Double-sided non-adhesive tape

Abstract

The utility model discloses a double-sided non-adhesive tape which comprises an adhesive layer and a non-adhesive carrier film arranged on one outer side surface of the adhesive layer, the bonding layer comprises a base material layer, a non-bonding layer and a hot-pressing bonding layer, the non-bonding layer and the hot-pressing bonding layer are stacked on the two sides of the base material layer respectively, and the base material layer is connected with the non-bonding carrier film through the non-bonding layer; and the room-temperature uncovering force of the non-adhesive layer and the non-adhesive carrier film is smaller than the hot-pressing adhesive force of the hot-pressing adhesive layer and the adhered object. The double-sided non-adhesive tape provided by the utility model basically keeps non-adhesive at room temperature, during hot pressing, the hot-pressing adhesive layer is firmly adhered to the welding part of the tab, and the cover film and the non-adhesive carrier film can be sequentially and smoothly stripped from the adhesive layer by virtue of differentiated setting of adhesive forces among the layers, so that the adhesive force between the cover film and the non-adhesive carrier film is greatly improved. The problems that a traditional adhesive tape is not uniform in adhesion or a carrier film is stripped to take away an electrode active material and the like are effectively solved, and the accuracy of tab welding mark protection and the stability of a production process are remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, and in particular to tapes for lithium batteries, especially a double-sided non-adhesive tape. Background Technology

[0002] Tabs are metallic conductors extending from the current collectors at the positive and negative electrodes of a battery, connecting to the battery casing or external module components to transmit current. Tabs are typically fixed to the current collectors by welding, but inadequate protection of these welded areas can lead to a series of safety hazards and performance issues. On one hand, weld slag and burrs generated during welding may puncture the battery separator, creating a risk of internal short circuits and affecting battery safety. On the other hand, the high temperatures at the welded areas can cause localized lithium-ion deposition, affecting the battery's conductivity and lifespan. Therefore, reliable physical isolation and protection of the tab welded areas to prevent welding defects from impacting battery performance has become a crucial technical requirement in battery manufacturing.

[0003] Currently, commonly used electrode tab welding protective tapes on the market typically use BOPP, PET, or other films as the substrate, with a pressure-sensitive adhesive layer coated on the surface to form a single-sided tape. Patent CN219156800U discloses a battery electrode tab welding tape, including a PP substrate with a polyacrylic acid adhesive layer coated on the center of one side. The substrate has a melting point of 120℃-200℃. When this tape is used to adhere to the final weld mark of the electrode tab, it not only utilizes the adhesive force of the polyacrylic acid adhesive layer to stick the tape to the final weld mark, but also heats the substrate to cause it to slightly melt and thermally bond with the adhesive layer, further improving the tape's adhesion. However, the substrate in this patent serves as both a carrier film and a hot-melt layer, resulting in a relatively high overall tape thickness, which is detrimental to improving battery energy density. Furthermore, the substrate deforms significantly, resulting in a marked decrease in puncture resistance. Furthermore, a carrier film can be separately incorporated into the tape. Removing the carrier film after bonding effectively reduces the tape thickness. A common usage method for this type of tape is as follows: the back of the substrate layer is adhered to the carrier film, which is tacky at room temperature, and then die-cut (the die-cutting removes the substrate and adhesive layer, leaving the exposed carrier film still tacky); the other side of the tape is covered with a cover film. During use, the cover film is first removed, allowing the adhesive layer to adhere to the welding area, followed by hot pressing, and finally the carrier film is removed. However, this single-sided pressure-sensitive adhesive design of such tapes has the following drawbacks: the adhesion between the cover film and the adhesive layer is low, making it prone to slippage, which may lead to positioning misalignment during unwinding or pasting, affecting production efficiency and assembly accuracy; the entire carrier film is tacky, and after hot pressing, it can easily remove the electrode active layer, thereby damaging the integrity of the electrode material and affecting battery performance and stability.

