Multilayer composite tab adhesive film

Abstract

The utility model relates to a multi-layer composite tab adhesive film which comprises a battery aluminum plastic film, a battery cell, two battery metal belts and a tab adhesive film arranged between the battery aluminum plastic film and the battery metal belts, each tab adhesive film comprises a tab adhesive core layer and heat sealing layers located on the upper side and the lower side of the tab adhesive core layer, the melting point of each heat sealing layer is lower than that of the corresponding tab adhesive core layer, each heat sealing layer is a colorless layer, and the tab adhesive core layer of at least one tab adhesive film on the two battery metal belts is a colored layer; the heat sealing layer sequentially comprises a modified layer, a homopolymerization layer and a copolymerization layer from outside to inside. According to the utility model, the heat sealing layer is a colorless layer, and the tab rubber core layer of at least one tab rubber film on the two battery metal belts is a colored layer, so that the positive electrode and the negative electrode can be quickly distinguished, the operation is simple, the use is convenient, and the influence on the tab function during the tab processing is avoided.

Description

Technical Field

[0001] This utility model relates to the technical field of new energy electronic products, and in particular to a multi-layer composite tab film. Background Technology

[0002] Currently, lithium batteries are widely used in electronic products. On the tabs of lithium batteries, tab films are widely used. The function of the tab film is to prevent short circuits between the metal strip and the aluminum-plastic film during battery encapsulation, and to prevent leakage by heat-sealing and sealing it together with the aluminum-plastic film during encapsulation. A tab consists of two tab films, upper and lower, sandwiching the metal strip in the middle.

[0003] A search revealed a Chinese patent publication number, CN207690938U, which discloses a low-temperature tab adhesive, comprising a first acid-modified resin outer layer, a tab adhesive core layer, and a second acid-modified resin outer layer. The tab adhesive core layer is disposed between the first and second acid-modified resin outer layers, and the first, second, and third acid-modified resin outer layers are sequentially bonded together. The melting point of the tab adhesive core layer is higher than that of the first and second acid-modified resin outer layers. This invention, by using a low-melting-point acid-modified resin in the outer layer of the tab adhesive core layer, ensures the bonding strength with the metal tab while reducing the encapsulation temperature of the tab adhesive, thus improving the encapsulation performance of the tab and the aluminum-plastic film in the low-temperature heat-sealing process. Simultaneously, the fixed-axis micro-stretching technology ensures the stiffness of the tab adhesive.

[0004] In existing technologies, colorless hot-melt electrode adhesive is generally used on the electrode tabs, making it difficult to distinguish between the positive and negative electrodes. Furthermore, relying on the external structural features of the electrode tab itself to distinguish between the positive and negative electrodes can affect the function of the electrode tab during processing.

[0005] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create a multi-layer composite tab film, which would have greater industrial application value. Utility Model Content

[0006] To solve any of the above-mentioned technical problems, the purpose of this utility model is to provide a multilayer composite tab film.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A multi-layer composite tab adhesive film includes a battery aluminum-plastic film, a battery cell and two battery metal strips, and a tab adhesive film disposed between the battery aluminum-plastic film and the battery metal strips;

[0009] The tab adhesive film includes a tab adhesive core layer and a heat-sealing layer located on the upper and lower sides of the tab adhesive core layer. The melting point of the heat-sealing layer is lower than that of the tab adhesive core layer. The heat-sealing layer is a colorless layer. The tab adhesive core layer of at least one tab adhesive film on the two battery metal strips is a colored layer.

[0010] The heat-sealing layer consists of a modified layer, a homopolymer layer, and a copolymer layer from the outside to the inside.

[0011] As a further improvement of this utility model, the total thickness of the two heat-sealing layers and the tab core layer is 40~130μm.

[0012] As a further improvement of this utility model, the thickness of both heat-sealing layers is 5~20μm, and the thickness of the tab core layer is 30~90μm.

[0013] As a further improvement of this utility model, the melting point of the heat-sealing layer is 100-120°C, and the melting point of the tab core layer is 120-180°C.

