The Quest To Find A Second Life For Electric Vehicle Batteries

Rechargeable lithium chemistry battery cells found their mass market foothold in the field of personal electronics. The technology has since matured enough to be scaled up (in both physical size and production volume) to electric cars, making long range EVs far more economical than what was possible using earlier batteries. Would the new economics also make battery reuse a profitable business? Eric Lundgren is one of those willing to make a run at it, and [Gizmodo] took a look at his latest venture.

This man is a serial entrepreneur, though his previous business idea was not successful as it involved “reusing” trademarks that were not his to use. Fortunately this new business BigBattery appears to be on far more solid legal footing, disassembling battery packs from retired electric vehicles and repacking cells for other purposes. Typically EV batteries are deemed “worn out” when their capacity drops below a certain percentage (70% is a common bar) but that reduced capacity could still be useful outside of an EV. And when battery packs are retired due to problems elsewhere in the car, or just suffering from a few bad cells, it’s possible to extract units in far better shape.

We’ve been interested in how to make the best use of rechargeable lithium batteries. Ranging from tech notes helping battery reuse, to a comparison of different types, to looking at how their end-of-life recycling will be different from lead-acid batteries. Not to mention countless project wins and fails in between. A recurring theme is the volatility of mistreated or misbehaving batteries. Seeing a number of EV battery packs stacked on pallets and shelves, presumably filled with cells of undetermined quality, fills us with unease. Like the rest of California, Chatsworth is under earthquake risk, and the town was uncomfortably close to some wildfires in 2019. Eric is quick to give assurance that employees are given regular safety training and the facility conforms to all applicable workplace safety rules. But did those rules consider warehouses packed full of high capacity lithium battery cells of unknown quality? We expect that, like the business itself, standards for safety will evolve.

Concerns on safety aside, a successful business here would mean electric vehicles have indeed given battery reuse a profitable economy of scale that tiny little cell phone and laptop batteries could not reach. We are optimistic that Eric and other like-minded people pursuing similar goals can evolve this concept into a bright spot in our otherwise woeful state of e-waste handling.

Hackaday Links: October 20, 2019

It’s Nobel season again, with announcements of the prizes in literature, economics, medicine, physics, and chemistry going to worthies the world over. The wording of the Nobel citations are usually a vast oversimplification of decades of research and end up being a scientific word salad. But this year’s chemistry Nobel citation couldn’t be simpler: “For the development of lithium-ion batteries”. John Goodenough, Stanley Whittingham, and Akira Yoshino share the prize for separate work stretching back to the oil embargo of the early 1970s, when Goodenough invented the first lithium cathode. Wittingham made the major discovery in 1980 that adding cobalt improved the lithium cathode immensely, and Yoshino turned both discoveries into the world’s first practical lithium-ion battery in 1985. Normally, Nobel-worthy achievements are somewhat esoteric and cover a broad area of discovery that few ordinary people can relate to, but this is one that most of us literally carry around every day.

What’s going on with Lulzbot? Nothing good, if the reports of mass layoffs and employee lawsuits are to be believed. Aleph Objects, the Colorado company that manufactures the Lulzbot 3D printer, announced that they would be closing down the business and selling off the remaining inventory of products by the end of October. There was a reported mass layoff on October 11, with 90 of its 113 employees getting a pink slip. One of the employees filed a class-action suit in federal court, alleging that Aleph failed to give 60 days notice of terminations, which a company with more than 100 employees is required to do under federal law. As for the reason for the closure, nobody in the company’s leadership is commenting aside from the usual “streamlining operations” talk. Could it be that the flood of cheap 3D printers from China has commoditized the market, making it too hard for any manufacturer to stand out on features? If so, we may see other printer makers go under too.

For all the reported hardships of life aboard the International Space Station – the problems with zero-gravity personal hygiene, the lack of privacy, and an aroma that ranges from machine-shop to sweaty gym sock – the reward must be those few moments when an astronaut gets to go into the cupola at night and watch the Earth slide by. They all snap pictures, of course, but surprisingly few of them are cataloged or cross-referenced to the position of the ISS. So there’s a huge backlog of beautiful but unknown cities around the planet that. Lost at Night aims to change that by enlisting the pattern-matching abilities of volunteers to compare problem images with known images of the night lights of cities around the world. If nothing else, it’s a good way to get a glimpse at what the astronauts get to see.

