Lithium (from Greek lithos or stone) is a silvery-white alkali metal that is the lightest solid element. Just one atomic step up from Helium, this magic metal seems to be in everything these days. In addition to forming the backbone of many kinds of batteries, it also is used in lubricants, mood-stabilizing drugs, and serves as an important additive in iron, steel, and aluminum production. Increasingly, the world is looking to store more and more power as phones, solar grids, and electric cars continue to rise in popularity, each equipped with lithium-based batteries. This translates to an ever-growing need for more lithium. So far production has struggled to keep pace with demand. This leads to the question, do we have enough lithium for everyone?
It takes around 138 lbs (63 kg) of 99.5% pure lithium to make a 70 kWh Tesla Model S battery pack. In 2016, OICA estimated that the world had 1.3 billion cars in use. If we replace every car with an electric version, we would need 179 billion pounds or 89.5 million tons (81 million tonnes) of lithium. That’s just the cars. That doesn’t include smartphones, laptops, home power systems, massive grid storage projects, and thousands of other products that use lithium batteries.
In 2019 the US Geological Survey estimated the world reserves of identified lithium was 17 million tonnes. Including the unidentified, the estimated total worldwide lithium was 62 million tonnes. While neither of these estimates is at that 89 million ton mark, why is there such a large gap between the identified and estimated total? And given the general rule of thumb that the lighter a nucleus is, the more abundant the element is, shouldn’t there be more lithium reserves? After all, the US Geological Survey estimates there are around 2.1 billion tonnes of identified copper and an additional 3.5 billion tonnes that have yet to be discovered. Why is there a factor of 100x separating these two elements?
Electric bikes have increased in popularity dramatically over the past few years, and while you can easily buy one from a reputable bicycle manufacturer, most of us around here might be inclined to at least buy a kit and strap it to a bike we already have. There aren’t kits available for every bike geometry, though, so if you want an electric BMX bike you might want to try out something custom like [Shea Nyquist] did with his latest build. (Video, embedded below.)
BMX frames have a smaller front triangle than most bikes, so his build needed to be extremely compact. To that end, it uses two small-sized motors connected together with a belt, which together power a friction drive which clamps against the rear tire to spin it directly. This keeps the weight distribution of the bike more balanced as well when compared to a hub drive, where the motor is installed in the rear wheel. It also uses a more compact lithium polymer battery pack instead of the typical 18650 lithium ion packs most e-bikes use, and although it only has a range of around three miles it’s more than enough charge to propel it around a skate park.
Anyone who enjoys opening up consumer electronics knows iFixit to be a valuable resource, full of reference pictures and repair procedures to help revive devices and keep them out of electronic waste. Champions of reparability, they’ve been watching in dismay as the quest for thinner and lighter devices also made them harder to fix. But they wanted to cheer a bright spot in this bleak landscape: increasing use of stretch-release adhesives.
Once upon a time batteries were designed to be user-replaceable. But that required access mechanisms, electrical connectors, and protective shells around fragile battery cells. Eliminating such overhead allowed slimmer devices, but didn’t change the fact that the battery is still likely to need replacement. We thus entered into a dark age where battery pouches were glued into devices and replacement meant fighting clingy blobs and cleaning sticky residue. Something the teardown experts at iFixit are all too familiar with.
This is why they are happy to see pull tabs whenever they peer inside something, for those tabs signify the device was blessed with stretch-release adhesives. All we have to do is apply a firm and steady pull on those tabs to release their hold leaving no residue behind. We get an overview of how this magic works, with the caveat that implementation details are well into the land of patents and trade secrets.
But we do get tips on how to best remove them, and how to reapply new strips, which are important to iFixit’s mission. There’s also a detour into their impact on interior design of the device: the tabs have to be accessible, and they need room to stretch. This isn’t just a concern for design engineers, they also apply to stretch release adhesives sold to consumers. Advertising push by 3M Command and competitors have already begun, reminding people that stretch-release adhesive strips are ideal for temporary holiday decorations. They would also work well to hold batteries in our own projects, even if we aren’t their advertised targets.