[0004] Invention CN117820972A discloses a double-sided protective tape, with one side of its substrate layer being a non-adhesive rubber layer at room temperature and the other side being a pressure-sensitive adhesive layer soluble in electrolyte. In use, the pressure-sensitive adhesive layer is applied to the welding area of ​​the electrode tabs. After the battery cell is wound, the rubber layer of the tape contacts the battery separator. After battery formation, the rubber layer releases its adhesiveness and adheres to the separator after hot pressing. The pressure-sensitive adhesive layer completely dissolves upon contact with the electrolyte. Because the tape remains fixed to the separator, it still protects the welding area and prevents lithium plating. However, this invention uses a soluble pressure-sensitive adhesive layer to bond the electrode tab welding area, which makes it difficult to provide long-term stable physical protection for the electrode tab solder joints. This may expose the welding area to the external environment, affecting the battery's electrochemical performance. Furthermore, the dissolved pressure-sensitive adhesive layer may clog the battery separator, affecting ion transport within the battery, reducing overall performance, and posing safety hazards.

[0005] Therefore, how to provide a tape structure that can reliably fix the electrode tab welding part without affecting the electrode active material or the battery electrochemical performance remains a problem that needs to be solved by those skilled in the art. Utility Model Content

[0006] To address the shortcomings of the existing technology, this utility model provides a double-sided non-adhesive tape. Through the design of the layer structure and interlayer adhesion, it meets the requirements for protecting the electrode tabs while avoiding the problems of unstable adhesion or the removal of electrode active material by the peeling off of the carrier film, which are common in existing tapes.

[0007] This utility model provides a double-sided non-adhesive tape, including an adhesive layer and a non-adhesive film disposed on an outer side of the adhesive layer;

[0008] The adhesive layer includes a substrate layer, and a non-adhesive layer and a hot-press adhesive layer respectively stacked on both sides of the substrate layer. The substrate layer is connected to the non-adhesive film through the non-adhesive layer.

[0009] The room temperature peel force between the non-adhesive layer and the non-adhesive film is less than the hot-press adhesive force between the hot-press adhesive layer and the substrate.

[0010] The tape provided by this invention adopts a double-sided non-adhesive structure. The non-adhesive carrier film, substrate layer, and the non-adhesive layers on both sides of the tape, as well as the hot-pressing adhesive layer, have virtually no adhesive force at room temperature. Therefore, the tape remains essentially non-adhesive at room temperature, only functioning as an adhesive under hot pressing. This avoids the accidental adhesion problems encountered with traditional pressure-sensitive tapes during storage, unwinding, and lamination. Utilizing the room-temperature non-adhesiveness and hot-pressing adhesiveness of the non-adhesive layer, it exhibits suitable adhesion above 50°C (generally, the higher the temperature, the greater the adhesive force). It can bond with the carrier film and substrate layer under hot pressing conditions, connecting the substrate layer to the non-adhesive carrier film, improving processing efficiency and ease of operation, and avoiding the risk of electrode active materials being pulled away by adhesive carrier films.

[0011] Secondly, by designing that the room-temperature peel force between the non-adhesive layer and the non-adhesive carrier film is less than the hot-press adhesion force between the hot-press adhesive layer and the substrate, this design ensures that the tape can reliably adhere to the tab welding area after hot pressing, while also allowing the non-adhesive carrier film to be easily peeled off from the adhesive layer after hot pressing. This gradient adhesive force design effectively avoids the risk of the electrode active material being taken away during carrier film peeling, as is common in existing technologies, and also improves the protection of the battery tab welding area.

[0012] Furthermore, a cover film is provided on the other outer side of the adhesive layer, and the substrate layer is connected to the cover film by a hot-press adhesive layer.

[0013] Furthermore, the room temperature peel force of the non-adhesive layer and the non-adhesive film is greater than that of the hot-pressed adhesive layer and the cover film.

