Lighting purpose organic light-emitting devices have to be answer to high electrical and thermal requirements. Design of these devices needs special engineering. The electrical current and dissipated power distribution in an OLED needs electro-thermal field simulation. The algorithm in our simulation tool, SUNRED, had to be extended to be able to handle highly nonlinear electrical OLED characteristics, and nonlinear temperature dependence. We have created an electro-thermal model for the OLED samples given by our project partner. The nonlinear semiconductor junction model is applied in SUNRED. This article surveys the new OLED model and presents the application in electro-thermal simulations. Finally we compare the measurement, model and simulation results.