Supercapacitors are not enough for sports cars to succeed?

Recently, Lamborghini, the world's top sports car manufacturer, announced that it will jointly develop a new supercar with MIT. The car will use supercapacitors to provide power, which is very different from conventional batteries. The supercapacitor is made of carbon material, which is smaller and lighter than conventional batteries, and can even be integrated with body panels.

It is understood that supercapacitor is a new type of energy storage device with the characteristics of short charging time, long service life, better tolerance to high and low temperature differences than batteries, energy saving and environmental protection, and is widely used.

According to Ruan Dianbo, director, chief engineer and chief technical expert of CRRC Supercapacitor Institute, there is no problem in using supercapacitors in sports cars, but they must be used in conjunction with conventional batteries and cannot be used alone. "The characteristics of supercapacitors are high discharge power, and the stored electrical energy can be released in a very short time, but it is not continuous. The characteristics of conventional batteries are just the opposite. They are a device that discharges continuously and can provide power for a long time. Supercapacitors are like a 100-meter runner with strong explosive power, while conventional batteries are more like a 10,000-meter runner with good endurance. Lamborghini sports cars can use supercapacitors when starting, accelerating and overtaking, or when emergency braking energy is fed back. When a sports car has accelerated to the highest speed and needs to maintain the highest speed, conventional batteries should be used. The battery used in a sports car should be a mixture of supercapacitors and conventional batteries." Ruan Dianbo said.

The combination of supercapacitors and conventional batteries in sports cars can avoid the high power output of conventional batteries. Accordingly, the safety of conventional batteries will be improved, and their service life will also be extended. Ruan Dianbo said that through experiments, it was found that if supercapacitors and batteries are used together, the service life of conventional batteries will be increased by 3 times.

At present, there are three types of supercapacitors: double-layer supercapacitors, hybrid supercapacitors and battery-like supercapacitors. The most basic is the double-layer supercapacitor, which has an energy density of about 5-10 watt-hours/kg, a power density of more than 6,000 watts/kg, and a particularly long charge-discharge cycle life of about 1 million charge-discharge cycles. At the same time, it is resistant to low temperatures and can be used at -40°C. "Supercapacitors not only have ultra-high charge and discharge efficiency, but also have a ratio of more than 98% of the energy released to the energy charged, which is much higher than conventional batteries. Basically, they charge as much as they discharge, and their process performance is also very good, and they can charge and discharge quickly. However, its disadvantage is also obvious, that is, the energy density is relatively low, only 5-10 watt-hours/kg, while lead-acid batteries can reach 30 watt-hours/kg, and lithium batteries can reach more than 100 watt-hours/kg." Ruan Dianbo said.

Ruan Dianbo introduced that hybrid supercapacitors, also known as lithium-ion supercapacitors, are a mixture of batteries and capacitors. The positive electrode is the positive electrode of the supercapacitor, and the negative electrode is the negative electrode of the lithium battery. It can increase the energy density from 10 watt-hours to 20 watt-hours, but its life will also be shortened, and the number of charge and discharge times will be reduced from 1 million to 100,000 times. The third type is a battery-like supercapacitor. CRRC can now achieve about 38-60 watt-hours/kilogram, and the life is about 30,000 to 50,000 times. (Reporter Lu Chengkuan)