Perhaps the single greatest barrier to widespread adoption of plug-in automobiles is the time it takes to charge them. We have looked into charging times in the past, and even with the most advanced infrastructure in place at charging stations, you are still looking at one hour or more to fully recharge your battery. The automobile industry (and investors), however, have not been deterred, and many have pointed to a trend in developing lower-cost, more efficient rechargeable batteries. Lately, it seems, their optimism has been warranted.
Researchers from the University of Illinois at Urbana Champaign have built a prototype battery that can conceivably reduce charge times down to mere minutes.
Lithium-ion batteries, like all batteries, work by connecting two electrodes through an electrically conductive material — called an electrolyte. When that battery is charging and discharging, negatively-charged electrons flow between each electrode while positively-charged ions flow to balance out the charges. As the image to the right shows, lithium has recently become the material of choice due to the amount of energy it can store relative to its weight. Nickel-metal hydride batteries are still in use, however, and come at a cheaper cost.
The breakthrough in this instance comes from increasing the surface area between the electrodes and the electrolyte: a critical factor in determining the recharging rate. At the same time, they were able to maintain a large battery volume, a key attribute to storing maximum energy. The researchers were able to accomplish this by starting off with a material made up of closely packed polystyrene spheres, each about one-millionth of a meter in diameter. The gaps between the spheres were filled with nickel through a process called electrodeposition. The porosity of this nickel-layer could be increased using electropolishing, creating a framework conducive for placing electric cathodes.
Both a nickel-metal hydride and a lithium-ion battery were created using this material, and in both cases the area of contact between the nickel, the electrolyte, and the cathodes were greatly increased. The researchers claimed that they were able to re-charge a lithium-ion battery to 90% capacity in two minutes! Furthermore, they say the increase in production costs to manufacture such a battery should only be 20-30% higher than current techniques, once these batteries start becoming mass produced.
So, will these new batteries revolutionize plug-in cars? The answer is not so simple. The huge current that is necessary to charge a battery so quickly would require significant upgrades to a car’s electrics as well as to charging stations. It is also uncertain whether these faster-charging batteries affect battery life. These concerns aside, however, this could be a major step in the right direction. Like we mentioned earlier, charge-times are a major barrier to customer adoption of plug-ins. Charging overnight is fine — but wasting significant time at a charging station is most likely a deal-breaker. If advances in battery technology such as this one shatter that barrier, the positives of electric cars might finally outweigh the negatives… which would indeed create a revolution.