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119 Articles

Fail Of The Week: Taking Apart A Tesla Battery

September 7, 2019 by 86 Comments

It takes a lot of energy to push a car-sized object a few hundred miles. Either a few gallons of gasoline or several thousand lithium batteries will get the job done. That’s certainly a lot of batteries, and a lot more potential to be unlocked for their use than hurling chunks of metal around on wheels. If you have an idea for how to better use those batteries for something else, that’s certainly an option, although it’s not always quite as easy as it seems.

In this video, [Kerry] at [EVEngineering] has acquired a Tesla Model 3 battery pack and begins to take it apart. Unlike other Tesla batteries, and even more unlike Leaf or Prius packs, the Model 3 battery is extremely difficult to work with. As a manufacturing cost savings measure, it seems that Tesla found out that gluing the individual cells together would be less expensive compared to other methods where the cells are more modular and serviceable. That means that to remove the individual cells without damaging them, several layers of glue and plastic have to be removed before you can start hammering the cells out with a PEX wedge and a hammer. This method tends to be extremely time consuming.

If you just happen to have a Model 3 battery lying around, [Kerry] notes that it is possible to reuse the cells if you have the time, but doesn’t recommend it unless you really need the energy density found in these 21700 cells. Apparently they are not easy to find outside of Model 3 packs, and either way, it seems as though using a battery from a Nissan Leaf might be a whole lot easier anyway.

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What Happens To Tesla When The Sleeping Auto Giants Awake?

August 12, 2019 by 158 Comments

The history of automotive production is littered with the fallen badges of car companies that shone brightly but fell by the wayside in the face of competition from the industry’s giants. Whether you pine for an AMC, a Studebaker, or a Saab, it’s a Ford or a Honda you’ll be driving in 2019.

In the world of electric cars it has been a slightly different story. Though the big names have dipped a toe in the water they have been usurped by a genuinely disruptive contender. If you drive an electric car in 2019 it won’t be that Ford or Honda, it could be a Nissan, but by far the dominant name in EV right now is Tesla.

Motor vehicles are standing at the brink of a generational shift from internal combustion to electric drive. Will Tesla become the giant it hopes, or will history repeat itself?

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Tesla Eyes Ultracapacitor Future With Maxwell Acquisition

February 4, 2019 by 29 Comments

As reported by Bloomberg, Tesla has acquired the innovative energy storage company Maxwell Technologies for $218 Million. The move is a direct departure from Tesla’s current energy storage requirements; instead of relying on lithium battery technology, this acquisition could signal a change to capacitor technology.

The key selling point of capacitors, either of the super- or ultra- variety, is the much shorter charge and discharge rates. Where a supercapacitor can be used to weld metal by simply shorting the terminals (don’t do that, by the way), battery technology hasn’t yet caught up. You can only charge batteries at a specific rate, and you can only discharge them at a specific rate. The acquisition of an ultracapacitor manufacturer opens the possibility of these powerhouses finding their way into electric vehicles.

While there is a single problem with super- and ultra-capacitors — the sheer volume and the fact that a module of ultracaps will hold much less energy than a module of batteries of the same size — the best guess is that Tesla won’t be replacing all their batteries with caps in the short-term. Analysts think that future Teslas may feature a ‘co-battery’ of sorts, allowing for fast charging and discharging through a series of ultracapacitors, with the main energy storage in the car still being the lithium battery modules. This will be especially useful for regenerative braking, as slowing down a three thousand pound vehicle produces a lot of energy, and Tesla’s current battery technology can’t soak all of it up.

Wireless Charging Without So Many Chargers

January 15, 2019 by 11 Comments

[Nikola Tesla] believed he could wirelessly supply power to the world, but his calculations were off. We can, in fact, supply power wirelessly and we are getting better but far from the dreams of the historical inventor. The mainstream version is the Qi chargers which are what phones use to charge when you lay them on a base. Magnetic coupling is what allows the power to move through the air. The transmitter and receiver are two halves of an air-core transformer, so the distance between the coils exponentially reduces efficiency and don’t even think of putting two phones on a single base. Well, you could but it would not do any good. [Chris Mi] at San Diego State University is working with colleagues to introduce receivers which feature a pass-through architecture so a whole stack of devices can be powered from a single base.

Efficiency across ten loads is recorded at 83.9% which is phenomenal considering the distance between each load is 6 cm. Traditional air-gap transformers are not designed for 6 cm, much less 60 cm. The trick is to include another transmitter coil alongside the receiving coil. By doing this, the coils are never more than 6 cm apart, even when the farthest unit is a long ways from the first supply. Another advantage to this configuration is that tuned groups continue to work even when a load changes in the system. For this reason, putting ten chargeables on a single system is a big deal because they don’t need to be retuned when one finishes charging.

