Tesla is taking the lead again. Is the second spring of supercapacitors coming?

Compared with batteries, supercapacitors have many advantages, such as wide operating temperature (from -40℃ to +70℃), high energy density (up to 5kWh/kg), and green raw materials. And its lifespan is amazing, it can withstand 500,000 deep charge and discharge cycles, while ordinary batteries will probably die after 1,000 deep cycles.

Although supercapacitors are also energy storage systems, they are different from ordinary batteries as we know them. If ordinary lithium batteries are like gasoline, then supercapacitors are like explosives. Supercapacitors can charge and discharge very quickly, far exceeding traditional batteries.

But there are also disadvantages. Supercapacitors are not as good as batteries in long-term discharge capacity, so they cannot be used for continuous trickle energy output. And supercapacitors cannot be charged with AC power, but can only be charged at dedicated DC charging stations.

Supercapacitor buses in cities

In fact, supercapacitors are not a new technology. As early as August 2006, Shanghai Bus Group began to use supercapacitor buses for daily operations.

Because buses travel on fixed routes and points, buses using supercapacitor technology can replenish sufficient mileage by using the time when passengers get on and off the bus at stops until they reach the next charging station.

Compared with the old-fashioned "pigtail" buses, buses using supercapacitors are not restricted by wires, so there will be no "pigtails falling off" that will cause the vehicle to be unable to operate. And after removing the wires arranged above the city roads, the city environment has been significantly improved.

Of course, early supercapacitor buses also had shortcomings, such as untimely heat dissipation causing the vehicle to stop suddenly, slow running speed, loud air-conditioning noise, and charging equipment being occupied resulting in long waiting times.

However, with the innovation of technology, in December 2012, Shanghai Bus Group upgraded the high-energy supercapacitor system technology for buses No. 11 and No. 26. In September 2019, No. 11 and No. 26 were upgraded again, and 10 new-generation fast-charging high-energy smart supercapacitor buses were put into operation.

The new bus has completely improved the problems of poor high temperature performance, high noise, and short driving range of the early supercapacitor systems. The supercapacitor bus currently in use can achieve a single charge of 40 seconds and a driving range of 10 kilometers. And with the increase of charging stations and lines, supercapacitor buses will become more and more convenient.

Can supercapacitors be used in private cars?

Because supercapacitors cannot output energy continuously, and private cars cannot run at fixed points and routes like buses, it is difficult for private cars to use supercapacitors as the only energy source. However, if you change your mindset, supercapacitors will have great potential in electric vehicles - and may even lead a new energy revolution.

Just like the "supercapacitor + power battery" technology that Tesla is likely to release, supercapacitors can be a powerful auxiliary to traditional batteries - you can imagine supercapacitors as the Dantian often mentioned in martial arts novels. The martial arts masters have continuous internal force in their Dantian, and once needed, they can instantly burst out with huge internal force.

And from the perspective of braking energy recovery, the recovery and storage efficiency of supercapacitors is also higher than that of batteries.

During the charging stage, supercapacitors can enable the vehicle to complete energy replenishment in a very short time, effectively eliminating the anxiety of waiting during charging.

In the intervals between vehicles, such as when the vehicle is stopped, such as when waiting for a red light, the supercapacitor charges the battery pack. You can think of it as an electric car with a fast DC charging station. When the vehicle needs to accelerate quickly, the supercapacitor can directly output a large current to the motor. Even if the capacitor has no power, it doesn't matter. The battery pack can reverse the power input to the supercapacitor, thereby achieving instantaneous high current output.

In other words, it is difficult for supercapacitors to be widely popularized in electric vehicles, but if used in combination with batteries, they can be of infinite use.

Moreover, after being equipped with supercapacitors, the battery power and weight can be effectively reduced while ensuring the endurance. The battery can be made smaller, which can not only effectively reduce the weight of electric vehicles, improve energy efficiency, and reduce the cost of the entire vehicle, especially the cost of battery maintenance and replacement.

In this way, engineers can save a lot of brain cells in terms of battery collision protection...

In addition, supercapacitors can also be used in charging pile technology. The biggest problem currently limiting the popularization of super-fast charging piles is not the cost and technology of super-fast charging piles, but the network load capacity of the power system. Simply put, if a regular community has 5 100kW fast charging piles using full power at the same time, it will definitely paralyze the power system of the community or even the entire block.

If supercapacitor technology is applied to super-fast charging piles, perhaps this situation will change completely.

In idle state, supercapacitors can be charged with low-power high-voltage direct current without causing load pressure on the power grid; in the charging state, high-power DC output can be achieved to quickly charge power batteries or on-board supercapacitors!

You can think of it as the relationship between a trickle and a basin - the trickle fills the basin, and then the basin is poured out. However, in this case, the fast charging pile cannot be plugged in and charged, because the supercapacitor in the charging pile, that is, the "basin", needs a long time of trickle energy storage recovery process after each pouring of water.

This problem has no impact on private charging piles, and the impact on public charging piles is also limited. After all, can't the problem be solved by building more charging piles?

How safe are supercapacitors?

As mentioned above, the energy density of supercapacitors can reach up to 5kWh/kg, which means that a 20kg supercapacitor can provide 100kWh of energy storage. Such a high energy density is bound to bring safety concerns.

An expert in the field of supercapacitor technology said that supercapacitors are actually very suitable for installation in future pure electric vehicles, and because of their small size, supercapacitors do not take up space and are very easy to manage, so safety will not be a problem.

If installed in the center of the bottom of the car, it can provide better protection in a collision accident. From the perspective of safety redundancy, supercapacitors are much higher than current power batteries.

As a leader in the industry, if Tesla applies the "supercapacitor + power battery" technology to its own products, it will inevitably lead other new energy vehicle companies and battery manufacturers to follow suit. Supercapacitors may become the technological trend of the new generation of pure electric vehicle energy systems.

All in all, I am very optimistic about this technology!