CN113054293A

CN113054293A - Packaging film and battery

Info

Publication number: CN113054293A
Application number: CN202110282452.3A
Authority: CN
Inventors: 王吉飞
Original assignee: Dongguan Poweramp Technology Ltd
Current assignee: Dongguan Poweramp Technology Ltd
Priority date: 2021-03-16
Filing date: 2021-03-16
Publication date: 2021-06-29

Abstract

The application provides an encapsulation film, including packaging structure, packaging structure includes: a first groove formed by primary pit punching and a second groove formed by secondary pit punching; the length of the first groove is greater than that of the second groove, and the width of the first groove is greater than that of the second groove; the second groove is positioned in the first groove and forms a gradient structure with the first groove. Foretell packaging film and battery dash the first recess and the second recess that the hole formed gradient structure through the secondary, compare in once dashing the hole, break through the restriction of dashing the hole degree of depth, avoid dashing the damaged corruption of tie coat or the metal level damage that the increase of the hole degree of depth leads to moreover, adopt this packaging film structure to realize that the electricity core of laminate polymer improves appearance by a wide margin in thickness direction.

Description

Packaging film and battery

Technical Field

The application relates to the technical field of energy storage, in particular to a packaging film and a battery.

Background

The soft package battery core is formed by punching a hole on a packaging material (such as an aluminum plastic film or a steel plastic film) and then packaging at a high temperature, the punching depth needs to be matched with the thickness of the battery core, the thicker battery core needs to be the deeper the punching depth is, but the increase of the punching depth can cause the damage corrosion of the angular position PP or the damage and leakage of a metal layer. The scheme that present conventionality adopted reaches the purpose of drawing the pit through thickening packaging material's metal level thickness, but the thickening of metal level can lead to packaging material's anti bending property to worsen, makes with later stage transportation at electric core, and the metal level breaks easily to appear in some stress concentration region and influences long-term encapsulation reliability, directly leads to electric core weeping even when serious. In addition, the packaging material is heated firstly when the pits are punched, so that the extending capability of the metal layer is improved, but the mode not only reduces the equipment productivity in unit time and increases the equipment investment cost, but also the pit punching capability is not obviously improved.

Disclosure of Invention

Accordingly, there is a need for an encapsulation film and a battery that can break through the limitation of the depth of the punched pits and increase the capacity of the battery.

An embodiment of the present application provides an encapsulation film, including an encapsulation structure, the encapsulation structure includes: a first groove formed by primary pit punching and a second groove formed by secondary pit punching; the length of the first groove is greater than that of the second groove, and the width of the first groove is greater than that of the second groove; the second groove is positioned in the first groove and forms a gradient structure with the first groove.

Further, in some embodiments of the present application, the encapsulation film includes a bonding layer, a metal layer, and a protective layer, the metal layer being located between the bonding layer and the protective layer.

Further, in some embodiments of the present application, a corner of the first groove is used as a first corner, a corner of the second groove is used as a second corner, and a thickness of the encapsulation film at a position where the first corner and the second corner are located is at least 40% of a thickness of the encapsulation film before the pit punching.

Further, in some embodiments of the present application, the depth of the first groove is H1, 0 < H₁Less than or equal to 15mm, and the depth of the second groove is H₂，0＜H₂≤15mm。

Further, in some embodiments of this application, the packaging film includes two packaging structure, two be equipped with the fifty percent discount district between the packaging structure, the fifty percent discount district is followed the length direction or the width direction setting of first recess, the width in fifty percent discount district is 0.5 ~ 40 mm.

The embodiment of the application also provides a battery, which comprises an electrode assembly and a lug and further comprises the packaging film, wherein the electrode assembly is arranged in the packaging structure, and the lug is connected with the electrode assembly and extends out of the packaging structure.

Further, in some embodiments of the present application, the electrode assembly has a thickness T and the first groove of the encapsulation film has a depth H in a thickness direction of the encapsulation structure₁The depth of the second groove of the packaging film is H₂Wherein T-8mm is less than or equal to (H)₁+H₂) T +8mm is not less than 2 and H is more than 0₁≤15mm，0＜H₂≤15mm。

Further, in some embodiments of the present application, the battery further includes an elastic body disposed at an outer side of the electrode assembly and within the first groove.

Further, in some embodiments of the present application, the electrode assembly is disposed in a gradient structure, and the battery is disposed in a gradient structure as a whole or stacked in a gradient structure.

