A lithium battery tab adhesive film
By designing an adhesive film for lithium battery tabs with inner and outer film layers and an intermediate blocking layer, the problem of lithium battery damage caused by excessive current was solved, thus improving safety performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- KUNSHAN ZHI XIN TIAN CHENG ELECTRONIC MATERIALS CO LTD
- Filing Date
- 2025-06-23
- Publication Date
- 2026-06-05
AI Technical Summary
Existing lithium battery tab films cannot effectively block excessive current, leading to damage to lithium battery components.
Design a film for lithium battery tabs, comprising an inner film layer, a middle layer and an outer film layer from the inside out. The melting points of the inner and outer film layers are both lower than those of the middle layer. The middle layer is a blocking layer with recesses on its inner and outer sides. It is bonded to the inner and outer film layers by an adhesive layer. The blocking layer can block the current when it is too high.
It effectively blocks excessive current, avoids damage to lithium batteries, and improves safety performance.
Smart Images
Figure CN224323708U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of new energy electronic products, and in particular to an adhesive film for lithium battery tabs. Background Technology
[0002] Currently, lithium batteries are widely used in electronic products. On the lithium battery tabs, tab adhesive film is widely used. The function of the tab adhesive film is to prevent short circuits between the metal strip and the aluminum-plastic film during battery encapsulation, and to prevent leakage by heating and hot-melting the adhesive film together during encapsulation.
[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] The existing low-temperature tab adhesive is mainly used to ensure the bonding performance and stability of the battery tabs in low-temperature environments. However, it cannot effectively block the current when it is too high, which can damage the lithium battery components.
[0005] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create a new type of adhesive film for lithium battery tabs, 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 an adhesive film for lithium battery tabs.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A lithium battery tab adhesive film includes, from the inside out, an inner film layer, an intermediate layer and an outer film layer, wherein the melting points of the inner film layer and the outer film layer are both lower than the melting point of the intermediate layer;
[0009] Both the inner and outer membrane layers are modified CPP layers;
[0010] The inner membrane layer is used to adhere to and fully cover the welding area between the tab and the substrate;
[0011] The intermediate layer includes a blocking layer, with several recesses on both the inner and outer sides of the blocking layer. The inner and outer membrane layers respectively enclose the intermediate blocking layer.
[0012] As a further improvement of this utility model, the blocking layer is bonded to the inner membrane layer and the outer membrane layer respectively by an adhesive layer.
[0013] As a further improvement of this utility model, the blocking layer is bonded together with the inner and outer membrane layers and then subjected to hot pressing molding.
[0014] As a further improvement of this utility model, the adhesive layer is a silane coupling agent or an epoxy resin.
[0015] As a further improvement of this utility model, the blocking layer is an alumina mixed layer, polyvinylidene fluoride, or PTC material.
[0016] As a further improvement of this utility model, the total thickness of the inner film layer, the intermediate layer and the outer film layer is 65~130μm.
[0017] As a further improvement of this utility model, the thickness of the inner film layer is 10~30μm, the thickness of the middle layer is 40~60μm, and the thickness of the outer film layer is 15~40μm.
[0018] As a further improvement to this invention, colorant is added to the blocking layer.
[0019] By means of the above solution, this utility model has at least the following advantages:
[0020] This invention utilizes the structural design of the blocking layer. When the current is too large, the blocking layer can effectively block the current by means of its own insulation properties or by the interaction between the inner and outer membrane layers after structural changes.
[0021] This invention can, to a certain extent, avoid damage to lithium batteries caused by excessive current and improve their safety performance.
[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 an adhesive film for lithium battery tabs according to this utility model;
[0025] Figure 2 yes Figure 1 Schematic diagram of the middle layer;
[0026] Figure 3 yes Figure 2 A schematic diagram of the structure of the middle blocking layer.
[0027] The meanings of the labels in the figures are as follows.
[0028] Inner membrane layer 1, intermediate layer 2, outer membrane layer 3;
[0029] Blocking layer 21, adhesive layer 22, concave hole 23. Detailed Implementation
[0030] 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.
[0031] 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.
[0032] like Figures 1-3 A lithium battery tab adhesive film includes, from the inside out, an inner film layer 1, an intermediate layer 2 and an outer film layer 3, wherein the melting points of the inner film layer 1 and the outer film layer 3 are both lower than the melting point of the intermediate layer 2.
[0033] Both the inner membrane layer 1 and the outer membrane layer 3 are modified CPP layers. The inner membrane layer 1 is used to adhere to and fully cover the welding area between the tab and the substrate.
[0034] The intermediate layer 2 includes a blocking layer 21. Several recesses 23 are provided on the inner and outer sides of the blocking layer 21. The inner film layer 1 and the outer film layer 3 respectively wrap the intermediate blocking layer 21. The blocking layer 21 is bonded to the inner film layer 1 and the outer film layer 3 respectively through an adhesive layer 22. The adhesive layer 22 is a silane coupling agent or epoxy resin.