[0014] As a further improvement of this utility model, both heat-sealing layers are bonded together with the inner tab core layer.

[0015] As a further improvement of this utility model, the modified layer is a modified polypropylene layer, the homopolymer layer is a homopolymer polypropylene layer, and the copolymer layer is a copolymer polypropylene layer.

[0016] As a further improvement of this utility model, the thickness ratio of the modified layer, the homopolymer layer and the copolymer layer is 1:1 to 2:1.

[0017] As a further improvement of this utility model, the modified layer, homopolymer layer and copolymer layer are co-extruded together.

[0018] As a further improvement of this utility model, the tab core layer is an acid-modified polypropylene layer, and colorant is added to the tab core layer.

[0019] By means of the above solution, this utility model has at least the following advantages:

[0020] This invention features a structure where the heat-sealing layer is colorless and the core layer of the tab adhesive film on at least one of the two battery metal strips is colored. This allows for quick identification of the positive and negative electrodes, is simple to operate and convenient to use, and avoids affecting the function of the tabs during processing.

[0021] This invention utilizes a heat-sealing layer composed of a modified layer, a homopolymer layer, and a copolymer layer, which are co-extruded together to improve the high-temperature resistance of the tab adhesive to a certain extent.

[0022] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of a multilayer composite tab film according to this utility model;

[0025] Figure 2 yes Figure 1 Schematic diagram of the structure of the middle pole ear diaphragm;

[0026] Figure 3 yes Figure 2 A schematic diagram of the structure of the intermediate heat seal layer.

[0027] The meanings of the labels in the figures are as follows.

[0028] 1. Battery aluminum-plastic film; 2. Battery cell; 3. Battery metal strip; 4. Electrode tab adhesive film;

[0029] Heat-sealing layer 41, tab core layer 42;

[0030] Modified layer 411, homopolymer layer 412, copolymer layer 413. Detailed Implementation

[0031] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0032] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Example

[0033] like Figures 1-3As shown, the present invention provides a multi-layer composite tab adhesive film, comprising a battery aluminum-plastic film 1, a battery cell 2, two battery metal strips 3, and a tab adhesive film 4 disposed between the battery aluminum-plastic film 1 and the battery metal strips 3.

[0034] The tab film 4 includes a tab core layer 42 and heat-sealing layers 41 located on the upper and lower sides of the tab core layer 42. The heat-sealing layers 41 include a modified layer 411, a homopolymer layer 412 and a copolymer layer 413 from the outside to the inside.

[0035] The total thickness of the tab film 4 is 40~130μm, the thickness of the two heat-sealing layers 41 is 5~20μm, the thickness of the tab core layer 42 is 30~90μm, and the thickness ratio of the modified layer 411, the homopolymer layer 412 and the copolymer layer 413 is 1:1~2:1.

[0036] The melting point of the heat-sealing layer 41 is lower than that of the tab core layer 42. The melting point of the heat-sealing layer 41 is 100-120℃, and the melting point of the tab core layer 42 is 120-180℃.

[0037] The heat-sealing layer 41 is a colorless layer, and the tab adhesive core layer 42 of at least one tab adhesive film 4 on the two battery metal strips 3 is a colored layer, with colorant added inside the tab adhesive core layer 42.

[0038] The first embodiment of this utility model:

[0039] The tab film 4 includes a tab core layer 42 and heat-sealing layers 41 located on the upper and lower sides of the tab core layer 42. The heat-sealing layers 41 include a modified layer 411, a homopolymer layer 412 and a copolymer layer 413 from the outside to the inside.

[0040] The total thickness of the tab film 4 is 80 μm, the thickness of the two heat-sealing layers 41 is 10 μm, the thickness of the tab core layer 42 is 60 μm, and the thickness ratio of the modified layer 411, the homopolymer layer 412 and the copolymer layer 413 is 1:1:1.