Further, in some embodiments of the present application, the first groove and the second groove are provided with a first step portion and a second step portion along a width direction of the package structure, and a width of the first step portion is W₁The width of the second step part is W₂The maximum width of the battery is W, and W is not less than 10mm₁+W₂≤W。

Foretell packaging film dashes the first recess and the second recess that the hole formed gradient structure through the secondary, compares in once dashing the hole, breaks through the restriction of dashing the hole degree of depth, avoids the damaged corruption of tie coat or the metal level damage that leads to of the increase of dashing the hole degree of depth moreover, adopts this packaging film structure to realize that soft-packaged electrical core improves appearance by a wide margin in thickness direction.

Drawings

Fig. 1 shows a schematic structural diagram of an encapsulation film at a first viewing angle in an embodiment of the present application.

Fig. 2 shows a schematic diagram of the structure of the encapsulation film of fig. 1 from a second viewing angle.

Fig. 3 shows a schematic structural diagram of an encapsulation film at a first viewing angle in another embodiment of the present application.

Fig. 4 shows a schematic diagram of a second viewing angle of the encapsulation film in fig. 3.

Fig. 5 shows a schematic structural diagram of a battery in an embodiment of the present application.

Fig. 6 is a schematic cross-sectional view of a battery according to an embodiment of the present invention.

Fig. 7 shows a schematic diagram of a battery according to another embodiment of the present application.

Fig. 8 is a schematic cross-sectional view showing a battery according to another embodiment of the present application.

Description of the main elements

Packaging film 100

Fold back region 101

Package structure 10

First groove 11

The first step part 11a

First angular position 111

Second groove 12

Second step portion 12a

Second angular position 121

Battery 1000

Electrode assembly 200

First pole piece 201

Second pole piece 202

Diaphragm 203

Tab 300

Elastic member 400

The following specific examples will further illustrate the application in conjunction with the above figures.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments.

It will be understood that when an element is referred to as being "mounted on" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following embodiments, features of the embodiments may be combined with each other without conflict.

Referring to fig. 1 and fig. 2, an embodiment of the present disclosure provides an encapsulation film 100, where the encapsulation film 100 includes an encapsulation structure 10, and the encapsulation structure 10 is formed by performing secondary pit punching on the encapsulation film 100. In an embodiment, the package structure 10 includes a first groove 11 and a second groove 12 formed by twice-punching, wherein the length and the width of the first groove 11 are respectively greater than the length and the width of the second groove 12, and the second groove 12 is located in the first groove 11 and forms a gradient structure with the first groove 11.

In one embodiment, the depth of the first groove 11 is H₁，0＜H₁E.g.. ltoreq.15 mm, e.g. 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, the depth of the second grooves 12 being H₂，0＜H₂Less than or equal to 15mm, e.g., 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm,13mm, 14mm and 15 mm. When the depth of the first groove 11 is the same as the depth of the second groove 12, compared with the common pit punching structure, the sum of the depth of the first groove 11 and the depth of the second groove 12 is twice the depth of the groove formed by the common pit punching structure, which significantly improves the packaging space of the package structure 10.

Referring to fig. 1, a distance between a side of a first groove 11 along a length direction and a side of an adjacent second groove 12 along the length direction is L₁The distance between the other side edge of the first groove 11 along the length direction and the other side edge of the adjacent second groove 12 along the length direction is L₂. The distance between the side edge of the first groove 11 arranged along the width direction and the side edge of the adjacent second groove 12 in the width direction is L₃The distance between the other side edge of the first groove 11 in the width direction and the other side edge of the adjacent second groove 12 in the width direction is L₄。

In one embodiment, L₁Is equal to L₂，L₃Is equal to L₄I.e. the centers of the first groove 11 and the second groove 12 are located at the same position.

In another embodiment, L₁Greater than L₂，L₃Greater than L₄Or L is₁Less than L₂，L₃Less than L₄I.e. the second grooves 12 are offset substantially in the direction of the diagonal of the first grooves 11.

In yet another embodiment, L₁Greater or less than L₂，L₃Is equal to L₄I.e. the second grooves 12 are offset in the width direction of the first grooves 11.

In yet another embodiment, L₁Is equal to L₂，L₃Greater or less than L₄I.e. the second grooves 12 are offset in the length direction of the first grooves 11.

In one embodiment, the packaging film 100 includes a bonding layer, a metal layer, and a protective layer, wherein the metal layer is located between the bonding layer and the protective layer. In an embodiment, the tie layer is the polypropylene layer, when encapsulating film 100 encapsulates, plays the effect of sealing the bonding, and the metal level is the aluminium system layer for after encapsulating film 100 encapsulates, prevent that external steam etc. from getting into and inside electrolyte from oozing outward, the protective layer is the nylon layer, and the melting point on nylon layer is high, and mechanical properties is strong, plays the guard action to the battery in packaging structure 10.

