Cell Review: Sodium-ion NFPP, 18650
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Inside Look at Sodium-Ion Cells
Why this matters: Sodium-ion is growing and there are many new variants available, this post talks about specifically NFPP the Sodium-ion cousin to LFP (LiFePo).
- 18650 NFPP cylindrical cell (900 mAh class) — in stock now for bench testing, prototyping, education, and low-voltage packs.
- 160Ah prismatic sodium-ion cell — large-format cell for serious storage builds (solar, backup, BESS).
Both cells run on sodium, not lithium. No lithium, no cobalt, no nickel pricing drama. This is the early shape of lithium-free stationary storage.
Chemistries at a Glance
These are phosphate-based sodium-ion cathodes (often called NFPP / sodium iron fluorophosphate type) paired with hard-carbon style anodes. They behave a lot like LiFePO₄ (LFP): stable voltage plateau around 3V, abuse tolerance, and excellent low-temp discharge.
They are not NFM layered oxide (NaNi₁/₃Fe₁/₃Mn₁/₃O₂). NFM tends to chase higher energy density and higher nominal voltage, while NFPP-style sodium cells lean into safety, long cycle life, and cold-weather behavior. (If you want “best Wh/kg,” that’s NFM. If you want “will it still give current at –20°C,” that’s this chemistry.)
Product #1: NFPP Sodium-Ion 18650 Cylindrical Cell (In Stock)
This is a high-rate rechargeable sodium-ion 18650 cell. Spec sheet calls it “18650-900mAh High Rate.” It’s meant to actually move current, not just sit in a lab notebook.
Key Electrical Specs
| Parameter | Spec | Notes |
|---|---|---|
| Chemistry | Sodium-ion (NFPP-type cathode) | No lithium, cobalt, or nickel |
| Nominal Voltage | 3.0 V | Flat discharge curve ~3V |
| Voltage Window | 1.5 V – 3.7 V | Standard charge limit 3.7 V per cell |
| Rated Capacity | 900 mAh @ 0.2C (1.5–3.7 V) | Minimum 850 mAh @ 0.2C to 1.5 V |
| Internal Resistance | ≤ 20 mΩ | AC 1 kHz after standard charge |
| Standard Charge Current | 0.5C | CC/CV to 3.7 V; stop at ≤0.05C |
| Max Continuous Charge Current | Up to 1C @ 3.7 V limit | Can go higher C-rate with lower voltage limit (down to 3.4 V) |
| Standard Discharge Current | 0.5C | To 1.5 V cutoff |
| Max Continuous Discharge | 20C | High-rate capable |
| Peak Discharge | 40C for ≤5 s | Short bursts |
| Cycle Life | ≥1000 cycles to ≥85% capacity | Tested at 1C charge / 1C discharge 3.7→1.5 V |
| Operating Temp (Charge) | 0 °C to +60 °C | Charge rate is limited at low temps (≤0.1C from 0–10 °C) |
| Operating Temp (Discharge) | –40 °C to +60 °C | See C-rate limits by temp below |
| Dimensions | 18.41 mm × 65.50 mm | Standard 18650 can |
| Mass | ~33 g | Heavier than typical Li-ion 18650 because sodium chemistry is lower Wh/kg |
Source: Sodium Ion Cell Specification, Model 18650-900mAh.
Temperature / Rate Behavior
- –20 °C discharge: ≥85% of rated capacity at 0.5C.
- –40 °C discharge: ≥60% of rated capacity at 0.5C. You can still pull energy at –40 °C.
- 55 °C discharge: ≥95% of rated capacity at 0.5C after hot soak.
- Discharge rate limits by temp: spec allows up to 20C discharge between 20–45 °C, tapering down at very low and very high temperatures.
That temperature window is the story. Typical LFP hates cold and needs heat below freezing. This cell will still deliver current at –20 °C (and even –40 °C, with reduced output).
Abuse / Safety
- Overcharge to 6.0 V @1C for up to 1 hr → no fire, no explosion.
- Forced overdischarge to 0 V and then held under load → no fire, no explosion, no leakage.
- External short at ≤5 mΩ for up to 24 hr → no fire, no explosion.
- Drop, crush, 130 °C heat soak, high/low temp shock cycling → no fire, no explosion.
This is classic phosphate behavior: it resists runaway under abuse.
Typical Uses
- Bench testing sodium-ion pack design (12 V / 24 V / 48 V nominal strings).
- Low-voltage backup / UPS / portable storage prototypes.
- Education, demos, YouTube content, R&D proof-of-concept.
- High pulse current experiments (the datasheet literally calls out 20C continuous, 40C burst). :contentReference[oaicite:17]{index=17}
➜ Order NFPP Sodium-Ion 18650 Cells (In Stock)
Product #2: 160Ah Sodium-Ion Prismatic Cell (For Stationary Storage)
This is a large-format sodium-ion prismatic cell: model SIB-P71173208-160Ah. This is not a flashlight cell — this is rack-level building block hardware for solar storage, backup power, and BESS.
