Thermoelectric generator (TEG) devices have attracted worldwide scientists for several decades. However, the application of TEG worldwide has been limited due to its low power density and complex system layout. The purpose of this research is to improve the TEG power mounted in proton exchange membrane fuel cell (PEMFC) vehicles. Hence, the cases of channel structure of TEG are modeled and simulated to compare among cases. In these cases, the experimental bench model is set up to demonstrate precisely with numerical simulation results. Furthermore, this experimental model utilized an input heat source of 100 °C, assuming whether the release heat of the fuel cell devices or cooling systems of the engine. All results of simulation and experiments are compared to evaluate precisely.