Which Pi is the best Pi when it comes to machine learning? That depends on a lot of things, and Evan at Edje Electronics has done some good work comparing the Pi 3 and Pi 4 in a machine vision application. The SSD-MobileNet model was compiled to run on TensorFlow, TF Lite, or the Coral USB accelerator, using both a Pi 3 and a Pi 4. Evan drove around with each rig as a dashcam, capturing typical street scenes and measuring the frame rate from each setup. It’s perhaps no surprise that the Pi 4 and Coral setup won the day, but the degree to which it won was unexpected. It blew everything else away with 34.4 fps; the other five setups ranged from 1.37 to 12.9 fps. Interesting results, and good to keep in mind for your next machine vision project.

Have you accounted for shrinkage? No, not that shrinkage – shrinkage in your 3D-printed parts. James Clough ran into shrinkage issues with a part that needed to match up to a PCB he made. It didn’t, and he shared a thorough analysis of the problem and its solution. While we haven’t run into this problem yet, we can see how it happened – pretty much everything, including PLA, shrinks as it cools. He simply scaled up the model slightly before printing, which is a good tip to keep in mind.

And finally, if you’ve ever tried to break a bundle of spaghetti in half before dropping it in boiling water, you likely know the heartbreak of multiple breakage – many of the strands will fracture into three or more pieces, with the shorter bits shooting away like so much kitchen shrapnel. Because the world apparently has no big problems left to solve, a group of scientists has now figured out how to break spaghetti into only two pieces. Oh sure, they mask it in paper with the lofty title “Controlling fracture cascades through twisting and quenching”, but what it boils down to is applying an axial twist to the spaghetti before bending. That reduces the amount of bending needed to break the pasta, which reduces the shock that propagates along the strand and causes multiple breaks. They even built a machine to do just that, but since it only breaks a strand at a time, clearly there’s room for improvement. So get hacking!

Better Battery Management Through Chemistry

The lead-acid rechargeable battery is a not-quite-modern marvel. Super reliable and easy to use, charging it is just a matter of applying a fixed voltage to it and waiting a while; eventually the battery is charged and stays topped off, and that’s it. Their ease is countered by their size, weight, energy density, and toxic materials.

The lithium battery is the new hotness, but their high energy density means a pretty small package that can get very angry and dangerous when mishandled. Academics have been searching for safer batteries, better charge management systems, and longer lasting battery formulations that can be recharged thousands of times, and a recent publication is generating a lot of excitement about it.

Consider the requirements for a battery cell in an electric car:

  • High energy density (Lots of power stored in a small size)
  • Quick charge ability
  • High discharge ability
  • MANY recharge cycles
  • Low self-discharge
  • Safe

Lithium ion batteries are the best option we have right now, but there are a variety of Li-ion chemistries, and depending on the expected use and balancing and charging, different chemistries can be optimized for different performance characteristics. There’s no perfect battery yet, and conflicting requirements mean that the battery market will likely always have some options.

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Cheaply Charging Cylindrical Cells

For one reason or another, a lot of us have a bunch of 18650 cells sitting around. Whether they’re for flashlights, our fancy new vape pen, remote controlled toys, or something more obscure, there is a need to charge a bunch of lithium ion cells all at once. This project, by [Daren Schwenke], is the way to do it. It’ll charge ten 18650 cells quickly using a stock ATX power supply and less than twenty bucks in Amazon Prime parts.

The idea began when [Daren] realized his desktop lithium ion charger took between 4-6 hours to fully charge two 18650 cells. With a Mountainboard project, or a big ‘ol electric skateboard waiting in the wings, [Daren] realized there had to be a better solution to charging a bunch of 18650 cells. There is, and it’s those twenty bucks at Amazon and a few 3D printed parts.

