There HAS to be a way to automate this process and make it work at scale.
The problem is likely cost effectiveness compared to just replacing a whole group of cells, compared to one single cell. The unit economics of getting the remaining life from single used laptop battery are not very good. There's certainly lots of potential value for someone willing to do the work, if they can afford the opportunity cost, or if a business can source extremely dirt cheap cells and cheap high skilled labor.
You would be amazed how many battery packs are multiple 18650s in a trenchcoat. Even EV battery packs use them. Though it does raise the question - wouldn't an old EV battery be a better solution than stripping apart laptops?
There's a lot that goes into manufacturing battery packs beyond the cells. How's your thermal path to ambient in your home wall battery? How is the inter-cell thermal isolation? Is there a path for gas discharge in the event of a cell failure? Is the pack appropriately fused at the cell or module level? When a cell fails, does it take the whole pack with it, catch someone's apartment building on fire and kill a family of 5, or merely become stinky with a hotspot visible on IR?
How good is your cell acceptance testing? Do you do X-ray inspection for defects, do ESR vs cycle and potentially destructive testing on a sample of each lot? When a module fails health checks in the field, will you know which customers to proactively contact, and which vendor to reassess?
Yeah lots of batteries are 18650/26650 in a trenchcoat. The trenchcoats run the gamut from "good, fine" to "you will die of smoke inhalation and have a closed casket" in quality and I think that bears mentioning.
Where would you put this battery in that trenchcoat gamut? Inside a server rack, fwiw. https://signaturesolar.com/eg4-lifepower4-v2-lithium-battery...
Was definitely one of the harder parts of our solar install to get comfortable with.
Bigger, fewer, more chill cells, fairly robust trenchcoat.
(IIRC, these packs are 16 100ah LiFePO4 cells in a steel case w/ built-in fuse, breaker, and BMS that monitors individual cell health and pack temperature, w/ automatic cut-off if any of that goes out of spec. The weakness is primarily the MOSFETs on the BMS potentially failing shorted. Fortunately, they've added some sort of additional fire suppression beyond just "steel case" in recent-ish versions of these packs)
Ah yeah, unfortunately I think we have the version before they added fire suppression, but at least it’s a more relaxed chemistry. Thanks for the analysis!
I can't see what the construction looks like but the mention of 'fire arrestors' gives me a lot of hope. If you haven't designed a battery that can take a cell runaway safely, you haven't done the work, and clearly they've done at least that much.
I think the previous version of this lacks the arrestors, unfortunately, wonder if they can be retrofitted. Thanks for sharing your take!
I get that the trenchcoat needs to be well designed and tested, but I am still flat out amazed that you both agree with “meh, most battery packs are made up of rechargeable domestic batteries you find in a kids toy”
I just assumed there was … special stuff in there
For a highly engineered battery like a premium EV, there are coolant channels, temp monitoring, voltage monitoring, etc.
Soldering some connectors onto some random cells and knowing they shouldn't go over 4.2v is one thing, but measuring cell health via internal resistance, programming a controller to do temp shutoff and wiring up temp sensors, keeping cells balanced, is a lot of extra work, but critical if you at all care about not potentially burning down wherever they're stored.
Keeping the cells small and just using a hundred of them in parallel (and a hundred of these parallel packs in series to get up to the hundreds of volts needed), thus using ~10,000 cells, in EV batteries limits the maximum damage from one cell going worst-case, assuming your enclosure can contain it.
That being said, it seems there is a slow movement towards larger cells, from 18650 to 26650 or similar. But each cell on its own is still a dumb can of chemicals ready to go boom if you mistreat it.
I used to joke with my buddy back when he first got his Tesla that we were driving around on "over 7000 vape batteries!", as that was the fad at the time and where most normal consumers recognized them.
There's some optimization that happens in the chemistry and construction details for specific uses.
