Patent ID: 8168314

Claim:
A method for evaluating the safety of a battery upon an internal short-circuit, the battery comprising: an electrode group comprising a positive electrode, a negative electrode, and an insulating layer for electrically insulating the positive and negative electrodes from each other, the positive electrode comprising a positive electrode active material layer and a positive electrode current collector, the negative electrode comprising a negative electrode active material layer and a negative electrode current collector, the positive and negative electrodes and the insulating layer being wound or laminated; an electrolyte; a housing for housing the electrode group and the electrolyte, the housing including an external terminal; and a current-collecting terminal for electrically connecting the electrode group and the external terminal, the method comprising: causing an internal short-circuit in the battery and detecting the occurrence of the internal short-circuit by detecting battery information obtained from the battery or by visual inspection, wherein the internal short circuit is caused by inserting a foreign object into a location inside the electrode group of the battery where the positive electrode and the negative electrode face each other from a direction parallel to a surface of the positive electrode or the negative electrode, and applying a pressure to the location into which the foreign object is inserted to locally crush either the insulating layer interposed between the positive electrode and the negative electrode or at least one selected from the positive electrode active material layer and the negative electrode active material layer, together with the insulating layer, and the foreign object is present independently between the positive electrode and the negative electrode and is not joined to the positive electrode or the negative electrode.