[0014] When using a non-adhesive cover film, the room temperature peel force between the heat-pressed adhesive layer and the cover film can be below 10 g / inch, preferably 1-5 g / inch. This avoids tape slippage and misalignment during unwinding due to insufficient adhesion, thus improving construction accuracy. On the other hand, the non-adhesive film and the non-adhesive layer can still maintain a certain adhesive force after heat-pressing, which is greater than the room temperature peel force between the heat-pressed adhesive layer and the cover film, ensuring that the cover film can be easily peeled off at room temperature.

[0015] After setting the non-adhesive film, the thickness of the adhesive layer can be effectively reduced, which is beneficial to improving the energy density of the battery in the application scenario. The thickness of the adhesive layer can be expressed as the distance from the outer side of the hot-pressed adhesive layer to the outer side of the non-adhesive layer. After setting the cover film, the thickness of the adhesive layer can also be expressed as the average distance between the inner side of the non-adhesive film and the inner side of the cover film. Depending on the thickness of each layer, the thickness of the adhesive layer is 8-40μm, preferably 10-30μm.

[0016] Furthermore, the thickness of the substrate layer is 1-25 μm, and the substrate layer includes at least one of PP film layer, PI film layer, PE film layer, PET film layer, and PPS film layer.

[0017] Furthermore, the thickness of the non-adhesive layer is 0.5-12 μm, and the non-adhesive layer includes a hot melt adhesive layer.

[0018] Furthermore, the thickness of the hot-pressed adhesive layer is 2-15 μm, and the hot-pressed adhesive layer includes a hot melt adhesive layer.

[0019] Furthermore, the non-adhesive film is a single-sided release film or a double-sided release film with a thickness of 19-100 μm. For example, when the cover film is not used, the non-adhesive film is preferably a double-sided release film. During winding, the heat-pressed adhesive layer contacts the other outer side of the non-adhesive film, and the room temperature peel force between them is less than the room temperature peel force between the non-adhesive layer and the non-adhesive film, thus preventing interlayer adhesion and damage to the tape.

[0020] Furthermore, the cover film is a release film or an electrostatic film with a thickness of 10-40 μm.

[0021] Furthermore, the adhesive layer includes multiple adhesive units, which are spaced apart on the non-adhesive film. When a cover film is used, the multiple adhesive units are spaced apart between the non-adhesive film and the cover film.

[0022] Setting the adhesive layer as a discontinuous adhesive unit can further improve construction efficiency while still meeting adhesive performance requirements.

[0023] Furthermore, in the direction perpendicular to the extension of the tape, the length L of the adhesive unit is less than the width W of the non-adhesive film to ensure the hot pressing effect.

[0024] It is understood that the specific dimensions of the adhesive unit can be die-cut according to actual application requirements to match the bonding and protection needs of batteries of different sizes and areas. For example, the adhesive unit satisfies at least one of the following conditions:

[0025] 1) The length L of the adhesive unit is 5-20mm;

[0026] 2) The width B of the adhesive unit is 1-5mm;

[0027] 3) The spacing G between adjacent adhesive units is 5-20mm.

[0028] In this context, taking the tape extension direction X (or longitudinal direction) and the perpendicular direction Y (or transverse direction) of the tape extension direction as references, the length L of the adhesive unit refers to the dimension of the adhesive unit in the perpendicular direction Y of the tape extension direction, that is, the continuous spreading length of the adhesive area in the transverse direction; similarly, the width W of the non-adhesive film refers to the dimension of the non-adhesive film in the Y direction. The width B of the adhesive unit refers to the dimension of the adhesive unit along the tape extension direction X, that is, the continuous spreading dimension of the adhesive area in the longitudinal direction of the tape main axis.

[0029] The spacing G between adjacent adhesive units refers to the distance between the non-adhesive areas of two adjacent adhesive units. That is, the length of the non-adhesive functional area retained between adjacent adhesive units on the non-adhesive film (or cover film), which is the distance space left after the non-adhesive film is peeled off after bonding. It is determined by the size of the die-cut pieces of different sizes according to the needs of the production line process.