Also with bigger packs inter-cell consistency is really important (good cell integrators will test and bin them by ESR even if they're from the same lot, and using a really reliable cell mfg/vendor is critical because you're selling expensive systems with a number of failure points that scales with the number of cells and you want their process development to be super mature.
There's a lot of risk in creativity when you're selling crap to the public at scale. Way better to just use what everyone else is using.
For most things cylindrical cells are the right answer. They don't puff up, they're available with protection circuits, they're cheap and highly available, you can get them in a variety of sizes and capacities, even in different chemistries.
Using a custom cell might make sense if you are making a) one megakajillion of a thing or b) you have extreme volume limits which mean you're probably using a pouch cell.
In HW engineering, Not Invented Here syndrome costs you big money. You have to have an actual business case for re-engineering something that already exists plus the capital.
95% with my stuff of the time COTS cylindrical is the answer, which means my shit comes in on budget.
Probably, but EV batteries are large enough that there might be an industrial recycling process for them, while old laptop batteries are basically free because it's too much labor to extract useful value from them.
I'm pretty sure most industrial recycling methods for lithium batteries involve grinding them up, so pack size isn't as much a factor as sheer volume. I think there just wasn't much juice for the squeeze until demand from EVs made recycling worthwhile.
Here's a video inside a recycling plant: https://www.youtube.com/watch?v=s2xrarUWVRQ
> You would be amazed how many battery packs are multiple 18650s in a trenchcoat
Also laptop batteries used to be many (usually three or six) 18650s in a plastic trenchcoat.
You could literally rebuild your battery when it died, and pick the cells you liked the most. In theory you could pick higher-quality cells than those you find in the batteries sold on ebay from chinese stores. In theory.
>You would be amazed how many battery packs are multiple 18650s in a trenchcoat
$50 of 18650s in a $500 trenchcoat with DRM protection. So wasteful.
When battery packs that have a non-zero chance of literally killing your users are commonplace, it actually does make sense to vendor-lock the battery. Believe it or not there is actual engineering that goes into making batteries beyond spot welding them to an interconnect and stuffing them into $.50 of ABS enclosure.
The "actual engineering" you are referring to is a $1.00 BMS board.
We are well past the point where we should have standardized batteries. We have bunch of standardized wall outlets that accommodate an array of "non-zero chance of literally killing your users" end products. No reason for battery packs to not be standardized (other than vendor lock in).
I'm sorry but you're dead wrong about the BMS. BMS doesn't address any of the things I listed.
You're also wrong about standardization - standarization at the cell form factor level is correct. Different applications have different capacity vs power density requirements, temperature range requirements, cost, lifecycle... a pouch cell that goes in a drone looks a lot like one that goes in a cell phone but they're optimized for completely different workloads.
Also we already have standardized interfaces for external batteries with most power banks using USB-C, so in a way your wish has already come true.
Ironically this news dropped yesterday while we were having this discussion
https://www.protoolreviews.com/doge-mandates-power-tool-manu...
Probably the only thing I can agree with doge on.
> When battery packs that have a non-zero chance of literally killing your users are commonplace, it actually does make sense to vendor-lock the battery.
Linus from Linus Tech Tips made a few episodes on building a battery out of individual 18650 cells, and one of the thing he stressed (as in, underlined) a lot on is that spot-welding cells is extremely dangerous and there aren't easy ways to put out a lithium fire.
Water is not only not going to help you, it's going to make things worse.
You __have__ to have a bucket of sand with you and if anything goes even slightly wrong you just toss everything in the bucket of sand and bring the whole bucket outside.
Went and found the LTT video. It's unclear what he did there. He said there was a spark, and then he ran outside with his pack. Spot welding the cells isn't usually that fraught.
Yeah burying a thing in sand is legit. Depending on the size of the thing that's on fire, water might be fine. Standard protocol for electronics that catch fire on a plane is to apply water to cool the device and extinguish materials around it, and then to put it in a special fireproof bag with a bunch of water.
