In the five minutes that it takes you to read this article, your electric vehicle (EV) could have charged its batteries. Well, maybe not with current technology, but if engineers at Nanyang Technological University (NTU) are right, ultra-fast charging batteries could be available in two years. Researchers at NTU’s School of Materials Science and Engineering have developed a rapid charging battery that can charge up to 70% capacity in two minutes and full capacity in five minutes. That’s good news, especially for the electric vehicle market. The better news is that it’s just a slight variation of existing lithium-ion (Li-ion) battery technology, so Tesla and other EV battery makers won’t need to retool their production facilities. And to top it all off, these batteries are expected to deliver up to 10,000 charge cycles, about ten times more than conventional Li-ion batteries. If this is true, then electric vehicle batteries could theoretically last 1,000,000 miles (1,610,000 km).
The trick is changing the chemistry of the anode, the negative terminal of the battery. Instead of using graphite, the standard anode material in most Li-ion batteries, the new batteries use a gel made of titanium-dioxide (TiO2) nanotubes. The gel allows chemical reactions to take place much more quickly, giving the battery its fast charging ability. TiO2 is cheap and abundant, so the gel won’t make the batteries too costly.
Image courtesy of Nanyang Technological University
Integrated Motor and Inverter
If you remember the early days of personal computers, the motherboard was supported by a video card, audio card, drive controller, and external ports, each being its own expansion card. Gradually all those functions became integrated into the motherboard and the drives, making it less expensive to produce a PC.
Taking a page from the consumer electronics industry, Siemens just announced work on a new electric vehicle motor that integrates an inverter right inside the motor housing. Electric vehicles run on DC electricity produced by a battery, but AC motors tend to be more efficient, so the inverter converts the battery’s DC output to AC before it gets to the motor. Integrating the inverter into the motor reduces weight, size, and complexity.
Image courtesy of Siemens
The company suggests that heat will be the biggest issue with this integration. Both the motor and the inverter require cooling systems, and Siemens has developed a method of using the same cooling system for both. The cool water reaches the electronics first and then loops around to cool the motor housing. The water itself acts as a thermal insulator between the inverter and the motor.
Although they’ve addressed cooling, the press release has no mention of electromagnetic interference (EMI). Electrically, a motor is a very noisy environment, and I’m wondering how they’ll protect the electronics from all that EM noise. I don’t think the cooling water will provide a sufficient shield. At this point it’s still being worked on by people in lab coats; we’ll see whether they can work out the bugs and get something that’s production-worthy.
Small Inverter - Big Improvements
Engineers at Oak Ridge National Laboratory (ORNL) are working on an inverter that’s optimized for size, efficiency, and weight. What makes all this possible? 3D printing. “With additive manufacturing, complexity is basically free, so any shape or grouping of shapes can be imagined and modeled for performance,” said project leader Madhu Chinthavali. It’s that innovative grouping of shapes that allows components to be packed into an optimal space. As a nice side-effect, additive manufacturing reduces waste, which decreases costs.
Image courtesy of Oak Ridge National Laboratory
The team has developed a prototype that’s achieved an incredible 99% efficiency. That design has about half of its parts made by 3D printing. ORNL plans to build another with more parts made with additive manufacturing, hoping to achieve even smaller sizes and higher powers.
Maybe these folks should get together with engineers at Siemens. Seems to me that the two technologies could be a good marriage.
EV Charging and Smart Grid Protocols
If the whole world converts to electric vehicles, it’ll put an awful strain on an already maxed-out electric grid. That’s why a consortium led by the Electric Power Research Institute (EPRI) is working on a set of smart charging protocols that allow a smart grid to talk to electric vehicles and regulate their charging. (Before you scream about someone else controlling your electric usage, be aware that this would be strictly an “opt-in” protocol for the consumer.) The intent is to be sure that everyone’s car isn’t charging at the same time, especially if that’s peak demand time, which usually occurs when people are getting home from work (and presumably plugging in their EVs to charge overnight.) Rather than charging right away, the grid could request that your car hold off until the wee hours of the morning. You’ll still be able to plug it in when you get home from the office and you’ll have a fully charged battery in the morning, but you won’t be overloading the grid when it can’t handle the excess load. This initiative is supported by numerous electricity providers and EV manufacturers. They all know that it’s in their best interests to cooperate on this.
Image courtesy of Tesla Motors
So Long, Dinosaurs
The switch to electric vehicles is inevitable. They’re simpler to design, build, and maintain, and their total cost of ownership is lower than that of gasoline powered vehicles. The only remaining drawback is range, but with improvements in battery and charging technology, that’s soon to be a non-issue. Perhaps in my lifetime I’ll see the day when vehicles powered by fossil fuels are only seen in museums and antique car shows.
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