Supercapacitor Module
EDLC / Hybrid Supercap Cell Block (~5 Wh/kg, >1M cycles)
Module of electric double-layer capacitors (EDLCs) or hybrid asymmetric supercapacitors providing ultra-fast, high-cycle-count energy storage for transient power buffering, peak shaving, and ride-through during reactor restarts.
Purpose
Absorb millisecond-scale load steps, smooth source-bus transients, and provide instantaneous power that cannot be drawn from batteries or fuel cells without damage — at >1,000,000-cycle life with minimal aging.
Context
Stacked into racks (L3-ESS-SCAP-RACK), balanced by L3-ESS-SCAP-BAL, connected via L3-ESS-SCAP-DCDN to the L1-PDM bus, supervised by L3-ESS-SCAP-CTRL. ESA evaluation confirms COTS supercaps tolerate gamma/proton radiation; operating range typically –40 to +65 °C with cycle life >10⁶.
Principles
- ▸Electric Double-Layer Capacitor (EDLC) stores charge in the electrochemical double-layer at high-surface-area carbon electrodes (no Faradaic reaction)
- ▸Specific energy 3–10 Wh/kg, specific power 5,000–15,000 W/kg — opposite of Li-ion (high energy, low power)
- ▸Cycle life >10⁶ (vs. Li-ion 5,000) because no chemical conversion during charge/discharge
- ▸Self-discharge ~10%/day (much higher than batteries) — not for long-duration storage
- ▸Cell voltage limited to 2.5–3.0 V; many cells series-stacked for higher voltage
- ▸Hybrid asymmetric supercapacitors (battery-type cathode + EDLC anode) reach 15–25 Wh/kg at lower cycle life (~50,000)
Typical implementations
- ▸Maxwell Technologies BCAP3400 EDLC (commercial reference)
- ▸Skeleton Technologies SkelCap (high-power, automotive)
- ▸Nesscap / LSCM hybrid supercapacitors (commercial)
- ▸ESA in-orbit supercap demonstrations (gamma/proton tested per Passive Components Europe 2018)
- ▸ScienceDirect thermal-vacuum supercap evaluation
- ▸Tesla auto braking-energy supercap modules (legacy)
Lunar considerations
- ▸Standard temperature window –40 to +65 °C — comparable to Li-ion battery thermal management envelope
- ▸Radiation tolerance: COTS supercaps show no significant performance change after gamma/proton exposure per ESA evaluation
- ▸Self-discharge dominates for storage durations >1 day; supercaps used only for transient buffering not lunar-night storage
- ▸Vacuum and thermal cycling characterized by ScienceDirect 'Evaluation of Supercapacitors for Space Applications Under Thermal Vacuum Conditions' study
- ▸ESR (equivalent series resistance) rises with cumulative cycles — track in L3-ESS-SCAP-CTRL
- ▸Long-mission >10⁹ cycles possible without exceeding cell life — true 'unlimited' for typical Ark transients
Specifications
Functional
| primary function | Store and discharge electrical energy at millisecond-to-second timescales |
| inputs | Charging current at C/10 to C/1 rate, Voltage from L1-PDM bus via DC-DC, Coolant interface (thermal management) |
| outputs | Discharge current up to 200 A peak, Cell-level voltage telemetry, ESR and aging telemetry |
| module capacitance f | 500 |
| module voltage v nominal | 48 |
| module voltage v max | 54 |
| module energy wh | 175 |
| module peak power kw | 50 |
| specific energy wh per kg | 6 |
| specific power w per kg | 5000 |
| cycle life | 1000000 |
| calendar life years | 15 |
| self discharge percent per day | 10 |
| operating temperature c | -40, 65 |
Physical
| mass kg | 28 |
| dimensions | 350 × 200 × 100 mm |
| materials | High-surface-area activated carbon electrodes (S > 1500 m²/g), Acetonitrile + TEABF4 electrolyte (or aqueous variant), Aluminum current collectors, Polypropylene separator, Cylindrical or pouch package with hermetic seal, Aluminum enclosure with cooling plate |
| operating temperature c | -40, 65 |
| vacuum compatibility | Hermetic cells |
| radiation tid krad | 100 |
Operational
| power consumption w | 0 |
| thermal range c | -40, 65 |
| lifetime years | 15 |
| mtbf hours | 1000000 |
Interfaces
Provides
- 48 V module output
- Cell voltage, ESR telemetry
Requires
- Cell balancing
- Thermal interface (~50 W during peak operation)
Cite this entry
Lunar Ark Codex. "Supercapacitor Module" (L3-ESS-SCAP-MOD). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-ESS-SCAP-MOD
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.