The relevant parts are just a ten-pack of 18650 cell holders (with PC pins) and a ten-pack of 5V, 1A charging modules (non-referral Amazon link, support truly independent journalism) meant to be the brains of a small USB power bank. These parts were wired up to the 5V rail of a discarded ATX power supply (free, because you can scavenge these anywhere, and everything was wrapped up with a neat little 3D printed mount.

Is this the safest way to charge lithium ion cells? No, because you can build a similar project with bailing wire. There is no reverse polarity protection, and if there’s one thing you never want to do, it’s reverse the polarity. This is, however, a very effective and very cheap solution to charging a bunch of batteries. It does what it says it’ll do, nothing more.

DIY Arc Light Makes An Unnecessarily Powerful Bicycle Headlight

Remember when tricking out a bike with a headlight meant clamping a big, chrome, bullet-shaped light to your handlebar and bolting a small generator to your front fork? Turning on the headlight meant flipping the generator into contact with the front wheel, powering the incandescent bulb for the few feet it took for the drag thus introduced to grind you to a halt. This ridiculous arc-lamp bicycle headlight is not that. Not by a long shot.

We’re used to seeing [Alex] doing all manner of improbable, and sometimes impossible, things on his popular KREOSAN YouTube channel. And we’re also used to watching his videos in Russian, which detracts not a whit  from the entertainment value for Andglophones; subtitles are provided for the unadventurous, however. The electrodes for his arc light are graphite brushes from an electric streetcar, while the battery is an incredibly sketchy-looking collection of 98 18650 lithium-ion cells. A scary rat’s nest of coiled cable acts as a ballast to mitigate the effects of shorting when the arc is struck. The reflector is an old satellite TV dish covered in foil tape with the electrodes sitting in a makeshift holder where the feedhorn used to be. It’s bright, it’s noisy, it’s dangerous, and it smokes like a fiend, but we love it.

Mounting it to the front of the bike was just for fun, of course, and it works despite the janky nature of the construction. The neighbors into whose apartments the light was projected could not be reached for comment, but we assume they were as amused as we were.

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Getting The Lead Out Of Lithium Battery Recycling

When that fateful morning comes that your car no longer roars to life with a quick twist of the key, but rather groans its displeasure at the sad state of your ride’s electrical system, your course is clear: you need a new battery. Whether you do it yourself or – perish the thought – farm out the job to someone else, the end result is the same. You get a spanking new lead-acid battery, and the old one is whisked away to be ground up and turned into a new battery in a nearly perfect closed loop system.

Contrast this to what happens to the battery in your laptop when it finally gives up the ghost. Some of us will pop the pack open, find the likely one bad cell, and either fix the pack or repurpose the good cells. But most dead lithium-based battery packs are dropped in the regular trash, or placed in blue recycling bins with the best of intentions but generally end up in the landfill anyway.

Why the difference between lead and lithium batteries? What about these two seemingly similar technologies dictates why one battery can have 98% of its material recycled, while the other is cheaper to just toss? And what are the implications down the road, when battery packs from electric vehicles start to enter the waste stream in bulk?

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An E-Bike Battery Pack Without Spot Welding

In somewhat of a departure from their normal fare of heavy metal mods, [Make It Extreme] is working on a battery pack for an e-bike that has some interesting design features.

The guts of the pack are pretty much what you’d expect – recovered 18650 lithium-ion cells. They don’t go into details, but we assume the 52 cells were tested and any duds rejected. The arrangement is 13S4P, and the cells are held in place with laser-cut acrylic frames. Rather than spot weld the terminals, [Make It Extreme] used a series of strategically positioned slots to make contacts from folded bits of nickel strip. Solid contact is maintained by cap screws passing between the upper and lower contact frames. A forest of wires connects each cell to one of four BMS boards, and the whole thing is wrapped in a snappy acrylic frame. The build and a simple test are in the video below.

While we like the simplicity of a weld-less design, we wonder how the pack will stand up to vibration with just friction holding the cells in contact. Given their previous electric transportation builds, like this off-road hoverbike, we expect the pack will be put to the test soon, and in extreme fashion.

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