Battery Separator Technologies Advance

Growing demand for electric vehicles, energy storage systems and higher-performing batteries is creating new opportunities for nonwovens. As battery manufacturers seek improved safety and performance, nonwoven separators are finding increasing use in a growing range of battery applications.

Dave Rittenhouse, OmniSep team lead at Magnera, explains why separators play a vital role in battery performance and safety.

“Battery separators serve the critical function of preventing contact between the anode and cathode, thereby avoiding internal short circuits,” he says. “At the same time, they must enable efficient ion transport while acting as a barrier to unwanted materials, such as dendrites and shed electrode particles, that can negatively impact battery performance.”

As a result, separator properties play a significant role in determining battery life, reliability and overall performance. “Separators also contribute to battery safety, as their thermal and chemical stability are essential for maintaining integrity under operating conditions,” he explains. “To perform effectively, the separator must remain stable in the electrolyte and withstand the mechanical, chemical and thermal demands of repeated charge and discharge cycles.”

According to market research firm Smithers, the nonwoven battery separator market is a mid-sized but fast-growing segment of the total battery separator market. In 2025, nonwovens accounted for 21.3% of volume and 20.9% of value of the total battery separator substrate market, with the remainder split between polymer films/sheets and paper. Globally, nonwovens for battery separators reached 155,600 tons (8.1 billion square meters), valued at $1.7 billion in 2025.

The market is being driven by increasing demand for battery safety, growth in electric vehicles and energy storage systems, regulations and technology advances. “The main growth driver is the shift toward more complex, higher-performance separators used in newer battery types, particularly rising nonwoven penetration into lithium-ion batteries, which is pushing value growth ahead of volume growth,” says Phil Mango, nonwovens consultant, Smithers.

According to Smithers’ market report, The Future of Nonwoven Battery Separators to 2030, lithium-ion batteries are the fastest-growing end use, with projected 2020-30 CAGRs of 31.3% (tons) and 33.4% (value). Lithium-ion separators grew from just 8.1% of nonwoven battery separator tonnage in 2020 to a projected 55.7% by 2030—more than all other battery types combined. Of the six major ultimate end uses for nonwoven battery separators, which include automotive, consumer electronics, energy storage systems, industrial, power tools and ‘all others,’ automotive is the largest and fastest-growing market, with CAGRs of 21.6% (tons) and 26.9% (value) for 2020–30.

As the market expands, nonwovens manufacturers are developing new separator technologies to support evolving battery requirements.

Ahlstrom Targets Lead-Acid Battery Growth

Demand for nonwoven battery separators is being driven by the broader growth of electrification, energy storage and reliable backup power, according to Noora Blasi, Ahlstrom’s marketing manager, Filtration. “Lead-acid batteries remain important in automotive starting, start-stop systems, forklifts and motive power, industrial backup power, and in data centers,” she explains.

“For nonwoven separators specifically, growth is supported by demand for higher safety, better electrolyte management, improved cycle life and lighter, more efficient battery components.”

—Noora Blasi, marketing manager, Filtration, Ahlstrom

To address these market needs, Ahlstrom offers a range of fiber-based separator solutions for lead-acid batteries through its FortiCell LAB portfolio. The portfolio includes three main solutions: pasting papers, Absorbent Glass Mat (AGM) separators and glass fiber tissue.

The range offers excellent product uniformity, optimized fiber selection and dispersion, enhanced battery cycle life, strong wicking properties and low ionic contamination.  

The nonwovens manufacturer recently strengthened this area with a new advanced AGM battery separator platform manufactured at its facility in Turin, Italy.  The platform expands customization options from 100% microglass to microglass-synthetic fiber blends.

As the demand for high-performance energy storage solutions accelerates, AGM lead acid batteries continue to be a cornerstone of high-performance power solutions, according to Ahlstrom. They enable rapid charge and discharge cycles across automotive, renewable energy, telecommunications and industrial power backup applications. AGM separators—essential to battery safety, efficiency and longevity—are evolving to meet the industry’s growing need for higher energy efficiency, durability and sustainability.

Last month, the company strengthened the capabilities of its FortiCell energy storage portfolio with a new range of glass fiber tissue (GFT) solutions. The high-performance GFT solutions are designed to help battery manufacturers enhance efficiency, reliability and performance across demanding energy storage applications. 

Designed for seamless integration into existing production environments, the new range includes both thin grades for pasting processes, targeting battery manufacturers, as well as heavier grades for reinforcement of polyethylene (PE) separators. “This dual positioning enables us to support multiple applications with a single material platform,” Blasi explains.

Glass fiber tissues are designed to ensure consistent performance in demanding applications. High dimensional stability supports reliable behavior during high-speed assembly, while a controlled fibrous structure contributes to low electrical resistivity and efficient battery operation. Fast acid absorption and wicking enable efficient and uniform battery filling, and good processability allows smooth integration without process changes. 

Magnera Advances Separator Technology

Magnera’s OmniSep nonwoven separators compete primarily with polyethylene (PE) wet-process separators and stretched-film dry-process separators in the lithium-ion battery market. “Compared with conventional dry-process separators, OmniSep offers superior electrolyte wettability and electrolyte uptake,” Rittenhouse says.

A key differentiator of OmniSep is its thermal and dimensional stability. According to Rittenhouse, standard OmniSep separators remain stable at temperatures exceeding 150°C, while conventional polyethylene separators begin to melt at approximately 125°C. “Although ceramic coatings are often applied to PE and stretched-film separators to improve dimensional stability, these coatings can increase internal resistance and do not eliminate the inherent melting limitations of the polyethylene substrate,” he explains. “As a result, battery manufacturers may select OmniSep for its enhanced safety profile, particularly in applications requiring improved thermal stability.”

Magnera’s nonwoven separator does not shrink when exposed to elevated temperatures because it is not stretched during manufacturing, according to the company. In contrast, the stretching process is an integral part of producing both stretched film (also known as dry process) separators and polyethylene separators made through the wet process, Rittenhouse says.

Additionally, nonwoven separators provide both through and lateral channels that facilitate electrolyte wetting and wicking, enabling fast electrolyte filling of the cell. The high electrolyte conductivity fosters high ionic conductivity, contributing to faster charging and discharging, he explains.

Magnera’s manufacturing processes are amenable to the use and combination of a wide variety of materials, which Rittenhouse says has delivered a step-change in the ability to engineer separators to withstand high temperatures (>210°C). The high ionic conductivity also enables improved performance at low (-30°C) temperatures. 

The materials selected and the process flexibility enable the company to tailor the separator to the chemistry of the electrolyte and use case of the battery. “Consequentially, versions of our OmniSep Battery Separator may be used in either organic or aqueous electrolytes,” Rittenhouse adds.

Looking ahead, Magnera is developing separator solutions for emerging energy storage applications, including solid-state batteries and alternative chemistries such as sodium-ion, aluminum-ion, zinc-based and flow batteries, many of which are gaining traction in battery energy storage systems (BESS), Rittenhouse says.

In addition to supporting the evolving lithium-ion market, the company is expanding the OmniSep platform into the lead-acid battery sector, where it already maintains a strong presence through its DynaGrid pasting paper solutions.

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