18650 Sodium-Ion Battery Cell (NFPP) — Rechargeable Na-ion

Advanced Sodium Ion Battery Cells, finally a cheaper alternative to lithium-ion cells.

900 mAh per cell, 3.0V nominal, NFPP polyanion sodium-ion chemistry (Na₃V₂(PO₄)₂F₃). Built for builders who want long cycle life, extreme cold-weather operation down to -40°C, and high discharge rates up to 20C continuous.

Quick Specs:

Sodium-ion battery cells have gained attention as a promising alternative to traditional LFP cells. One significant advantage of sodium-ion cells is their superior performance at low temperatures compared to LFP. Sodium is more abundant and sustainably sourced than lithium, making it a more cost-effective and environmentally friendly option for energy storage.

Sodium-ion batteries are also known for their stable electrochemical performance, which translates to a long cycle life. This longevity can reduce the cost of ownership over time. While they offer lower energy density than LFP cells, sodium-ion cells outperform lead-acid in both weight and volume energy density.

These cells use a polyanion sodium-ion chemistry (NFPP, Na₃V₂(PO₄)₂F₃), known for excellent thermal and chemical stability, long cycle life, and superior low-temperature performance compared to layered oxide chemistries like NFM. This makes them ideal for applications where cost, safety, and material abundance matter.

Key Features:

• Stable NFPP Chemistry: Based on Na₃V₂(PO₄)₂F₃ polyanion structure, offering excellent cycle life, low-temperature performance, and safety.
• Reliable Power Source: Designed for consistent operation in extreme environments down to -40°C.
• Wide Operating Range: Usable voltage from 1.5V to 3.7V per cell.
• High Discharge Rate: Supports up to 20C continuous and 40C peak (≤5s) discharge currents.
• Sustainable Materials: Built from abundant, non-toxic elements for environmentally responsible storage solutions.

Full Product Specifications:

• Nominal Voltage: 3.0V
• Operating Voltage: 1.5V to 3.7V
• Cell Chemistry: Sodium-ion (NFPP, Na₃V₂(PO₄)₂F₃)
• Nominal Capacity: 900 mAh (at 0.2C, 1.5 to 3.7V)
• Minimum Capacity: 850 mAh
• Internal Impedance: ≤20 mΩ (AC 1kHz, after charge)
• Charging Temperature: 0°C to 60°C (limited current below 20°C)
• Discharging Temperature: -40°C to 60°C (see datasheet for current limits)
• Standard Charge Current: 0.5C
• Standard Discharge Current: 0.5C
• Max Continuous Discharge Current: 20C (18 A)
• Max Peak Discharge Current: 40C (36 A) for ≤5 seconds
• Cycle Life: 1000+ cycles to ≥85% capacity (25°C, 1C charge/discharge)
• Dimensions: 18.4 mm diameter x 65.5 mm length
• Weight: 33 ±0.5 g

Discharge and Storage Notes

While some sodium-ion chemistries can safely reach 0V for transport, this specific NFPP 18650-900 mAh 20C cell is not designed for regular 0V discharge.
For best performance and longevity:

• Minimum discharge voltage: 1.5V per cell
• Recommended cutoff under load: ~1.7 to 1.8V
• Storage voltage: 2.0 to 3.2V per cell

Running these cells to 0V may cause irreversible capacity loss. Always use a BMS or cutoff circuit to prevent over-discharge.

Cell Spot Welding Recommendations:

Note: Sodium-ion cells are more sensitive than lithium-ion during welding. Avoid high current pulses.

1. Start with the lowest power setting possible
2. Weld for 1.5 seconds max
3. If tabs are not welded, increase power slightly and retry

Datasheet: 18650 NFPP Sodium-ion Cell (PDF)