not seen someone use an actual tape measure showing the HxWxD of the product rather than just listing them. I think I prefer it.

I'd rather see the listing. Is the height 9", 10", 11"? Hard to tell because of the angle.

Agreed that having it listed is better, they do have exact dimensions in the listing as well. I was definitely shocked by how big this actually was when I picked it up in person. Not to mention that its 73Kgs! A good chunk of my van's weight budget.

May I see your van ?

I'll dig up a photo of the battery / electronics and post it here soon. To give you an overview of it: - 300W of flexible solar panels (~$90/pop, tend to get about 1.5kWh on great sunny days, enough to power my fan + fridge without having to run the van) - Victron MPPT charge controller (pretty impressed by their quality, and their app that talks to the controller over bluetooth, nothing comes close to them in simplicity of setup) - Victron battery to battery charger without ground isolation (gets triggered by engine hot signal, so I don't drain the van battery) - 2000W cheap inverter for running instantpot / magicbullet. I prefer to have DC appliances, but hard to find DC pressure cooker / mixers - couple of 12v regulators for 12vdc devices - ofc the BYD Lifepo battery, I haven't deep cycled this a ton, but my suspicion is that it's around 3.5kWH usable capacity.

I plan to add a cheap 360 camera system from aliexpress and run it off the aux battery mainly for security monitoring around the vehicle, the standard backup cams on any 2017+ vans are decent. If I get to it, it'd be interesting to get a Pi in there with OBD breakout to read in car data / gimmick.

I have a very similar system! What fridge do you have? I have an ARB.

where did you get 300W panels for $90?

I think he meant 300W total. He didn't say how powerful each $90 panel is.

There's so many different directions for jokes on this comment, but yes, I too would be interested in seeing the mods.

Used EV batteries could just be used in cars, but Tesla makes it incredibly difficult to fix their crashed vehicles. It's almost impossible for regular consumers to buy OEM parts unless it's for their specific purchased car. This guy has salvaged batteries and tons of other parts from junkyards:


This is done for a soccer stadium in Amsterdam.


Glad it doesn't go unnoticed, actually was the team lead for that project (Mobility House -- real time battery control). If you have any questions about it or other cool projects we have done -- https://www.mobilityhouse.com/int_en/magazine/press-releases... actually works with the batteries to do the same thing.

So we can use them in the car to charge when there is excess renewables, and then use the second-life batteries in large stationary storage installations to do the same. Tying into the different grid systems is a bit of a nightmare with everyone having their own standards unfortunately, otherwise it would be easier to roll these out more often.

(I am speaking for myself, not Mobility House).

With the new gen of software-defined inverters, this makes more and more sense. The inverter's logic knows RT efficiency, depth of charge, and chemical age of the battery. It changes how it treats each and every battery.

Think of batteries like hard drives in a hyperscale datacenter.

I was curious about this, anyone else who is curious may find this article of interest: https://www.solarpowerworldonline.com/2019/03/smart-inverter...

It's for inverting electricity at grid-scale, not referring to a household "inverter". Still quite interesting.

That was interesting.

The IQ inverter is for household and small commercial scale. For example, I would happily team with a few neighbors to cache, say 85kWHr at each home.

How recyclable are these newer battery chemistries? I know that lead acid batteries are fairly easy to recycle, but many of these more exotic ones seem harder to recycle.

It is more complicated because there are more compounds to recover, and the batteries have a finer structure, but you can still do a broadly similar process.

Compare lead-acid recycling: https://www.youtube.com/watch?v=wxCFDWMPu38

To lithium recycling: https://www.youtube.com/watch?v=wxCFDWMPu38

Both link are the same

Ultimately, you can smelt them. It's not very economical, but the elements don't go away.

Ideally, you'd be able to 'refresh' the electrode material inexpensively. This involves removing lithium plating from the anode, and oxidized electrolyte from the cathode. This isn't a mature process, and it won't be until battery chemistries and manufacturing get more standardized and scale up. But there aren't strong theoretical reasons why this should be uneconomical. These issues take place at the surface of the electrode grains, and can likely be solved with bulk treatment. It's still going to require a fair amount of work to harvest the electrode material, but materials cost is a large percentage of battery production.

I'm curious why the refresh process is not popular now.

This is something I'm super excited about. People should note that people started trying this out long time ago with batteries from used laptops. I believe couple people were even able to create DIY household energy storage solutions with just old battery laptops!

Once the industry figures out the problem of scaling, this could be very impactful.

The humble automotive sealed lead acid battery can also find a second life in a solar setup, be it for a home or a RV. It's a good reuse for truck batteries, I find.

Sure SLA batteries are a mess environmentally, but if you can keep them out of the landfill for a few years this way, why not?

