| CPC H01M 50/586 (2021.01) [H01M 50/103 (2021.01); H01M 50/15 (2021.01)] | 18 Claims |
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1. An energy storage device, comprising an insulation film and an electrode assembly, wherein the electrode assembly is wrapped by the insulation film, and the insulation film comprises a bottom film, a first side film, and a second side film;
the bottom film comprises a first side, a second side, and a third side, wherein the first side is opposite to the second side in a width direction of the bottom film, and the third side is connected to the first side and the second side;
the first side film is connected to the first side, and the first side film comprises a first wrapping section and a second wrapping section connected to the first wrapping section in a length direction of the bottom film; and the first wrapping section is connected to the first side, and the second wrapping section exceeds the third side in the length direction of the bottom film;
the second side film is connected to the second side, and the first side film comprises a third wrapping section and a fourth wrapping section connected to the third wrapping section in the length direction of the bottom film; and the third wrapping section is connected to the second side, and the fourth wrapping section exceeds the third side in the length direction of the bottom film;
the bottom film, the first side film, and the second side film are integrally formed;
when the electrode assembly is wrapped by the insulation film, the first side film is folded relative to the bottom film along the first side, the second side film is folded relative to the bottom film along the second side, the second wrapping section is folded relative to the first wrapping section, the fourth wrapping section is folded relative to the third wrapping section, and the second wrapping section and the fourth wrapping section are connected and at least partially overlapped;
a first groove and a second groove are defined on the third side, the first groove extends along the first side, and the second groove extends along the second side; the first groove is defined between the bottom film and the first side film, and the second groove is defined between the bottom film and the second side film; and
the first side film further comprises a first bending section defined by the first groove, and the second side film further comprises a second bending section defined by the second groove; in the length direction of the bottom film, two opposite sides of the first bending section are respectively connected to the first wrapping section and the second wrapping section, and two opposite sides of the second bending section are respectively connected to the third wrapping section and the fourth wrapping section; and when the electrode assembly is wrapped by the insulation film, the first bending section and the second bending section are bent and deformed, to make the second wrapping section folded relative to the first wrapping section and the fourth wrapping section folded relative to the third wrapping section;
the second wrapping section has a first cutting edge facing away from the first wrapping section and close to the fourth wrapping section, and the fourth wrapping section has a second cutting edge facing away from the third wrapping section and close to the second wrapping section; and the first cutting edge is angled relative to the third side, and the second cutting edge is angled relative to the third side;
the first cutting edge and the third side define an angle α, and the second cutting edge and the third side define an angle β, wherein 1°≤α≤8°, and 1°≤β≤8°;
in the length direction of the bottom film, the first bending section has a length M1, and the second bending section has a length M2, wherein 1.75 mm≤M1≤10.35 mm, and 0.9≤M1/M2≤1.1;
in the width direction of the bottom film, the bottom film further comprises a third bending section and a fourth bending section facing away from each other; the first side is located at the third bending section, the second side is located at the fourth bending section, and in the width direction of the bottom film, the third bending section has a width M3, and the fourth bending section has a width M4, wherein 1 mm≤M3≤2.55 mm, and 0.9≤M3/M4≤1.1;
the energy storage device further comprises a cover plate, a lower plastic, and a housing, wherein the cover plate comprises a first outer side surface and a second outer side surface that are connected at an angle; the lower plastic is connected to the cover plate, the lower plastic comprises a third outer side surface facing the same direction as the first outer side surface, and a fourth outer side surface facing the same direction as the second outer side surface; the third outer side surface is connected to the fourth outer side surface, the first outer side surface exceeds the third outer side surface, and the second outer side surface exceeds the fourth outer side surface;
the third outer side surface has a first bonding region, the fourth outer side surface has a second bonding region, and the insulation film is connected to the first bonding region and the second bonding region; in a thickness direction of the lower plastic, the first bonding region is located at an end of the third outer side surface away from the cover plate, the second bonding region is located at an end of the fourth outer side surface away from the cover plate; and an edge of the first bonding region is spaced apart from the cover plate by a distance S1, wherein 1.55 mm≤S1≤2.85 mm.
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