[0035] In addition, the blocking layer 21 is bonded together with the inner membrane layer 1 and the outer membrane layer 3 and then hot-pressed.
[0036] The blocking layer 21 is an alumina mixed layer, polyvinylidene fluoride, or PTC material.
[0037] The total thickness of the inner membrane layer 1, the intermediate layer 2 and the outer membrane layer 3 is 65~130μm, of which the thickness of the inner membrane layer 1 is 10~30μm, the thickness of the intermediate layer 2 is 40~60μm and the thickness of the outer membrane layer 3 is 15~40μm.
[0038] In addition, colorants can be added to the blocking layer 21.
[0039] The first embodiment of this utility model:
[0040] A lithium battery tab adhesive film comprises, from the inside out, an inner film layer 1, an intermediate layer 2, and an outer film layer 3.
[0041] 1. Both the inner film layer 1 and the outer film layer 3 are modified CPP layers. The inner film layer 1 is used to adhere to and fully cover the welding area between the tab and the substrate.
[0042] The intermediate layer 2 includes a blocking layer 21, which is an alumina mixed layer. Several recesses 23 are formed on both the inner and outer sides of the blocking layer 21. The inner film layer 1 and the outer film layer 3 respectively enclose the intermediate blocking layer 21. The blocking layer 21 is bonded to the inner film layer 1 and the outer film layer 3 by an adhesive layer 22, which is either a silane coupling agent or an epoxy resin. Taking a silane coupling agent as an example, one end of it can undergo a condensation reaction with the hydroxyl groups on the surface of the alumina mixed layer, while the organic groups at the other end can physically entangle or chemically react with the CPP layer molecules, thereby firmly bonding the two together.
[0043] Then, the three layers are hot-pressed under certain temperature and pressure. During the hot-pressing process, the inner film layer 1 and the outer film layer 3 melt upon heating, which can better fill the micropores and uneven areas (i.e., pits 23) on the surface of the blocking layer 21, and achieve a tight bond between the two after cooling. At the same time, appropriate pressure can reduce the intermolecular distance between the two, increase the intermolecular force, and improve the bonding strength.
[0044] The aforementioned alumina mixed layer can be synthesized by chemical vapor deposition, physical vapor deposition, or hydrothermal synthesis.
[0045] The total thickness of the inner membrane layer 1, the intermediate layer 2, and the outer membrane layer 3 is 80 μm, of which the thickness of the inner membrane layer 1 is 20 μm, the thickness of the intermediate layer 2 is 40 μm, and the thickness of the outer membrane layer 3 is 20 μm.
[0046] In addition, colorants can be added to the blocking layer 21. Normally, the alumina mixture layer is white, but by adding a specific colorant, effective identification can be achieved.
[0047] The second embodiment of this utility model:
[0048] A lithium battery tab adhesive film comprises, from the inside out, an inner film layer 1, an intermediate layer 2, and an outer film layer 3.
[0049] 1. Both the inner film layer 1 and the outer film layer 3 are modified CPP layers. The inner film layer 1 is used to adhere to and fully cover the welding area between the tab and the substrate.
[0050] The intermediate layer 2 includes a blocking layer 21, which is a polyvinylidene fluoride layer. Several recesses 23 are formed on both the inner and outer sides of the blocking layer 21. The inner membrane layer 1 and the outer membrane layer 3 respectively wrap around the intermediate blocking layer 21. The blocking layer 21 is bonded to the inner membrane layer 1 and the outer membrane layer 3 respectively through the adhesive layer 22.
[0051] Then, the three layers are hot-pressed under certain temperature and pressure. During the hot-pressing process, the inner film layer 1 and the outer film layer 3 melt upon heating, which can better fill the micropores and uneven areas (i.e., pits 23) on the surface of the blocking layer 21, and achieve a tight bond between the two after cooling. At the same time, appropriate pressure can reduce the intermolecular distance between the two, increase the intermolecular force, and improve the bonding strength.
[0052] The polyvinylidene fluoride (PVDF) layer possesses excellent chemical stability, corrosion resistance, and mechanical properties, while also exhibiting certain insulation and thermal stability. It maintains good performance in lithium battery environments and is not easily affected by substances such as electrolytes. Through its inherent insulating properties and stability at high temperatures, it prevents abnormal current conduction. When the current is too high, the PVDF layer can effectively block the current through structural changes or interactions with other layers, and it also protects the tab film, ensuring its stability in the complex battery environment.
