Structure for Better Batteries

Editor’s note:  This is the second article in our two-part series on the basics of CoEx technology.

co-extrusion_flow_battery-parc (2)Battery manufacturers currently have a complicated trade-off. With the limited space available inside the battery, they typically have to choose between power or energy densities. It’s an already tough choice that’s getting even tougher as the demand for electric vehicles and other applications truly require both. And, of course, it all needs to be done with less expense.

For typical battery electrodes, increased power requires greater conductivity, and greater conductivity is usually achieved through reducing electrode thickness or Lithium ion density for freer movement of charged particles. However, this directly reduces the amount of energy actually stored in the battery, so the technique is only useful for applications where high power is needed for a short duration, not a widely applicable situation.

When batteries are manufactured, typically the electrode material (cathode or anode) is deposited as a monolithic unstructured slurry without any design control. But by structuring an electrode to vary material composition, the ion flow paths can be shortened without compromising capacity.

Co-Extrusion technology (CoEx) is an incredibly cost-effective way to manufacture structured electrodes for the first time, and it can be applied to both cathodes and anodes for most battery chemistries. In one structural embodiment with CoEx, small vertical regions are created. Some of these regions are more energy dense and others more porous so that the ions can easily transfer. The shape allows manufacturers to deposit much thicker electrodes within current size constraints and still get the lithium ions in and out very quickly. The illustration below shows the performance improvement derived from increased lithium utilization.

battery-performance (2)

The end result is that the relative interior dimensions can be changed to achieve optimal performance in terms of both increased power and energy. Plus manufacturers have the flexibility to customize the benefits for batteries based on their specific application – whether it’s for EV batteries, coin cells, and more.

So how much increase are we actually talking about here? PARC’s research has demonstrated up to 30% increase in energy or power density. For example, if we translate the energy density benefit to real-world terms, this would increase an EV’s range from 100 miles to 130 miles, a marked difference. CoEx can also deliver size reduction benefits, which would be valuable to both EVs and small consumer electronics devices.

The best part for battery manufacturers is that CoEx is already a proven manufacturing process in use for the production of solar photovoltaic cells, and it requires only one piece of equipment that can be easily dropped into the manufacturing line where it operates at compatible line speeds. The change is only required at one point in the long list of steps to manufacture a battery.

While many groups are experimenting with incredible new battery innovations that are also very important, such as lithium air and other far-out technologies, these are anywhere from three to 10 years from hitting the market. CoEx can be used for many existing battery chemistries and is an immediate drop-in replacement for the way material is deposited today and provides a sizable boost in energy and power.

CoEx has exciting potential for battery manufacturers. After recently showcasing the technology in Japan, we are furthering our discussions with global organizations to bring CoEx into the manufacturing line and your EV battery soon.

To learn more about CoEx for batteries and work with PARC, please email engage@parc.com.

Stay up-to-date on all the latest from PARC! Subscribe to our newsletter.