WO2024093482A1

WO2024093482A1 - Battery cell and preparation method therefor, and battery

Info

Publication number: WO2024093482A1
Application number: PCT/CN2023/115719
Authority: WO
Inventors: 孙韩丽; 项宇; 盛东辉; 谢继春
Original assignee: 珠海冠宇电池股份有限公司
Priority date: 2022-10-31
Filing date: 2023-08-30
Publication date: 2024-05-10
Also published as: CN219626707U

Abstract

A battery cell and a preparation method therefor, and a battery. The battery cell comprises a battery cell body and a packaging body for packaging the battery cell body; the packaging body comprises a sol layer for packaging the battery cell body; the packaging body is provided with a side packaging edge and a first edge; a first sol is formed at an included angle between the side packaging edge and the first edge of the sol layer; and the side edge of the first sol close to the battery cell body is a first arc. The sol at a top corner formed by the side packaging edge and a top edge in the battery cell achieves the effect of spreading outwards, so that the sealing strength is improved, the risk that the positions of the top corner and a bottom corner are extremely prone to break when the battery cell generates gas, collides or falls is effectively avoided, the potential failure source of battery liquid leakage is eliminated, and the battery cell has stable performance and high safety.

Description

Battery cell and preparation method thereof, and battery

Technical Field

The present application relates to the field of battery technology, and more specifically to a battery cell and a preparation method thereof, and a battery.

Background technique

Lithium-ion batteries have been widely used in people's daily lives, so its safety performance is the first assessment indicator. The roll core or stacked core of soft-pack lithium batteries is generally packaged with aluminum-plastic film. Whether the packaging of the aluminum-plastic film is reliable is related to the safety of the entire battery cell. However, the sol area of the intersection of the side seal and the top edge of the current lithium-ion battery seal body has not been specially processed, resulting in insufficient bonding strength. As a result, when the battery cell produces gas, collides or falls, the intersection area is very easy to break, which will become a potential failure source of battery leakage, causing battery cell failure, thereby causing safety problems.

Summary of the invention

In view of this, the present application provides a battery cell and a preparation method thereof, and a battery, which can solve the problem of potential safety hazards.

The present application provides a battery cell, comprising a battery cell body and a packaging body that encapsulates the battery cell body; the packaging body comprises a sol layer that encapsulates the battery cell body; the packaging body has a side seal and a first edge; a first sol is formed on the sol layer at an angle corresponding to the side seal and the first edge; the side of the first sol close to the battery cell body is a first arc.

Optionally, in the above battery cell, the first arc line and the side sealing edge have a first intersection point; the first arc line and the first side have a second intersection point.

Optionally, in the above battery cell, the intersection of the side sealing edge and the first edge is a first vertex; and the protrusion of the first arc is close to the first vertex.

Optionally, in the above battery core, the distance between the first intersection and the first vertex is 0.5 mm to 10 mm.

Optionally, in the above battery core, the distance between the second intersection and the first vertex is 0.5 mm to 10 mm.

Optionally, in the above battery cell, the arc angle of the first arc line ranges from 0° to 90°.

Optionally, in the above battery cell, the arc radius of the first arc line ranges from 2 mm to 20 mm.

Optionally, in the above battery cell, the packaging body further has a second side arranged opposite to the first side, a second sol is formed on the sol layer corresponding to the angle between the side seal and the second side, and the side of the second sol close to the battery cell body is a second arc.

Optionally, in the above battery core, the second arc line and the side sealing edge have a third intersection; the second arc line and the second side have a fourth intersection.

Optionally, in the above battery cell, the intersection of the side sealing edge and the second edge is the second vertex; and the protrusion of the second arc is close to the second vertex.

Optionally, in the above battery core, the distance between the third intersection and the second vertex 104 is 0.5 mm to 10 mm.

Optionally, in the above battery core, the distance between the fourth intersection and the second vertex 104 is 0.5 mm to 10 mm.

Optionally, in the above battery cell, the arc angle of the second arc line ranges from 0° to 90°.

Optionally, in the above battery cell, the arc radius of the second arc line ranges from 2 mm to 20 mm.

Optionally, in the above battery cell, the first sol and the second sol are symmetrically arranged about the central axis of the side edge seal.

Optionally, in the above battery cell, the region where the sol layer is located includes the following three integrally formed regions: the region where the side seal is located, the region where the first sol is located, and the region where the second sol is located.

