China Loves Battery Swapping EVs, But Will They Ever Make It Here?

February 9, 2022 by 122 Comments

Electric vehicles promise efficiency gains over their gas-fuelled predecessors, but the issue of recharging remains a hurdle for many eager to jump on board with the technology. The problem is only magnified for those that regularly street park their vehicles or live in apartments, without provision to charge a vehicle overnight at home.

Battery swapping promises to solve that issue, letting drivers of EVs change out their empty battery for a freshly charged one in a matter of minutes. The technology has been widely panned and failed to gain traction in the US.

However, as it turns out, battery swapping for EVs is actually thing in China, and it’s catching on at a rapid rate.

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Retrofitting Fast Charging To A Nissan Leaf EV

June 28, 2021 by 21 Comments

Electric cars have been around for a while now, and thus they’re starting to get chopped up and modded just like any other car. [Daniel Öster] is one such person doing the work, and recently posted his efforts to retrofit fast charging to an base-model Nissan Leaf that didn’t ship with the feature.

[Daniel] uses special high-voltage insulated tools when working on EVs for safety.
It’s an involved swap, requiring the substitution of several parts and surgery on the wiring loom. Cost of components was just 700 euros but the swap required 20 hours of labor. The vehicle in question is an early model Leaf that was already fitted with an upgraded 40 kWh battery, and the owner desired an upgrade to CHAdeMO fast charging to better use the larger pack.

The swap required the power distribution unit to be replaced, and the CHAdeMO port to be installed in the front of the car. The vehicle control module (VCM) also had to be opened in order to run a wire to a relay to activate the fast charging subsystem. Finally, wires had to be spliced to get everything to play nicely between the car and the fast charger.

[Daniel] had the benefit of quality forum resources and a Nissan Leaf that already had CHAdeMO to reference, which helped a lot. At the end of the day, the fast charger worked first time, much to [Daniel]’s relief. We’ve featured his work before, too. Video after the break.

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Improving More Leaf Design Flaws

September 16, 2020 by 19 Comments

[Daniel] was recently featured here for his work in improving the default charging mode for the Nissan Leaf electric vehicle when using the emergency/trickle charger included with the car. His work made it possible to reduce the amount of incoming power from the car, if the charging plug looked like it might not be able to handle the full 1.2 kW -3 kW that these cars draw when charging. Thanks to that work, he was able to create another upgrade for these entry-level EVs, this time addressing a major Leaf design flaw that is known as Rapidgate.

The problem that these cars have is that they still have passive thermal management for their batteries, unlike most of their competitors now. This was fine in the early ’10s when this car was one of the first all-electric cars to market, but now its design age is catching up with it. On long trips at highway speed with many rapid charges in a row the batteries can overheat easily. When this happens, the car’s charging controller will not allow the car to rapid charge any more and severely limits the charge rate even at the rapid charging stations. [Daniel] was able to tweak the charging software in order to limit the rapid charging by default, reducing it from 45 kW to 35 kW and saving a significant amount of heat during charging than is otherwise possible.

While we’d like to see Nissan actually address the design issues with their car designs while making these straighforward software changes (or at least giving Leaf owners the options that improve charging experiences) we are at least happy that there are now other electric vehicles in the market that have at least addressed the battery thermal management issues that are common with all EVs. If you do own a Leaf though, be sure to check out [Daniel]’s original project related to charging these cars.

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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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How Much Of A Battery Pack Does Your Electric Car Need?

December 25, 2017 by 143 Comments

[Elon Musk] recently staged one of his characteristic high-profile product launches, at which he unveiled a new Tesla electric semi-truck. It was long on promise and short on battery pack weight figures, so of course [Real Engineering] smelled a rat. His video investigating the issue is below the break, but it’s not the link that caught our eye for this article. As part of the investigation he also created an online calculator to estimate the battery size required for a given performance on any electric vehicle.

It’s not perfectly intuitive, for example it uses SI units rather than real-world ones so for comparison with usual automotive figures a little mental conversion is needed from kilometres and hours to metres and seconds if you’re a metric user, and miles if you use Imperial-derived units. But still it’s a fascinating tool to play with if you have an interest in designing electric cars or conversions, as you can tweak the figures for your chosen vehicle indefinitely to find the bad news for your battery pack cost.

It’s very interesting from a technical standpoint to see a credible attempt at an electric truck, and we hope that the existing truck manufacturers will show us more realistic prototypes of their own. But we can’t help thinking that the overall efficiency of electric long-distance trucking could be improved hugely were they to make a truck capable of hauling more than one trailer at once. Any safety issues could be offset by giving these super-trucks their own highways, and with such dedicated infrastructure the power could be supplied from roadside cables rather than heavy batteries. In such circumstances these long trains of electrically hauled containers could be rather successful, perhaps we might call them railroads.

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Tesla Model S Battery Pack Teardown

February 28, 2017 by 78 Comments

We’ve heard a lot about the Tesla Model S over the last few years, it’s a vehicle with a habit of being newsworthy. And as a fast luxury electric saloon car with a range of over 300 miles per charge depending on the model, its publicity is deserved, and that’s before we’ve even mentioned autonomous driving  driver-assist. Even the best of the competing mass-produced electric cars of the moment look inferior beside it.

Tesla famously build their battery packs from standard 18650 lithium-ion cells, but it’s safe to say that the pack in the Model S has little in common with your laptop battery. Fortunately for those of a curious nature, [Jehu Garcia] has posted a video showing the folks at EV West tearing down a Model S pack from a scrap car, so we can follow them through its construction.

The most obvious thing about this pack is its sheer size, this is a large item that takes up most of the space under the car. We’re shown a previous generation Tesla pack for comparison, that is much smaller. Eye-watering performance and range come at a price, and we’re seeing it here in front of us.

The standard of construction appears to be very high indeed, which makes sense as this is not merely a performance part but a safety critical one. Owners of mobile phones beset by fires will testify to this, and the Tesla’s capacity for conflagration or electrical hazard is proportionately larger. The chassis and outer cover are held together by a huge array of bolts and Torx screws, and as they comment, each one is marked as having been tightened to a particular torque setting.

Under the cover is a second cover that is glued down, this needs to be carefully pried off to reveal the modules and their cells. The coolant is drained, and the modules disconnected. This last task is particularly hazardous, as the pack delivers hundreds of volts DC at a very low impedance. Then each of the sixteen packs can be carefully removed. The packs each contain 444 cells, the pack voltage is 24 V, and the energy stored is 5.3 kWh.

The video is below the break. We can’t help noticing some of the rather tasty automotive objects of desire in their lot.

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Hackaday Prize Entry: SunLeaf

June 25, 2016 by 13 Comments

If there’s one place where the Internet of Things makes sense, it’s agriculture. From vast fields of soybeans, corn, and a different variety of corn, to the backyard garden, knowing how much sun, and rain crops get can vastly increase yields. For their Hackaday Prize project, [Adam] and [Shane] are building  a board designed explicitly for plants. It’s called the SunLeaf, and it has all the sensors and radios a good remote sensing board needs.

The SunLeaf is built around an ARM Cortex M4 microcontroller with an ESP8266 module for WiFi connectivity. Sensors are important for any remote sensing board, and for this the guys are going with SeeedStudio Grove connectors, providing four UARTs, four I2C, and four analog ports.For remote sensing applications, you generally can’t rely on mains power, so SunLeaf includes a port for a solar panel and a battery charger.

Although this project was originally a redesign of [Adam] and [Shane]’s Hackaday Prize entry from last year, what they’ve come up with is a great device for data logging, autonomous control, and environmental sensing for anything, from farms to weather stations.

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