Textile connecting multi-wire ribbons with high electrical conductivity

VÚB a.s.  has  been engaged in research and development in the field of smart textiles and wearable electronics.

Within this work, a number of conductive hybrid threads were developed, which show different appearance, purpose of use, mechanical-physical parameters, but especially different electrical characteristics - especially the electrical resistance determining the possibility of specific use of threads.

We followed up on these results and continue further development, which is focused on the implementation of these conductive threads into elastic ribbons or tapes, which could be used as electrical signal buses.

Our CleverTex® conductive textile ribbons offer a wide range of applications, especially in the field of e-textiles and wearables.

The electrically conductive flexible ribbons can advantageously be used as bus bars or as "textile conductors" wherever a variable length of conductive element is required without their electrical resistance being affected during the change in length. In addition, it is possible to place electronic components such as LEDs, sensors or connectors on these ribbons. Flexible conductive ribbons thus enable an easy and reliable way of implementing e-textiles.

Generally elastic ribbons are produced in a volume of about 25% of the entire production of ribbons and the production of this specific ribbon type does not differ from the production of solid ribbons, so called belts.

The elasticity of the ribbon in general is ensured by the presence of flexible/elastic components, which can be in the form of elastomer or classic rubber bands of natural rubber.

The number and extensibility of the woven elastic components provide the resulting elastic parameters of the ribbon. Usual flexible ribbon shows 200% extension.

In our solution when preparing CleverTex® conductive textile ribbons some of elastic components are replaced by CleverTex® conductive threads in the warp system.

Thus, a new product is created which combines textile and electrical properties and acquires new possibilities of application in the ​​e-textiles area.

During the research and development, various types of CleverTex® elastic ribbons were developed, which differ mainly in the purpose of their use and thus in the number and structure of implemented hybrid conductive threads.

The most frequently used elastic ribbons are the following two types:

• Single-conductor elastic ribbons

 It is a flexible ribbon with one wide conductive strip composed of several individual electrically conductive hybrid threads. This ribbon can be used as a collecting electrode for textile heating elements. If necessary the width of the conductive strip is variable depending on the number of conductive threads implemented.

• Multi-conductor flexible ribbons

This type of the ribbon is a "multi-conductor" ribbon type, where multiple electrically separated conductive paths, usually 2 - 4, can be placed in the ribbon.

Such ribbons can then be used as a replacement of litz-wires and buses in textile products. A huge advantage of this solution is the ability to create turnoffs and tree structures, as the conductive tracks are accessible from one or both sides of the ribbon.

Core product properties:

•  ribbon width usually 8 - 12 mm; 
•  variable amount of conductive paths in the ribbon - usually 1 - 4;
•  standardized spacing of conductive tracks 2.54 mm (for ribbons with two or more tracks).
•  solderable, weld-able, crimp-able;
•  possibility of direct mounting of SMD components on conductive tracks by low- temperature   soldering (SnBi) or gluing;
•  linear resistance of one conductive path <1 Ω / m independent of stretching;
•  high abrasion resistance and bending resistance;
•  high resistance to maintenance stress - they can withstand up 90 washing cycles without   deterioration of functionality;
•  medical safety.

Advantages of CleverTex® conductive textile ribbons application:

 -  The production and especially the use of rigid or flexible conductive ribbons allow moving the integration of electronic components into textiles to a significantly higher level.

-  The conductive ribbons can not only serve as carriers for individual electronic components or entire electronic modules, but can also be used as connecting wires or bus-bare. 

-  Wide variability and customization of conductive ribbons- the can be  tailored exactly to the required parameters, i.e. it is possible to change the current carrying capacity, change the electrical characteristics of conductive elements, numbers of conductive elements, spacing of conductive paths etc.

 -  High resistance to maintenance stress allowing  to achieve a long life of the  e-textile end products.

The design and topology of elastic ribbons with conductive tracks realized by means of hybrid conductive threads is protected by Czech patent No. 308 614 "Conductive elastic woven ribbon".