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 separator interposed between the negative electrode plate and the positive electrode plate. The negative electrode plate includes a negative electrode material. The negative electrode material includes a nonionic surfactant including one or more hydrophobic groups and one or more hydrophilic groups. At least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms. A content of the nonionic surfactant in the negative electrode material is 8 ppm or more on a mass basis.