[0053] Polyvinylidene fluoride (PVDF) is a semi-crystalline polymer. When excessive current generates heat, the crystalline regions of the PVDF layer may undergo changes. As temperature increases, the mobility of its molecular chains increases, and the crystallinity may change, leading to alterations in the material's physical properties. For example, expansion or deformation of the crystalline regions may make the internal structure of the PVDF layer more compact, thereby increasing its resistance to current flow.
[0054] When the current is too high, the interaction between the polyvinylidene fluoride (PVDF) layer and adjacent layers will change. For example, the adhesion between the PVDF layer and the electrode material may change with increasing temperature, leading to an increase in the contact resistance between the electrode material and the PVDF layer.
[0055] The total thickness of the inner membrane layer 1, the intermediate layer 2 and the outer membrane layer 3 is 100 μm, of which the thickness of the inner membrane layer 1 is 15 μm, the thickness of the intermediate layer 2 is 60 μm and the thickness of the outer membrane layer 3 is 25 μm.
[0056] The third embodiment of this utility model:
[0057] A lithium battery tab adhesive film comprises, from the inside out, an inner film layer 1, an intermediate layer 2, and an outer film layer 3.
[0058] 1. Both the inner film layer 1 and the outer film layer 3 are modified CPP layers. The inner film layer 1 is used to adhere to and fully cover the welding area between the tab and the substrate.
[0059] The intermediate layer 2 includes a blocking layer 21, which is made of PTC material. Several recesses 23 are formed on both the inner and outer sides of the blocking layer 21. The inner film layer 1 and the outer film layer 3 respectively wrap around the intermediate blocking layer 21. The blocking layer 21 is bonded to the inner film layer 1 and the outer film layer 3 respectively through the adhesive layer 22.
[0060] Then, the three layers are hot-pressed under certain temperature and pressure. During the hot-pressing process, the inner film layer 1 and the outer film layer 3 melt upon heating, which can better fill the micropores and uneven areas (i.e., pits 23) on the surface of the blocking layer 21, and achieve a tight bond between the two after cooling. At the same time, appropriate pressure can reduce the intermolecular distance between the two, increase the intermolecular force, and improve the bonding strength.
[0061] PTC material refers to a material whose resistance increases significantly with increasing temperature within a certain temperature range. Based on this characteristic of resistance changing with temperature, when the current passing through a PTC material is too large, it will generate heat, increasing its temperature and resistance, thereby limiting further increases in current and playing a role in automatic current limiting.
[0062] The aforementioned PTC materials can be ceramic PTC materials, etc.
[0063] The total thickness of the inner membrane layer 1, the intermediate layer 2 and the outer membrane layer 3 is 120 μm, of which the thickness of the inner membrane layer 1 is 30 μm, the thickness of the intermediate layer 2 is 60 μm and the thickness of the outer membrane layer 3 is 30 μm.
[0064] 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.
[0065] 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.
[0066] 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 lithium battery tab adhesive film, comprising an inner film layer (1), an intermediate layer (2) and an outer film layer (3) from the inside to the outside, wherein the melting points of the inner film layer (1) and the outer film layer (3) are both lower than the melting point of the intermediate layer (2); Its features are: Both the inner membrane layer (1) and the outer membrane layer (3) are modified CPP layers; The inner membrane layer (1) is used to adhere to and fully cover the welding area between the electrode tab and the substrate; The intermediate layer (2) includes a blocking layer (21), and several recesses (23) are provided on the inner and outer sides of the blocking layer (21). The inner membrane layer (1) and the outer membrane layer (3) respectively wrap the intermediate blocking layer (21).
2. The adhesive film for lithium battery tabs as described in claim 1, characterized in that, The blocking layer (21) is bonded to the inner membrane layer (1) and the outer membrane layer (3) respectively through the adhesive layer (22).
3. The adhesive film for lithium battery tabs as described in claim 2, characterized in that, The blocking layer (21) is bonded together with the inner membrane layer (1) and the outer membrane layer (3) and then hot-pressed.
4. The adhesive film for lithium battery tabs as described in claim 2, characterized in that, The adhesive layer (22) is a silane coupling agent or an epoxy resin.
5. The adhesive film for lithium battery tabs as described in claim 1, characterized in that, The blocking layer (21) is an alumina mixed layer, polyvinylidene fluoride, or PTC material.
6. The adhesive film for lithium battery tabs as described in claim 1, characterized in that, The total thickness of the inner membrane layer (1), the intermediate layer (2) and the outer membrane layer (3) is 65~130μm.
7. The adhesive film for lithium battery tabs as described in claim 6, characterized in that, The thickness of the inner membrane layer (1) is 10~30μm, the thickness of the intermediate layer (2) is 40~60μm, and the thickness of the outer membrane layer (3) is 15~40μm.
8. The adhesive film for lithium battery tabs as described in claim 1, characterized in that, Add colorant to the blocking layer (21).