EP-4738495-A1 - SECONDARY BATTERY AND ELECTRONIC DEVICE

EP4738495A1EP 4738495 A1EP4738495 A1EP 4738495A1EP-4738495-A1

Abstract

This application discloses a secondary battery and an electronic device, including a housing, an electrode assembly, a first adhesive member, and a second adhesive member. The electrode assembly is disposed within the housing, and the electrode assembly includes a first electrode plate, a separator, and a second electrode plate that are stacked and wound. The first electrode plate includes a first segment, the first segment constitutes an outermost portion of the electrode assembly, and the first segment has a first surface facing a winding central axis and a second surface facing away from the winding central axis. Along the winding direction of the first segment, the first segment includes a terminating segment, where a first surface and a second surface of the terminating segment are blank foil regions. At least part of the first adhesive member is bonded to the first surface of the terminating segment. The second adhesive member is disposed on the second surface of the terminating segment and bonds the second surface of the terminating segment to the housing. Along a direction perpendicular to the first surface, a projection of the second adhesive member partially overlaps a projection of the first adhesive member. For the secondary battery of this application, a risk of failure due to dropping or collision is reduced.

Inventors

TAN, Kang
TANG, Xuqing
LI, SHENG

Assignees

Ningde Amperex Technology Limited

Dates

Publication Date: 20260506
Application Date: 20240627

Claims (17)

