Super Capacitor batteries have always been the envy of batteries for a couple of very good reasons. They are very fast to charge and discharge. Some have dry electrolytes which means that there is no end to the amount of cycles that can be achieved. These characteristics are a just a dream for chemical batteries which are often limited to fewer than 5,000 cycles and have a very slow relative charge and discharge time. Up until this point though, a chemical battery has been able to take the lead in terms of energy. Batteries are about volumes and capacitors are about surface area. A good metaphor is an open-top glass vase and a normal bottle, with a thin neck, both full of water. The vase is like the capacitor. When its tipped over, all the water comes out immediately and you can fill it up fast too. In electrical terms, all the available stored energy comes out, a high power rating, all at once. The bottle on the other hand, is like the battery and when tipped the water comes out of its neck at a limited rate and it takes much longer to empty. The same is true of filling them both up or recharging them again.
For example, on a cold morning, you may have difficulty starting your car. The cold, lead acid battery can’t provide enough energy, all at once, to turn over the starter motor. If you attach a supercapacitor to the battery though, you can charge up the capacitor from the battery for a few minutes and then discharge this electricity much faster, and start the engine. Another example is where the battery and capacitor work together combining their capabilities. A bus might need a lot of power when its accelerating, but batteries might be unable to help. Super-capacitors already charged from the battery though, can dump enough energy on that electric motor to make sure acceleration goes without a hitch. The bus has regenerative braking, but its lithium ion batteries are unable to absorb the charge fast enough. Luckily the capacitors can rapidly absorb all the electrical energy from the brakes first and then feed it at an appropriate rate to the lithium-ion batteries. This teaming up of battery and capacitor is only a temporary phenomenon however.
The arrival on the scene of graphene has caused capacitors to suddenly have a significant amount of energy density instead of simply power. This is a key distinction. Until this point, a chemical battery had energy but not power while the capacitor has power but not energy. This relationship is now undergoing rapid transformation. The key relationship is the energy on a capacitor in joules is proportional to half the capacitance (in farads) times the voltage squared.
Careful examination of the components of a capacitor have resulted in incredible breakthroughs in two areas in that formula. In one case, represented by Eestor, a Texas based capacitor company headed up by CEO, Ian Clifford, has managed to combine a very high functioning dielectric, barium titanate, between electric plates with a dry electrolyte at very high voltages. Eestor’s voltages are as high as 3,500 volts, meaning that the capacitors have a significant amount of energy capacity, rivaling the lithium-ion battery. Even a single, 1 Farad capacitance at 3,500 volts means the capacitor is holding 1.7 kilowatt hours of electrical energy. These particular, disruptive capacitors are addressing the grid demand/supply smoothing market and will have few competitors.
The impact of Edison Power is to increase the capacitance or Farads using graphene and emphasizing the surface area issue with this new approach with the result that you also obtain an elevated energy storage level. It’s clear that in this environment, a safe, cheap, fast charging and discharging, electrical energy storage device (EESD) that can cycle endlessly has huge advantages. Maybe lithium’s days are numbered?