Secondary battery and method for manufacturing secondary battery

A method for manufacturing a secondary battery including an electrode group having a positive electrode plate and a negative electrode plate arranged with a porous insulating layer interposed therebetween, the method comprising the steps of:

• (a) preparing the electrode group having the positive electrode plate and the negative electrode plate arranged in such a manner that the porous insulating layer is interposed therebetween and an end portion of at least one of the positive and negative electrode plates protrudes from the porous insulating layer;
• (b) preparing a current collector plate provided with a projection formed on one principle surface of the current collector plate and having a gap thereinside;
• (c) bringing the end portion of the electrode plate protruding from the porous insulating layer into contact with the other principle surface of the current collector plate;
• and
• (d) joining the end portion of the electrode plate to the current collector plate by locally heating the projection, wherein
• the end portion of the electrode plate is welded to the current collector plate in the step (d) with a fused material obtained by fusing the projection.