Towards Thermoelectric Fabrics
Abstract
Thermoelectric fabrics offer an ideal solution for portable lightweight energy sources or for conformable thermoelectric refrigeration. Such flexible functional thermoelectric materials could surround heat sources such as the human body for energy harvesting or for active cooling while offering freedom of motion. Such a thermoelectric fabric can be woven into clothing or conveniently shaped to surround heat sources of any shape, acting either as a power source for battery charging or as a refrigerating jacket, actively pumping heat away for cooling in adversely high temperatures. The first step to creating such active thermoelectric fabrics is to develop individual thermoelectric threads with a high thermoelectric figure-of-merit ZT, from which such a thermoelectric fabric could be woven. The goal of this DARPA Seedling Proposal is therefore to make 3D printed flexible n-type and p-type thermoelectric threads, as the initial step towards woven thermoelectric fabrics. This proof-of-concept for creating such threads strives to match today’s industry-standard thermoelectric materials with figure-of-merit ZT = 0.6. If such performance can be achieved, these fabrics could either passively charge one cell phone battery per day from the waste heat of one person at rest in an outside ambient 65 F (18 C); or actively cool a person to a comfortable 73 F (23 C) for 2 hours in a hot ambient 82 F (28 C) using 4 Li-ion cell phone batteries weighing merely 3 oz (0.1 kg.) To date, standard thermoelectrics are rigid, and their functional device structure does not allow for flexibility or wear-ability, greatly reducing the opportunities for strategic low-power applications. A woven thermoelectric platform allows both large and small-scale solutions, literally tailored to the needs of any application. Once thermoelectric threads can be made with uniform thickness & strength on a large scale, these fabrics can be mass-produced on industrial-scale looms for a thermoelectric textiles. The research plan is to fabricate thermoelectric threads via 3D printing. Extruded threads dry quickly enough to be directly spooled for subsequent weaving. The thermoelectric Seebeck coefficient and electrical conductivity would be characterized, as would their bending radius and mechanical strength as a function of thread diameter.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 18, 2017
- Source ID
- HR00111710005
Entities
People
- Matthew Grayson
Organizations
- Defense Advanced Research Projects Agency
- Northwestern University