The ongoing transition to electric vehicles

With environmental regulations and exhaust-gas restrictions growing stricter in Europe and elsewhere—and efforts to restrict CO2 emissions expanding around the world—different nations and regions have different regulations and policies regarding electric vehicles and other emerging vehicle technologies such as hybrid and fuel-cell vehicles.

Although CO2 emissions from automobiles are already regulated at strict levels, in the future we will see increasingly stringent emission standards that will not be achievable through improvements in engine efficiency alone.

Energy and storage

The no.1 challenge in EV (electric vehicle) batteries is to increase their energy density. By increasing the energy density, the range of the vehicle can be extended without sacrificing space or weight.
With over 20 years of experience making advanced engineering plastics for automobile batteries, Asahi Kasei is ready to meet your production needs.

for EV batteries xyron

What is XYRON™?

XYRON™ is polymer alloy combining polyphenylene ether (PPE) with other resins. Asahi Kasei’s The XYRON™ family, which Asahi Kasei has been producing since 1979, boasts an extensive track record—occupying a key role in the history of engineering plastics—and today encompasses an extensive lineup of polymer alloys.

XYRON™ materials offer multiple excellent physical properties. In addition to their outstanding heat resistance, they boast flame retardance, electrical insulation property, good dimensional stability, and hydrolysis resistance, as well as low specific gravity. These polymer alloys combine the advantages of PPE with the specialized properties of various other plastics to yield unique functional properties.

Modified PPE resin XYRON™ lineup
A wide range of modified PPE resin XYRON™

XYRON™ resins have a high oxygen index (a measure of the volume of oxygen required for burning), making them highly flame retardant.  In the figure below, a flammability test was conducted using the burner and flame used in UL's flammability test. Under unique conditions,  XYRON™ was able to confirm the high flame retardancy.

ザイロン 燃焼性試験
Flammability test

Case studies: Applications of XYRON™ for EV batteries

  • Intercell spacer: XYRON™ 340Z, TF series

The intercell spacer, which is an insulating component used between battery cells, is made of XYRON™ 340Z, which has excellent tracking resistance, hydrolysis resistance, acid/alkali resistance, and long-term stable physical properties, and in addition to these characteristics, it also has oil resistance. We suggest the use of PP/PPE Alloy XYRON™ TF series, which has chemical resistance.
Good thin wall formability contributes to space saving and weight reduction. Furthermore, it has excellent creep properties and flame resistance (non-halogen), contributing to vehicle safety.

Click here for the physical properties table of XYRON™ 340Z

ザイロン バッテリーEVセル間スペーサー
  • Bus bar cover:XYRON™ 440Z, 443Z

If weight reduction and dimensional stability are important for insulating protective covers for conductors that carry high voltage and large current, we recommend XYRON™ 440Z and 443Z, which have thin wall formability, insulation properties, and heat resistance.
There is also an oil resistance XYRON™ T series that is easier to handle.

Click here for the physical properties table of XYRON™ 440Z

Click here for the physical properties table of XYRON™ 443Z

Battery components
  • Connector:XYRON™ 644Z

XYRON™ 644Z is used for connectors in automotive battery systems.
Resin materials must be highly reliable to comply with the stringent automotive OEM standards demanded by LV214 and USCAR.
XYRON™ 644Zoffers outstanding flame retardance (UL 94 V-0, 5VA), long-term stability of physical properties (UL746B RTI 125°C), tracking resistance (CTI PLC=2), weather resistance (UL746C f1), and other excellent features.

Click here for the physical properties table of XYRON™ 644Z

XYRON™ 644Z Automotive Connector

These superior properties have earned XYRON™ 644Z an extensive track record of use in junction boxes for solar-power generation systems and other similar applications. (Click here to learn more about solar-power generation.)
The same features have also led to XYRON™ 644Z being chosen by a large Chinese battery manufacturer for use in automotive battery connectors.

  • Peripheral components for fuel cell stacks:XYRON™ 500H

XYRON™ 500H for the peripheral components of fuel cell stacks. Asahi Kasei recommends 
This material features low elution (of ions, oligomers, and other species) and excellent resistance to heat, water, and acid, and their physical properties exhibit minimal degradation upon long-term immersion in liquids.

Click here for the physical properties table of XYRON™ 500H

Peripheral components for fuel cell stacks
  • Nickel metal hydride battery cell case:Flame-retardant XYRON™ grades

XYRON™ grades for NiMH battery-case components are lower in weight than the metals conventionally used for battery cases, and Asahi Kasei has developed these materials to feature the properties required for battery-cases applications:Flame-retardant 
low weight (low specific gravity), alkali resistance, gas-barrier strength, and resistance to metal degradation.

Also, as part of Asahi Kasei’s lineup of ”Contribution through Business Activities” products, these products help to reduce CO2 when in use. 

XYRON™ resin (vehicle secondary battery components)

Polyamide resins feature excellent heat resistance, strength, and rigidity Leona

What is LEONA™?

Asahi Kasei’s LEONA™ polyamide resins are engineering plastics featuring excellent strength, rigidity, heat resistance, and chemical resistance.

These materials may be reinforced with fillers such as glass fibers to improve strength, rigidity, durability, and dimensional stability. 

Case studies: Applications of LEONA™ for EV batteries

  • Battery end plate: LEONA™ SN Series

For battery end plates—positioned at either end of a battery module to compress and hold in place a stack of battery cells—Asahi Kasei recommends our LEONA™ SN series of resin grades. These materials offer good moldability, feature high strength, high rigidity, good electrical properties (CTI), and good heat resistance.