A secondary battery, characterized in that the secondary battery comprises: a housing; an electrode assembly, disposed within the housing, the electrode assembly comprising a first electrode plate, a second electrode plate, and a separator located between the first electrode plate and the second electrode plate, wherein the first electrode plate, the second electrode plate, and the separator are stacked and wound, and a direction of a winding central axis of the electrode assembly is a first direction; the first electrode plate comprises a first segment, the first segment constitutes an outermost part of the electrode assembly, and the first segment has a first surface facing the winding central axis and a second surface facing away from the winding central axis; along the winding direction of the first segment, the first segment comprises a terminating segment, wherein both a first surface and a second surface of the terminating segment are blank foil regions; a first adhesive member, at least partially bonded to the first surface of the terminating segment; and a second adhesive member, disposed on the second surface of the terminating segment and bonding the second surface of the terminating segment to the housing, wherein along a direction perpendicular to the first surface, the second adhesive member partially overlaps the first adhesive member.
The secondary battery according to claim 1, characterized in that an overlapped portion between the second adhesive member and the first adhesive member serves as a first portion, an area of the first portion is S1, an area of the second adhesive member is S2, and 15% ≤ S1 / S2 ≤ 50%.
The secondary battery according to claim 1 or 2, characterized in that along the winding direction of the first segment, a distance between the first adhesive member and an end of the terminating segment is a first distance, and the first distance is greater than or equal to 2 mm.
The secondary battery according to any one of claims 1 to 3, characterized in that the first segment further comprises a coating segment connected to the terminating segment.
The secondary battery according to claim 4, characterized in that one end of the first adhesive member is bonded to the coating segment, the other end thereof is bonded to the terminating segment, and the first adhesive member covers a junction between the coating segment and the terminating segment; and along the first direction, a length of the first adhesive member is L1 mm, a length of the first segment is L2 mm, and 0 ≤ L1 - L2 ≤ 3.
The secondary battery according to claim 4 or 5, characterized in that the first adhesive member comprises: a first sub-adhesive member, disposed on the first surface; and a second sub-adhesive member, disposed on the first surface, wherein the second sub-adhesive member is bonded to the first sub-adhesive member at the terminating segment, and a projection of the second sub-adhesive member on the second surface along a direction perpendicular to the first surface partially overlaps the second adhesive member.
The secondary battery according to claim 6, characterized in that one end of the first sub-adhesive member is bonded to the coating segment, the other end thereof is bonded to the terminating segment, and the first sub-adhesive member covers a junction between the coating segment and the terminating segment; and along the first direction, a length of the first sub-adhesive member is L3 mm, the length of the first segment is L2 mm, and 0 ≤ L3 - L2 ≤ 3.
The secondary battery according to claim 6 or 7, characterized in that the first adhesive member comprises a plurality of second sub-adhesive members; the plurality of second sub-adhesive members are sequentially arranged on the first surface along the winding direction of the first segment, and adjacent second sub-adhesive members are bonded to each other; and along the winding direction of the first segment, the second sub-adhesive member at an arrangement starting end is bonded to the first sub-adhesive member on the terminating segment, and along the direction perpendicular to the first surface, the projection of the second sub-adhesive member at an arrangement terminal end partially overlaps a projection of the second adhesive member.
The secondary battery according to any one of claims 1 to 8, characterized in that the first adhesive member and the second adhesive member are adhesive tapes.
The secondary battery according to any one of claims 1 to 9, characterized in that the first segment comprises a first straight segment, a first curved segment, a second straight segment, and a second curved segment that are connected; the first straight segment and the second straight segment are oppositely arranged in a second direction, the first curved segment and the second curved segment are both connected between the first straight segment and the second straight segment, and the first curved segment and the second curved segment are oppositely arranged in a third direction; and the second adhesive member is disposed on the first straight segment or the second straight segment, and the first direction, the second direction, and the third direction are mutually perpendicular to each other.
The secondary battery according to any one of claims 1 to 10, characterized in that a peel strength between the separator and the first electrode plate or the second electrode plate is 8 N/m to 12 N/m.
The secondary battery according to any one of claims 1 to 11, characterized in that the first adhesive member is a single-sided adhesive tape with adhesion on only one side, and the single-sided adhesive tape comprises a first substrate layer and a first binder layer coated on one side of the first substrate layer.
The secondary battery according to any one of claims 1 to 11, characterized in that the second adhesive member is a double-sided adhesive tape with adhesion on both sides, the double-sided adhesive tape comprises a second substrate layer and second bonding layers coated on both sides of the second substrate layer, and the second bonding layers are binder layers and/or hot melt adhesive layers.
The secondary battery according to any one of claims 1 to 13, characterized in that the housing is a packaging bag.
The secondary battery according to any one of claims 1 to 14, characterized in that the first electrode plate is a cathode electrode plate, and the second electrode plate is an anode electrode plate; and the first segment has an active material layer disposed only on the first surface, and the active material layer is disposed on the first surface of the coating segment.
The secondary battery according to any one of claims 1 to 15, characterized in that the second adhesive member is used for fixing the terminating segment.
An electronic device, characterized in that the electronic device comprises the secondary battery according to any one of claims 1 to 16.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202310796380.3, entitled "Secondary Battery and Electronic Device", filed with the China Patent Office on June 30, 2023, which is incorporated herein by reference in its entirety. TECHNICAL FIELD The embodiments of this application relate to the field of electrochemical technology, and in particular, to a secondary battery and an electronic device. BACKGROUND With the development of technology, consumer electronic products such as mobile phones and notebook computers have gained widespread popularity. As a core component of electronic devices, secondary batteries (lithium-ion batteries) have become a critical factor in the advancement of electronic products due to their advantages such as high operating voltage and long service life. A lithium-ion battery typically includes a housing and an electrode assembly. To reduce a risk of failure of the lithium-ion battery due to dropping, the commonly adopted practice is to bond the electrode assembly to the housing using an adhesive, thereby minimizing relative movement between the electrode assembly and the housing, so as to reduce collision-induced failures between the electrode assembly and the housing. However, for the outermost electrode plate of the electrode assembly, there remains a risk of tearing electrode plate at the joint between the adhesive-covered and non-covered regions. Moreover, in a case of adhesive terminating, an ending of the electrode plate remains in a semi-constrained state, which can easily lead to tearing of the electrode plate during the drop of a lithium-ion battery, resulting in the failure of the lithium-ion battery. SUMMARY Embodiments of this application aim to provide a secondary battery and an electronic device to address an issue of an outermost electrode plate being prone to tearing, thereby reducing a failure risk of a lithium-ion battery. In order to resolve technical problems, the following technical solutions are used in embodiments of this application. This application discloses a secondary battery, including a housing, an electrode assembly, a first adhesive member, and a second adhesive member. The electrode assembly is disposed within the housing, the electrode assembly includes a first electrode plate, a second electrode plate, and a separator located between the first electrode plate and the second electrode plate, where the first electrode plate, the second electrode plate, and the separator are stacked and wound, and a direction of a winding central axis of the electrode assembly is a first direction. The first electrode plate includes a first segment, the first segment constitutes an outermost part of the electrode assembly, and the first segment has a first surface facing the winding central axis and a second surface facing away from the winding central axis. Along a winding direction of the first segment, the first segment includes a terminating segment, where both a first surface and a second surface of the terminating segment are blank foil regions. The first adhesive member is at least partially bonded to the first surface of the terminating segment. The second adhesive member is disposed on the second surface of the terminating segment and bonds the second surface of the terminating segment to the housing, where along a direction perpendicular to the first surface, the second adhesive member partially overlaps the first adhesive member. In the above-mentioned technical solution, the first adhesive member being at least partially bonded to the first surface of the terminating segment may enhance the tensile strength of the terminating segment, thereby reducing a risk of tearing in the terminating segment. The second adhesive member is disposed on the second surface of the terminating segment and bonds the terminating segment to the housing, thereby reducing relative movement between the electrode assembly and the housing and increasing the tensile strength of the terminating segment again, thus further lowering the risk of tearing in the terminating segment. Meanwhile, along the direction perpendicular to the first surface, a projection of the second adhesive member partially overlaps a projection of the first adhesive member. When the secondary battery drops or collides, it is allowed that part of the shear force on the second adhesive member to be transmitted to the first adhesive member, thereby reducing shear force concentration and further lowering the risk of tearing at the terminating segment. In some preferred embodiments, the overlapped portion between the second adhesive member and the first adhesive member serves as a first portion. Along the direction perpendicular to the first surface, a projection of the first portion falls within the projection of the first adhesive member. The transmission of a shear force between the first adhesive member and the second adhesive member may effectively re