Sodium-Ion Battery Evaluation Service Charge Discharge Curve Analysis BMS Design

Product Specification

Sodium-Ion Battery Evaluation and BMS Integration: Power Your Products at Half the Battery Cost

Lithium-ion batteries have dominated portable electronics for three decades—but their cost structure is fundamentally constrained by lithium, cobalt, and nickel raw material prices that show no sign of declining. Sodium-ion (Na-ion) batteries offer a compelling alternative: sodium is 400* more abundant than lithium, costs less than 5% as much per kilogram, and eliminates cobalt entirely from the cathode. For cost-sensitive applications like TWS earbuds, IoT sensors, and smart wearables—where the battery represents 8-15% of total BOM—switching to Na-ion can reduce battery cost by 30-50%. Our evaluation and BMS integration service characterizes Na-ion cells for your specific application, designs the charging and protection circuitry, and delivers a production-ready power solution.

Why Sodium-Ion Now

The Engineering Challenge: Different Chemistry, Different Behavior

Na-ion cells cannot be treated as drop-in replacements for Li-ion. Their charge and discharge characteristics differ in ways that require BMS adaptation:

Our Evaluation and BMS Design Service

Phase 1: Cell Characterization

We characterize candidate Na-ion cells across the full range of your application's operating conditions:

• Charge/Discharge Curves: Galvanostatic charge-discharge at C/5, C/2, 1C, and 2C rates. Full dQ/dV analysis to identify phase transitions and optimal charge termination voltage.
• Rate Capability: Discharge capacity vs. C-rate from C/10 to 5C. Critical for TWS which draws 50-100mA peak (1-2C for a 50mAh cell) during BT TX bursts.
• Cycle Life: 500-cycle accelerated aging at 1C charge/1C discharge. Capacity fade curve and internal resistance growth tracked every 50 cycles.
• Temperature Performance: Discharge characterization at -20°C, -10°C, 0°C, 25°C, 45°C, and 60°C. Charge characterization at 0°C, 25°C, and 45°C.
• Self-Discharge: 30-day voltage decay at 25°C and 45°C. Critical for IoT devices with months-long deployment between charges.

Phase 2: BMS Design

We design a complete battery management system tailored to Na-ion characteristics:

• Charger IC Selection: Identifies charger ICs with programmable termination voltage in the 3.95-4.0V range. Options include TI BQ25185 (I²C programmable), Microchip MCP73833 (resistor-programmable), and several domestic alternatives at 40-60% lower cost.
• Protection Circuit: Overcharge protection at 4.05V ±25mV (vs. 4.28V for Li-ion). Over-discharge at 2.0V (vs. 2.5V). Overcurrent at application-specific threshold. The wider voltage window requires careful comparator threshold resistor selection.
• Fuel Gauge: SOC estimation using voltage-lookup table or coulomb counting with Na-ion-specific parameters. The sloping discharge curve is actually advantageous for voltage-based SOC—a 100mV change reliably indicates 10-15% SOC change, unlike Li-ion's flat plateau where 100mV represents 30-50% SOC uncertainty.
• Cell Balancing: For multi-cell series configurations, passive balancing with Na-ion-appropriate thresholds. The sloping voltage profile makes voltage-based balancing triggers more reliable than for Li-ion.

Phase 3: Production Integration

We deliver a complete production package: BMS schematic and BOM with pre-negotiated component pricing, PCB layout guidelines, production test specification including end-of-line charge/discharge verification, and a qualified cell supplier list with pricing and lead time data.

Real-World Results

Strategic Timing

Sodium-ion battery technology is at the inflection point where LiFePO4 was in 2015—performance is sufficient for mainstream applications, manufacturing capacity is scaling rapidly (CATL, HiNa Battery, and Natron Energy each commissioning multi-GWh facilities), and cell prices are declining 15-20% annually. Early adopters who qualify Na-ion solutions now will lock in a structural battery cost advantage that competitors still dependent on lithium supply chains cannot match for at least 3-5 years. The BMS design expertise required for Na-ion integration—understanding the different voltage window, discharge curve shape, and SOC estimation approach—is a specialized skill set that creates a genuine competitive moat.

Contact our team with your device power requirements (capacity, voltage, form factor, peak current). We will recommend Na-ion cell candidates and deliver a preliminary BMS architecture within 2 weeks.