Study on the series resistance of betavoltaic batteries

Series resistance (R_s ) is an essential factor that affects the performance of betavoltaic batteries. However, the R_s value of betavoltaic batteries tends to be anomaly high when it is extracted from the IV characteristic curve. To explore the reasons for this phenomenon, different injection conditions and their impacts on R_s of betavoltaic and photovoltaic cells were compared and analyzed, since photovoltaic cells have been studied in-depth in respect of R_s and have similar principles to betavoltaic batteries. The results show that R_s will be significantly affected by the injection conditions, and the high resistance of the depletion region under low-level radiation injection of betavoltaic batteries is the main reason for their high R_s . The effect of high R_s on betavoltaic battery performance was further explored, and the results show that the IV characteristic curve will be distorted obviously when R_s is close to or higher than the shunt resistance. This thus leads to a significant decrease in the battery’s fill factor and energy conversion efficiency. The effect of the input power on R_s should be considered in the future analysis of betavoltaic batteries. This work provides theoretical support for the parameter analysis of betavoltaic batteries.