My understanding is that if a lead acid battery ends life in the landfill, somebody has seriously messed up. In the US at least, the vast majority of lead from batteries is recycled, usually into fresh batteries, thanks to financial incentives and a very efficient collection system primarily run by auto parts stores. It's unclear to me whether it's actually more efficient to reuse an old lead acid battery, or to recycle its lead into a modern battery with higher capacity, it probably depends on the specific circumstances.

True in the US and Europe, yes. (About 1 on 8 human beings on Earth)

I'm not sure how realistic this is on a commercial scale. There are a bunch of people doing this for their own solar offgrid projects, maybe even a few doing it as a cottage industry. However, I can't really see striping, testing and reconfiguring lithium batteries being a big part of future solar farms.

In a few years will be hundreds of thousands of Tesla EV batteries getting to the point they want replaced. If we can find a use for them it’s pretty awesome.

Tesla has been talking about this for years and I've already read about old ev batteries used for this purpose. So its a good idea.

Tesla's previous CTO, JB Straubel, left to found Redwood Materials. He intends to commercialize recycling of batteries at scale, and the rumor is Tesla will be a customer of the output from Redwood for battery manufacturing.


Would be sweet. Could bring new life (and new range) into a 10 year old car to swap in the battery.

I think the problem is mostly logistics. To get good use out of an old array, you have to QA all of the cells and discard the worst ones, because when you wire batteries in sequence (to get higher voltage), then the weakest link effect is very prominent. And if memory serves, to get the most out of a battery array you want to 'match' the cells, so you have to bin the used batteries the same way Intel bins CPUs.

If memory serves, you have to charge a battery to measure this, which takes time and therefore space.

So to get the cost to be cheaper than just building a new pack (possibly using binned new packs), this all has to be pretty automated. If they bin new cells (if they don't maybe they should!), then most of this hardware would already exist. Which would mean you only need to talk about how to make a robot to desolder battery packs. Given how crap my soldering skills are this feels like a potentially hard or at least expensive problem.

You don't have to do that to a Tesla battery. The individual cells when they go bad disconnect themselves using a fuse wire. All you have to do is test the pack to see how much power it can store.

I saw a film about battery recycling recently and the first thing they have to do with incoming cells is discharge them. They were using the energy to power the site. Clearly it wouldn’t be much more work to cycle the batteries.

I recall something like that too, but they worked it a bit like a counter-flow heat exchanger - drain one batch of cells to charge another.


Look at the Battery Recycling section.

Back when Nissan was doing their dog-and-pony show ("come take a test drive!" in a very controlled environment) for the Leaf (2009), that was their exact spiel for what would be done with the batteries when they were past their prime. Now that the early Leafs are at the point of needing new batteries, I'm curious if Nissan is following through (but not curious enough to go looking.)

Well there you go: https://www.johancruijffarena.nl/default-showon-page/amsterd... (from comment by louwrentius)

Nissan also has the XStorage home consumer brand rival (in the UK at least) to Tesla's PowerWall: https://www.nissan.co.uk/experience-nissan/electric-vehicle-...

Nissan planned the project well in advance of Tesla's PowerWall, but Tesla beat them to market (and brand/name recognition advantage) by building PowerWalls with new stock batteries, whereas Nissan waited for enough car batteries to return second hand from the market before starting their XStorage brand and so far as they have admitted have never sold a new battery in an XStorage.

(It's an interesting factor to consider that Nissan had to wait so long to start their second hand battery use systems. As much, sometimes warranted, flak as Leafs get for battery degradation, the batteries overall have lasted generally longer in "first use" directly in cars than Nissan at first projected, even despite higher sales than Nissan projected for the Leaf. It fits other statistics that EVs are kept by first owners for longer than average compared to other cars, and in general are lasting longer as cars than early EV skeptics predicted.)

Ours is one of the first Leafs off the line, still has a usable battery (if it were still under warranty, it would have one battery bar left before we could make a claim). Living in Seattle probably helps a lot. So, yeah, Nissan might still be waiting on batteries, even from early first-gen. At this point we’ll probably just keep ours until it is no longer usable, or VW releases that electric van they’ve taunted us with (2023, they claim).

Hey there,

I am the tech team lead at Mobility House (the company behind taking the batteries and doing the real time control in that setup) for that particular project. https://www.mobilityhouse.com/int_en/magazine/press-releases...

It's actually a really cool setup that allows us to take in excess solar (that isn't used onsite) to charge the batteries, the batteries actually act as backup power for the event days (that AFC Ajax plays). When not needed they provide frequency containment (grid stabilization to prevent brownouts+blackouts) for the European electrical grid at large (on days where it is financially viable to do so).

