High-barrier flexible film for packaging lithium battery

Abstract

The utility model discloses a high-barrier flexible film for packaging a lithium battery. The high-barrier flexible film comprises an aluminum foil layer, wherein a plurality of deformation parts are uniformly distributed on the aluminum foil layer; the outer layer is fixedly connected with the front surface of the aluminum foil layer through an outer bonding layer; the inner layer is fixedly connected with the back surface of the aluminum foil layer through an inner bonding layer; a reinforcing connecting piece is arranged between the outer layer and the outer bonding layer, a reinforcing connecting piece is arranged between the inner side and the inner bonding layer, and the reinforcing connecting pieces are fiber lines. Due to the arrangement of the deformation part, the roughness of the surface of the aluminum foil layer can be increased, so that the connection strength between the inner bonding layer and the aluminum foil layer and between the outer bonding layer and the aluminum foil layer is improved, the layering probability of the aluminum plastic film is reduced, and the barrier property of the aluminum plastic film is improved; due to the arrangement of the fiber lines, the connection strength between the outer layer and the outer bonding layer and the connection strength between the inner layer and the inner bonding layer can be improved, the probability of layering of the aluminum-plastic film is further reduced, and the barrier property of the aluminum-plastic film is further improved.

Description

Technical Field

[0001] This utility model belongs to the field of aluminum-plastic film technology, and in particular relates to a high-barrier flexible film for lithium battery packaging. Background Technology

[0002] Aluminum-plastic film features excellent barrier properties, puncture resistance, superior cold stamping forming ability, chemical stability, and electrical insulation. It is primarily used for pouch lithium battery packaging, and also in the packaging of food, pharmaceuticals, and electronics, protecting the contents and extending product shelf life.

[0003] The layers of the existing aluminum-plastic film are connected to each other by adhesives. If the adhesive has insufficient adhesion, cohesion and other properties, the layers are prone to separation when subjected to external forces or environmental factors. For products such as lithium batteries that require high barrier performance, the separation of the aluminum-plastic film layers will reduce the isolation effect between the battery and the external environment, which may lead to a decrease in battery performance, a shortened lifespan, or even safety hazards.

[0004] Therefore, it is necessary to improve the aluminum-plastic film in the existing technology. Utility Model Content

[0005] The purpose of this invention is to overcome the defects in the existing technology and provide a high-barrier flexible film for lithium battery packaging, thereby improving the barrier performance of aluminum-plastic film.

[0006] To achieve the above objectives, the specific technical solution of the high-barrier flexible film for lithium battery packaging of this utility model is as follows:

[0007] A high-barrier flexible film for lithium battery packaging, comprising:

[0008] An aluminum foil layer, wherein multiple deformable portions are uniformly distributed in the aluminum foil layer;

[0009] The outer layer is fixedly connected to the front side of the aluminum foil layer through an outer adhesive layer;

[0010] The inner layer is fixedly connected to the back of the aluminum foil layer via an inner adhesive layer;

[0011] A reinforcing connector is provided between the outer layer and the outer adhesive layer, and a reinforcing connector is provided between the inner layer and the inner adhesive layer. The reinforcing connector is a fiber thread.

[0012] Preferably, in order to maintain the barrier properties of the aluminum foil layer, the deformed portion is a hemispherical structure that arches towards the outer layer or the inner layer.

[0013] Preferably, in order to maintain the barrier properties of the aluminum foil layer, the deformed portion and the aluminum foil layer are connected by an arc transition.

[0014] Preferably, in order to maintain the barrier properties of the aluminum foil layer, the change in the thickness of the aluminum foil in the deformed portion is less than ±5%.

[0015] Preferably, in order to improve the connection strength between the layers of the aluminum-plastic film, a fiber mesh is uniformly embedded inside both the inner layer and the outer layer, one end of the fiber thread is intertwined with the fiber mesh, and the other end of the fiber thread extends into the adhesive layer.

