EP-4738504-A1 - SECONDARY BATTERY AND ELECTRONIC DEVICE

EP4738504A1EP 4738504 A1EP4738504 A1EP 4738504A1EP-4738504-A1

Abstract

A secondary battery and an electronic device are provided. The secondary battery includes a housing, an electrode assembly disposed in the housing, and a first conductive plate. The electrode assembly is a stacked structure. The electrode assembly includes a first electrode plate, a separator, and a second electrode plate that are stacked sequentially in a first direction. The first conductive plate is connected to the first electrode plate. The first conductive plate extends out of the housing along a second direction perpendicular to the first direction. The first electrode plate includes a first outer electrode plate located at an outermost layer of the electrode assembly. When viewed in a third direction perpendicular to both the first direction and the second direction, the first outer electrode plate includes a first region and a second region connected in the second direction. When viewed in the third direction, the first region includes a first end connected to the second region and a second end disposed opposite to the first end in the second direction. The first region extends from the first end so as to deviate from the second direction, and the second end is farther away from the second electrode plate in the first direction than the first end. This application improves anti-overcharge performance.

Inventors

YAN, Dongyang
JIANG, NAN
ZENG, Qiao

Assignees

Ningde Amperex Technology Limited

Dates

Publication Date: 20260506
Application Date: 20240619

Claims (20)

A secondary battery, comprising a housing, an electrode assembly disposed in the housing, and a first conductive plate, wherein the electrode assembly is a stacked structure, and the electrode assembly comprises a first electrode plate, a separator, and a second electrode plate that are stacked sequentially in a first direction, the first conductive plate is connected to the first electrode plate, and the first conductive plate extends out of the housing along a second direction perpendicular to the first direction, characterized in that : the first electrode plate comprises a first outer electrode plate, and the first outer electrode plate is an outermost layer of the electrode assembly; when viewed in a third direction perpendicular to both the first direction and the second direction, the first outer electrode plate comprises a first region and a second region connected in the second direction; and when viewed in the third direction, the first region comprises a first end connected to the second region and a second end disposed opposite to the first end in the second direction; the first region extends from the first end so as to deviate from the second direction, and the second end is farther away from the second electrode plate in the first direction than the first end.
The secondary battery according to claim 1, characterized in that , when viewed in the third direction, an angle α between a line connecting the first end and the second end and the second direction satisfies: 1° ≤ α ≤ 12°.
The secondary battery according to claim 2, characterized in that 3° ≤ α ≤ 10°.
The secondary battery according to claim 1, characterized in that , when viewed in the third direction, a length of extension of the first region extending from the first end to the second end is a first length, a length of the second region in the second direction is a second length, and a ratio of the second length to the first length is greater than or equal to 7 and less than or equal to 29.
The secondary battery according to claim 4, characterized in that a ratio of the second length to the first length is greater than or equal to 11 and less than or equal to 19.
The secondary battery according to claim 1, characterized in that , in the second direction, the first region is farther away from the first conductive plate than the second region.
The secondary battery according to claim 1, characterized in that in the second direction, the first region is closer to the first conductive plate than the second region.
The secondary battery according to claim 1, characterized in that the first direction comprises a first side oriented from the second electrode plate toward the first outer electrode plate; the housing is a packaging bag and comprises a main portion for accommodating the electrode assembly and a sealing portion connected to the main portion, and the first conductive plate extends out of the housing from the sealing portion; the main portion comprises a first end face connected to the sealing portion, and when viewed in the third direction, the first end face extends from the sealing portion to the first side; and when viewed in the third direction, the first region extends from the first end to the first side.
The secondary battery according to claim 1, characterized in that the first direction comprises a first side oriented from the second electrode plate toward the first outer electrode plate and a second side opposite to the first side; the housing is a packaging bag and comprises a main portion for accommodating the electrode assembly and a sealing portion connected to the main portion, and the first conductive plate extends out of the housing from the sealing portion; the main portion comprises a first end face connected to the sealing portion, and when viewed in the third direction, the first end face comprises a first part extending from the sealing portion to the first side and a second part extending from the sealing portion to the second side, and a length of the first part in the first direction is greater than a length of the second part in the first direction; and when viewed in the third direction, the first region extends from the first end to the first side.
The secondary battery according to claim 1, characterized in that the first direction comprises a first side oriented from the second electrode plate toward the first outer electrode plate; the housing is a packaging bag and comprises a main portion for accommodating the electrode assembly and a sealing portion connected to the main portion; the first conductive plate comprises a first conductive region and a second conductive region connected to each other, the first conductive region is disposed inside the sealing portion and extends out of the housing from the sealing portion, the second conductive region is electrically connected to the first electrode plate, the second conductive region comprises a first end portion connected to the first conductive region, and the second conductive region extends from the first end portion to the first side.
The secondary battery according to claim 1, characterized in that the first outer electrode plate comprises a first current collector and a first active material layer stacked in the first direction, the first current collector comprises a first surface facing the second electrode plate and a second surface opposite to the first surface, the first active material layer is disposed on the first surface, and the second surface is coated with no active material.
The secondary battery according to claim 11, characterized in that the first electrode plate further comprises a first inner electrode plate, the first inner electrode plate is located on an inner side of the first outer electrode plate, the first inner electrode plate comprises a second current collector, and in the first direction, a thickness of the first current collector is a first thickness, a thickness of the second current collector is a second thickness, and a ratio of the first thickness to the second thickness is greater than or equal to 1.2 and less than or equal to 2.5.
The secondary battery according to claim 11, characterized in that the secondary battery further comprises a first layer disposed on the second surface, and the first layer contains an insulation material.
The secondary battery according to claim 13, characterized in that , in the first direction, it is defined that a thickness of the first current collector is a first thickness and a thickness of the first layer is a third thickness, and the third thickness is less than twice the first thickness.
The secondary battery according to claim 13, characterized in that the first layer is bonded to the second surface and the housing.
The secondary battery according to claim 1, characterized in that the first outer electrode plate comprises a first active material layer, a first current collector, and a second active material layer stacked in the first direction, the first current collector comprises a first surface facing the second electrode plate and a second surface opposite to the first surface, the first active material layer is disposed on the first surface, and the second active material layer is disposed on the second surface.
The secondary battery according to claim 11 or 16, characterized in that the first electrode plate is a positive electrode plate, and a mass of an active material disposed on the first current collector per unit area is G, satisfying: G ≤ 23 mg/cm 2 .
The secondary battery according to claim 1, characterized in that a separator adjacent to the first outer electrode plate is bonded to the second region.
The secondary battery according to claim 18, characterized in that a second electrode plate adjacent to the first outer electrode plate comprises a third region and a fourth region connected in the second direction, and when viewed in the first direction, the first region and the third region overlap, and the second region and the fourth region overlap; and the separator adjacent to the first outer electrode plate is further bonded to the third region.
The secondary battery according to claim 19, characterized in that the third region comprises a first subregion and a second subregion connected in the second direction, and when viewed in the third direction, the second subregion comprises a third end connected to the first subregion; the first subregion overlaps the first region in the first direction, and when viewed in the first direction, the second subregion extends from the third end past the first region; and when viewed in the third direction, the second subregion extends from the third end along a direction facing away from the first outer electrode plate.

