Multi-Point Flexible Temperature Sensor Array and Thermoelectric Generator Made from Copper-Coated Textiles

Abstract

The integration of electrical functionality into flexible textile structures requires the development of new concepts for flexible conductive material. Conductive and flexible thin films can be generated on non-conductive textile materials by electroless metal deposition. By electroless copper deposition on lyocell-type cellulose fabrics, thin conductive layers with a thickness of approximately 260 nm were prepared. The total copper content of a textile fabric was analyzed to be 147 mg per g of fabric, so that the textile character of the material remains unchanged, which includes, for example, the flexibility and bendability. The flexible material could be used to manufacture a thermoelectric sensor array and generator. This approach enables the formation of a sensor textile with a large number of individual sensors and, at the same time, a reduction in the number of electrical connections, since the conductive textile serves as a common conductive line for all sensors. In combination with aluminum, thermoelectric coefficients of 3–4 µV/K were obtained, which are comparable with copper/aluminum foil and bulk material. Thermoelectric generators, consisting of six junctions using the same material combinations, led to electric output voltages of 0.4 mV for both setups at a temperature difference of 71 K. The results demonstrate the potential of electroless deposition for the production of thin-film-coated flexible textiles, and represent a key technology to achieve the direct integration of electrical sensors and conductors in non-conductive material.

Textile‐Based Flexible Temperature Sensors for Wearable and Sports Applications

“…Each of them exhibited high sensitivity of around 1.52 Ω °C −1 along with temperature coefficient of 0.002 23 °C −1 . Furthermore, Landsiedel et al [ 48 ] have presented a cellulose fabric with the help of conductive and flexible thin films. The proposed sensor has potential applications in flexible wearable textile applications.…”

“…[45,46] Textile-based temperature sensors have been designed with the help of metal wires and threads that are conductive in nature or can be made conductive with conductive elements or liquids. [47,48] These wires and threads are quite visible on textiles and are affected by hysteresis causing a compromise in aesthetics as well as making them unable to provide localized temperatures due to their large topology. The temperature sensors initially designed were rigid and mounted on textile yarns making them thick and causing discomfort to the fabric with rigid chips.…”

Recent Advances in the Nanomaterials, Design, Fabrication Approaches of Thermoelectric Nanogenerators for Various Applications

“…Unlike the metal chalcogenides discussed in the prior sections, pure metals have not been developed recently due to their very high thermal conductivity. [113,114] Although some metals such as copper, aluminum and silver are known to be good electrocatalysts with properties that enable operation near room temperature, [115][116][117] pure metal-based TEGs are generally more useful for high-temperature applications. Hence it is used for thermoelectric temperature sensors that resist temperatures above 400 K to temperatures above 1200 K. [118] Pure metal TE materials are also found in high-temperature waste heat recovery, such as from incinerators [119] and heat pipes.…”

Towards the Functional Ageing of Electrically Conductive and Sensing Textiles: A Review

“…Smart textiles can also be divided into “passive smart textiles”, e.g., humidity, temperature, pressure, gas sensors and “active smart textiles” which adapt their behaviour to their environmental exposure [ 3 ]. Apart from the typical functionality as a connector for signal transport and energy supply, conductive structures can also be utilised as a sensor and actuator areas in modern smart textiles, e.g., as temperature sensors, [ 4 ] pressure sensors [ 5 ] and piezo elements for energy harvesting [ 6 ].…”