We would love to see more of this convenient charging and hope that it catches on.

Via IEEE Spectrum.

Fail Of The Week: How Not To Electric Vehicle

December 3, 2018 by 92 Comments

If you ever doubt the potential for catastrophe that mucking about with electric vehicles can present, check out the video below. It shows what can happen to a couple of Tesla battery modules when due regard to safety precautions isn’t paid.

The video comes to us by way of [Rich], a gearhead with a thing for Teslas. He clearly knows his way around the EV world, having rebuilt a flood-soaked Tesla, and aspires to open an EV repair shop. The disaster stems from a novelty vehicle he and friend [Lee] bought as a side project. The car was apparently once a Disney prop car, used in parades with the “Mr. Toad’s Wild Ride” theme. It was powered by six 6-volt golf cart batteries, which let it maintain a stately, safe pace on a crowded parade route. [Rich] et al would have none of that, and decided to plop a pair of 444-cell Tesla modules into it. The reduced weight and increased voltage made it a real neck-snapper, but the team unwisely left any semblance of battery management out of the build.

You can guess what happened next, or spin up to the 3:00 mark in the video to watch the security camera mayhem. It’s not clear what started the fire, but the modules started cooking off batteries like roman candles. Quick action got it pushed outside to await the fire department, but the car was a total loss long before they showed up. Luckily no other cars in the garage were damaged, nor were there any injuries – not that the car didn’t try to take someone out, including putting a flaming round into [Lee]’s chest and one into the firetruck’s windshield.

[Rich] clearly knew he was literally playing with fire, and paid the price. The lesson here is to respect the power of these beefy batteries, even when you’re just fooling around.

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A 1940s Gangster-Mobile Gets An Electric Makeover

November 18, 2018 by 73 Comments

When referring to classic cars, there’s a good reason that “they don’t make ’em like that anymore.” Old cars represented the limits of what could be done in terms of materials and manufacturing methods coupled with the styles of the time and cheap fuel. The result was big, heavy cars that would cost a fortune in gas to keep on the road today.

Some people just don’t want to let those styles go, however, and send their beast off for some special modifications. This 1949 Mercury coupe with an electric drivetrain conversion is one way of keeping that retro look alive. Granted, the body of the car is not exactly showroom quality anymore, from the light patina of rust on its heavy steel body panels to the pimples cropping up under its abundant chrome. But that’s all part of the charm; this comes from conversion company Icon’s “Derelict” line, which takes old vehicles and guts them while leaving the outside largely untouched. This Mercury was given a fully electric, 298 kW drivetrain. The engine bay and trunk, together roomier than some Silicon Valley studio apartments, provided ample room for the 85 kWh Tesla battery pack and the dual electric motors, with room left over to craft enclosures for the battery controllers that look like a V8 engine. Custom electronic gauges and controls that look like originals adorn the chrome-bedazzled dash. The beast tops out at 120 mph (193 km/h) and has a 200 mile (322 km) range before it has to find a Tesla supercharger. Or a lemonade stand.

Say what you want about the old cars, but they had plenty of style. We appreciate the work that went into this conversion, which no doubt cost more than all the gas this thing has ever guzzled.

Thanks to [Qes] for the tip.

Fatalities Vs False Positives: The Lessons From The Tesla And Uber Crashes

June 18, 2018 by 174 Comments

In one bad week in March, two people were indirectly killed by automated driving systems. A Tesla vehicle drove into a barrier, killing its driver, and an Uber vehicle hit and killed a pedestrian crossing the street. The National Transportation Safety Board’s preliminary reports on both accidents came out recently, and these bring us as close as we’re going to get to a definitive view of what actually happened. What can we learn from these two crashes?

There is one outstanding factor that makes these two crashes look different on the surface: Tesla’s algorithm misidentified a lane split and actively accelerated into the barrier, while the Uber system eventually correctly identified the cyclist crossing the street and probably had time to stop, but it was disabled. You might say that if the Tesla driver died from trusting the system too much, the Uber fatality arose from trusting the system too little.

But you’d be wrong. The forward-facing radar in the Tesla should have prevented the accident by seeing the barrier and slamming on the brakes, but the Tesla algorithm places more weight on the cameras than the radar. Why? For exactly the same reason that the Uber emergency-braking system was turned off: there are “too many” false positives and the result is that far too often the cars brake needlessly under normal driving circumstances.

The crux of the self-driving at the moment is precisely figuring out when to slam on the brakes and when not. Brake too often, and the passengers are annoyed or the car gets rear-ended. Brake too infrequently, and the consequences can be worse. Indeed, this is the central problem of autonomous vehicle safety, and neither Tesla nor Uber have it figured out yet.

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