Description

TECHNICAL FIELD This application relates to the technical field of energy storage, and in particular, to a secondary battery and an electronic device containing the secondary battery. BACKGROUND With popularization of consumer electronics products such as a laptop computer, a mobile phone, a handheld game console, a tablet computer, a mobile power supply, and an unmanned aerial vehicle, people are placing higher requirements on a secondary battery (such as a lithium-ion secondary battery). However, secondary batteries may be thermally runaway when overcharged, reducing the reliability and service life of the secondary batteries. SUMMARY In view of the above disadvantages, it is necessary to provide a secondary battery of improved anti-overcharge performance. In addition, this application further provides an electronic device containing the secondary battery. A first aspect of this application provides a secondary battery. The secondary battery includes a housing, an electrode assembly disposed in the housing, and a first conductive plate. The electrode assembly is a stacked structure. The electrode assembly includes a first electrode plate, a separator, and a second electrode plate that are stacked sequentially in a first direction. The first conductive plate is connected to the first electrode plate. The first conductive plate extends out of the housing along a second direction perpendicular to the first direction. The first electrode plate includes a first outer electrode plate. The first outer electrode plate is an outermost layer of the electrode assembly. When viewed in a third direction perpendicular to both the first direction and the second direction, the first outer electrode plate includes a first region and a second region connected in the second direction. When viewed in the third direction, the first region includes a first end connected to the second region and a second end disposed opposite to the first end in the second direction; the first region extends from the first end so as to deviate from the second direction, and the second end is farther away from the second electrode plate in the first direction than the first end. In this application, the first region is set to extend so as to deviate from the second direction. When the secondary battery is overcharged, the first region or the second electrode plate corresponding to the first region can serve as a sacrificial position for depositing lithium first in the case of overcharge, thereby reducing the probability or degree of lithium plating at other positions. This also reduces the probability of contact shorting caused by the deposited lithium dendrites piercing the separator, thereby reducing the occurrence of thermal runaway. Furthermore, if gas is produced near the first region in the case of overcharge of the secondary battery, contact interfaces between the first outer electrode plate, the separator, and the second electrode plate that are adjacent can be burst open by the gas, thereby further reducing the probability of contact shorting caused by the lithium dendrites piercing the separator, and also facilitating timely dissipation of heat in the electrode assembly. Therefore, this application can improve the anti-overcharge performance of the secondary battery, thereby improving reliability and service life. In some possible embodiments, when viewed in the third direction, an angle α between a line connecting the first end and the second end and the second direction satisfies: 1° ≤ α ≤ 12°. By defining the lower limit of the angle α, this application leaves lithium to be first deposited in the first region or the second electrode plate corresponding to the first region in the case of overcharge of the secondary battery, thereby reducing the probability of the deposited lithium dendrites piercing the separator and consequently causing contact shorting. By defining the upper limit of the angle α, this application reduces the impact of the first region on the energy density and appearance smoothness of the secondary battery, reduces the probability that the active material in the first region peels off easily and causes a short circuit, and reduces the probability of an increase in the active material that is not capacity-boosting in the first region. In some possible embodiments, the angle satisfies: 3° ≤ α ≤ 10°, thereby further allowing lithium to be deposited first in the first region or the second electrode corresponding to the first region in the case of overcharge of the secondary battery, and reducing the probability of the deposited lithium dendrites piercing the separator and consequently causing contact shorting. Moreover, this further reduces the impact of the first region on the energy density and appearance smoothness of the secondary battery, reduces the probability that the active material in the first region peels off easily and causes a short circuit, and reduces the probability of an increase in the active materia