Experimental validation of energy harvesting-system availability improvement through battery heating

Operation of wireless sensor nodes or battery powered embedded systems in cold and harsh environments requires careful battery selection and management. In this paper, we first provide a general model of an energy harvesting sensor system and the respective energy flows. We then present a maximum power point tracking solar harvesting system according to that model. The system is coupled with rechargeable Li-ion batteries and equipped with a battery heating mechanism. The significant signals of that system are monitored to have a deeper insight into the energy distribution. Real-world experiments demonstrate benefits of battery heating during high irradiation periods at temperatures below safe charging conditions. The presented case study for a cold winter day shows that the additional energy, which can be stored thanks to battery heating would more than double the autonomy of the sensor system.