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

A battery cell, comprising:

• a pressure relief apparatus comprising:
• a pressure relief body, comprising a pressure relief portion, the pressure relief portion having a first surface and a second surface opposite to each other in a thickness direction of the pressure relief portion;
• and
• a plurality of score grooves sequentially arranged at the pressure relief portion in a direction from the first surface to the second surface;
• wherein:
• in two adjacent score grooves of the plurality of score grooves in the thickness direction, a maximum width of one of the two adjacent score grooves that is farther away from the first surface is less than a minimum width of another one of the two adjacent score grooves that is closer to the first surface;
• the plurality of score grooves comprise a first score groove, a second score groove, and a third score groove, the first score groove and the second score groove extend in a same direction, the first score groove is arranged on a bottom surface of the second score groove, the third score groove is arranged on the first surface, and the second score groove is arranged on a bottom surface of the third score groove;
• the second score groove comprises a first groove section, a second groove section, and a third groove section, the first groove section and the second groove section are arranged at an interval, and both the first groove section and the second groove section intersect with the third groove section;
• the pressure relief portion comprises an opening region jointly formed by the first groove section, the second groove section, and the third groove section;
• and
• the second surface is provided with a notch groove located in the opening region, the notch groove is spaced apart from the third groove section in an extension direction of the first groove section, the extension direction of the first groove section is perpendicular to the third groove section, and a distance between the notch groove and the third groove section along a direction parallel to the extension direction of the first groove section is less than a distance between the end of the first groove section and the third groove section along the extension direction of the first groove section.

A manufacturing method for a pressure relief apparatus, the method comprising:

• providing a pressure relief body, the pressure relief body comprising a pressure relief portion, the pressure relief portion having a first surface and a second surface opposite to each other in a thickness direction of the pressure relief portion;
• and
• sequentially processing a plurality of score grooves on the pressure relief portion in a direction from the first surface to the second surface;
• wherein:
• in two adjacent score grooves in the thickness direction, a maximum width of one of the two adjacent score grooves that is farther away from the first surface is less than a minimum width of another one of the two adjacent score grooves that is closer to the first surface;
• the plurality of score grooves comprise a first score groove, a second score groove, and a third score groove, the first score groove and the second score groove extend in a same direction, the first score groove is arranged on a bottom surface of the second score groove, the third score groove is arranged on the first surface, and the second score groove is arranged on a bottom surface of the third score groove;
• the second score groove comprises a first groove section, a second groove section, and a third groove section, the first groove section and the second groove section are arranged at an interval, and both the first groove section and the second groove section intersect with the third groove section;
• the pressure relief portion comprises an opening region jointly formed by the first groove section, the second groove section, and the third groove section;
• and
• the second surface is provided with a notch groove located in the opening region, the notch groove is spaced apart from the third groove section in an extension direction of the first groove section, the extension direction of the first groove section is perpendicular to the third groove section, and a distance between the notch groove and the third groove section along a direction parallel to the extension direction of the first groove section is less than a distance between the end of the first groove section and the third groove section along the extension direction of the first groove section.