Research on the Heating of Multi-Power Supply Units for Large-Area and Curved-Surface Transparent Electrothermal Films

Using multi-power supply units to power large-area electrothermal films can achieve high electrothermal power under low voltage. However, this method may result in poor contact between the electrodes and the electrothermal film, especially for films with large areas and curved surfaces, as well as for power supply units with small electrode spacing. This study found that the relative deviation between the measured value (RM) and the theoretical value (RP) of the parallel resistance, RM−RPRP, exceeds 12.8% when powering a planar Indium Tin Oxide (ITO) electrothermal film with an area of 5 cm × 5 cm and electrode spacing of less than 0.5 cm using four or more power supply units. This deviation is significantly higher than that observed for power supply units with electrode spacing ≥0.8 cm, where RM−RPRP is 1.4% and 0.3% for spacings of 0.8 cm and 1.1 cm, respectively. By using fine sand, springs, and airbags as power supply pedestals, close contact between the electrodes and the electrothermal film can be achieved for large-area and curved-surface films due to the deformation of the sand, springs, or airbags under the heater’s weight. When an airbag power supply pedestal with twelve power supply units is used to power the bottom of an electrothermal ceramic teacup with a 20 cm2 curved ITO transparent electrothermal film, the RM−RPRP is 13.3% and the heating temperature reaches 83.1 °C.