[0016] Preferably, in order to improve the strength of the fiber web and the fiber thread, both the fiber web and the fiber thread are made of glass fiber.

[0017] Preferably, in order to improve the protective effect of the outer layer on the aluminum foil layer, the outer layer is a PET layer with a thickness of 15μm-25μm.

[0018] Preferably, in order to improve the barrier effect of the aluminum foil layer, the thickness of the aluminum foil layer is 30μm-40μm.

[0019] Preferably, in order to improve the protective effect of the inner layer on the aluminum foil layer, the inner layer is a PE layer with a thickness of 60μm-80μm.

[0020] Preferably, in order to improve the connection strength between the fiber thread and the inner and outer adhesive layers, the thickness of both the inner and outer adhesive layers is greater than the diameter of the fiber thread.

[0021] The high-barrier flexible film for lithium battery packaging of this utility model has the following advantages: the deformable part can increase the surface roughness of the aluminum foil layer, thereby improving the connection strength between the inner and outer adhesive layers and the aluminum foil layer, reducing the probability of delamination of the aluminum-plastic film, and improving the barrier performance of the aluminum-plastic film; the fiber thread can improve the connection strength between the outer layer and the outer adhesive layer, as well as the connection strength between the inner layer and the inner adhesive layer, further reducing the probability of delamination of the aluminum-plastic film and further improving the barrier performance of the aluminum-plastic film. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the flexible membrane of this utility model;

[0023] Figure 2 for Figure 1 Enlarged view of part A;

[0024] Figure 3 This is a schematic diagram of the aluminum foil layer structure of this utility model;

[0025] The markings in the diagram are as follows: 1. Outer layer; 2. Outer adhesive layer; 3. Aluminum foil layer; 4. Inner adhesive layer; 5. Inner layer; 102. Fiber thread; 102; 301. Deformation section. Detailed Implementation

[0026] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0027] The terms "top surface," "bottom surface," and "full surface" are used with reference to the normal use state of the flexible membrane and are only for the convenience of describing this utility model and simplifying the description. They are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model.

[0028] like Figure 1 As shown, a high-barrier flexible film for lithium battery packaging includes:

[0029] Aluminum foil layer 3, with multiple deformable portions 301 evenly distributed in aluminum foil layer 3;

[0030] The outer layer 1 is fixedly connected to the front side of the aluminum foil layer 3 through the outer adhesive layer 2;

[0031] The inner layer 5 is fixedly connected to the back of the aluminum foil layer 3 through the inner adhesive layer 4;

[0032] A reinforcing connector is provided between the outer layer 1 and the outer adhesive layer 2, and a reinforcing connector is provided between the inner layer 5 and the inner adhesive layer 4. The reinforcing connector is a fiber thread 102.

[0033] The aforementioned flexible film is an aluminum-plastic film, suitable for lithium battery packaging. In this film, the aluminum foil layer 3 has a thickness of 30μm-40μm. The aluminum foil possesses excellent barrier properties, effectively preventing moisture from entering the battery and preventing electrolyte leakage. It also provides complete light shielding and offers some protection to the battery, effectively maintaining a stable internal environment. The outer layer 1 is a PET layer with a thickness of 15μm-25μm. This outer layer protects the aluminum foil layer 3 from the outside. The PET layer has good mechanical properties, chemical stability, and electrical properties; it is not easily damaged and has good corrosion resistance and insulation properties, effectively protecting the aluminum foil layer 3 and thus providing effective protection for the battery. The inner layer 5 is a PE layer with a thickness of 60μm. -80μm, the inner layer 5 is used to isolate the active materials such as electrodes inside the battery from the other layers of the aluminum-plastic film, avoiding unnecessary chemical reactions between the active materials and the outer layer materials, playing a buffering and protective role. At the same time, it can protect the internal structure of the battery from damage when the battery is squeezed or subjected to other external forces, improving the safety of the battery. The PE material has good resistance to chemicals such as electrolytes inside the battery, has a good sealing effect, is soft and tough, has strong puncture resistance, and has high electrical insulation performance, which can ensure the sealing and safety of the battery. The inner adhesive layer 4 and the outer adhesive layer 2 can be, but are not limited to, polyurethane adhesive layers. Polyurethane adhesive has good adhesion to PET and PE, can maintain a stable adhesion effect under different environmental conditions, has excellent flexibility, water resistance and chemical corrosion resistance, can adapt to the deformation and stretching of the aluminum-plastic film during use, and effectively prevents cracking at the adhesive parts.