Optionally, in the above battery cell, along the extension direction of the side edge seal, the sol width at both ends of the side edge seal corresponding to the sol layer is greater than the sol width in the middle area of the side edge seal corresponding to the sol layer.

The present application also provides a method for preparing a battery cell, comprising: S410: using an insulating side sealing head to fix the side sealing edge of the packaging body on the battery cell, wherein the side sealing edge comprises a first aluminum-plastic film layer and a second aluminum-plastic film layer folded in half, and the first aluminum-plastic film layer and the second aluminum-plastic film layer both comprise a hot-melt resin layer; S420: using an electromagnetic heating coil to perform heat-sealing treatment on the fixed side sealing edge, so that the two hot-melt resin layers are hot-melt connected to form a first sol at the angle formed by the side sealing edge and the first edge of the packaging body, wherein the side edge of the battery cell body of the battery cell close to the first sol is a first arc.

Optionally, in the above preparation method, the electromagnetic heating coil is used to perform heat sealing treatment on the fixed side seal, so that the two hot-melt resin layers are hot-melt connected to form a first sol at the angle formed by the side seal and the first edge of the packaging body, including: using the electromagnetic heating coil to perform heat sealing treatment on the fixed side seal, so that the two hot-melt resin layers are hot-melt connected to form a first sol at the angle formed by the side seal and the first edge, and forming a second sol at the angle formed by the side seal and the second edge of the packaging body, wherein the side edge of the second sol close to the battery body is a second arc, and the first edge and the second edge are arranged opposite to each other.

Optionally, the above preparation method further includes: controlling the time of the heat sealing treatment to control the size of the area of the first sol.

The present application also provides a battery, comprising any battery cell as described above.

In the battery cell provided in the present application, a first sol is formed at the top angle formed by the side seal and the first side of the package body, and the side edge of the first sol close to the battery cell body is a first arc. The outward diffusion effect of the sol at the enclosed top corners increases the sealing strength, effectively avoiding the risk of easy rupture at the top and bottom corners when the battery cell produces gas, collides or falls, eliminating the potential failure source of battery leakage, and the battery cell performance is stable and highly safe.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

FIG1 is a schematic diagram of the structure of a conventional battery cell.

FIG2 is a schematic diagram of the structure of the battery cell of the present application.

FIG3 is a schematic diagram of the heat-sealed structure and the structure of the battery cell of the present application.

FIG4 is a schematic diagram showing a process flow of a method for preparing a battery cell of the present application.

Reference numerals in Figures 1 to 3:
1-side sealing, 2-first side, 3-second side, 4-top sealing, 5-electromagnetic heating coil; 101-first sol, 102-second sol, 103-first vertex, 104-second vertex.

Detailed ways

The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

Please refer to Figure 1. Currently, lithium-ion batteries are packaged by heat sealing. The shape of the sol layer of the seal body is the shape of the side seal 1 of the seal body, which can be a rectangle. However, the sol area of the angle between the side seal 1 of the seal body and the top edge 2 of the seal body (i.e., the area indicated by the dotted circle in Figure 1) has not been specially processed, resulting in insufficient bonding strength. As a result, when the battery cell produces gas, collides or falls, the intersection area is very easy to break, which will become a potential failure source of battery leakage, causing battery cell failure, thereby causing safety issues.

As shown in FIG2 , an embodiment of the present application provides a battery cell, which includes a battery cell body and a packaging body that packages the battery cell body; the packaging body has a side sealing edge 1, a top sealing edge 4, and a first edge 2. The first edge 2 is the top edge of the packaging body; the top sealing edge 4 is located slightly below the top edge. The angle formed by the side sealing edge 1 and the top edge is the top angle; the sol layer forms a first sol 101 at the top angle of the packaging body; the side edge of the first sol 101 close to the battery cell body is the first arc line.

As above, the sol at the top corner formed by the side seal 1 and the top edge diffuses outward, thereby increasing The seal strength at the top corner can effectively avoid the risk of the top corner being easily broken when the battery cell produces gas, collides or falls, eliminating the potential failure source of battery leakage, and the battery cell has stable performance and high safety. The curved side of the first sol 101 is very smooth, which greatly reduces the edge stress of the first sol 101 and has better mechanical properties.

