SECONDARY BATTERY

PROBLEM TO BE SOLVED: To provide a secondary battery that improves heat dissipation of electrode plates and prevents a rise in temperature when a foreign object pierces therethrough.SOLUTION: A secondary battery 1 includes: a battery container 2 where an electrolyte is stored; a plurality of electrode plates 16 and 17 that are housed in the battery container 2 and are alternately laminated; first insulating members 9 and 10, each sandwiched between a pair, out of the electrode plates 16 and 17, adjacent to each other in a lamination direction of the electrode plates 16 and 17, in contact with the adjacent pair and each extending in a direction perpendicular to the lamination direction so as to be in contact with an inner wall 13b of the battery container 2; and second insulating members 11 and 12 that are sandwiched between the inner wall 13b of the battery container 2 and respective ones of the electrode plates 16 and 17 positioned at both respective ends in the lamination direction, in contact with the inner wall 13b and the respective ones of the electrode plates 16 and 17. Each of the first insulating members 9 and 10 and the second insulating members 11 and 12 has higher thermal conductivity than the electrolyte, and is deformed so as to cover a surface of a foreign object in the lamination direction when the foreign object pierces through the secondary battery 1 in the lamination direction.