[0030] The double-sided non-adhesive tape provided by this utility model has at least the following beneficial effects:

[0031] (1) The double-sided non-adhesive tape provided by this utility model, the non-adhesive film, the substrate layer and the non-adhesive layers and hot-press adhesive layers on both sides, and the optional cover film, have basically no adhesive force at room temperature. Therefore, the tape basically remains non-adhesive at room temperature and only plays an adhesive function under hot pressing, avoiding problems such as unwanted wear or slippage of the tape before use.

[0032] (2) The double-sided non-adhesive tape of this utility model is designed with different adhesive forces for each layer according to the order and characteristics of the manufacturing and use process. This not only effectively protects the electrode tab solder marks, but also effectively prevents the tape from causing adhesive damage to the electrode active layer material. This allows the double-sided non-adhesive tape to better meet the construction process, and the tape has minimal swelling and dissolution in the electrolyte, exhibiting strong electrolyte resistance. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the first embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of the second embodiment of the present invention;

[0035] Figure 3 This is a structural schematic diagram of the third embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the fourth embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram showing the distribution of the adhesive units of this invention on a non-adhesive film.

[0038] Explanation of reference numerals in the attached drawings: 100, 200, 300, 400 - double-sided non-adhesive tape, 1 - substrate layer, 2 - non-adhesive layer, 3 - hot-press adhesive layer, 4 - non-adhesive film, 5 - cover film, 10 - adhesive unit. Detailed Implementation

[0039] To better understand the above technical solutions, a detailed description of the solutions will be provided below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0040] The terminology used in the embodiments of this utility model is for the purpose of describing particular embodiments only and is not intended to limit the utility model. The singular forms “a,” “the,” and “the” used in the embodiments of this utility model and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0041] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0042] See appendix Figure 1-4 Double-sided non-adhesive tape (100, 200, 300, 400), comprising, in sequence: non-adhesive film 4, adhesive layer and optional cover film 5;

[0043] The thickness of the non-adhesive film 4 is 19-100μm, and it is a single-sided release film or a double-sided release film, preferably a silicon-containing release film. The non-adhesive film 4 is disposed on one outer side of the adhesive layer.

[0044] The cover film 5 has a thickness of 10-40 μm and is a release film, preferably a silicone release film or an electrostatic film. The cover film 5 is disposed on the other outer side of the adhesive layer.

[0045] The adhesive layer, with an overall thickness D of 8-40 μm, preferably 10-30 μm, comprises:

[0046] (1) Substrate layer 1, with a thickness of 1-25μm, including at least one of PP film layer, PI film layer, PE film layer, PET film layer and PPS film layer.

[0047] (2) Non-adhesive layer 2, with a thickness of 0.5-12μm, includes a hot melt adhesive layer, preferably a modified PP hot melt adhesive layer;

[0048] (3) Hot-pressed adhesive layer 3, with a thickness of 2-15 μm, includes a hot melt adhesive layer, preferably a modified PP hot melt adhesive layer; the hot-pressed adhesive layer 3 may have weak tack at room temperature, for example, the room temperature adhesive force may be below 10 g / inch, preferably 1-5 g / inch;

[0049] In the first embodiment, the non-adhesive layer 2 and the hot-pressed adhesive layer 3 are respectively stacked on both sides of the substrate layer 1, and the substrate layer 1 is connected to the non-adhesive carrier film 4 through the non-adhesive layer 2. (See attached figure) Figure 1In the second embodiment, when the cover film 5 is used, the substrate layer 1 is connected to the cover film 5 via a hot-press adhesive layer 3, see attached figure. Figure 2 .