The first groove 11 and the second groove 12 are respectively provided with corners, the corners are four corners formed by the first groove 11 or the second groove 12, the corner of the first groove 11 is used as a first corner 111, the corner of the second groove 12 is used as a second corner 121, and the thickness of the packaging film 100 corresponding to the positions of the first corner 111 and the second corner 121 is at least 40% of the thickness of the packaging film 100 before pit punching. Thereby preventing the bonding layer or the metal layer from being damaged and corroded at the corner positions of the first groove 11 and the second groove 12.

It is understood that the sequence of punching the first groove 11 and the second groove 12 may be to punch the first groove 11 first and then punch the second groove 12 in the first groove 11, or to punch the second groove 12 first and then punch the first groove on the periphery of the second groove 12.

It is understood that the package structure 10 is not limited to the first groove 11 and the second groove 12 forming a gradient structure, and a plurality of gradient structures, such as two, three, etc., may be provided according to the thickness of the package film 100, for example, in an embodiment, the package structure 10 includes a first groove 11, a second groove 12, and a third groove (not shown), wherein the first groove 11 and the second groove form a gradient structure, the third groove may be located in the second groove 12 and form a gradient structure with the second groove 12, or may be located on the peripheral side of the first groove 11, that is, the first groove 11 is located in the third groove, and the third groove and the first groove 11 form a gradient structure, that is, in this embodiment, the package structure is provided with two gradient structures.

Referring to fig. 1, in an embodiment, a packaging film 100 includes two packaging structures 10, and a folding area 101 is disposed between the two packaging structures 10 for folding the packaging film 100 so that the two packaging structures 10 are located correspondingly. The two packaging structures 10 are further provided with heat sealing areas located on the side edges of the first groove 11, and the two folded packaging structures 10 form a packaging space after being packaged through the heat sealing areas. The doubling area 101 is arranged along the length direction of the first groove 11, and the width of the doubling area 101 is 0.5-40 mm, such as 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, 15mm, 25mm, 35mm, 36mm, 37mm, 38mm, 39mm, 40mm, and the like. The area of heat-seal can be reduced through setting up fifty percent discount district 101 for the production rhythm is accelerated.

It is understood that the fold-back region 101 is not limited to be disposed along the length direction of the first groove 11, for example, please refer to fig. 3 and 4, and in another embodiment, the fold-back region 101 may also be disposed along the width direction of the first groove 11.

In an embodiment, the packaging film 100 further includes a gas storage region disposed outside the first groove 11 in the width direction, and configured to store gas generated during formation in the manufacturing process of the battery cell.

It is understood that only one package structure 10 may be provided on one package film 100, and a package space may be formed by packaging two package structures 10 on two package films 100.

Foretell packaging film 100 is compared in once towards the hole through the twice first recess 11 and the second recess 12 that dash the hole and form gradient structure, breaks through the restriction of towards the hole degree of depth, avoids moreover towards the damaged corruption of tie coat or the metal level damage that the increase of hole degree of depth leads to, realizes that soft-packaged electric core improves the appearance by a wide margin in thickness direction.

Referring to fig. 5 and 6, an embodiment of the present invention further provides a battery 1000 using the above-mentioned packaging film 100, where the battery 1000 includes an electrode assembly 200 and tabs 300, the electrode assembly 200 is disposed in a packaging space formed by two packaging structures 10, an electrolyte is further disposed in the packaging space, and the tabs 300 are connected to the electrode assembly 200 and extend out of the packaging structures 10.

The electrode assembly 200 includes a first pole piece 201, a second pole piece 202, and a separator 203 disposed between the first pole piece 201 and the second pole piece 202.

In one embodiment, the thickness of the electrode assembly 200 is T and the depth of the first groove 11 of the package structure 10 is H along the thickness direction of the package structure 10₁The depth of the second groove 12 of the package structure 10 is H₂Wherein T-8mm is less than or equal to (H)₁+H₂) T +8mm is not less than 2 and H is more than 0₁≤15mm，0＜H₂≤15mm。

Referring to fig. 5 and 7, the first pole piece 201 and the second pole piece 202 are respectively connected with a tab 300, wherein the tab 300 may be connected to the same side of the first pole piece 201 and the second pole piece 202, or connected to both sides of the first pole piece 201 and the second pole piece 202. Specifically, when the two package structures 10 are folded in half along the length direction of the first groove 11, the tabs 300 are respectively connected to two opposite sides of the first pole piece 201 and the second pole piece 202, and when the two package structures 10 are folded in half along the width direction of the first groove 11, the tabs 300 are connected to the same side of the first pole piece 201 and the second pole piece 202.