Our end-of-year gift-giving traditions will mean a new wave of gadgets. And while not all of them will be easily repairable, we’re happy that this tiny bit of reparability exists. Every bit helps to stem the flow of electronics waste.
The times they are a-changin’. It used to be that no household was complete without a drawer filled with an assortment of different sizes and types of batteries, but today more and more of our gadgets are using integrated rechargeable cells. Whether or not that’s necessarily an improvement is probably up for debate, but the fact of the matter is that some of these old batteries are becoming harder to find as time goes on.
Which is why [Stephen Arsenault] wants to preserve as many of them as possible. Not in some kind of physical battery museum (though that does sound like the sort of place we’d like to visit), but digitally in the form of 3D models and spec sheets. The idea being that if you find yourself in need of an oddball, say the PRAM battery for a Macintosh SE/30, you could devise your own stand-in with a printed shell.
The rather brilliantly named Battery Backups project currently takes the form of a Thingiverse Group, which allows other alkaline aficionados to submit their own digitized cells. The cells that [Stephen] has modeled so far include not only the STL files for 3D printing, but the CAD source files in several different flavors so you can import them into your tool of choice.
Over the years, the 1993 classic Doom has gained an almost meme-like status where it can seemingly run on anything. Everything from printers to smartwatches has been shown off running the now-iconic first level of Doom. Looking to up the bar, [Equalo] set out to run Doom on potatoes. However until we develop full biological computers, he had to settle for running Doom on a device powered by potatoes. (Video, embedded below.)
As we’ve seen with other hacks before, potatoes are a decent power source that just requires potato, zinc, and copper. Some have attempted to make it easier to scale potato power and others have focused on making the individual potatoes more powerful. The biggest obstacle when working with potatoes as a battery is that even though each potato can put out almost a volt, the current is laughably small.
The lack of current is what drove [Equalo] to dramatically scale up the typical potato battery. With a target device of a Raspberry Pi Zero requiring around 100 mA at 4.5V, this means he needed over 700 potato slices. After boiling hundreds of potatoes and with a bit of help from friends and family, the giant potato battery was constructed, and we can’t help but marvel at the sheer scale and audacity. The challenge of scaling up a potato battery is that by the time you’re wiring up the 400th potato, your first potato has already started to corrode.
Next time you’re looking for some inspiration for a monumental task, perhaps watch the tale of [Equalo’s] giant potato battery and remember what can be accomplished with some determination and a hundred pounds of spuds.
Telsa are one of the world’s biggest purchasers of batteries through their partnerships with manufacturers like Panasonic, LG and CATL. Their endless hunger for more cells is unlikely to be satiated anytime soon, as demand for electric cars and power storage continues to rise.
The 18650 is perhaps the world’s favorite lithium battery, even if electric car manufacturers are beginning to move towards larger cells such as the 21700. Used heavily in laptops and flashlights, it packs a useful amount of energy into a compact, easy to use package. There’s a small industry that has developed around harvesting these cells from old equipment and repurposing them, and [MakerMan] wanted to a piece of the action. Thus, he created a cell testing station to help in the effort.
Make no mistake, this is not a grandiose smart cell tester with 40 slots that logs every last iota of data into a cloud spreadsheet for further analysis. Nope, this is good old fashioned batch processing. [MakerMan] designed a single PCB that replicates the same cell testing circuit four times. Since PCB houses generally have a minimum order quantity of ten units, [MakerMan] ended up with forty individual cell testers on ten PCBs. Once populated, the boards were installed on a wooden frame with an ATX power supply which supplies the juice to run the system.
Overall, it’s a quick, cheap way for capacity testing cells en masse that should serve [MakerMan] well. We look forward to seeing where these cells end up. We’ve seen his work before, too – with a self-built laser engraver a particular highlight. Video after the break.