Battery and supercapacitor are often compared together because they are usually used as energy storage components, but there are many differences in key parameters of energy storage and battery management systems. This article makes a detailed comparison between supercapacitor vs battery, and how to choose them in different application scenarios.
1. The difference between the working principle of supercapacitor vs battery
Supercapacitor vs battery, they are both electrical energy storage systems. Lithium-ion batteries rely on chemical reactions and consist of cathode and anode. These two sides are submerged in a liquid electrolyte and separated by a microporous separator that allows only ions to pass through. During charging and discharging of lithium batteries, ions tend to flow back and forth between the anode and cathode. As these ions transfer, they cause the battery to heat up, expand, and then shrink. These reactions gradually degrade the battery, resulting in shortened battery life.
However, a significant advantage of lithium battery technology is that it has a very high specific energy, or energy density, and can store energy for later use. Compared supercapacitor vs battery, supercapacitors are different in that they don't rely on chemistry to function. Instead, it stores electrical energy electrostatically in it. A supercapacitor uses a dielectric, or insulator, between its plates to separate the positive and negative charges that build up on each side of the plates. It is this separation that allows the device to store energy and release it quickly. It basically captures static electricity for future use.
The most significant advantage of doing this is that today's 3V capacitors will still be 3V capacitors in 15-20 years. In contrast, lithium-ion batteries may lose voltage capacity over time and repeated use. Also, compared supercapacitor vs battery, a supercapacitor has a higher power throughput, which means it can be charged and discharged in a very short amount of time. Still, it has a very low specific energy compared to batteries. Supercapacitors are most suitable for applications with small capacity but high power bursts.
2. Supercapacitor vs battery - differences in energy storage applications
● Charging and discharging
Supercapacitors basically do not undergo chemical reactions during charging and discharging, do not use heavy metals, and this energy storage process is reversible. Because of this, one of the main characteristics of a supercapacitor is that there is no practical limit to its charging capacity, it can be repeatedly charged and discharged hundreds of thousands of times, it has a long cycle life, and it is more environmentally friendly and clean.
Compared supercapacitor vs battery energy storage, battery energy storage system is more of a chemical reaction process, and has a higher energy density than capacitor-based electrostatic energy storage. But with current battery chemistries, lithium and lead-acid types only last a few years and decay rapidly as chemistry reacts and operating and storage conditions change.
● Working temperature
Batteries are susceptible to operating temperature fluctuations that affect their normal operation. The typical operating temperature range of the battery is -20°C to +40°C, but it is prone to thermal runaway, which reduces the efficiency and may even bring great safety hazards. Compared supercapacitor vs battery, supercapacitors typically have lower internal resistance, so very little energy is wasted as heat.
Supercapacitors basically do not undergo chemical reactions, and greatly reduce the possibility of thermal runaway. Various reasons make supercapacitors have a wider operating temperature range, which can reach -40°C to +85°C, and have better thermal stability and efficiency, which can improve the safety and reliability of electronic products.
● Power density
Power density is directly related to the charge and discharge rate and discharge time of energy storage technology. From the perspective of charge and discharge capabilities between supercapacitor vs battery, supercapacitors can choose a variety of charging methods such as constant current, and because their power density is several times higher than that of batteries, their charging rate is also higher, and they can be charged and discharged in seconds. And the battery will take hours.
● Battery management system
A battery management system (BMS) is critical to ensure proper charging and discharging. These systems do this by monitoring, controlling, and optimizing battery temperature, voltage, current, state of charge, and more. In recent years, battery technology has become more and more complex, its applications have become wider and wider, and the requirements for safety have become more and more stringent. Correspondingly, the requirements for battery management systems have also increased.
The inherent stability of supercapacitor module technology greatly reduces the complexity of the management system. Different supercapacitor vs battery, supercapacitor modules can be pre-installed with balancing circuits, and unlike BMSs, they require no external control or monitoring, making their application simpler and less costly, overcoming the limitation of charging life.
3. Supercapacitor vs battery - how to choose in different scenarios
Since supercapacitors and batteries have their own advantages, in practical applications, we can choose one or even combine them according to the demand for energy storage.
● Internet of things terminal equipment
High power density and small size energy storage can meet the demand brought by the increase in the number of IoT terminal devices. Compared supercapacitor vs battery, the life of supercapacitors is about 2-4 times that of batteries, and there is almost no risk of thermal runaway, which meets the operating life requirements of IoT nodes.
● Data center and industrial plant
Supercapacitors are characterized by high quality, long life and environmental protection, suitable for backup power applications in data centers, industrial plants, medical and other mission-critical activities. Compared supercapacitor vs battery, supercapacitors have less wear and tear, no thermal runaway, and the battery management system BMS is simpler.
● Electronic communication equipment
Supercapacitors can be used as a single energy storage, or form a hybrid energy storage system with battery technology, which can achieve 1+1>2. Supercapacitors can provide stable and reliable power for many applications in electronic communications that require short bursts of power, such as mobile phones.
● New energy vehicles
The characteristics of supercapacitors such as high power output and ability to accept high current charge and discharge, combined with the high energy density characteristics of batteries, can better meet the stringent requirements of electric vehicles for energy storage. The combination of the two can meet the various power requirements of the internal system of the electric vehicle, share the power output of the lithium battery, improve the life of the electric vehicle, improve efficiency and save energy.
In the long run, supercapacitor vs battery still shine in different fields due to their respective advantages, and their selection will ultimately be determined according to the actual needs of customers. But it is undeniable that the emergence and rapid development of supercapacitors have solved the difficulties encountered in some current applications.