LEAD-ACID BATTERY

A lead-acid battery includes at least one cell including an element and an electrolyte solution. The element includes a positive electrode plate, a negative electrode plate, and a bag-shaped separator interposed between the positive electrode plate and the negative electrode plate. The negative electrode plate includes a negative current collector and a negative electrode material. The positive electrode plate includes a positive current collector and a positive electrode material. The negative electrode material contains a polymer compound having a peak in a range of 3.2 ppm or more and 3.8 ppm or less in a chemical shift of a 1H-NMR spectrum measured using deuterated chloroform as a solvent. The positive current collector contains Sn. The bag-shaped separator includes a rib protruding toward the positive electrode plate, and houses the positive electrode plate.