This article is contributed by Dr. Jonas Keil, Technical Lead of Battery Analytics, TWAICE
Beyond Lithium: Unveiling the Potential of Sodium-Ion Batteries with Advanced Simulation Models
As the demand for energy storage continues to surge, researchers and engineers are turning their attention to sodium-ion batteries as a promising alternative to the lithium-ion counterparts. TWAICE has now launched a battery simulation model for sodium-ion, helping engineers gain initial insights into this new technology, helping to explore its current status and potential uses in the energy landscape, whether battery energy storage, electric vehicles or micromobility.
In this whitepaper, we explore the growing demand for sodium-ion technology and explain how sodium-ion battery simulation models can help engineers gain initial insights into this new technology and compare it to lithium-ion cell chemistries.
Growing Demand for Sodium-ion Technology
Sodium-ion battery technology operates on similar principles to lithium-ion batteries, where energy is stored and released through the de-/intercalation of ions in the electrodes. The key components of sodium-ion batteries include the anode, typically made of hard carbon, the cathode, based on Prussian blue, sodium layered oxides or polyanionic materials[1], and the electrolyte, facilitating the ion transport. Unlike lithium, sodium is abundant in nature and widely available, offering a sustainable alternative for energy storage solutions.
Compared to lithium-ion batteries, sodium-ion technology has several compelling advantages:
- Sodium resources are more abundant and cost-effective than lithium, potentially driving down the overall cost of battery production.
- Sodium-ion batteries exhibit good energy density and comparable or better performance, making them suitable for a wide range of applications.
- The environmental footprint of sodium-ion batteries is significantly reduced, as they do not rely on scarce and environmentally damaging lithium resources. This abundance and sustainability make sodium-ion technology an attractive prospect for especially large-scale energy storage systems.
- They are considered to be safer than Li-ion batteries, which could have far-reaching advantages for the industry, whether storage, transportation or operation of batteries.
Additional comparison points between Li-ion and Na-ion are listed in the table below.[3]
Sodium-ion battery technology is largely still in the research and development phase, but significant progress has been made in recent years. Companies and research institutions worldwide are actively exploring sodium-ion battery chemistry, aiming to overcome technical challenges and scale up production. For example, as early as 2021, the battery giant CATL developed its first generation of sodium-ion batteries with an energy density of 160 Wh/kg, comparable to early lithium-ion[4]. For the next generation, they aim to reach 200 Wh/kg, nearing lithium-ion. They are already planning mass production of sodium-ion batteries[5].
As sodium-ion technology transitions from the lab to real-world deployment, it will be critical to ensure the reliability and longevity of these new battery systems. Consequently, battery simulation models, tailored specifically to sodium-ion batteries, will become crucial for optimizing performance and efficiency. With battery simulation models, engineers can simulate the behavior of battery systems under different operating conditions, aiding in the design, testing, and optimization of sodium-ion battery technologies.
At the Forefront of Technology: Sodium-ion Battery Simulation Models
Battery simulation models enable engineers to simulate battery behavior under various conditions and identify how these parameters impact the performance and lifetime of the battery. Recently, TWAICE introduced a simulation model for sodium-ion batteries to ensure that battery engineers around the world get advanced insights into the behavior of this up-and-coming battery technology.
For this initial model, the methodology used to measure and simulate sodium-ion batteries mirrors the approach applied to lithium-ion battery models. Various sodium-ion cells were tested at the TWAICE battery research center and analyzed using the company’s proprietary, standardized techniques. This process aims to provide valuable insights and enhance understanding of sodium-ion technology. TWAICE will continue to refine and validate their methods as they test additional cells.
Insights from the Sodium-ion Simulation Model
In their latest whitepaper, TWAICE shared insights on comparisons of the open circuit voltage for different cell chemistries and the model validity and accuracy of the electric model, the calendric aging and cyclic aging model.
For Na-ion batteries, for example, the large change in voltage during charging and discharging is advantageous for state estimation algorithms, especially in comparison to LFP.
Furthermore, TWAICE showcases the model validity and accuracy by comparing measurement and simulation for sodium-ion cells. For the first hundreds of days / cycle the simulated SoHc agree very well with the measured ones. The model also reveals information on the influence of stress factors like higher degradation for the calendric aging model at high SoCs.
References
[1] Roland Berger & PEM | RWTH Aachen University, 2023: Battery Monitor 2023 – The Value Chain between economy and ecology
[2] Roland Berger & PEM | RWTH Aachen University, 2023: Battery Monitor 2023 – The Value Chain between economy and ecology
[3] World Sustainability Collective, 2024: Sodium-ion vs Lithium-ion batteries, accessed June 19, 2024: https://worldsustainabilitycollective.com/sodium-ion-v-lithium-ion-batteries/
[4] PV-Magazine, 2021: CATL claims to have made sodium-ion batteries a commercial reality, accessed June 19, 2024: https://www.pv-magazine.com/2021/07/29/catl-claims-to-have-made-sodium-ion-batteries-a-commercial-reality/
[5] Sodium battery hub, 2024: CATL Advancements in sodium-ion batteries. Accessed June 19, 2024: https://sodiumbatteryhub.com/2024/03/18/catls-advancements-in-sodium-ion-battery-market/
[6] CIC EnergiGUNE, 2022: The Sodium-ion battery boom: the perfect (and sustainable) complement to lithium-ion batteries
