The Michigan Engineer News Center

Lithium ion batteries: Why they explode

When we hear of a cell phone, laptop, or car battery exploding, that can rightfully be a cause for concern.| Short Read

Lithium ion batteries are all around us. In our homes, our cars, even on our person at nearly all times. And so when we hear of a cell phone, laptop, or car battery exploding, that can rightfully be a cause for concern. A lot goes into the creation of any single lithium ion cell and even a small error in that process could lead to big problems during the battery’s life cycle, explains Greg Less, who manages the U-M Energy Institute’s Battery Fabrication and Characterization User Facility at Michigan Engineering.

The facility offers a rare look the production of lithium ion cells—errors during which have proven to be a critical factor in battery explosions. The lab gives users from the university and industry access to a typical battery fabrication production line, miniaturized and separated into its component parts. Users can experiment with new materials and battery designs in a factory-quality work environment. They can build and characterize several types of batteries: Coin cells, often used as proof-of-concept; 18650 batteries, similar to the familiar “AA” cylindrical shape used for many small electrical devices; and 72×110 mm prismatic pouch cells, the type most often used as laptop batteries. Both 18650 and pouch cells are also used in electric vehicles.

Researchers
  • Greg Less

    Greg Less

    Battery User Facility Senior Manager

The electrons absorb laser light and set up “momentum combs” (the hills) spanning the energy valleys within the material (the red line). When the electrons have an energy allowed by the quantum mechanical structure of the material—and also touch the edge of the valley—they emit light. This is why some teeth of the combs are bright and some are dark. By measuring the emitted light and precisely locating its source, the research mapped out the energy valleys in a 2D crystal of tungsten diselenide. Credit: Markus Borsch, Quantum Science Theory Lab, University of Michigan.

Mapping quantum structures with light to unlock their capabilities

Rather than installing new “2D” semiconductors in devices to see what they can do, this new method puts them through their paces with lasers and light detectors. | Medium Read