Freezing cold. Dead battery. Slow charging. EV owners will certainly relate to this frustrating trifecta that has forced some to return to the more resilient internal combustion engines. It makes electric cars almost unusable during the winter, particularly in areas with severe wintry conditions. However, a new breakthrough from University of Michigan engineers could change that radically.
Fortunately, the new tech doesn’t require new exotic materials. It won’t ever sacrifice other performance figures important in EVs, like energy density, range, or the long-term health of the battery. Namely, by tweaking how lithium-ion battery electrodes are made, the team has developed a method that allows EV batteries to charge five times faster in subzero conditions, as low as -10°C (14°F). It’s a practical, manufacturable solution. Patent-pending, too.
“We envision this approach as something that EV battery manufacturers could adopt without major changes to existing factories,” said lead researcher Neil Dasgupta.
To extend range, EV makers have been using thicker electrodes. That’s great for storing energy, but terrible for charging speed. This is especially true during the cold, when lithium ions move much, much slower. A thicker electrode only exaggerates the issue, of course.
In earlier work, Dasgupta’s team solved part of the problem by drilling microchannels — about 40 microns wide — into the graphite anode using lasers. These channels gave lithium ions a shortcut, improving fast charging at room temperature, but not during freezing conditions.
Still, the team later found that the real issue was chemistry. Namely, during the cold, a stubborn layer forms on the electrode, blocking lithium flow and causing harmful metal buildup. The simple fix: a 20-nanometer glassy coating of lithium borate-carbonate that stops this layer from forming. Pair it with laser-drilled channels, and the result is a battery that charges 500% faster in freezing temps and keeps 97% of its capacity after 100 fast-charge cycles.
The best part — this isn’t just another research paper that we’ll forget soon. Arbor Battery Innovations, which licensed the channel tech, is working to bring it to market. Follow-on development is funded by the Michigan Translational Research and Commercialization (MTRAC) program, and the tech has been built at U-M’s Battery Lab and studied at the Michigan Center for Materials Characterization.
This is a crucial development in the EV sector, which has been struggling recently due to range anxiety and slow charging speeds.
Article and image source by University of Michigan
