Patent ID: 7070880

Claim:
A coin shaped battery comprising: a strip of positive electrode plate formed of a plurality of positive electrode layer faces coupled together by a plurality of connecting pieces; a strip of negative electrode plate formed of a plurality of negative electrode layer faces coupled together by a plurality of connecting pieces; a separator interposed between the positive electrode plate and the negative electrode plate, the positive electrode plate and negative electrode plate being folded at the respective connecting pieces and coiled around into an electrode plate group of flat form such that the positive electrode layer faces and the negative electrode layer faces are alternately layered upon one another with the separator interposed therebetween; a sealing case forming an inner space together with a gasket and a cap case for accommodating the electrode plate group, characterized in that the positive electrode plate and the negative electrode plate are respectively formed with positional discrepancy detecting cut-outs for detecting positional displacement between the positive electrode layer faces and the negative electrode layer faces when both electrode plates are coiled around; the positional discrepancy detecting cut-outs being at least one hole in each of said electrode plates, said at least one hole being larger in either one of said electrode plates and than said at least one hole in the other; and said at least one hole in said positive electrode plate being axially adjacent and radially concentric with said at least one hole in said negative electrode plate when said electrode plates are coiled around; whereby a widthwise diameter difference between said larger and said smaller diameter holes indicating a positional relationship between said positive electrode layer faces and said negative electrode layer faces.