A finger points at a stack of yellow plastic plates sandwiched together like on a bookshelf. A grey metal rectangle holds the top together and black plastic sticks off to the left. The top of the pack has copper and nickel (or some other silver-colored metal) tabs pointing up out of the assembly.

Tearing Into A Sparky Sandwich

We’re still in the early days of modern EV infrastructure, so minor issues can lead to a full high voltage pack replacement given the lack of high voltage-trained mechanics. [Ed’s Garage] was able to source a Spark EV battery pack that had succumbed to a single bad cell and takes us along for the disassembly of the faulty module.

The Spark EV was the predecessor to the more well-known Chevy Bolt, so its nearly ten year old systems might not reflect the state-of-the-art in EV batteries, but they are certainly more modern than the battery in your great-grandmother’s Baker Electric. The Li-ion polymer pouch cells are sandwiched together with cooling and shock absorbing panels to keep the cells healthy and happy, at least in theory.

In a previous video, [Ed’s Garage] takes apart the full pack and shows how the last 2P16S module has assumed a darker color on its yellow plastic, seeming to indicate that it wasn’t receiving sufficient cooling during its life in the car. It would seem that the cooling plates inside the module weren’t quite up to the task. These cells are destined for other projects, but it doesn’t seem like this particular type of battery module would be too difficult to reassemble and put back in a car as long as you could get the right torque settings for the compression bolts.

If you’re looking for other EV teardowns, might we suggest this Tesla Model S pack or one from a passively-cooled Nissan Leaf?

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Ultimate Power: Lithium-Ion Batteries In Series

At some point, the 3.6 V of a single lithium ion battery just won’t do, and you’ll absolutely want to stack LiIon cells in series. When you need high power, you’ve either got to increase voltage or current, and currents above say 10 A require significantly beefed up components. This is how you’re able to charge your laptop from your USB-C powerbank, for instance.

Or maybe you just need higher voltages, and don’t feel like using a step-up converter, which brings along with it some level of inefficiency. Whatever your reasons, it’s time to put some cells into series. Continue reading “Ultimate Power: Lithium-Ion Batteries In Series”

Lithium-Ion Batteries Power Your Devboards Easily

Last summer, I was hanging out with a friend from Netherlands for a week, and in the middle of that week, we decided to go on a 20 km bike trip to a nearby beach. Problem? We wanted to chat throughout the trip, but the wind noise was loud, and screaming at each other while cycling wouldn’t have been fun. I had some walkie-talkie software in mind, but only a single battery-powered Pi in my possession. So, I went into my workshop room, and half an hour later, walked out with a Pi Zero wrapped in a few cables.

I wish I could tell you that it worked out wonders. The Zero didn’t have enough CPU power, I only had single-core ones spare, and the software I had in mind would start to badly stutter every time we tried to run it in bidirectional mode. But the battery power solution was fantastic. If you need your hack to go mobile, read on.

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A vanadium based flow battery made with 3D printed parts

A Vanadium Redox Flow Battery You Can Build

Vanadium flow batteries are an interesting project, with the materials easily obtainable by the DIY hacker. To that effect [Cayrex2] over on YouTube presents their take on a small, self-contained flow battery created with off the shelf parts and a few 3D prints. The video (embedded below) is part 5 of the series, detailing the final construction, charging and discharging processes. The first four parts of the series are part 1, part 2, part 3, and part 4.

The concept of a flow battery is this: rather than storing energy as a chemical change on the electrodes of a cell or in some localised chemical change in an electrolyte layer, flow batteries store energy due to the chemical changediagram of a vanadium flow battery of a pair of electrolytes. These are held externally to the cell and connected with a pair of pumps. The capacity of a flow battery depends not upon the electrodes but instead the volume and concentration of the electrolyte, which means, for stationary installations, to increase storage, you need a bigger pair of tanks. There are even 4 MWh containerised flow batteries installed in various locations where the storage of renewable-derived energy needs a buffer to smooth out the power flow. The neat thing about vanadium flow batteries is centred around the versatility of vanadium itself. It can exist in four stable oxidation states so that a flow battery can utilise it for both sides of the reaction cell.

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Harvard Claims Breakthrough In Anode Behavior Of Solid State Lithium Batteries

One of the biggest issues facing the solid-state lithium-based batteries we all depend upon is of the performance of the anode; the transport of lithium ions and minimization of dendrite formation are critical problems and are responsible for charge/discharge rates and cell longevity. A team of researchers at Harvard have demonstrated a method for using a so-called constriction-susceptible structure on a silicon anode material in order to promote direct metal lithium deposition, as opposed to the predominant alloying reaction. After the initial silicon-lithium alloy layer is formed, subsequent layers are pure lithium. Micrometre-scale silicon particles at the anode constrain the lithiation process (i.e. during charging) where free lithium ions are pushed by the charge current towards the anode area. Because the silicon particles are so small, there is limited surface area for alloying to occur, so direct metal plating of lithium is preferred, but crucially it happens in a very uniform manner and thus does not tend to promote the formation of damaging metal dendrites.

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A Simple Hack For Running Low-Power Gear From A USB Battery Pack

We’ve all been there. You’ve cooked up some little microcontroller project, but you need to unhook it from your dev PC and go mobile. There’s just one problem — you haven’t worked up a battery solution yet. “No problem!” you exclaim. “I’ll just use a USB battery pack!” But the current draw is too low, and the pack won’t stay on. “Blast!” you exclaim, because you’ve been watching too much Family Guy or something.

[PatH] had this very problem recently, when trying to work with Meshtastic running on a RAKwireless WisBlock Base Board. You’re supposed to hook up your own rechargeable LiPo battery, but [PatH] was in a hurry. Instead, a USB battery pack was pressed into service, but it kept shutting down. The simple trick was to just add a 100-ohm resistor across the device’s battery terminals. That took the current draw from just 15 mA up to 53 mA, which was enough to keep portable USB power banks interested in staying switched on.

It’s an easy hack for an oddball problem, and it just might get you out of a bind one day. If you’ve got any nifty tricks like this up your sleeve, don’t hesitate to let us know!

Power Tool Packs Make A Portable Powerhouse

The revolution in portable and cordless appliances has meant that we now own far fewer mains-powered gadgets than we might once have done, but it hasn’t entirely banished the old AC outlet from our lives. Particularly when away from a mains supply it can be especially annoying, but now instead of a generator there’s the option of an inverter. [Thijs Koppen] has made a very neat all-in-one mains power station in a plastic flight case using the ubiquitous and handy standardized Makita power tool packs.

From one perspective this is a simple enough build, because wiring a battery to an inverter isn’t the most difficult of tasks. But he’s designed his own 3D printed Makita battery receptacles which should be of interest to plenty of readers, and with three packs in series he’s sourced an unusual 72 volt inverter to supply mains. The photo of him charging a Tesla with the result is probably more for show than practicality though.

We’ve featured quite a lot of cordless tool battery hacks over the years as their ready availability and quick interchangeability is attractive. If you ever fancy engineering your own mounting, we’ve taken a look at someone doing just that.