As we sit in the middle of auto show season, we see the changes brought about by the change in CAFE standards for vehicle fuel economy. Manufacturers have lighter trucks, more efficient engines, and...of course...more electric and hybrid-electric vehicles. One might wonder, after a century of knowing the technology, and over a decade of implementation on new vehicles, why we do not see more electric and hybrid-electric vehicles. The problems rests on the limitations of current battery technology to deliver the performance we have come to expect under some of the high-output conditions: steering, braking, and acceleration. The solutions to this problem must come from either better batteries, or some form of supplemental electrical output that can provide the added power when needed. Recent research has developed capacitors that can provide the latter...and never missing an opportunity to turn anything into a superhero, we know them as ultra capacitors.
For those who remember their high-school physics or electronics shop classes, a capacitor in an electrical circuit stores charge at the circuit voltage for discharge at a later time. They perform several services in a circuit: resilience, stabilization, continuity, and their performance depends on their material makeup and the conditions surrounding them in the circuit. This stabilization function proves particularly useful in the setting of an electric vehicle.
The limitation in electric vehicles comes from the recharge and discharge rates of the battery. The electric power the car needs comes from a set of batteries optimally sized to provide the instantaneous power and duration of energy required. In times of constant power draw, the batteries perform well. When the car accelerates, performs high performance steering, or brakes quickly, the battery will experience draw or recharge faster than it expects. When this happens, it may hit the limit of the battery, limiting performance. To combat this, designers will sometimes install two battery systems: one for constant draw, and one for faster draw/recharge. This adds weight and complexity to the system that limits performance.
The ultracapacitor solves this problem by providing a constant draw device into the power circuit that can provide fast discharge when required. This prevents the battery from experiencing the sharp changes in draw/recharge that can damage the system if unchecked. In order for these capacitors to perform optimally, they have needed relatively significant cooling systems to keep them stable. As we demand more of them, the cost to install and maintain them has prohibited widespread adoption. Without a change in materials, ultracapacitors cannot find widespread adoption.
Recent research into materials holds hope for increased implementation of ultracapacitor technology. Ultracapacitors made out of ceramics can reduce the size of the device while supplying the same or greater performance. Also, the ceramics require measurably less cooling than current material choices. This reduces the demand on the electrical system, and improves the overall performance.
I expect that within the next five years we will see a significant increase in the number of electric vehicles, and expansion of the technology into more and more high performance vehicles. Ultracapacitors will drive that expansion. We will see increased issues with our electric grids (a topic for another day), but once we solve that, we will see a vehicle market no longer dependent on gasoline to get us from place to place.
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