A theory of the grid/positive active-mass (PAM) interface and possible methods to improve PAM utilization and cycle life of lead/acid batteries

Very often, the cycle life of batteries with antimony-free positive grids operating under deep-discharge cycling is determined by the grid/PAM interface. The properties of this interface are overviewed and the technological and design parameters influencing these properties, and hence determining the cycle life of the battery, are discussed. A new parameter ʹY is proposed. This is defined as grams of PAM per 1 ern" of grid-collector surface area. It has been established that the gridlPAM interface consists of two layers, namely, a corrosion layer (CL) and a layer of the active mass that collects the current from the remaining (capacity-bearing) part of the PAM (AMCL). The technological parameters that influence the specific resistivity of both CL and AMCL, as well as the surface area of the layers through which current flows between the PAM and the collector are discussed. On the basis of the principles derived from the theory of the grid/PAM interface, batteries are produced and tested.