[0050] The room temperature peel force between the non-adhesive layer 2 and the non-adhesive film 4 is less than the hot-press adhesion force between the hot-press adhesive layer 3 and the substrate. After hot pressing, the room temperature peel force between the non-adhesive layer 2 and the non-adhesive film 4 is 15-60 g / inch, and the hot-press adhesion force between the hot-press adhesive layer 3 and the substrate reaches 75-200 g / inch. The adhesive layer will not be torn off during the removal of the non-adhesive film 4.

[0051] The room temperature peel force of the non-adhesive layer 2 and the non-adhesive film 4 is greater than that of the hot-pressed adhesive layer 3 and the cover film 5, so that the cover film 5 can be easily removed before pasting without affecting the structure between the non-adhesive film 4 and the adhesive layer.

[0052] See appendix Figure 3 In the third embodiment, the adhesive layer may include a plurality of adhesive units 10, which are spaced apart between the non-adhesive film 4 and the cover film 5.

[0053] When the cover film 5 is not used, the fourth embodiment shows a plurality of adhesive units 10 spaced apart on the non-adhesive film 4, see Appendix Figure 4 .

[0054] In the third and fourth embodiments with adhesive unit 10, adhesive unit 10 and non-adhesive film 4 have a certain preferred relationship, see Appendix Figure 5 In the direction perpendicular to the extension of the tape (i.e., the Y direction), the length L of the adhesive unit 10 is less than the width W of the non-adhesive film 4.

[0055] As an example, the adhesive unit 10 satisfies at least one of the following conditions:

[0056] 1) The length L of the adhesive unit is 5-20mm;

[0057] 2) The width B of the adhesive unit is 1-5mm;

[0058] 3) The spacing G between adjacent adhesive units is 5-20mm.

[0059] It is understandable that, in order to meet the needs of bonding and protecting batteries of different sizes, the size of the bonding unit can be flexibly adjusted. The above range is just an example, and in actual applications, the size of the bonding unit can be outside the above range.

[0060] The manufacturing process of the double-sided non-adhesive tape (100, 200, 300, 400) of this utility model includes, but is not limited to, the following steps:

[0061] Step (1): Coating liquid of non-adhesive layer 2 is applied to one side of non-adhesive film 4, and after drying, it is bonded to substrate layer 1 by hot pressing.

[0062] Step (2): Apply the coating liquid of the hot-press adhesive layer 3 to the other side of the substrate layer 1, and dry to obtain the double-sided non-adhesive tape 100 of the first embodiment, which is non-adhesive at room temperature. See Appendix. Figure 1 .

[0063] Optionally, after step (2), a step (3) is included, in which a cover film 5 is adhered to the surface of the hot-pressed adhesive layer 3 away from the substrate layer 1, thereby obtaining the double-sided non-adhesive tape 200 of the second embodiment. See Appendix Figure 2 .

[0064] Furthermore, step (2) may also include die-cutting after drying. Since the adhesion between the non-adhesive layer 2 and the non-adhesive film 4 is relatively weak, the entire adhesive layer can be cut off from the non-adhesive film 4 to form multiple adhesive units 10, ultimately obtaining the double-sided non-adhesive tape 300 of the third embodiment. See Appendix. Figure 3 .

[0065] Optionally, die-cutting is performed after step (2). Since the adhesive force between the non-adhesive layer 2 and the non-adhesive film 4 is relatively weak, the entire adhesive layer can be cut off from the non-adhesive film 4 to form multiple adhesive units 10, thereby obtaining the double-sided non-adhesive tape 400 of the fourth embodiment. See Appendix. Figure 4 .

[0066] Taking the double-sided non-adhesive tape (200, 300) of the second or third embodiment as an example, its use includes, but is not limited to, the following steps:

[0067] (1) Uncover the cover film 5 and attach the hot-pressed adhesive layer 3 to the object to be adhered;

[0068] (2) Hot pressing, which heats and activates the hot-pressed adhesive layer 3 to bond it to the object to be bonded;

[0069] (3) Remove the non-adhesive membrane 4. Since the non-adhesive membrane 4 is not adhesive, the removal process will not stick to the electrode active layer material.