Referring to fig. 6, in this embodiment, the width of the electrode assembly 200 disposed in the packaging space is the same as the width of the second groove 12, and since the length and the width of the first groove 11 are greater than the length and the width corresponding to the second groove 12, a gap exists around the first groove 11, in order to prevent the packaging film 100 at the gap position from shrinking and stacking to form wrinkles during vacuum packaging, which affects the appearance of the battery 1000, an elastic member 400 is disposed in the gap, and the elastic member 400 is disposed outside the electrode assembly 200 and in the first groove 11 for supporting the gap, thereby ensuring the appearance of the battery 1000.

In one embodiment, the elastic member 400 may be a porous foam, which not only ensures the appearance of the battery 1000, but also absorbs more electrolyte to improve the cycle performance of the battery.

In one embodiment, the material of the porous foam comprises one of polyethylene and polypropylene, and is used for keeping the electrolyte stably existing for a long time.

Referring to fig. 8, in this embodiment, the structure of the electrode assembly 200 is matched to the package structure 10, i.e., the electrode assembly 200 is arranged in a gradient structure. The width of the first groove 11 is greater than the width of the second groove 12, so the first groove 11 and the second groove 12 are provided with a first step portion 11a and a second step portion 12a along the width direction of the package structure 10, and the width of the first step portion 11a is W₁The width of the second step portion 12a is W₂The maximum width of the battery 1000 is W, wherein W is not less than 10mm₁+W₂W is less than or equal to W. Thereby, not only the depth of the package structure 10 can be increased, but also the capacity of the battery can be increased.

In one embodiment, the gradient structure of the electrode assembly 200 is formed by adjusting the sizes of the first pole piece 201, the second pole piece 202, and the separator 203, and stacking, i.e., the entirety of the electrode assembly 200 is provided in a gradient structure.

In another embodiment, the electrode assembly 200 includes three electrode assemblies 200, wherein two electrode assemblies 200 have the same width as the second groove 12 and another electrode assembly 200 has the same width as the first groove 11, and the three electrode assemblies 200 are stacked, wherein the electrode assembly 200 having the larger width is disposed between the two electrode assemblies 200 having the smaller width.

It is understood that the electrode assembly 200 of the gradient structure may also be formed by winding.

The battery 1000 adopts the packaging film 100, and the depth of the groove formed by punching the pit is large, so that the thickness of the packaged battery is correspondingly increased, and the capacity of the battery is obviously improved.

It should be understood by those skilled in the art that the above embodiments are only for illustrating the present application and are not to be taken as limiting the present application, and that suitable changes and modifications to the above embodiments are within the scope of the present disclosure as long as they are within the spirit and scope of the present application.

Claims

1. An encapsulation film comprising an encapsulation structure, wherein the encapsulation structure comprises: a first groove formed by primary pit punching and a second groove formed by secondary pit punching;

the length of the first groove is greater than that of the second groove, and the width of the first groove is greater than that of the second groove;

the second groove is positioned in the first groove and forms a gradient structure with the first groove.

2. The encapsulation film of claim 1, wherein the encapsulation film comprises a bonding layer, a metal layer, and a protective layer, the metal layer being positioned between the bonding layer and the protective layer.

3. The packaging film of claim 2, wherein the thickness of the packaging film at the first and second corners is at least 40% of the thickness of the packaging film before punching, taking the corner of the first groove as a first corner and the corner of the second groove as a second corner.

4. The encapsulation film of claim 1, wherein the first groove has a depth H1, 0 < H₁Less than or equal to 15mm, and the depth of the second groove is H₂，0＜H₂≤15mm。

5. The packaging film according to claim 1, wherein the packaging film comprises two packaging structures, a double-folding region is arranged between the two packaging structures, the double-folding region is arranged along the length direction or the width direction of the first groove, and the width of the double-folding region is 0.5-40 mm.

6. A battery comprising an electrode assembly provided in the package structure and tabs connected to the electrode assembly and protruding from the package structure, and further comprising the packaging film according to any one of claims 1 to 5.

7. The battery of claim 6, wherein the electrode assembly has a thickness T and the first groove of the encapsulation film has a depth H in a thickness direction of the encapsulation structure₁The depth of the second groove of the packaging film is H₂Wherein T-8mm is less than or equal to (H)₁+H₂) T +8mm is not less than 2 and H is more than 0₁≤15mm，0＜H₂≤15mm。

8. The battery of claim 7, further comprising an elastomer disposed on an exterior side of the electrode assembly and within the first recess.

9. The battery of claim 6, wherein the electrode assembly is arranged in a gradient structure, and the battery is arranged in a gradient structure as a whole or stacked in a gradient structure.

10. The battery of claim 6, wherein the first and second grooves have a first step portion and a second step portion along a width direction of the package structure, and the first step portion has a width W₁The width of the second step part is W₂The maximum width of the battery is W, and W is not less than 10mm₁+W₂≤W。