The discharge performance of the flooded lead/acid cell has been modelled. The model takes account of the diffusion-precipitation mechanism in the negative electrode. The effect of the dissolution of lead, the diffusion of lead ions and the precipitation of lead sulfate crystals is not even neglected at low current discharge and is increased as the discharge current increases. The discharge curves predicted by the model are in good agreement with the experimental data. (C) 1999 Elsevier Science S.A. All rights reserved.