3D Modeling of Physico-Chemical Processes in Lead-Acid Batteries with Spatial Resolution

The value of today's world market for energy storage systems is constantly increasing. It is caused by demand for reliable energy storage solutions for renewable energies, off-grid and rural electricity systems as well as for the growing number of uninterruptible power supply (UPS) solutions needed especially for data centers. Nowadays, lead-acid batteries are used primarily for automotive and stationary applications like already mentioned UPS, traction or for IT / telecommunications applications. With the existing supply chain from manufacturing to recycling the lead-acid battery offers today a robust, mature and economically attractive solution for stationary applications. However, an efficient utilization of this technology in the new market requires further improvements considering cycle life stability combined with an additional cost reduction. Better understanding of the known ageing effects of lead-acid batteries is necessary to achieve these goals. A novel simulation approach features a 3D resolution of all physico-chemical effects that have a strong influence on battery's performance. Additionally, it considers inhomogeneities that are present in every application and significantly contribute to the overall ageing of each battery. The 3D model gives a closer look at the physico-chemical processes in the active material, at the interface of electrodes and electrolyte and in the electrolyte itself. The most important effects from the application point of view have been implemented using an electrical equivalent circuit and a volume elements approach. The model as the main part of the presented work is going to provide an in-depth understanding of the processes and could deliver suggestions for novel cell designs.