[0034] Compared with existing aluminum-plastic films, in the above-mentioned aluminum-plastic film, deformable portions 301 are evenly distributed on the aluminum foil layer 3. The deformable portions 301 make the surface of the aluminum foil layer 3 rougher. The contact area between the rough aluminum foil layer 3 and the inner adhesive layer 4 and the outer adhesive layer 2 is larger, and they are easier to form an interlocking structure, which can effectively improve the adhesion strength, thereby improving the connection strength between the layers of the aluminum-plastic film, maintaining the integrity of the aluminum-plastic film structure, and thus improving the barrier performance of the aluminum-plastic film. At the same time, fiber lines 102 are provided between the outer layer 1 and the outer adhesive layer 2 and between the inner layer 5 and the inner adhesive layer 4. The fiber lines 102 connect the two layers, which can improve the connection strength between the two layers, further improving the connection strength between the layers of the aluminum-plastic film, maintaining the integrity of the aluminum-plastic film structure, and thus further improving the barrier performance of the aluminum-plastic film.

[0035] Further improvements include, for example Figure 2 As shown, the deformable part 301 is a hemispherical structure that arches outward toward the outer layer 1 or the inner layer 5; the deformable part 301 and the aluminum foil layer 3 are connected by an arc.

[0036] In the aforementioned aluminum-plastic film, a deformable portion 301 can be formed on the surface of the aluminum foil by stamping. A portion of each deformable portion 301 protrudes outward toward the adhesive layer 2, while the remaining portion protrudes inward toward the adhesive layer 4. Simultaneously, a corresponding depression is formed on the other side of the protrusion. This creates an uneven structure on both sides of the aluminum foil layer 3, making the surface of the aluminum foil layer 3 rougher and thus improving the bonding strength between the aluminum-plastic film layers. The hemispherical structure and the arc transition structure both have relatively smooth surfaces, which is beneficial for the adhesives of the inner adhesive layer 4 and the outer adhesive layer 2 to fill the gaps between the inner adhesive layer 4, the outer adhesive layer 2 and the aluminum foil layer 3, thereby improving the bonding strength between the layers. Furthermore, when processing the smooth surface, it is beneficial to maintain uniform stretching at all points of the deformable portion 301, thus keeping the thickness of the deformable portion 301 uniform to maintain the barrier performance of the aluminum foil layer 3 and ultimately improve the barrier performance of the aluminum-plastic film.

[0037] A further improvement is that the variation in the thickness of the aluminum foil in the deformable portion 301 is less than ±5%. By controlling the stretching amount of the deformable portion 301, the thickness variation of the deformable portion 301 relative to the rest of the aluminum foil layer 3 can be effectively controlled. When the thickness variation is small, that is, the stretching amount of the deformable portion 301 is small, the thickness of the aluminum foil layer 3 can be kept uniform, thereby improving the barrier effect of the aluminum foil layer 3 and ultimately improving the barrier effect of the aluminum-plastic film.

