Heiwit Sodium Ion Cells: The New Frontier of Energy Storage for Photovoltaic Systems

Sodium-ion batteries represent an innovative and sustainable solution in the field of energy storage, offering an alternative to traditional lithium-ion batteries. Thanks to the use of abundant materials such as sodium and their ability to operate over a wide temperature range without the need for external heating, these batteries are gaining increasing attention in the renewable energy sector. Heiwit has developed a series of high-efficiency sodium-ion batteries that are designed to provide excellent performance even in harsh climatic conditions. This article will explore the technical specifications of the cell, analysing its capacity, durability, safety and, most importantly, the ability to operate at ambient temperatures without the need for salt melting.

Technical characteristics of Heiwit sodium ion batteries

• Nominal capacity: 210 Ah with a typical capacity of 215 Ah at 25 °C.
• Voltage range: maximum voltage of 3.95V and minimum voltage of 1.50V.
• Internal resistance: less than 0.50 mΩ.
• Energy density: over 140 Wh/kg, with a battery weight of approximately 4.7 kg.
• Battery dimensions: length 173.6 mm, thickness 71.25 mm and height 203.7 mm.

Performance under different temperature conditions

• Operating temperature of the NA-48V210Ah battery: discharge from -25°C to +60°C, charge from 0°C to +60°C, indoors.
• Details of discharge performance:
  • At low temperatures the discharge capacity decreases compared with that at 25°C.
  • At high temperatures (60°C), the capacity remains at 95% compared to that at 25°C, demonstrating adaptability to various climates.

Advantages of Heiwit technology: ambient operating temperatures

• Explanation of ambient operating temperatures: it does not require the salt to be melted to function, unlike other technologies.
• This makes Heiwit sodium ion batteries particularly practical for applications where temperature management is critical.
• Stable performance at normal temperatures and the ability to work over a wide temperature range without significant degradation contribute to higher energy efficiency and a long life cycle.

Service life and charge/discharge cycles

• Number of cycles: over 6,500 cycles at 90% DoD with 70% residual capacity (NA-48V210Ah, layered-oxide cells), from the endurance test.
• This makes these batteries particularly suitable for long-term applications such as renewable energy storage systems.

Security and reliability

• The batteries have passed the UN 38.3 transport tests.
• Safety tests include vibration, short-circuit, overload, overdischarge, heavy impact, compression and low pressure tests.
• Test results: no explosion, fire or leakage even under stress conditions, demonstrating a high level of safety.

Conclusions

• Heiwit sodium ion batteries are a sustainable and safe option for energy storage, especially in renewable energy applications.
• The ability to operate at ambient temperatures without the need for additional heating makes them ideal for different climatic environments, reducing operating costs.

The cells are the starting point. The finished system — pack, BMS, electronics, inverter — is the Heiwit range.