Abstract: Disclosed are a pole plate, cell, and battery. The pole plate includes a current collector and a coating layer formed on at least one surface of the current collector. The coating layer includes a first coating zone and a second coating zone arranged on two sides of the first coating zone. A compaction density of the second coating zone is larger than that of the first coating zone.

Abstract: The present disclosure provides a secondary battery and a manufacturing method therefore. The secondary battery comprises a case, an electrode assembly and a cap assembly. The case has four side walls and a bottom wall which enclose an internal space; the electrode assembly is received in the internal space of the case. The cap assembly is provided to a top of the case and seals the electrode assembly in the internal space; the cap assembly comprises a safety mechanism configured to make an electrical current not flow through the electrode assembly when a gas pressure in the internal space reaches a predetermined value. At least one of the four side walls of the case bulges outwardly, and the internal space protrudes correspondingly.