According to their installation places, the solar cells are often under the effect of the electro-magnetic field coming from outside sources as telecommunication antennas, radio antennas... These magnetic fields have a big influence on the distribution and mobility of charge carriers in the base of the solar cell and therefore on its efficiency. This work presents a tree-dimensional study of bifacial silicon solar cell under intense light concentration (more than 50 suns) and under a constant magnetic field. This approach is based on the resolution of the minority continuity equation, taking into account the distribution of the electric field in the bulk evaluated as a function of both majority and minority carrier densities. In this approach new analytical expression of carrier’s density is established for rear side illumination. The effects of light concentration and magnetic field on excess minority carriers distribution, photocurrent and photovoltage in solar cell base are analysed.