The Failure Analysis of Bus-bar for a Lead-acid Battery

The bus-bar of a lead-acid battery used for an automobile exhibited failure phenomenon. Some dark yellow products appeared in the area connected to the battery positive electrode, and melting and deformation phenomena were found around the bolt hole. Climbing acid experiments were used to simulate the bus-bar failure process. The cross-sectional morphology was observed using laser scanning confocal microscope. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to observe and analyze the yellow products. The results show that the yellow products mainly consisted of PbO and PbSO4, and melting and deformation phenomena of positive electrode were caused by the heat from charging and discharging process. To prevent potential safety hazard, the charge current should not be too large, charging time should not be too long.