Battery grids structure

Blanyer, R., Battery Grid Structure Made of Composite Wire, U.S. Patent 4,865,933, 1989. 

Fig. 4. Grain structure of lead—2 wt % antimony alloy battery grid at a magnification of 50x (a) no nucleants (b) containing 0.025 wt % selenium as a grain...

Unlike the automobile-type battery that is quite portable, the stationaiy lead-acid batteries that provide uninterruptible power to hospitals and other important facilities are not. Some may weigh over several tons because of the much heavier grid structure and other features to extend life expectancy and improve deep discharge capabilities. 

All these experimental data prove that the composition of the lead alloys for positive battery grids exerts an influence not only on the mechanical and electrochemical properties of the grids but also on the structure of the PAM and hence on the cycle life performance of the batteries. 

There is no question that the development and commercialization of lithium ion batteries in recent years is one of the most important successes of modem electrochemistiy. Recent commercial systems for power sources show high energy density, improved rate capabilities and extended cycle life. The major components in most of the commercial Li-ion batteries are graphite electrodes, LiCo02 cathodes and electrolyte solutions based on mixtures of alkyl carbonate solvents, and LiPF6 as the salt.1 The electrodes for these batteries always have a composite structure that includes a metallic current collector (usually copper or aluminum foil/grid for the anode and cathode, respectively), the active mass comprises micrometric size particles and a polymeric binder. 

Each of the above parameters exerts an influence on the formation of the structure of the active masses and on the nature of their interfaces with the grids. Thus, the parameters affect the performance of the battery. The algorithm of the formation should take into account the zonal processes that occur on both types of plate so as to ensure the formation of appropriate active-mass structures, which would guarantee high battery performance characteristics. 

One conductive additive which is relatively stable is barium plumbate (BaPbOs) [11]. This is a ceramic [12] with the perovskite structure and is easily made by standard ceramic-powder technology. Addition of this material to positive plates in a lead-acid battery significantly improves the formation efficiency. The formation mechanism is changed when the conductive particles are dispersed in the plate. Formation not only proceeds from the grid towards the centre of the pellet, but also takes place slowly around the conductive particles in the plate. The conductive paths of Pb02 grow and make connection with each other during formation to establish a network, which further facilitates the formation. 

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