SECONDARY BATTERY

A positive electrode used in a secondary cell that is an example of the present embodiment is provided with a positive electrode collector, an intermediate layer formed on the positive electrode collector, and a positive electrode mixture layer formed on the intermediate layer. The positive electrode mixture layer has a thermally expandable material and a positive electrode active material. The thermally expandable material content of the positive electrode mixture layer is at least 0.1% by mass and less than 5% by mass. The intermediate layer has an insulating inorganic material and a conductive agent. The insulating inorganic material content of the intermediate layer is 80-99% by mass.