If you have any questions I would be more than happy to discuss more :)

How often does it happen that this is financially viable? The way the European electricity market is set up is quite interesting, so I wonder how the ArenA-system ties in.

Also, is the system also charging up when there's negative electricity prices like there were recently? And get payed to take in power?

Thanks for the link (you, too, louwrentius), I think I might have grown just a little less cynical today.

> Thanks for the link...

That is very cool, and that was done during the Ghosn pump/dump era no less; as a long time Nissan enthusiast, which then turned being a technician for Nissan for a period I knew Nissan was involved in tons of new tech: Radar based Cruise control was available back in 2002, CVT transmissions, they were one of the first to adopt throttle by wire, and if you've even been in a GTR its more video game than it was car, especially when it first came out.

So these battery's being up-cycled is not so much a surprise, either.

I only recently, like a year ago or so, found out they had Aerospace division since 1953 and even had a facility in Mountain View.

To think this the same company that was insolvent in the crash of the Japanese Bubble era of the 90s, they really did try to expand into to so many sectors, much like Yamaha, but didn't really get the same notoriety because of it. In fact most non car people, especially in Japan, will recall their real estate holdings collapse alongside the Nikkei index, which was really their core business.

It's dark days for Nissan right now, and as a die-hard Nissan fan boy I hope they separate from Renault and make it out of this as their transition to a more EV lineup manufacturer is looking promising, as does their I2V technology but it shows how first-mover advantage can be destroyed from within by short-sighted crooks like Carlos Ghosn (that is a wanted fugitive in Japan after fleeing in some crazy movie-like scenario with ex green berets [1]) and the complicate delivery systems and dealerships that created horrible incentives.

1: https://www.armytimes.com/news/your-army/2020/06/09/former-g...

The farm itself probably wouldn't be doing it, but buying from someone who does.

I find myself thinking of lead acid battery recycling: https://www.energy-storage.news/news/lead-acid-batteries-are...

Perhaps if the facility is designed with a lot of fault tolerance from the start? Some places aren't short on space so should be fine if you can separate things enough to mitigate fire risk?

Why not? Refurbishing of household appliances and electronics is a big industry, for example.

So how much life is left in a battery? I assumed they are dead.

Most Teslas will still have more than 80% capacity after a decade.

Chances are the battery is available because the car was written off in an accident, rather than because the batteries are dead.

My 11 year old laptop battery still has a third of its capacity left. Car batteries are made to last a long longer than laptop batteries.

Hot potatoe? Last one left holding the battery pays the disposal costs?

Or sells it off for scrap metal.

Metals such as nickel, cobalt, aluminium and copper make up nearly half of the bill of materials in a li-ion cell.

I thought solar farms produced power.

Solar farms still require traditional gas, coal or nuclear plants to provide idle power. Except for certain regions, you can't have consistent solar, and you need to have backup power for brownouts.

The idea with better batteries is that solar stations could provide their own excess capacity storage.

But battery tech is still not good enough for large scale storage. The break down chemically and are not easy to refurbish. The only real "battery" that sorta works is the Racoon Mountain hydro station, which uses extra electricity to pump water into a resistor and then drains it for power during high peaks.

We should be building these all over the country, but they don't really provide that much capacity; plus you kinda destroy the environment around an entire hill and have to build it back up afterwards (Racoon Mtn does have really good mountain biking trails now).

But this is just more fluff to green wash technology that really cannot ever truly replace hydrocarbons. We really need to minimize and reduce energy consumption. That's probably never going to happen.

High voltage inter-connectors will help with this. If we wire up the world we won’t need much backup power at all.

Would really love to see HVDC cables laid alongside undersea fiber, saves on deployment costs. Oceanic version of “Dig Once”.

They do. But as some people keep complaining, not at night. This can shift the output of a solar farm to when it’s dark.

It might not be literal truth, but it’s close enough to be understood — like saying “this food comes from a supermarket” even though the food actually comes from five different farms in different countries.

I was sort of hoping the solar farms would produce power...

Not sure this will happen if these plans of "1 million mile" EV batteries come to fruition.

Quite the opposite. Other parts of the car will wear out at 25% of that (or less), so you'll have second use batteries available with 75% of their life still in them. People won't want to build new cars with old batteries for safety concerns, but if these go into containers in a solar farm in a field somewhere, the risks are far less - you won't stress them as much in regular use, and any emergency will be more contained.

If they are able to be used in cars for a million miles, they will still be able to be used after that at a lower performance. It's likely that a used "million mile" battery will be even more valuable, since it presumably loses performance more slowly than other batteries. So at the point where it's performance drops below "useful in EVs," it will still have a ton of life left before the performance drops below "useful as part of the grid."

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