Furthermore, the battery cell also includes a second side 3; the second side 3 is the bottom side of the package body. The angle formed by the side sealing edge 1 and the bottom side is the bottom angle; the sol layer forms a second sol 102 at the bottom angle of the package body; the side of the second sol 102 close to the battery cell body is a second arc.

As set above, the sol at the bottom corner surrounded by the side seal 1 and the bottom edge diffuses outward, thereby increasing the sealing strength at the bottom corner, which can effectively avoid the risk of the bottom corner being easily broken when the battery cell produces gas, collides or falls, eliminating the potential failure source of battery leakage, and the battery cell has stable performance and high safety. The arc-shaped side of the second sol 102 is very smooth, which greatly reduces the edge stress of the second sol 102 and has better mechanical properties.

In certain embodiments of the present application, the first arc line and the side edge seal 1 have a first intersection point; the first arc line and the first edge 2 have a second intersection point.

The first arc line of the first sol 101 forms a closed space with the side sealing edge 1 and the first edge 2; the above arrangement greatly increases the formation area of the first sol 101 at the top corner, thereby effectively increasing the packaging strength of the sol layer at the top corner.

Furthermore, the intersection of the side seal 1 and the top edge is the first vertex 103, and the bulge of the first arc is close to the first vertex 103. As above, the smoothness of the contour line of the first sol 101 at the vertex formed by the side seal 1 and the top edge can be ensured, and the area of the first sol 101 will not be too large and will not occupy too much space, thereby ensuring the energy density of the battery.

In certain embodiments of the present application, the second arc line and the side edge seal 1 have a third intersection point; the second arc line and the second side 3 have a fourth intersection point.

The second arc of the second sol 102 forms a closed space with the side sealing edge 1 and the second edge 3; as set above, the formation area of the second sol 102 at the bottom corner is greatly increased, thereby effectively increasing the packaging strength of the sol layer at the bottom corner.

Furthermore, the intersection of the side seal 1 and the bottom edge is the second vertex 104, and the bulge of the second arc is close to the second vertex 104. As described above, the smoothness of the contour line of the second sol 102 at the bottom corner formed by the side seal 1 and the bottom edge can be ensured, and the area of the second sol 102 will not be too large and will not occupy too much space, thereby ensuring the energy density of the battery.

In some embodiments of the present application, the distance between the first intersection point and the first vertex 103 is a, and the value range of a is 0.5 mm to 10 mm; the distance between the second intersection point and the first vertex 103 is b, and the value range of b is 0.5 mm to 10 mm.

The above arrangement can ensure that the first sol 101 has sufficient bonding strength; at the same time, the area of the sol will not be too large, so as to avoid occupying too much space in the battery cell and ensure the energy density of the battery.

In certain embodiments of the present application, the distance between the third intersection point and the second vertex 104 is 0.5 mm to 10 mm; the distance between the fourth intersection point and the second vertex 104 is 0.5 mm to 10 mm.

As described above, the second sol 102 can be ensured to have sufficient bonding strength, while not causing the area of the sol to Too large to avoid taking up too much space in the battery cell and ensure the energy density of the battery.

In certain embodiments of the present application, the arc angle of the first arc line ranges from 0° to 90°; the arc radius of the first arc line ranges from 2mm to 20mm; the arc angle of the second arc line ranges from 0° to 90°; the arc radius of the first arc line ranges from 2mm to 20mm.

The above arrangement can ensure that the first sol 101 and the second sol 102 have sufficient bonding strength; at the same time, the area of the sol will not be too large, so as to avoid occupying too much space in the battery cell and ensure the energy density of the battery.

In some embodiments of the present application, the first sol 101 and the second sol 102 are symmetrically arranged about the central axis of the side sealing edge 1. As above, the sol layer is formed in a regular shape, and the packaging strength at the top and bottom corners of the packaging body is ensured to be consistent.

In certain embodiments of the present application, the region where the sol layer is located includes the region where the integrally formed side edge seal 1 is located, the region where the first sol 101 is located, and the region where the second sol 102 is located.

In one example, the area where the side seal 1 is located is a rectangle.

The first sol 101 and the second sol 102 appear simultaneously when the side edge seal 1 is heat-sealed. The first sol 101 and the second sol 102 are integrally connected with the sol in the rectangular area of the side edge seal 1, which simplifies the process of forming the sol layer while ensuring the sealing strength at the top corners and the bottom corners.

