This work describes the measurement of the change in current of two types of Li-ion batteries, both commercial off-the-shelf and in-house-assembled coin cells, under radiation exposure. The discharging batteries were irradiated with a neutron beam with a 30-mm diameter (adjustable to 10 mm and 5 mm) using the Ohio State University Research Reactor and was measured for the change of electric current with a Keithley SourceMeter. We have observed an increase in current when the batteries were exposed to gamma rays and a decrease in current when only thermal neutrons were applied. We discussed the mechanisms that are responsible for inducing such changes, including the electrode polarization caused by irradiation. The immediate application of a single coin cell in a current mode can be a small neutron or gamma-beam monitor or a near-core flux monitor in a high-flux environment.