Battery Separator

Next-gen cellulose separator for lithium-ion batteries.
Enables enhanced cycle life, low internal resistance, and improved safety through thermal stability.

Advanced Cellulose Separator for High-Efficiency Lithium-Ion Batteries

NAGASE’s cellulose-based battery separator offers a breakthrough alternative to conventional polyolefin separators. It is made from 100 % cellulose and delivers exceptional heat resistance, ultra-high porosity, and outstanding electrolyte compatibility. These features reduce internal resistance, enable higher charge/discharge efficiency, and significantly extend cycle life – even under demanding conditions.

With its natural affinity for various electrolytes and excellent retention characteristics, the separator ensures stable performance in automotive and industrial lithium-ion battery applications.

NAGASE supplies cellulose-based battery separators globally for BEV, HEV, and 12V Li-ion battery systems – supported by technical expertise and international logistics solutions.

Applications

The cellulose separator is suitable for various high-demand lithium-ion battery configurations.

  • Li-ion batteries for Battery Electric Vehicles (BEVs)
  • Strong Hybrid Electric Vehicles (HEVs) requiring durable thermal materials
  • 48V Mild HEVs with advanced charge/discharge performance
  • 12V Li-ion start-stop batteries – as lead-acid replacement
  • Industrial energy storage systems using high-performance LiB

Features

The cellulose separator offers safety, performance, and efficiency – all in one design.

  • High heat resistance – Improves safety through stable thermal characteristics
  • Superior ionic conduction – High porosity and density enable low resistance
  • Excellent electrolyte affinity – Retains liquid for extended cycle performance

High Heat Resistance

Comparison of wettability and cycle life between cellulose separator and PP film, demonstrating superior electrolyte absorption and long-term battery performance.

Far superior ionic conduction by high porosity and highly dense structure

Comparison of cellulose separator and PP film after 12 hours at 150 °C, showing superior thermal stability of cellulose with no deformation.

Excellent affinity to electrolyte and high liquid retention rate

SEM image and DCR comparison of cellulose separator vs. PP film, highlighting superior microstructure and lower resistance during charge/discharge cycles.

Product Varieties

Material Cellulose
14 µm 20 µm 25 µm
Thickness [µm] 14 20 25
Density [g/cm³] 0.53 0.46 0.48
Porosity [%]* 65 69 68
Tensile Strength [N/15 mm] 9.0 11.1 14.7
Gurley [s]* 9 8 10

*Reference

Precaution:
1) Because separator is made from cellulose, it tends to absorb moisture, and depending on circumstances, it might contain 7-10 % moisture. When assembling cell with our separator, sufficient drying is required.
2) Recommended drying condition is in the range of 100~140 °C within 24 hours by vacuum drying.
3) After drying procedure, please handle the products under the low dew point environment. Recommended dew point is less than -60 °C.
4) In the drying procedure, the products may shrink about 1 % lenghtwise and widthwise, so please design your product after taking this shrinkage into consideration.
5) Compared to general micro porous film separator, our separator has higher porosity, so please adjust the amount of electrolytic solution to fit the porosity.

Advantage

  • Contributing to your green solution
  • Increasing performance of your battery
  • Reducing your production and cost burden
  • 100 % plant based
  • High recyclability
  • Excellent affinity between heat-resistant, high void and electrolyte to contribute to better battery performance
  • Cost effectiveness
  • Production efficiency

Frequently Asked Questions about Battery Separator

What is NAGASE’s cellulose-based battery separator?
It is the first high-performance lithium-ion separator made entirely from 100 % cellulose, offering superior safety and efficiency.

How does it compare to polyolefin separators?
Cellulose separators outperform polyolefin-based ones in thermal stability, porosity, and electrolyte retention – making them safer and more efficient.

Why is high porosity important for Li-ion batteries?
High porosity allows lithium ions to move faster while maintaining separation, reducing internal resistance and boosting charging/discharging performance.

What advantages does electrolyte affinity provide?
Strong affinity ensures that even high-viscosity electrolytes are absorbed and retained, supporting longer cycle life and stable battery operation.

In which battery types is the cellulose separator used?
It is suitable for BEVs, Strong HEVs, 48V mild hybrids, and 12V lithium-ion systems replacing lead-acid batteries.

Could not find what you were looking for?

Please get in touch. We strive to meet your needs.

Mobility

Tobias Back
Sales Manager