That depends on the problem you're trying to solve. If it's only to build a home power system, sure, but if the goal is "I want to prevent these laptop batteries from ending up in a landfill" then using an old EV battery doesn't really help you much.
FWIW a lot of EVs use prismatic cells, not cylinder cells. Tesla, Rivian, and Lucid use cylindrical cells. Hyundai, Volkswagen, BMW, GM, Ford, and BYD all use prismatic cells.
There is a lot of liability in sticking your name on a hodge podge of random used lithium cells.
I feel like for home battery backup there needs to be some kind of lower energy density solution that has zero fire risk.
Weight is not a factor for home energy storage, there is no need for lithium cells.
Currently, that is LiFePO4. It is cheaper than LiPo packs used in electronics, half the energy density, twice as many charge cycles, and doesn't burst into flame. The lithium is flammable but requires external ignition.
Larger batteries, including some electric cars, have switched.
LiFePO₄ (LFP) is overwhelmingly safe and cheap. Lithium isn't the problem here exactly.
It seems unlikely that there's any practical chemical batteries with 0 fire risk.
But I do think there should be home energy storage that doesn't involve chemical batteries. Where are all the pumped hydro, flywheels, and compressed air storage for consumer use?
There’s no perfectly safe energy storage. The danger comes from the concentration of energy. Water can cause flooding or you can drown in it. Flywheels can disintegrate into shrapnel. It’s always risk management.
LFP is the present solution, but sodium ion is the next step. Given the abundance of sodium in the sea there should never be any problem sourcing it.
https://cambridgerenewables.co.uk/product/eleven-energy-4-5-...
Weight is not a factor for home energy storage, there is no need for lithium cells.
That depends on your living situation. I live in a third-floor apartment, so weight is very definitely a factor.
Weight always is a factor since heavy batteries cost more to transport, period. It's always relevant, not least for the installation too.
We're talking on the order of millions of kilograms for the building materials that needed to be transported to build it. The batteries needed for backup power for its occupants won't come anywhere close to that, even at far lower energy density than lithium.
The apartment building can have unified power backup in its foundation/basement.
If you reduce the energy density by a factor of 10, the weight for power backup needs will still be far lighter than the concrete.
Yes, with cheap third world labour, the same way many other technological marvels of the modern era are "automated".
This can't be done remote so you will need to bring that labor to where the work is.
There's already a pipeline sending old electronics to cheap labor for possible refurbishing, recycling and/or incorrect disposal. A small percentage they repackage into replacement laptop batteries and ship back, but they could also send more of them back as a value UPS with different value add parts.
Personally, I expect there to be a massive conversion to USB-PD as the primary power in the cellphone only regions.
Does USB-PD mean USB power distribution ?
And yeah - some LEDs and a usb wire around the ceiling solves lighting a house more sensibly than a three-phase converter under the stairs and enough power going through a light switch to kill me …
It means USB Power Delivery and is a standard for negotiating custom-other-than-5V voltages from a USB Type-C power supply and communicating to the device how much current it is allowed to draw.
It's why you can charge your phone with your laptops power brick without anything exploding, and why most laptops can charge (very slowly) from pretty underpowered phone chargers now.
Building large battery arrays out of old recycled cells does not require bringing the workers to the battery cells, any more than building iPhones requires you to bring the workers to where they mine ore. Large-scale product development often involves shipping materials and half-finished products around the world multiple times.
You would never do this in a production product. You need batteries with similar internal impedances or undesirable things happen. This is the battery equivalent of the guy who welds two car front ends together and drives it around. It's cool and quirky but not a useful product for most people.
From what I've heard, it is more economical to recycle the raw materials than to reuse small packs.
Reuse of vehicle sized packs seems to be pretty common, though. I'd guess that a DIY home backup could be built pretty easily from used vehicle batteries.
