Flow Cell for Simultaneous In Situ Analysis of Local Electrolyte Distribution and Porous Morphology within the Negative Electrode in a Lead-Acid Battery

Abstract

While lead-acid is without doubt the oldest battery technology still in use and despite continuous research over many years, mystery still surrounds certain key aspects of its operation. A complex relationship exists between the characteristics of the electrolyte and those of the solid lead sulfate that is alternately deposited and removed during discharge-charge. A premature mode of failure is the often-cited “plate sulfation” that affects the negative electrode and this was investigated by forcing electrolyte flow through the electrode to probe structural changes. A new design of Flow cell that measures flow through the porous electrode has been developed. Under forced electrolyte flow, the discharge capacity and recharge efficiency both increased significantly confirming that local sulfuric acid concentration has a strong effect. Also contributing to decreased electrolyte flow was the production of hydrogen gas during charging, which may make this technique useful in studies of fast-charging. Beyond this, the Flow cell can be used to investigate types of duty where the deposition of lead sulfate triggers catastrophic loss of performance. The ability to monitor electrolyte flow accurately provides an important additional operating parameter that will help characterize modes of electrode failure that until now have remained opaque.