Electric Double Layer Capacitors (EDLC), Supercapacitors
1. What are Electric Double Layer Capacitors (EDLC), Supercapacitors?
EDLC (electric double-layer capacitor) is an energy storage element that stores charge through polarized electrolytes, which is between traditional capacitors and batteries. Its core principle is to use the ions in the electrolyte to form an electric double-layer structure (Electric Double Layer) on the electrode surface to store energy. Unlike traditional capacitors, the electrodes of EDLC use porous materials such as activated carbon, which greatly increases the surface area (up to 2000m²/g) and combines it with a very small charge separation distance (<10Å) to achieve ultra-high capacitance.
2. What are the Structural Characteristics of Electric Double Layer Capacitors (EDLC), Supercapacitors?
Electrode Material: Porous activated carbon electrode, which forms a double layer by adsorbing ions in the electrolyte.
Electrolyte and Diaphragm: The electrolyte is mostly organic or aqueous solution, and the diaphragm is used to isolate the positive and negative electrodes and allow ions to pass.
Low Internal Resistance Design: Some products (such as the Emerald BCE series) use full-ear technology to significantly reduce internal resistance, and improve charging and discharging efficiency and cycle life.
3. What are the Technical Advantages of Electric Double Layer Capacitors (EDLC), Supercapacitors?
High Power Density: Low resistance characteristics support large current charging and discharging, and the power density is much higher than that of traditional batteries.
Long Cycle Life: Due to the lack of chemical reaction, the number of charge and discharge times can reach hundreds of thousands.
Wide Temperature Adaptability: It can still work stably at extreme temperatures, which is better than traditional electrolytic capacitors.
High Energy Density: TDK and other manufacturers have achieved a single capacitor capacity of 500mF and a rated voltage of 3.2V–4.2V by optimizing electrodes and electrolytes.
4. Where are Electric Double Layer Capacitors (EDLC), Supercapacitors Used?
New Energy Field: Used for instantaneous energy recovery and release in hybrid vehicles and energy storage systems.
Industrial Equipment: As a backup power supply or power buffer module, it guarantees the instantaneous high power demand of the equipment.
Consumer Electronics: Energy replenishment and fast charging scenarios for low-power devices.
5. Development Trend of Electric Double Layer Capacitors (EDLC), Supercapacitors
Current EDLC technology is breaking through in the direction of higher voltage and lower internal resistance. For example, the 3V/750F low internal resistance series launched by Emerald further expands its application potential in smart grids, rail transit, and other fields. At the same time, material innovation (such as new carbon-based composite materials) and packaging technology optimization (such as TDK’s miniaturized design) continue to promote product performance improvement.
EDLC FAQs
1) What are the differences between EDLC and batteries and traditional capacitors?
Compared with batteries:
EDLC has no chemical conversion during charging and discharging, and has a longer life (>1 million times);
The energy density is lower than that of lithium batteries (about 0.28 kWh/kg vs. 0.12 kWh/kg), but the power density is higher;
The application scenarios are different: batteries are suitable for long-term energy storage, and EDLC is suitable for short-term high-power output (such as vehicle starting).
Compared with traditional capacitors:
EDLC has high capacity (farad level vs. microfarad level), but low withstand voltage (usually <20V);
Traditional capacitors rely on dielectrics to store charge, while EDLC uses the double layer of the electrode/electrolyte interface.
2) What is the life of EDLC? Does it require maintenance?
EDLC can be charged and discharged more than 1 million times in normal use, and the capacity decay is minimal. Its solid-state structure avoids the risk of electrolyte leakage and does not require special maintenance. However, care should be taken to avoid overvoltage or high-temperature environments to extend the service life.
3) How does the latest technology improve the performance of EDLC?
Material optimization: Use high-purity barium titanate or full-ear structure to reduce internal resistance and improve power density; Packaging improvement: Metal foil laminated film packaging achieves low resistance and lightweight design; Hybrid technology: Combine the advantages of lithium-ion batteries and EDLC to develop hybrid capacitors (such as lithium-ion capacitors).
4) How safe is EDLC?
EDLC has no flammable electrolyte and no violent chemical reaction. It is safer than lithium batteries and is suitable for high-reliability scenarios (such as medical equipment and military equipment). In addition, some products use flame-retardant materials and pressure relief valve designs to further reduce risks.