[0041] The heat-sealing layer 41 has a melting point of 100°C, and the tab core layer 42 has a melting point of 150°C. During processing, both heat-sealing layers 41 are bonded to the inner tab core layer 42 with adhesive.

[0042] The heat-sealing layer 41 includes, from the outside to the inside, a modified layer 411, a homopolymer layer 412, and a copolymer layer 413. The modified layer 411 is a modified polypropylene layer, the homopolymer layer 412 is a homopolymer polypropylene layer, and the copolymer layer 413 is a copolymer polypropylene layer.

[0043] Modified polypropylene layers are materials obtained by modifying polypropylene (PP) as the base resin through the addition of various additives or specific processing techniques. The purpose of modification is to improve certain properties of PP, making it more suitable for specific applications. Different additives can be added to enhance the material's performance. For example, adding flame retardants can give PP flame-retardant properties, improving the material's safety.

[0044] Homopolymer polypropylene is a polypropylene material polymerized from a single propylene monomer. It has high crystallinity, thus exhibiting good rigidity, hardness, and heat resistance. Its mechanical properties are good, with relatively high tensile strength and flexural strength, making it suitable for applications requiring high strength and rigidity.

[0045] The copolymer polypropylene layer is a polypropylene material copolymerized from propylene monomers and a small amount of other monomers (such as ethylene). Its surface properties can be further improved after corona treatment.

[0046] Due to the introduction of other monomers, the molecular chain structure of the copolymer polypropylene layer is altered, resulting in lower crystallinity compared to homopolymer PP. This leads to better toughness and impact resistance, while maintaining a certain level of rigidity and heat resistance. Corona treatment is a surface modification technique that uses a high-voltage electric field to ionize air, generating plasma that bombards the surface of the copolymer PP, thereby increasing its surface energy, roughness, and polarity. After corona treatment, the surface hydrophilicity of the copolymer PP layer is enhanced, and its printability, coatability, and adhesion are significantly improved, facilitating subsequent processing such as printing patterns, applying adhesives, or laminating with other materials.

[0047] Three different polypropylene materials—modified layer 411, homopolymer layer 412, and copolymer layer 413—are added to separate extruders. The materials are heated to a molten state in each extruder, then combined in a common mold to form a multi-layered structure. Finally, after cooling and shaping, a three-layered product is obtained. This process allows for the composite of multiple materials in a single operation, resulting in high production efficiency and precise control over the thickness and proportion of each layer, ensuring consistent product quality. Furthermore, because the composite is performed in a molten state, the bonding strength between layers is good, forming a strong interfacial bond.

[0048] The tab core layer 42 is an acid-modified polypropylene layer. A colored pigment is added to one tab core layer 42, which is the positive electrode, and the other is the negative electrode.

[0049] The second embodiment of this utility model:

[0050] The tab film 4 includes a tab core layer 42 and heat-sealing layers 41 located on the upper and lower sides of the tab core layer 42. The heat-sealing layers 41 include a modified layer 411, a homopolymer layer 412 and a copolymer layer 413 from the outside to the inside.

[0051] The total thickness of the tab film 4 is 100 μm, the thickness of the two heat-sealing layers 41 is 10 μm, the thickness of the tab core layer 42 is 80 μm, and the thickness ratio of the modified layer 411, the homopolymer layer 412 and the copolymer layer 413 is 1:1:1.

[0052] The heat-sealing layer 41 has a melting point of 120°C, and the tab core layer 42 has a melting point of 180°C. During processing, both heat-sealing layers 41 are bonded to the inner tab core layer 42 with adhesive.

[0053] The heat-sealing layer 41 includes, from the outside to the inside, a modified layer 411, a homopolymer layer 412, and a copolymer layer 413. The modified layer 411 is a modified polypropylene layer, the homopolymer layer 412 is a homopolymer polypropylene layer, and the copolymer layer 413 is a copolymer polypropylene layer.

[0054] The modified layer 411, the homopolymer layer 412, and the copolymer layer 413 are co-extruded together.

