Secondary battery

摘要

A safety valve is disposed to cover at least a portion of the center line of the lid plate between the pair of terminals for the positive electrode and the negative electrode. The distance from the center line of the lid plate to end portions of the components to be energized on the safety valve side is equal to or less than the distance from the center line of the lid plate to the outermost circumference of the safety valve. The shadow area obtained by projecting an opening portion of the safety valve in operation onto the plane of the lid plate does not overlap with the respective shadow areas obtained by projecting the electrically connected components, such as the external output terminals for the positive electrode and the negative electrode, onto the plane of the lid plate.

主权项

1. A secondary battery comprising:
an electrode group including one or more negative electrodes each having a negative current collecting member and a negative active material held on the negative current collecting member, one or more positive electrodes each having a positive current collecting member and a positive active material held on the positive current collecting member, and a separator holding an electrolyte, the one or more negative electrodes and the one or more positive electrodes being alternately layered via the separator; a battery case including a case body having an opening portion and receiving the electrode group and a lid plate closing the opening portion; a negative output terminal member provided with the lid plate and electrically connected to the one or more negative electrodes; a positive output terminal member provided with the lid plate and electrically connected to the one or more positive electrodes; and a safety valve provided at the lid plate at a position between the negative output terminal member and the positive output terminal member and including an opening area to be opened when the internal pressure of the battery case rises to a predetermined pressure or higher, wherein: the safety valve is disposed to partially overlap with an imaginary center line passing through the center between the negative output terminal member and the positive output terminal member and extending along a plate surface of the lid plate to divide the lid plate into two halves; and the safety valve, the negative output terminal member, and the positive output terminal member are configured such that the minimum distance from the imaginary center line to respective end edges of the negative output terminal member and the positive output terminal member on the side of the safety valve is equal to or less than the minimum distance from the imaginary center line to the outermost end edge of the safety valve, and such that respective shadow areas obtained by projecting the negative output terminal member and the positive output terminal member onto an imaginary plane extending along the plate surface of the lid plate partially overlap with areas defined between the imaginary center line and an imaginary line extending in parallel to the imaginary center line and passing through the outermost end edge of the safety valve, but a shadow area obtained by projecting the opening area of the safety valve onto the imaginary plane does not overlap with respective shadow areas obtained by projecting the negative output terminal member and the positive output terminal member onto the imaginary plane.