The dude has a warehouse/workshop to do this work and house the system. I’m super impressed by what he’s accomplished, don’t get me wrong; but, what he’s done just isn’t viable for 99.99999999999% of people.
Give me an array and battery system that can pull off the grid and/or array and power most of my home without me having to think a whole lot or pay a vendor thousands to install while making the total cost under $1000 and I’ll do it.
Until then, it just isn’t financially viable when my electricity costs are well under $70/month average across the year.
Recouping the costs for install of solar systems are estimated at 30-40 years as of 4 years ago when I researched it. I’m sorry, but that’s just not worth it for me and most others.
I enjoyed noticing that your percentage (1×10⁻¹³) was so precise that it excluded the man himself (he is 1 in 8×10⁹).
I don't want to detract from your point. I just wanted to appreciate the hyperbole.
It's April Fools, so you have to pay close attention today; glad you caught my hilarious joke.
Sure, but it does get a lot simpler if you start from modules instead of cells. Nothing will get around the requirement to have electrical knowledge.
Cost is always an issue. These rarely make sense from a pure $$ sense, as everything in electrical is expensive. You could burn up that $1000 budget just to get a subpanel installed.
Usually the value proposition is some combination of savings, combined with the ability to backup critical loads. A generator could do that too, but a proper generator setup isn't cheap either, and it wouldn't save $$ at all. Battery solutions sometimes beat that.
When I priced out solar, it was never sold as a backup solution; it was apparently intended as a 'sell back to grid' solution. To add a battery effectively doubled the cost.
When I had solar, ~10 years ago, it was similar. We had net metering, no batteries, and zero backup if the grid went down. This was in an area where that rarely happened anyway, so I didn't really care. It'd be easy to add batteries, though.
But net metering is becoming less common, and if you can't sell to the grid at retail, then it'd make sense to store it locally. In some cases, it can also make sense to use batteries even without solar. A good sized battery can keep your refrigerator running for days, which is useful for areas prone to weather related outages. It can also easily fully power the electronics on a gas oven for a long time. And honestly, a big battery these days isn't even that expensive.
And if that isn't enough, some batteries can be topped up with the power from a large battery EV. DCFC tends to come back before a lot of residential power, so this can be really useful.
Unfortunately, that 'sell back to grid' price is often only a small fraction of the ~17 cent/kWh purchase price from the grid. The battery is less for backup but is instead to help make economic sense for your home, by storing the excess you produce when it is sunny...
Buying a used Nissan Leaf and using V2H feature in CHAdeMO is it. Or you can remove and use its well-reverse-engineered minimum nominal 24kWh semi-removable battery. But no one wants a Leaf, so there's that.
Standardizing battery packs would probably help with the automation; like with USB-C.
Isn't the problem with parasitic charging? Suppose you had a bunch of used 18650 cells. To scale the electronics, they'll be wired up in parallel and/or series so the charging logic can be shared, but since the batteries are wildly mismatched, it results in parasitic charging.
That is why you sort them.
Some recent research into that: https://www.sae.org/publications/technical-papers/content/20...
You can also consider maintaining packs together to avoid complicated disassembling processes.
> maintaining packs together
(This might already be happening, but I haven't heard about it) The big thing EVs need right now is standardized battery packs. It reduces replacement cost, takes away anxiety that a replacement will exist when you need it, and enables down-cycle uses like stationary storage.
I think that may be a trickier proposition than it appears.
Certainly a standard form factor for a pack would be helpful for a specific manufacturer (similar to building multiple cars on top of the same basic frame).
Some of the issues I think one runs into is battery chemistries are rapidly changing so even if the shape of the pack remains the same the performance of it is rather different depending on what is put inside.
Then even with standard form and chemistry one pack to another can be rather different depending on the history of it's use (age, charge cycles, driven hard).
There is second life storage applications currently, and still more research going into it now.
Personally I think smarter controls and smarter diagnostic and pack sorting will be more useful.