Bipolar Lead Accumulator Cell with High Energy Density

摘要

A cell design using bipolar electrodes was proposed for increasing the energy density of the familiar PbO2/H2SO4/Pb system. Weight reductions have been achieved by improving several details of the battery construction and grid design, and reducing the amount of electrolyte. Requirements for low-maintenance have been equally fulfilled by reducing water consumption. Lead-coated Cu was chosen for the grid of the negative electrode and lead-coated Al for the grid of the positive electrode. An 80 to 100 micrometers lead-coating was found to offer sufficient protection for the Cu-grid because anodic corrosion of the negative electrode could be discounted. Cu itself, in contact with negative active material remains stable with the normal range of electrochemical potential. Al, as the positive grid, required a protective lead-coating of at least 250 micrometers, without pinholes or other defects or anodic corrosion could be intense. The negative and positive component of the bipolar electrodes were connected centrally by riveting and soft soldering with an insulating foil separating the electrolyte compartments. Devices for topping up with water and for gas escape are incorporated. An energy density of 44.2 Wh5/kg was obtained, virtually achieving the high target value.