The rapid transition toward electric mobility is redefining performance expectations for battery materials. As electric vehicle (EV) platforms move from 400‑volt to 800‑volt architectures, battery cell components are exposed to increasingly severe electrical, thermal, and mechanical stresses. These demands are pushing conventional insulation materials to their limits and accelerating the adoption of new coating technologies.
Among these, UV‑curable coatings based on Laromer® oligomers have emerged as a highly effective solution – combining exceptional dielectric performance, fast processing, and formulation flexibility. Rather than incremental improvement, these systems represent a step change in how insulation for high‑voltage battery cells can be designed and manufactured.
High‑Voltage EV Architectures Demand a Rethink of Insulation Materials
Next‑generation EV platforms increasingly rely on 800‑volt battery systems to enable faster charging, higher power efficiency, and extended driving range. While these advances benefit vehicle performance, they place unprecedented requirements on cell insulation materials.
Traditional polymer insulation films, often used as secondary protection layers, typically fail to withstand breakdown voltages beyond ~2,500 volts. Under high electrical stress, these films can delaminate or peel away from the cell surface – leading to loss of insulation integrity and, in worst cases, safety‑critical failure.
In contrast, modern battery insulation solutions must reliably withstand breakdown voltages in the 3,000–4,000-volt range and beyond, while maintaining adhesion, flexibility, and chemical resistance throughout the battery’s lifetime.
Why UV‑Curable Coatings Are Gaining Traction in Battery Manufacturing
UV‑curable coatings offer a unique combination of performance and productivity advantages that directly address the challenges of battery cell insulation:
• Instant curing enables high‑speed production lines
• Low thermal load protects sensitive battery components
• 100% solids systems minimize emissions and energy consumption
• Excellent film control enables functional layers at defined thickness
However, the performance of a UV‑curable insulation coating is ultimately defined by its binder chemistry. This is where Laromer oligomers play a decisive role.
Laromer Oligomers: Designed for Electrical Insulation Performance
Laromer UV oligomers are specifically engineered to deliver a balance of flexibility, adhesion, and dielectric strength, which is essential for high‑voltage battery applications.
Key design requirements addressed by Laromer include:
• High electrical resistivity and dielectric breakdown strength
• Strong adhesion to metallic substrates such as aluminum
• Mechanical flexibility to accommodate thermal expansion
• Controlled reactivity for uniform curing at higher film builds
These requirements are met through tailored urethane and polyester acrylate architectures, allowing formulators to fine‑tune performance without compromising processability.
Tailored Binder Selection: Balancing Mechanical Integrity and Electrical Insulation
For EV battery cell insulation, binder selection plays a decisive role—not only in coating adhesion and flexibility but also in electrical insulation performance. In UV‑curable systems, dielectric strength and volume resistivity are governed by polymer backbone polarity, crosslink density, and network homogeneity after curing. Laromer® oligomers are specifically engineered to address these requirements.
Flexible Urethane Acrylates as Primary Insulating Binders
Flexible urethane acrylates are commonly selected as the main binder backbone for battery insulation coatings due to their ability to combine mechanical compliance with high electrical resistivity.
Laromer® UA 9186 E and UA 8987 E
These urethane acrylates offer excellent flexibility and strong adhesion to aluminum substrates while forming a dense, uniform polymer network after UV curing. Their balanced polarity contributes to high volume resistivity, making it well suited for insulation layers subjected to elevated voltage stress.
Laromer UA 9089
A tough yet flexible urethane acrylate, Laromer® UA 9089 supports reliable electrical insulation by enabling stress‑relieved coating films, reducing the risk of micro‑defects that can initiate dielectric breakdown. Its undiluted use further supports high solids formulations without compromising insulation performance.
Laromer UA 9073
This oligomer is characterized by outstanding flexibility and lower intrinsic reactivity, which promotes more controlled curing and uniform crosslink density at higher film thicknesses. This attribute is particularly advantageous for electrical insulation, as homogeneous networks are known to enhance dielectric breakdown strength and voltage withstand capability.
Co‑Binders for Enhanced Dielectric Stability and Durability
To further optimize insulation performance, selected co‑binders are incorporated to adjust network stiffness, reactivity, and chemical robustness – without sacrificing electrical properties.
Laromer UA 9136
With higher reactivity and excellent chemical resistance, this oligomer contributes to dielectric stability over time, particularly under thermal and chemical exposure typical of battery environments.
Laromer PE 8800 and Laromer PE 9182
These polyester acrylates increase hardness or flexibility and toughness while maintaining good electrical insulation characteristics, supporting coatings that retain dielectric strength even at reduced film thickness.
Insulation Performance by Design, Not Thickness
By combining flexible urethane acrylates with carefully selected co‑binders, Laromer‑based systems enable insulation coatings that achieve high volume resistivity and dielectric breakdown strength at practical film builds. This binder‑driven approach allows formulators to decouple electrical performance from excessive coating thickness – supporting compact battery designs and efficient material usage.
In high‑voltage EV battery applications, this formulation‑level control of electrical insulation is a key differentiator of Laromer UV oligomers.
Proven Electrical Performance at Practical Film Thickness
In battery manufacturing, insulation coatings must perform not only in the lab but under industrial conditions. UV‑curable Laromer®‑based coatings demonstrate strong and reproducible performance at application‑relevant film thicknesses.
When applied to aluminum substrates pretreated with Chemetall® Oxsilan, representative Laromer®‑based systems achieve:
• Single‑layer film thicknesses of 70–130 µm
• Low viscosity (~600 cPs), suitable for industrial application
• Excellent adhesion
Electrical testing confirms:
• Volume resistivity on the order of 10¹³ Ohm·cm at 500 V
• AC dielectric breakdown values up to 9 kV
• Successful DC voltage withstands at 6 kV
These results demonstrate that high electrical insulation is achievable without excessive coating thickness, enabling compact cell designs and efficient material usage.
Monomer Selection: Completing the Insulation Design
While oligomers define the coating backbone, reactive diluents (monomers) play a critical role in electrical performance. Studies clearly show that monomer polarity and functionality can significantly influence volume resistance and breakdown behavior.
In Laromer‑based formulations, careful monomer selection enables:
• High solids content without sacrificing insulation performance
• Uniform crosslink density after UV curing
• Reduced defect formation that can lead to electrical failure
This reinforces an important insight: electrical insulation is a formulation‑level property, driven by synergy between oligomer design and monomer choice—not by any single raw material.
Laromer as a Platform, not a Single Product
What distinguishes Laromer in EV battery applications is not one individual product but the breadth and consistency of the portfolio. From highly flexible urethane acrylates to tougher polyester systems, Laromer enables:
• Tailored insulation solutions across different battery designs
• Robust processing across a wide curing window
• Scalable, production‑ready UV technologies for global battery manufacturing
As battery voltages continue to rise and production volumes accelerate, materials must deliver both performance headroom and process robustness—areas where Laromer UV oligomers consistently demonstrate value.
Conclusion: Enabling High‑Voltage Battery Safety Through Smart Resin Design
The shift toward high‑voltage EV batteries is redefining insulation requirements – and creating new opportunities for advanced coating technologies. UV‑curable coatings based on Laromer oligomers offer a powerful combination of high dielectric performance, fast processing, and formulation flexibility, addressing both technical and manufacturing challenges.
By enabling insulation performance beyond traditional films and supporting scalable production, Laromer solutions help transform high‑voltage battery design from a constraint into a competitive advantage – supporting safer, faster, and more efficient electric mobility.