[0070] Example 1-1

[0071] Double-sided non-adhesive tape 300, see Figure 3 In order, they include:

[0072] (1) Non-adhesive film 4, with a thickness of 50μm, is a silicone release film for PET substrate;

[0073] (2) Non-adhesive layer 2, with a thickness of 1μm, is made of modified PP hot melt adhesive. After hot pressing, the room temperature peel force between non-adhesive layer 2 and non-adhesive carrier film 4 is 15g / inch.

[0074] (3) Substrate layer 1 is a PET film with a thickness of 5μm;

[0075] (4) Hot-pressed adhesive layer 3, with a thickness of 4μm, is made of modified PP hot melt adhesive. The peeling force between the hot-pressed adhesive layer and the cover film at room temperature is 5g / inch.

[0076] (5) Cover film 5, with a thickness of 25μm, is made of PET substrate silicone release film;

[0077] The adhesive layer includes multiple adhesive units 10, which are spaced apart between the non-adhesive film 4 and the cover film 5. The length L of the adhesive unit 10 is 11 mm, the width B is 2.5 mm, and the spacing G between adjacent adhesive units 10 on the non-adhesive film is 8 mm.

[0078] Examples 1-2

[0079] The difference between this embodiment and Embodiment 1-1 is that the adhesive unit specifications and dimensions in the double-sided non-adhesive tape 300 are different. The specific differences are as follows:

[0080] The adhesive unit has a length L of 5.5 mm, a width W of 2.2 mm, and a spacing G of 13 mm between adjacent adhesive units on the non-adhesive film.

[0081] Examples 1-3

[0082] The double-sided non-adhesive tape 400 of this embodiment differs from that of Embodiment 1-1 in that it does not use a cover film 5. The outermost non-adhesive carrier film 4 and the hot-pressed adhesive layer 3 of the adhesive unit 10 are essentially non-adhesive at room temperature. Therefore, the tape as a whole is non-adhesive at room temperature. See Appendix. Figure 4 The non-adhesive film 4 is a double-sided release film. When the tape is wound up, the hot-pressed adhesive layer 3 contacts the other side of the non-adhesive film 4, and the room temperature peel force between them is less than the room temperature peel force between the non-adhesive layer 2 and the non-adhesive film 4.

[0083] Examples 1-4

[0084] The difference between the double-sided non-adhesive tape 200 in this embodiment and that in Embodiment 1-1 is that the adhesive layer is a continuous layer comprising a non-adhesive layer 2, a substrate layer 1, and a hot-pressed adhesive layer 3 in sequence; that is, the adhesive layer is not die-cut into multiple adhesive units. See Appendix. Figure 2 .

[0085] Examples 1-5

[0086] The difference between the double-sided non-adhesive tape 100 in this embodiment and those in embodiments 1-4 is that it does not use a cover film 5. The outermost non-adhesive carrier film 4 and the hot-pressed adhesive layer 3 are essentially non-adhesive at room temperature. Therefore, the tape as a whole is non-adhesive at room temperature. See Appendix. Figure 1 The non-adhesive film 4 is a double-sided release film. When the tape is wound up, the hot-pressed adhesive layer 3 contacts the other side of the non-adhesive film 4, and the room temperature peel force between them is less than the room temperature peel force between the non-adhesive layer 2 and the non-adhesive film 4.

[0087] Example 2

[0088] This embodiment has the same structure as Embodiment 1-1, except that the composition of each layer is different, as detailed below:

[0089] (1) The thickness of the non-adhesive film 4 is 50μm, and the material is a PET substrate silicone release film;

[0090] (2) The thickness of the non-adhesive layer 2 is 0.5 μm, and the material is modified PP hot melt adhesive, the same as in Example 1-1. After hot pressing, the room temperature peel force between the non-adhesive layer 2 and the non-adhesive carrier film 4 is 20 g / inch.

