Bipolar VRLA Technology

Atraverda has achieved bi-polar VRLA technology manufacturing that simplifies lead acid battery technology for expanded uses and unparalled performance. This technology fits perfectly as the solution for electrified vehicle and renewable energy applications.

Conventional Lead-Acid Battery Technology

Conventional lead acid batteries are comprised of two electrodes: a positive electrode made of lead dioxide (PbO2) and a negative electrode made of sponge lead (Pb). Both the lead dioxide and sponge lead materials are pasted onto lead grids that act as the current collector. Two half reactions occur on the electrodes during charge and discharge that are described by the well known double sulphate theory for lead acid batteries:

Lead battery design consists of lead alloy grids (current collectors), pasted with active electrode material to make plates (positives and negatives), which are in turn alternately stacked with separators between each plate in sufficient number to produce the desired battery size. Tabs on the plates (lugs) of common polarity are connected to a lead alloy strap (called cast-on-strap). This stack (commonly referred to as a cell) is then inserted into an individual plastic compartment. Each cell operates at approximately 2.0 volts and the desired voltage of the battery is achieved by connecting a sufficient number of cells together, each in their own plastic compartment, through the strap, one cell to the next in series. For example, 6 cells, at 2.0 volts each, connected in series to produce 12 volts. The strap of the end cells in the series string is connected to the battery terminals by a lead post to provide the positive and negative terminals of the battery. This basic construction scheme has prevailed for 100 years, and in spite of significant investment in research, little improvement in basic energy density, power density or number of duty cycles has been achieved in the last few decades. Today, lead battery technology is mature, offering little differentiation among products from different producers. And although lead batteries are forecast to maintain their position in established markets, their performance is not likely to meet the needs of many new high growth applications such as HEVs, which are currently being served by nickel based rechargeable batteries. Figure 1 is an illustration of a conventional lead battery with the stacking concept of separators, electrodes and grids