Furthermore, along the extension direction of the side seal 1, the sol width at both ends of the sol layer is greater than the sol width in the middle area of the sol layer; that is, the sol width of the sol layer at the top corner of the packaging body and the sol width at the bottom corner of the packaging body are both greater than the sol width in the middle area of the sol layer.

Please refer to FIG. 3 , the present application may also adopt a heat sealing structure to heat seal the side sealing edges of the battery cell described above; the heat sealing structure includes an electromagnetic heating coil 5 and an insulating side sealing head.

Furthermore, the insulating side sealing head is made of epoxy resin; the insulating side sealing head is provided with two membrane limiters, and the size of the insulating side sealing head is consistent with that of a conventional side sealing metal head.

It should be noted that the packaging body is a flexible packaging aluminum-plastic film; the single-layer aluminum-plastic film includes a hot-melt resin layer, an aluminum layer and a nylon layer stacked in sequence from inside to outside; and the side seal 1 includes a first aluminum-plastic film layer and a second aluminum-plastic film layer folded in half.

In one embodiment, as shown in FIG4 , a method for preparing a battery cell includes: S410: fixing a side seal of a packaging body on the battery cell using an insulating side seal head, wherein the side seal includes a first aluminum-plastic film layer and a second aluminum-plastic film layer folded in half, and the first aluminum-plastic film layer and the second aluminum-plastic film layer both include a hot-melt resin layer; S420: performing a heat-sealing treatment on the fixed side seal using an electromagnetic heating coil, so that the two hot-melt resin layers are hot-melt connected to form a first sol at an angle formed by the side seal and the first side of the packaging body, wherein the side of the battery body of the battery cell close to the first sol is a first arc.

The electromagnetic heating coil is used to heat-seal the fixed side sealing edge so that the two hot-melt resin The layers are hot-melt connected to form a first sol at the angle formed by the side seal and the first edge of the packaging body, including: using the electromagnetic heating coil to perform the heat sealing treatment on the fixed side seal, so that the two hot-melt resin layers are hot-melt connected to form a first sol at the angle formed by the side seal and the first edge, and a second sol is formed at the angle formed by the side seal and the second edge of the packaging body, wherein the side edge of the second sol close to the battery body is a second arc, and the first edge and the second edge are arranged opposite to each other.

The electromagnetic heating coil 5 generates a changing magnetic field, and the aluminum layer generates eddy currents in the changing magnetic field, thereby generating heat, thereby achieving the hot-melt connection of the two folded hot-melt resin layers at the opposite side sealing edge 1. The formed hot-melt connection is the sol layer of the package body.

Furthermore, the side seal 1 has a folded portion on the side away from the center of the battery cell; when the side seal 1 is heat-sealed by the above-mentioned heat-sealing structure, the folded portion is first turned up, and then the side seal 1 is clamped by the insulating side seal head, and then the electromagnetic heating coil 5 is charged; the heat-sealing time does not exceed 5s. As above, a first sol 101 can be formed at the top angle formed by the side seal 1 and the top edge, and a second sol 102 can be formed at the bottom angle formed by the side seal 1 and the bottom edge. Ensure that the contour line of the first sol 101 away from the first vertex 103 is an arc, and the arc-shaped protrusion is close to the first vertex 103; ensure that the contour line of the second sol 102 away from the second vertex 104 is an arc, and the arc-shaped protrusion is close to the second vertex 104; greatly reduce the edge stress at the intersection area and the bottom angle, enhance the sealing strength, and effectively avoid the risk of the intersection area being easily broken when the battery cell produces gas, collides or falls, eliminate the potential failure source of battery leakage, and the battery cell has stable performance and high safety. By controlling the time of the heat sealing process, the area of the first sol 101 and the second sol 102 can be controlled.

In some embodiments of the present application, during heat sealing, the distance between the electromagnetic heating coil 5 and the side sealing edge 1 does not exceed 5 mm. The above arrangement can ensure that the heat generated by the aluminum layer in the packaging body is large enough, thereby ensuring the hot melting effect of the hot-melt resin layer.

The components and devices involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the drawings. As will be appreciated by those skilled in the art, these components and devices can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, meaning "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and/or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with it.

It should also be noted that in the device of the present application, each component can be decomposed and/or reassembled, and these decompositions and/or reassemblies should be regarded as equivalent solutions of the present application.

