HJC (Huarong) Supercapacitors

Supercapacitors and batteries store energy through different mechanisms: 1) Energy Storage - Supercapacitors store energy electrostatically (physical charge separation)

batteries store energy chemically (electrochemical reactions), 2) Power Density - Supercapacitors: 10-100 kW/kg (high power)

Batteries: 0.1-1 kW/kg (lower power), 3) Energy Density - Supercapacitors: 1-10 Wh/kg

Batteries: 100-250 Wh/kg (lithium-ion), 4) Cycle Life - Supercapacitors: 500,000+ cycles

Batteries: 500-2000 cycles, 5) Charge Time - Supercapacitors: seconds

Batteries: minutes to hours, 6) Temperature Range - Supercapacitors: -40°C to +65°C

Batteries: 0°C to +45°C typically. Applications: Use supercapacitors for high-power, short-duration, frequent cycling

use batteries for high-energy, long-duration storage. Many systems use both - supercapacitors for peak power, batteries for energy storage.

Choose supercapacitors for high-power, frequent cycling applications; batteries for high-energy, long-duration storage.

To calculate required HJC supercapacitor capacitance: 1) Energy Required - E = 0.5 × C × (Vmax² - Vmin²), rearrange to C = 2E / (Vmax² - Vmin²), 2) Power Required - For constant power discharge: C = P × t / (0.5 × (Vmax² - Vmin²)), where P is power, t is time. Example: Backup power for 10W load for 60 seconds, voltage range 5.0V to 3.0V (using two 2.7V cells in series): C = 2 × 10W × 60s / (5.0² - 3.0²) = 1200 / 16 = 75F. Use 100F for margin. 3) Current Capability - Check that ESR allows required discharge current: I = V / ESR. For high-current pulses, parallel multiple capacitors to reduce effective ESR. HJC provides an online calculator or contact our FAE team for complex applications.

Use the energy formula C = 2E/(Vmax²-Vmin²) or contact our FAE team for application-specific calculations.

HJC supercapacitors (2.5V-3.0V per cell) can be connected in series for higher voltage: 1) Series Connection - Connect positive to negative

voltages add, capacitance reduces (Ctotal = C/n), 2) Voltage Balancing - Essential for series connection

use active balancing circuits or passive balancing resistors, 3) Balancing Resistors - Size to pass 10-50x leakage current

typically 1kΩ-10kΩ per cell, 4) Active Balancing - More efficient

uses ICs or circuits to transfer charge between cells. Example: For 12V system, use 5 cells in series (5 × 2.7V = 13.5V). With 100F cells: Ctotal = 100F/5 = 20F. Use balancing circuit to prevent overvoltage on individual cells. HJC offers modules with built-in balancing, or we can recommend balancing circuits for custom configurations. Never connect supercapacitors in series without balancing.

Use series connection with active or passive balancing; never connect in series without balancing circuit.

HJC supercapacitors have leakage current that affects standby power and hold-up time: 1) Typical Leakage - 0.5-5µA per Farad at rated voltage and 25°C, 2) Temperature Effect - Leakage doubles approximately every 10°C increase, 3) Time Dependence - Leakage is highest immediately after charging and decreases over hours to days. Design considerations: 1) Standby Power - Calculate leakage power: P = V × Ileakage, 2) Hold-Up Time - Leakage reduces actual hold-up time

factor into calculations, 3) Balancing Circuit - Balancing resistors add to leakage current, 4) Charging Circuit - Ensure charging circuit can supply leakage current to maintain voltage. Example: 100F supercapacitor at 2.7V has ~100µA leakage

standby power = 0.27mW. For battery-powered applications, this may be significant. For mains-powered applications, leakage is usually negligible.

Factor leakage current into hold-up time calculations; consider impact on battery life for portable applications.

HJC supercapacitors offer exceptional cycle life compared to batteries: 1) Rated Cycle Life - 500,000 to 1,000,000 cycles at rated voltage and temperature, 2) Degradation Mechanism - Gradual ESR increase and capacitance decrease over cycles, 3) End of Life - Typically defined as 20% capacitance loss or 2x ESR increase, 4) Factors Affecting Life - Voltage (higher voltage reduces life), temperature (higher temperature reduces life), current (very high currents cause heating). Typical degradation: After 100,000 cycles: <5% capacitance loss, <20% ESR increase. After 500,000 cycles: <10% capacitance loss, <50% ESR increase. Unlike batteries, supercapacitors do not have sudden catastrophic failure - they degrade gracefully. For applications with frequent cycling (energy harvesting, regenerative braking), supercapacitors last 10-100x longer than batteries.

Expect 500,000+ cycles with minimal degradation; supercapacitors are ideal for high-cycling applications.