FLEET Quasi-Solid State Batteries
High Energy Density | Lithium-Metal Cells | Stratosphere-Ready
FLEET pairs a lithium-metal anode with a quasi-solid electrolyte to hold stable power output in the extreme cold and high radiation of the stratosphere, down to -60°C. With cell energy density up to 525 Wh/kg, FLEET powers pseudo-satellites and high-altitude drones for weeks or even months — a key energy carrier for 'never-landing' airborne base stations.
Key Benefits
Holds >80% capacity at -70°C — built for long-term operation in the stratosphere
Cell energy density up to 525 Wh/kg for extreme lightweighting and long-endurance flight
Long cycle life under extreme conditions — lowering total life-cycle operating cost
Aviation-grade safety — passes nail-penetration and thermal-abuse tests: smoke, not fire
Pouch cell formats: 3.5Ah, 9.7Ah and 13.3Ah
Ideal For
FLEET powers high-altitude platforms, pseudo-satellites, low-orbit satellites and stratospheric drones, as well as emergency communication relay platforms. It was engineered for high energy in a lightweight, compact form factor — proven in record-setting flight for the High-Altitude Pseudo-Satellites (HAPS) that deliver 24/7 5G and LTE coverage from the stratosphere with HAPS Mobile.
Enpower Greentech's 3.5Ah lithium-metal battery was selected by SoftBank Corp., among many competitors, to advance both their ESG and SDG goals with the most efficient technology available — the FLEET 3.5Ah pouch cell.
Are you a battery cell buyer or a pack integrator?
The Fleet battery may be customized through joint-development. Inquire with our engineers to explore the Fleet platform for your energy dense high power battery needs.
Available Configurations
FLEET is available in multiple lithium-metal pouch-cell capacities, all built for stratospheric, long-endurance flight.
FLEET 3.5Ah
Cell
- Energy density
- 420 Wh/kg
- Voltage platform
- 3.84 V
- Maximum continuous discharge
- 5C
- Temperature range
- -20~50°C
- Cycle life
- >400 cycles @ 0.2C/0.5C
FLEET 9.7Ah
Cell
- Energy density
- 430 Wh/kg
- Voltage platform
- 3.84 V
- Maximum continuous discharge
- 5C
- Temperature range
- -20~50°C
- Cycle life
- ≥400 cycles
FLEET 13.3Ah
Cell
- Energy density
- 500 Wh/kg
- Voltage platform
- 3.84 V
- Maximum continuous discharge
- 2C
- Temperature range
- -20~50°C
- Cycle life
- ≥100 cycles
More Advanced Battery Platforms
SWIFT Semi-Solid State Batteries
The SWIFT platform is Enpower's flagship aerospace-grade semi-solid state battery, engineered for aviation applications — industrial drones, eVTOL, and heavy-load drones — with breakthroughs in lightweight design, flight range, temperature adaptability, and instant power response. With energy density up to 403 Wh/kg and over 3 million cells delivered, SWIFT is proven at industrial scale.
KOSMOS All-Solid-State Batteries
KOSMOS is Enpower's all-solid-state battery platform with sulfide electrolyte and lithium-metal anode, engineered for maximum safety and performance. KOSMOS broke the ASSB 400 Wh/kg energy density barrier.
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