The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general The principles may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

A battery cell, characterized in that it comprises a battery cell body and a packaging body that packages the battery cell body;

The packaging body includes a sol layer that packages the battery core body;

The packaging body has a side sealing edge and a first edge,

A first sol is formed at the sol layer at an angle corresponding to the side edge seal and the first edge;

The side of the first sol close to the battery core body is a first arc line.
The battery cell according to claim 1 is characterized in that the first arc line and the side sealing edge have a first intersection; the first arc line and the first side have a second intersection.
The battery cell according to claim 2 is characterized in that the intersection of the side seal and the first side is a first vertex; and the bulge of the first arc is close to the first vertex.
The battery cell according to claim 3, characterized in that the distance between the first intersection and the first vertex is 0.5 mm to 10 mm.
The battery cell according to claim 3 or 4, characterized in that the distance between the second intersection and the first vertex is 0.5 mm to 10 mm.
The battery cell according to any one of claims 1 to 5, characterized in that the arc angle of the first arc line ranges from 0° to 90°.
The battery cell according to any one of claims 1 to 6, characterized in that the arc radius of the first arc line ranges from 2 mm to 20 mm.
The battery cell according to any one of claims 1 to 7 is characterized in that the packaging body further has a second side arranged opposite to the first side, a second sol is formed on the sol layer corresponding to the angle between the side seal and the second side, and the side of the second sol close to the battery cell body is a second arc.
The battery cell according to claim 8 is characterized in that the second arc line and the side sealing edge have a third intersection; the second arc line and the second side have a fourth intersection.
The battery cell according to claim 9, characterized in that the intersection of the side seal and the second side is a second vertex; and the bulge of the second arc is close to the second vertex.
The battery cell according to claim 10, characterized in that the distance between the third intersection and the second vertex is 0.5 mm to 10 mm.
The battery cell according to claim 10 or 11, characterized in that the distance between the fourth intersection and the second vertex is 0.5 mm to 10 mm.
The battery cell according to any one of claims 8 to 12, characterized in that the arc angle of the second arc line ranges from 0° to 90°.
The battery cell according to any one of claims 8 to 13, characterized in that the arc radius of the second arc line ranges from 2 mm to 20 mm.
The battery cell according to any one of claims 8 to 14, characterized in that the first sol and the second sol are symmetrically arranged about the central axis of the side seal.
The battery cell according to any one of claims 8 to 15, characterized in that the area where the sol layer is located includes the following three integrally formed areas: the area where the side seal is located, the area where the first sol is located, and the area where the second sol is located.
The battery cell according to any one of claims 1 to 16, characterized in that, along the extension direction of the side seal, the sol width at both ends of the side seal corresponding to the sol layer is greater than the sol width in the middle area of the side seal corresponding to the sol layer.
A method for preparing a battery cell, characterized by comprising:

S410: fixing the side sealing edge of the packaging body on the battery cell by using an insulating side sealing head, wherein the side sealing edge comprises a first aluminum-plastic film layer and a second aluminum-plastic film layer folded in half, and the first aluminum-plastic film layer and the second aluminum-plastic film layer both comprise a hot-melt resin layer;

S420: Using an electromagnetic heating coil, heat-seal the fixed side seal to melt-connect the two hot-melt resin layers to form a first sol at an angle formed by the side seal and the first edge of the packaging body, wherein the side edge of the first sol close to the battery body of the battery cell is a first arc.
The preparation method according to claim 18 is characterized in that the electromagnetic heating coil is used to heat-seal the fixed side edge seal so that the two hot-melt resin layers are hot-melt connected to form a first sol at the angle formed by the side edge seal and the first side of the packaging body, comprising:

The electromagnetic heating coil is used to perform the heat sealing treatment on the fixed side seal, so that the two hot-melt resin layers are hot-melt connected to form a first sol at the angle formed by the side seal and the first edge, and a second sol is formed at the angle formed by the side seal and the second edge of the packaging body, wherein the side edge of the second sol close to the battery cell body is a second arc, and the first edge and the second edge are arranged opposite to each other.
The preparation method according to claim 18 or 19, characterized in that it also includes:

The time of the heat sealing treatment is controlled to control the area of the first sol.
A battery, comprising: a battery cell as claimed in any one of claims 1 to 17.