[0055] The tab core layer 42 is an acid-modified polypropylene layer. A colored pigment is added to one tab core layer 42, which is the positive electrode, and the other is the negative electrode.

[0056] The third embodiment of this utility model:

[0057] The tab film 4 includes a tab core layer 42 and heat-sealing layers 41 located on the upper and lower sides of the tab core layer 42. The heat-sealing layers 41 include a modified layer 411, a homopolymer layer 412 and a copolymer layer 413 from the outside to the inside.

[0058] The total thickness of the tab film 4 is 120 μm, the thickness of the two heat-sealing layers 41 is 10 μm, the thickness of the tab core layer 42 is 100 μm, and the thickness ratio of the modified layer 411, the homopolymer layer 412 and the copolymer layer 413 is 1:2:1.

[0059] The heat-sealing layer 41 has a melting point of 100°C, and the tab core layer 42 has a melting point of 160°C. During processing, both heat-sealing layers 41 are glued together with the inner tab core layer 42 using adhesive.

[0060] The heat-sealing layer 41 includes, from the outside to the inside, a modified layer 411, a homopolymer layer 412, and a copolymer layer 413. The modified layer 411 is a modified polypropylene layer, the homopolymer layer 412 is a homopolymer polypropylene layer, and the copolymer layer 413 is a copolymer polypropylene layer.

[0061] The modified layer 411, the homopolymer layer 412, and the copolymer layer 413 are co-extruded together.

[0062] The tab core layer 42 is an acid-modified polypropylene layer. A black pigment is added to one tab core layer 42, which is the positive electrode, and a white pigment is added to the other tab core layer 42, which is the negative electrode.

[0063] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element 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 of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0064] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0065] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A multilayer composite tab adhesive film, comprising a battery aluminum-plastic film (1), a battery cell (2) and two battery metal strips (3), and a tab adhesive film (4) disposed between the battery aluminum-plastic film (1) and the battery metal strips (3). Its features are: The tab film (4) includes a tab core layer (42) and a heat-sealing layer (41) located on the upper and lower sides of the tab core layer (42). The melting point of the heat-sealing layer (41) is lower than that of the tab core layer (42). The heat-sealing layer (41) is a colorless layer. The tab core layer (42) of at least one tab film (4) on the two battery metal strips (3) is a colored layer. The heat-sealing layer (41) includes, from the outside to the inside, a modified layer (411), a homopolymer layer (412), and a copolymer layer (413).

2. The multi-layered composite tab gum film according to claim 1, wherein, The total thickness of the two heat-sealing layers (41) and the tab core layer (42) is 40~130μm.

3. The multi-layered composite tab gum film according to claim 2, wherein the polyolefin-based resin is a polypropylene-based resin. The thickness of both heat-sealing layers (41) is 5~20μm, and the thickness of the tab core layer (42) is 30~90μm.

4. The multilayer composite electrode film as described in claim 1, characterized in that, The melting point of the heat-sealing layer (41) is 100-120°C, and the melting point of the tab core layer (42) is 120-180°C.

5. The multilayer composite electrode film as described in claim 1, characterized in that, Both heat-sealing layers (41) are bonded together with the inner tab core layer (42).

6. The multi-layered composite tab gum film according to claim 1, wherein The modified layer (411) is a modified polypropylene layer, the homopolymer layer (412) is a homopolymer polypropylene layer, and the copolymer layer (413) is a copolymer polypropylene layer.

7. The multi-layered composite tab gum film according to claim 6, wherein the polyolefin-based resin is a polypropylene-based resin. The thickness ratio of the modified layer (411), the homopolymer layer (412), and the copolymer layer (413) is 1:1 to 2:

1.

8. The multi-layered composite tab gum film according to claim 6, wherein, The modified layer (411), homopolymer layer (412) and copolymer layer (413) are co-extruded together.

9. The multi-layered composite tab gum film according to claim 1, wherein The tab core layer (42) is an acid-modified polypropylene layer, and colorant is added to the tab core layer (42).

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