Pressure relief apparatus, battery cell, battery, and electrical device

A pressure relief apparatus, comprising:

• a pressure relief part having a first surface and a second surface opposite to each other in a thickness direction of the pressure relief part;
• and
• a plurality of stages of score grooves sequentially arranged on the pressure relief part in a direction from the first surface to the second surface, wherein of two adjacent stages of score grooves in the thickness direction, one stage of score groove that is farther from the first surface is arranged on a bottom surface of another stage of score groove that is closer to the first surface;
• wherein:
• the plurality of stages of score grooves comprise a first-stage score groove, the first-stage score groove comprising a first groove segment, a second groove segment, a third groove segment, and a fourth groove segment,
• the first groove segment and the second groove segment being oppositely arranged,
• the first groove segment and the second groove segment both intersecting with the third groove segment,
• the fourth groove segment being a rectilinear groove located between the first groove segment and the second groove segment, intersecting with the third groove segment, being parallel to the first groove segment and the second groove segment, and being perpendicular to the third groove segment;
• the pressure relief part comprises an opening region, the first groove segment, the second groove segment, and the third groove segment being arranged along an edge of
• the opening region, and the opening region being configured to be openable with the first groove segment, the second groove segment, and the third groove segment as boundaries;
• the second surface is provided with a notch groove only located within the opening region, and the notch groove is at a distance from the third groove segment in a direction of extension of the first groove segment;
• and
• the notch groove is at a distance from both the first groove segment section and the second groove segment section in a direction of extension of the third groove segment;
• and
• the notch groove is located between the third groove segment and an end of the first groove segment extending in a direction perpendicular to the third groove segment and an end of the second groove segment extending in the direction perpendicular to the third groove segment.

A pressure relief apparatus, comprising:

• a pressure relief part having a first surface and a second surface opposite to each other in a thickness direction of the pressure relief part;
• and
• a plurality of stages of score grooves sequentially arranged on the pressure relief part in a direction from the first surface to the second surface, wherein of two adjacent stages of score grooves in the thickness direction, one stage of score groove that is farther from the first surface is arranged on a bottom surface of another stage of score groove that is closer to the first surface;
• wherein:
• the plurality of stages of score grooves comprise a first-stage score groove, the first-stage score groove comprising a first groove segment, a second groove segment, a third groove segment, and a fourth groove segment, the first groove segment and the second groove segment being oppositely arranged, the first groove segment and the second groove segment both intersecting with the third groove segment, and the fourth groove segment being located between the first groove segment and the second groove segment, and intersecting with the third groove segment;
• the pressure relief part comprises an opening region, the first groove segment, the second groove segment, and the third groove segment being arranged along an edge of the opening region, and the opening region being configured to be openable with the first groove segment, the second groove segment, and the third groove segment as boundaries;
• the second surface is provided with only one notch groove only located within the opening region, and the only one notch groove is at a distance from the third groove segment in a direction of extension of the first groove segment;
• and the only one notch groove is at a distance from both the first groove segment and the second groove segment in a direction of extension of the third groove segment;
• and the only one notch groove is a rectilinear groove extending in the direction of extension of the third groove segment, and
• the only one notch groove is parallel to the third groove segment and perpendicular to the fourth groove segment.