Prismatic Sodium-ion Battery development is moving forward at Remplir in 2026. The South Korean battery startup has expanded beyond prismatic lithium iron phosphate cells and has now introduced the country’s first prismatic sodium-ion battery. Moreover, the company has started customer qualification for the new product, with a clear focus on energy storage systems and uninterruptible power supply markets.
Remplir’s prismatic sodium-ion battery enters qualification
Remplir developed a 170Ah prismatic sodium-ion battery in June 2026. The company says it is the only battery maker in South Korea that currently produces both prismatic LFP batteries and prismatic sodium-ion batteries. In addition, even the nation’s three largest battery manufacturers do not produce prismatic sodium-ion batteries domestically.
As a result, Remplir has positioned itself in a notable segment of the advanced battery market. Earlier in 2026, the company received an Innovation Award at InterBattery 2026 in March. That recognition highlighted growing industry interest in its cell design, materials expertise, and production strategy.
Why the prismatic sodium-ion battery matters
Sodium-ion batteries use sodium instead of lithium. Therefore, they offer an alternative chemistry for stationary storage applications. Remplir designed its prismatic sodium-ion battery mainly for ESS and UPS use. These applications value long cycle life, strong safety characteristics, and reliable low-temperature operation.
The battery uses a sodium iron phosphate, or NFPP, cathode. This chemistry relies on widely available raw materials such as sodium, iron, and phosphorus. Consequently, the cell supports strong cost competitiveness. It also avoids nickel and cobalt. That material profile can improve pricing flexibility while supporting safer operation and long service life.
Remplir also says the battery maintains stable structural behavior during charging and discharging. Because of that, the company expects the chemistry to perform well in demanding storage settings. The operating temperature range extends from minus 40 degrees Celsius to 60 degrees Celsius. That wide range makes the cell suitable for varied environments and industrial conditions.
How Remplir built its prismatic sodium-ion battery
Remplir manufactured prototype cells at its facility in Hwaseong, Gyeonggi Province. The company is now evaluating performance with overseas customers. At the same time, it is preparing for broader commercialization after qualification work with North American customers.
One of Remplir’s biggest advantages is manufacturing flexibility. The company can produce sodium-ion batteries on its existing LFP production facilities. Since sodium-ion and Lithium-ion cells share most manufacturing steps, Remplir does not need a fully separate production line. Instead, it only needs to adjust the mixing process, where electrode materials are blended.
This approach can speed up scale-up. It can also reduce capital intensity during early commercialization. Furthermore, Remplir says its proprietary materials formulation improves performance. That know-how gives the company another layer of differentiation in prismatic cell production.
Prismatic sodium-ion battery strategy supports ESS growth
Remplir’s near-term strategy centers on energy storage systems. That focus fits the strengths of sodium-ion chemistry. In particular, the company is targeting ESS and UPS applications first. These segments often prioritize safety, durability, and dependable performance across different temperatures.
Chief Executive Kim Su-jin said the company plans to commercialize ESS products after completing customer qualification with North American customers. The company also intends to expand its broader product portfolio. Therefore, sodium-ion batteries could become a meaningful new growth area alongside Remplir’s established prismatic LFP business.
Remplir expands production alongside its prismatic sodium-ion battery
Remplir currently operates a 100MWh production line at its Hwaseong plant. Annual capacity stands at about 150,000 battery cells. Meanwhile, the company is seeking 100 billion won in a Series B funding round. It plans to use the capital to expand production capacity to the gigawatt-hour level, enlarge manufacturing facilities, and support research and development.
The new lines will mainly produce prismatic LFP batteries. However, part of the capacity will support drone batteries as well. This broader manufacturing base can also strengthen the company’s position as customer demand rises for locally produced battery cells in South Korea.
Remplir’s battery portfolio adds scale and relevance
Alongside its new sodium-ion product, Remplir already supplies prismatic LFP cells for several industrial uses. The company provides 340Ah cells for ESS applications and 230Ah cells for heavy equipment and agricultural machinery. These products support electrification trends in construction equipment, agricultural machinery, forklifts, and golf carts.
Rather than offering only standard cells, Remplir develops customized battery cells from the electrode design stage. That approach helps the company tailor performance to specific customer applications. In turn, that customization can improve relevance in industrial battery markets where operating conditions differ widely.
Kim said domestic demand for prismatic LFP batteries is increasing as industrial equipment electrification accelerates. He also noted stronger interest in locally produced alternatives. Remplir expects revenue to exceed 12 billion won in 2026, which would be more than ten times the prior year’s level.
What Remplir’s prismatic sodium-ion battery means in 2026
Remplir’s launch of South Korea’s first prismatic sodium-ion battery marks an important step in the country’s battery sector. The 170Ah cell, the NFPP cathode, the wide operating range, and the ability to use existing LFP production lines all support the company’s commercialization plan. In addition, customer qualification work and expansion funding could help Remplir scale faster in ESS and UPS markets.
In 2026, Remplir is not only expanding its chemistry portfolio. It is also building a stronger position in prismatic battery manufacturing with a practical path to growth.
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