our technical films for battery cell production


What are films for batteries?

Battery foils are foils that are used for the production of batteries or accumulators. Especially with regard to electromobility or renewable energies, high-performance and reliable storage technologies play a decisive role. Typical applications for technical films in the production of batteries and rechargeable batteries are in insulation or as battery separators. 

The importance of battery cells

As electronic devices become more advanced and compact, they require more power and incorporate more complex internal technologies. Densely packed components significantly increase the power density of devices and storage technologies, creating a higher risk of electrical sparks and short circuits.

The introduction of electrically powered vehicles is also changing things in the field of mobility. The increasing importance of climate protection, dwindling fossil fuels and rising demand are leading to a growing significance of electric vehicles.

Central to the success of electric vehicles is storage technology, without which electromobility would simply be unthinkable. The lithium-ion batteries used in electric vehicles have improved continuously in recent years and will certainly continue to develop at ever shorter intervals. The lithium-ion batteries used today - and thus the vehicle's battery - are much more powerful than they were a short time ago. The higher capacity and battery quality of these cells allow vehicles to have a greater range.

The lithium-ion batteries generate heat during operation and charging. Therefore, in addition to heat dissipation, the use of insulation is necessary for the safety of the battery cells and other battery components. These protective, flame-retardant insulations made of plastic are installed between the components of the individual cell, module and battery during the manufacturing process. Therefore, film solutions for this application are also called separator film or battery separator film. These separator films are designed to provide thermal and electrical insulation protection and to isolate flame and spark voltages.

Technical films are therefore of central importance for the safe and reliable operation of battery cells and their service life. These so-called battery films therefore play an important role in battery production.

What materials are used to insulate lithium-ion batteries?

Films made of different materials are used for the electrical and thermal battery insulation of rechargeable batteries. Usually, stamped parts for the electrical insulation of batteries are made from them, which act as battery separators. These films offer a long service life and reliable insulation. Depending on the material, they also have other interesting properties. We offer polycarbonate and polyester films for battery applications in various formats. In addition to standard formats or rolls, we can also supply you with film cut to your desired dimensions.

Polycarbonate films for increased continuous use temperature.

Polycarbonate offers a variety of advantages and properties and is suitable for a wide range of applications. PC films are stable for a permanent temperature of at least 105 degrees Celsius. For short periods, they can even withstand temperatures of up to 160 degrees Celsius, and only become thermoelastic above 190 / 200 degrees Celsius. The films have very good thermoforming properties and are also extremely impact resistant and mechanically resilient. 

We offer films from the two leading brands Lexan and Makrofol and have an enormously wide range of products. Polycarbonate filma are available in various surfaces (polished, matt, fine matt, velvet matt), colours and thicknesses (thickness range from 0.125 mm - 1 mm). This means that PC films cover an enormously wide range of applications and are very often used for heat-resistant requirements such as insulation in batteries.

You can find more information on the properties, areas of application and all product details on our website www.folien-zentrum.com. As a specialist for technical films, we can advise you on the selection of the right battery film for your project and find a suitable solution for you.

UL listed films for compliance with fire protection standards.

Especially for the production of batteries, insulation made of flame retardant films is required to meet certain fire protection classes. Flame retardant materials act as flame barriers or insulation, which helps to obtain UL certification and pass UL testing. As a specialist in technical films, we offer various products that meet the UL 94 V0 fire protection standard.

The UL 94 rating ensures that electrical insulators can withstand direct exposure to intense heat and flame for a specified period of time. Since many components made of film are used worldwide, the American UL 94 standard has become the accepted standard in most industrial applications. This is accepted worldwide and is more important than most national standards. Class V0 is the highest flammability class of plastics according to UL 94.

Halogen-free polycarbonate films with UL 94 V0 listing.

Halogen-containing products (chlorine, bromine) are often used in the production of flame-retardant polycarbonate films. Particularly in electronics and automotive technology, attempts are increasingly being made to dispense with these ingredients. Due to legal regulations, the requirements of EU directives and consumer demands, special films have been developed that are halogen-free.

The manufacturer SABIC therefore offers its flame-retardant materials from the halogen-free, UL-compliant film range LEXAN EFR. These PC films offer bromine and chlorine free flame retardancy in a range of thicknesses and colours. They enable manufacturers of electronic products and batteries to comply with environmental regulations and to produce high-quality and safe components.

Biaxially oriented polyester (PET) films.

Also popular in the film industry are polyester (PET) films. Polyester films are used in many applications where electrical insulation, heat resistance and dimensional stability are required. PET film is characterised by high resistance to temperatures. It also has good tensile strength and tear resistance, excellent resistance to chemicals, high mechanical and thermal stability and excellent transparency. Polyester films are good electrical insulators, show low moisture absorption (0.3%) and high dielectric strength up to 180 kV/mm. With a printing pre-treatment (coating), most of our polyester films can be printed well and homogeneously. These film properties make them an ideal material in the automotive industry and for storage technologies. You will find further information on the areas of application and the properties as well as all other product details on our website. 

We will be happy to advise you on the selection of a suitable film for your battery application.

Applications of battery films.

Films are often used as battery separators in battery cell production. Typical applications in storage technologies such as lithium-ion batteries and other batteries are:

  • Battery insulation.
  • Die-cut insulating gasket.
  • Thermal / electrical shielding and insulation.
  • Battery enclosures.
  • Batteries and adapters for computers, notebooks, mobile phones.
  • Housing insulation.
  • Insulation gaskets for positive connectors.
  • Cell insulation.
  • Serial connector insulation.
  • BMU insulation.

The films are usually punched into moulded parts and can also be cut very well with other technologies. As a specialist for films, we will be happy to recommend a suitable film for your application.

Service, cutting and delivery.

As a wholesaler for special technical films, we offer only high quality products and have a very large range and stock. Thanks to our flexible systems and various machines, we can supply you with battery films on rolls / by the metre in various widths or in rectangular sheets / formats. Ask us for the required dimensions and we will provide you with a suitable offer. You can also order our battery films online. 

We can also help you in recycling films with our new REVINK programme. We will be happy to recycle your Film remnants via professional partners. In addition to easy disposal, you benefit from a certificate confirming your participation in the programme. 

If you have any further questions or customer requests regarding processing, material selection, formats and dimensions, accessories, please do not hesitate to contact us. You are also welcome to contact us at any time with queries about possible applications or our company. We will be happy to help you with the necessary product details or data sheets from the manufacturers. Please contact us if you would like advice, solutions or a concrete offer. The team of the König Film Centre is looking forward to your call!