  • Bus bar cover:LEONA™ SN11B

When insulating protective covers for conducting elements carrying high currents at high voltages must have high strength and long-term stability of physical properties (RTI compliance), Asahi Kasei recommends LEONA™ SN11B, which is well-suited to fabrication of thin-walled components, offers high strength against dielectric breakdown, and features excellent tracking resistance (CTI 600V), flame retardance (UL 94 V-0), and long-term heat resistance (RTI).

Flame-retardant PA66 has expanded its range of applications, primarily in the E&E and automotive domains. Recent years have witnessed growing demands to eliminate materials containing halogens and red phosphorus, both to reduce environmental impact and to improve worker safety.
To support these environmental and worker-safety initiatives, Asahi Kasei embarked on a program to develop new LEONA™ grades using flame retardants without halogens or red phosphorus. This program is now nearing completion.

Engineering plastic foams help to reduce weight and improve thermal insulation for EV batteries Sunforce

What is SunForce™?

SunForce™ is Asahi Kasei’s family of XYRON™-based foam materials that combine the unique lightweight and thermal-insulation characteristics of foams with superior properties—far beyond the capabilities of conventional foams—as a result of the use of modified polyphenylene ether (m-PPE) ingredients. These properties include excellent flame retardance (UL-94 V-0), dimensional precision, and suitability for fabricating thin-walled components. 

The foamy structure of SunForce™ beads means that this material contains less resin than solid materials—and, as a consequence, fewer pathways for heat to flow through the material, ensuring low thermal conductivity and high thermal insulation.

engineering plastics particle foam beads Sunforce

Case studies: Applications of SunForce™ materials for EV batteries

SunForce™ beads facilitate thermal management for EV batteries.The superior thermal-insulation properties of 

The superior thermal-insulation properties of SunForce™ beads facilitate thermal management for EV batteries.

A well-known property of batteries is that their output falls dramatically at low temperatures. To avoid this behavior, various strategies have been devised for electric and high-output hybrid vehicles, involving heaters and other mechanisms, for keeping batteries at sufficiently high temperatures. Asahi Kasei recommends insulating vehicle batteries with SunForce™ beads. This prevents batteries from releasing heat and cooling while the vehicle is at rest, preserving the battery’s high output power for hours with no need for a heater.

When heaters are present, the insulation provided by SunForce™ beads minimizes external thermal loss.

SunForce™beads also reduce the power used to cool batteries while driving by reducing the influx of external heat through the vehicle chassis. This improves heat-exchange efficiency and maximizes battery performance.

Sunforce Battery Thermal Management

Also, SunForce™ materials are foams that may be used wherever flame-retardant behavior is required.

SunForce™ is a foam-bead material to achieve compliance with the V-0 level of the UL-94 flame-retardant standard for plastic components, indicating an extremely high level of flame retardance.

SunForce™ materials are lightweight foams with self-extinguishing behavior for fires, and have been adopted or are under consideration for an increasing variety of peripheral components of EV battery packs.

For example, using SunForce™ beads for cell holders in vehicle-mounted battery packs offers the following advantages.

  1. Improved safety: Use of foam materials with UL-94 V-0 flame retardance
  2. Weight reduction:  SunForce™ foams can reduce weight compared to injection-molded resin materials. (The specific gravity of 10x foam grades is 0.1 kg/L.) 
cylindrical lithium ion battery cell holder

High strength, stiffness, and impact properties  レンセン™ロゴ

What is LENCEN™ (c-GFRTP)?

LENCEN™ (c-GFRTP) is a continuous glass fiber reinforced thermoplastic formed by stacking layers of a continuous glass fiber textile with polyamide-66 (PA66) films.

We intend to propose this material as a material which may provide collision safety and weight reduction because it has tensile strength and impact properties equal to or greater than those of metals, and may also contribute to improved reliability and fuel efficiency.


Proposal to EV battery cases

Battery cases in electric vehicles are typically made from metals such as steel or aluminum. The goal of reducing component weight to extend vehicle travel distance suggests the possibility of switching to resin materials, but typical resins cannot offer the required thermal resistance; also, cost reduction is a perennial issue.

Advantages of 

  1. 1.Lightweight: Specific gravity approximately 1/4 that of steel.(Specific gravity:  LENCEN™ 1.9 Steel 7.9 Aluminum 2.7)
  2. 2.Heat-resistant: No holes appeared in burning tests after 30 minutes at 1000°C.
  3. 3.Cost-effective: Cost reduction can be possible through integration or reduction of components
      ・Upper cover: Potential reduction in need for anti-rust paint and thermal insulation.
      ・Lower case: Potential reduction in need for undercover.
▲Heat-resistant: No holes appeared in burning tests after 30 minutes at 1000°C.
  • Go here for details on LENCEN™ (c-GFRTP)

Related information

XYRON™ m-PPE resins

XYRON™ has excellent flame retardancy, electrical properties, dimensional stability, and water resistance. It is used in photovoltaics (PV), batteries, and 5G communication components.

LEONA™ polyamide resin

LEONA™ has excellent heat resistance, strength and toughness, insulation, and oil resistance. It is widely used in automotive parts, electrical and electronic parts.


SunForce™ is a lightweight foam with excellent flame retardancy, heat resistance, and thermal insulation properties, and is applicable to EV battery peripheral components.


LENCEN™ is a continuous glass fiber-reinforced thermoplastics (c-GFRTP) composite with tensile strength and impact absorption equivalent to or better than metal.

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