Tesla’s New Tabless Batteries Unlock New Levels Of Performance

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.

As announced at their Battery Day keynote, Tesla has been working hard on a broad spectrum of projects to take battery technology to the next level in order to reach their goal of 3 TWh annual production by 2030. One of the most interesting aspects of this was the announcement of Tesla’s new tabless 4680 battery, which will be manufactured by the company itself. Let’s take a look at what makes the 4680 so exciting, and why going tabless is such a big deal. Continue reading “Tesla’s New Tabless Batteries Unlock New Levels Of Performance”

Building A Cell Testing Station For 18650s

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.

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Lithium Sulfur Batteries Slated For Takeoff

Spectrum recently published a post on a new lithium sulfur battery technology specifically targeting electric aviation applications. Although lots of electric vehicles could benefit from the new technology, airplanes are especially sensitive to heavy batteries and lithium-sulfur batteries can weigh much less than modern batteries of equivalent capacity. The Spectrum post is from Oxis Energy who is about to fly tests with the new batteries which they claim have twice the energy density of conventional lithium-ion batteries. The company also claims the batteries are safer, which is another important consideration when flying through the sky.

The batteries have a cathode comprised of aluminum foil coated with carbon and sulfur — which avoids the use of cobalt, a cost driver in traditional lithium cell chemistries. The anode is pure lithium foil. Between the two electrodes is a separator soaked in an electrolyte. The company says the batteries go through multiple stages as they discharge, forming different chemical compounds that continue to produce electricity through chemical action.

The safety factor is due to the fact that, unlike lithium-ion cells, the new batteries don’t form dendrites that short out the cell. The cells do degrade over time, but not in a way that is likely to cause a short circuit. However, ceramic coatings may provide protection against this degradation in the future which would be another benefit compared to traditional lithium batteries.

We see a lot of exciting battery announcements, but we rarely see real products with them. Time will tell if the Oxis and similar batteries based on this technology will take root.

Hackaday Podcast 062: Tripping Batteries, Ventilator Design, Stinky Prints, And Simon Says Servos

Hackaday editors Elliot Williams and Mike Szczys check out the week’s awesome hacks. From the mundane of RC controlled TP to a comprehensive look into JTAG for Hackers, there’s something for everyone. We discuss a great guide on the smelly business of resin printing, and look at the misuse of lithium battery protection circuits. There’s a trainable servo, star-tracking space probes, and a deep dive into why bootstrapped ventilator designs are hard.

Take a look at the links below if you want to follow along, and as always tell us what you think about this episode in the comments!

Direct download (~60 MB)

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Turn Off Those Batteries With Their Protection Chip

It should be a feature of every device powered by a lithium-ion battery, that it has a protection chip on board that automatically disconnects it should it go out of its safe voltage range. A chip most often used for this purpose in single-cell applications is the Fortune Semiconductor DW01, and [Oliver] shares a tip for using this chip to power down the battery. The DW01 has a CS, or current sense pin, which if taken high momentarily will put the chip into an off state until the battery is disconnected.

Looking at the DW01 datasheet we can see that this would work, but we can’t help having a few questions. The CS pin is a safety sensor pin, providing over current, short circuit, and reverse polarity detection. It’s the kind of pin one might mess with only when one is absolutely certain it’s not likely to trigger a dangerous fault condition, so a bit of care should be required. However, we can see that leaving its resistor in place and supplying it a momentary logic level through another resistor should work. We’d be interested in the views of any readers with more experience in the world of lithium battery protection on this hack.

Meanwhile, a good read for any reader should be our look last year at lithium-ion safety.

Hackaday Podcast 056: Cat Of 9 Heads, Robot Squats, PhD In ESP32, And Did You Hear About Sonos?

Hackaday editors Elliot Williams and Mike Szczys gab on great hacks of the past week. Did you hear that there’s a new rev of the Pi 4 out there? We just heard… but apparently it’s release into the wild was months ago. Fans of the ESP8266 are going to love this tool that flashes and configures the board, especially for Sonoff devices. Bitluni’s Supercon talk was published this week and it’s a great roadmap of all the things you should try to do with an ESP32. Plus we take on the Sonos IoT speaker debacle and the wacky suspension system James Bruton’s been building into his humanoid robot.

Take a look at the links below if you want to follow along, and as always tell us what you think about this episode in the comments!

Direct download (~60 MB)

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Continue reading “Hackaday Podcast 056: Cat Of 9 Heads, Robot Squats, PhD In ESP32, And Did You Hear About Sonos?”

Lessons In Li-Ion Safety

If you came here from an internet search because your battery just blew up and you don’t know how to put out the fire, then use a regular fire extinguisher if it’s plugged in to an outlet, or a fire extinguisher or water if it is not plugged in. Get out if there is a lot of smoke. For everyone else, keep reading.

I recently developed a product that used three 18650 cells. This battery pack had its own overvoltage, undervoltage, and overcurrent protection circuitry. On top of that my design incorporated a PTC fuse, and on top of that I had a current sensing circuit monitored by the microcontroller that controlled the board. When it comes to Li-Ion batteries, you don’t want to mess around. They pack a lot of energy, and if something goes wrong, they can experience thermal runaway, which is another word for blowing up and spreading fire and toxic gasses all over. So how do you take care of them, and what do you do when things go poorly?

Continue reading “Lessons In Li-Ion Safety”