Key Electrical Specs
| Parameter | Spec | Notes |
|---|---|---|
| Model | SIB-P71173208-160Ah | Prismatic sodium-ion cell |
| Nominal Voltage | 3.0 V | Same ~3V class as the 18650 |
| Charge Voltage (max) | 3.8 V | CC/CV to 3.8 V, stop at ≤0.05C |
| Discharge Cutoff | 1.5 V | Same 1.5 V floor |
| Nominal Capacity | 160 Ah @ 0.2C | Measured 0.2C to 1.5 V must be ≥160 Ah |
| Standard Charge / Discharge Current | 0.5C (≈80 A) | For rated performance |
| Max Continuous Discharge | 2C (≈320 A) | High current for a stationary-format cell |
| Pulse Discharge | 3C for 30 s @ 100% SOC | ≈480 A bursts at 25 °C ±2 °C |
| Internal Resistance | ≤0.65 mΩ | AC 1 kHz after standard charge |
| Operating Temp (Charge) | 0 °C to +55 °C | Charge current must be managed at low temp |
| Operating Temp (Discharge) | -40 °C to +60 °C | Full output in deep cold is the point |
| Mass | 4.2 ±0.2 kg | Per cell |
| Dimensions | ~71.7 mm (thick) × 173.7 mm (wide) × 207.2 mm (tall) | Specified under preload (the cell wants compression) |
Source: PORFFOR Product Specification, SIB-P71173208-160Ah.
Cycle Life / Degradation
-
Standard cycle test: 0.5C charge to 3.8 V, 0.5C discharge to 1.5 V at 25 °C. Spec calls out:
- ≥6000 cycles to 80% of initial capacity
- ≥10000 cycles to 70% of initial capacity
- Charge retention after 30 days at 25 °C: ≥90% of original capacity, and after recharge ≥95% recovery.
- Low-temp discharge test at -20 °C (1C to 1.5 V after cold soak): ≥80% of room-temp capacity.
That’s LFP-grade cycle life, but it keeps working below freezing without a heater blanket.
Abuse / Safety
- Overcharge to 6 V @1C for 90 min → no fire, no explosion.
- External short at ≤5 mΩ → no fire, no explosion.
- Crush until 0 V or 30% deformation or 200 kN → no fire, no explosion.
- Heat to 130 °C for 30 min → no fire, no explosion, no leakage.
- Seawater immersion (3.5% NaCl) for 2 hours → no fire, no explosion.
This is what you want sitting in a steel box bolted to the side of a building.
Intended Use
- Stationary storage (off-grid solar, backup power, microgrids, commercial ESS).
- Outdoor / unheated enclosures where lithium packs normally need heaters just to wake up.
- Sites where you want to avoid lithium (insurance, AHJ comfort level, policy).
- High-cycle daily-use storage (PV + shifting). 6k–10k cycle spec is in the qualification sheet, not marketing copy. :contentReference[oaicite:28]{index=28}
➜ 160Ah Sodium-Ion Prismatic Cells (Stationary Storage)
NFPP vs NFM vs LFP — When to Use What
| Chemistry | Nominal V | Energy Density | Cycle Life | Cold Performance | Main Use Case |
|---|---|---|---|---|---|
| NFPP / sodium phosphate (these cells) | ≈3.0 V | Lower Wh/kg than NFM, similar to early LFP | Up to 6000–10000 cycles in prismatic format | Excellent (–20 °C and even –40 °C discharge allowed) | Solar storage, backup, outdoor enclosures |
| NFM layered oxide (NaNi₁/₃Fe₁/₃Mn₁/₃O₂) | ≈3.1 V | Higher Wh/kg | Good (typically a few thousand cycles) | Good, but usually not spec’d for –40 °C discharge at useful load | Where size/weight matters more than extreme abuse tolerance |
| LFP (LiFePO₄) | ≈3.2 V | High Wh/L in mature prismatic formats | 6,000+ cycles is normal | Fair — wants heaters below freezing | Home batteries, commercial storage, EV packs today |
In plain English:
NFPP sodium-ion = rugged, cold, safe.
NFM sodium-ion = higher energy density sodium.
LFP lithium = mature technology, better energy density, but not cold tolerant.
Integration / BMS Notes
- Both cells expect a max charge voltage ≤3.7–3.8 V per cell depending on format. Do not treat them like 4.2 V Li-ion cells. That will overcharge them.
- Both want a 1.5 V cutoff on discharge. Your BMS must enforce this, especially for packs in storage.
- Do not charge below 0 °C. The 160Ah spec is explicit: only charge between 0 °C and 55 °C, and the BMS needs to limit current at the low end.
- In multi-cell packs, you must balance. The prismatic datasheet requires that the battery management system include active equalization across cells.
- Compression: the 160Ah prismatic cell is spec’d and tested under preload. Treat it like modern LFP prismatics — they are designed to live clamped in a module, not loose in a tote bin.
Bottom Line
Sodium-ion is past “hype deck” and into real hardware:
- The 18650 NFPP cell is ready for builders, educators, and anyone who wants to measure real sodium behavior instead of reposting LinkedIn slides.
- The 160Ah prismatic cell is aimed at actual storage systems, with multi-thousand-cycle life and real subzero discharge. This is an LFP alternative you can mount in an unheated shed.
If NFM is the high-energy sodium chemistry, these NFPP-style sodium cells are the workhorses — the sodium answer to LFP.
➜ Buy NFPP Sodium-Ion 18650 Cells
➜ 160Ah Sodium-Ion Prismatic Cells for Storage Builds
Specs are taken directly from current manufacturer datasheets for 18650-900mAh and SIB-P71173208-160Ah cells and may evolve. Always confirm pack voltage limits and BMS settings against the latest sheet before final integration.