[0038] Further improvements include, for example Figure 2 As shown, fiber mesh 101 is uniformly embedded in both the inner layer 5 and the outer layer 1. One end of fiber thread 102 is intertwined with fiber mesh 101, and the other end of fiber thread 102 extends into the adhesive layer. Both fiber mesh 101 and fiber thread 102 are glass fibers. The choice of materials for fiber filaments 102 and fiber mesh 101 is not limited to glass fiber; high-strength fiber materials such as carbon fiber and aramid fiber can also be used. Glass fiber has advantages such as high strength, high modulus, low thermal conductivity, good electrical insulation, good thermal stability, strong corrosion resistance, low cost, and good processability. When fiber mesh 101 made of glass fiber is placed inside the inner layer 5 and the outer layer 1, it can effectively improve the strength of the inner layer 5 and the outer layer 1, and improve their protective performance against the aluminum foil layer 3. The intertwining of fiber mesh 101 and fiber filaments 102 can improve the connection strength between fiber filaments 102 and the inner layer 5 and the outer layer 1, thereby improving the connection strength between the inner layer 5 and the inner adhesive layer 4, as well as the connection strength between the outer layer 1 and the outer adhesive layer 2, ultimately improving the interlayer connection strength of the aluminum-plastic film and enhancing the overall performance of the aluminum-plastic film.

[0039] Further improvements include, for example Figure 2As shown, the thicknesses of both the inner adhesive layer 4 and the outer adhesive layer 2 are greater than the diameter of the fiber filament 102. This arrangement allows the fiber filament 102 to be completely embedded within the inner adhesive layer 4 and the outer adhesive layer 2, thereby increasing the contact area between the fiber filament 102 and the adhesive, improving the connection strength between the fiber filament 102 and the inner adhesive layer 4 and the outer adhesive layer 2, and ultimately enhancing the connection strength between the layers of the aluminum-plastic film, thus improving the barrier properties of the aluminum-plastic film.

[0040] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Furthermore, under the teachings of this utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this utility model.

Claims

1. A high-barrier flexible film for lithium battery packaging, characterized by, Include: An aluminum foil layer (3) uniformly distributed with a plurality of deformations (301); An outer layer (1) fixedly connected with the front of the aluminum foil layer (3) through an outer adhesive layer (2); An inner layer (5) fixedly connected with the back of the aluminum foil layer (3) through an inner adhesive layer (4); The outer layer (1) and the outer adhesive layer (2) are provided with a reinforcing connecting piece, and the inner layer (5) and the inner adhesive layer (4) are provided with a reinforcing connecting piece, and the reinforcing connecting piece is a fiber line (102).

2. The high-barrier flexible film for lithium battery packaging according to claim 1, characterized by, The deformation (301) is a semispherical structure arched towards the outer layer (1) or the inner layer (5).

3. The high-barrier flexible film for lithium battery packaging according to claim 2, characterized by, The deformation (301) and the aluminum foil layer (3) are transitioned by a circular arc.

4. The high-barrier flexible film for lithium battery packaging according to claim 1, characterized in that, The change amount of the aluminum foil thickness of the deformation (301) is less than ±5%.

5. The high-barrier flexible film for lithium battery packaging according to claim 1, characterized in that, The inner layer (5) and the outer layer (1) are uniformly embedded with a fiber net (101), one end of the fiber line (102) is wound with the fiber net (101), and the other end of the fiber line (102) extends to the inside of the adhesive layer.

6. The high-barrier flexible film for lithium battery packaging according to claim 5, characterized in that, The fiber net (101) and the fiber line (102) are both glass fibers.

7. The high-barrier flexible film for lithium battery packaging according to claim 1, characterized in that, The outer layer (1) is a PET layer, and the thickness of the outer layer (1) is 15-25μm.

8. The high-barrier flexible film for lithium battery packaging according to claim 1, characterized in that, The thickness of the aluminum foil layer (3) is 30-40μm. 9.The high-barrier flexible film for lithium battery packaging according to claim 1, characterized in that, The inner layer (5) is a PE layer, and the thickness of the inner layer (5) is 60-80μm.

10. The high-barrier flexible film for lithium battery packaging according to claim 5, characterized in that, The thickness of the inner adhesive layer (4) and the outer adhesive layer (2) is greater than the wire diameter of the fiber line (102).

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