[0091] (3) Substrate layer 1 is a BOPP film with a thickness of 8μm;

[0092] (4) The thickness of the hot-pressed adhesive layer 3 is 5μm, the material is modified PP hot melt adhesive, and the peeling force between the hot-pressed adhesive layer 3 and the cover film 5 at room temperature is 5g / inch;

[0093] (5) The thickness of the cover film 5 is 25μm, and the material is PET substrate silicone release film.

[0094] Example 3

[0095] This embodiment has the same structure as Embodiment 1-1, except that the composition of each layer is different, as detailed below:

[0096] (1) The thickness of the non-adhesive film 4 is 50μm, and the material is a PET substrate silicone release film;

[0097] (2) The thickness of the non-adhesive layer 2 is 1 μm, and the material is modified PP hot melt adhesive, which is the same as that in Example 1-1. After hot pressing, the room temperature peel force between the non-adhesive layer 2 and the non-adhesive carrier film 4 is 20 g / inch.

[0098] (3) Substrate layer 1 is a PI film with a thickness of 5.5 μm;

[0099] (4) The thickness of the hot-pressed adhesive layer 3 is 4μm, the material is modified PP hot melt adhesive, and the peeling force between the hot-pressed adhesive layer 3 and the cover film 5 at room temperature is 5g / inch;

[0100] (5) The thickness of the cover film 5 is 25μm, and the material is PET substrate silicone release film.

[0101] Test methods and results

[0102] Taking Examples 1-1, 2, and 3 as examples, samples were prepared for performance testing based on the composition parameters of each layer: a non-adhesive coating liquid was applied to one side of the non-adhesive film, dried, and then bonded to the substrate layer by hot pressing. A hot-press adhesive coating liquid was applied to the other side of the substrate layer, dried, and then cut to a size of 20mm × 100mm (the sample does not need to be die-cut into adhesive units). A cover film was pasted on the surface of the hot-press adhesive layer away from the substrate layer to obtain the corresponding tape sample. Each tape sample was tested, and the results are shown in Table 1.

[0103] (1) Non-adhesive film peeling force test: Remove the cover film of the tape sample, and heat press it onto the steel plate. The peeling force of the non-adhesive film at 180° between the non-adhesive film and the substrate layer is the non-adhesive film peeling force. The peeling speed is 300mm / min.

[0104] (2) Hot-pressing initial tack test @Al foil: Remove the cover film of the tape sample, heat press it onto the aluminum foil, and then stick the aluminum foil onto the steel plate with double-sided tape. Remove the non-adhesive film and test the 180° peel force between the hot-pressed adhesive layer and the aluminum foil. The peeling speed is 300 mm / min.

[0105] (3) Immersion adhesive strength test: Immerse the tape sample in the electrolyte, age it in an 85℃ oven for 4 hours, take it out and wipe it dry, and test the adhesive strength according to the above method (2), which is the immersion adhesive strength.

[0106] (4) Swelling rate test: Take 2±0.1g of non-adhesive layer and hot-pressed adhesive layer respectively, record the mass as M1, soak them in 50g of electrolyte, place them in an 85℃ oven and age for 24 hours, take out the adhesive blocks, wipe off the electrolyte on their surface, weigh them to obtain M2, and calculate the swelling rate according to the formula (M2-M1)×100% / M1.

[0107] (5) Dissolution rate test: Take 1.4±0.1g of non-adhesive layer and hot-pressed adhesive layer respectively, and record the mass as M1. Soak them in 7±0.5g of electrolyte, and record the mass as M2. Then seal them in a vial and place them in an 85℃ oven. After aging for 24 hours, take 20±5mg of the clear liquid. Heat it to 300℃ at a rate of 10℃ / min using a thermogravimetric analyzer (TGA) and read the weight percentage of the residual material, and record it as A. Calculate the dissolution rate according to the formula A×M2 / M1.

[0108] Table 1. Test results of Examples 1-1, 2, and 3

[0109]

[0110] The test results show that the room temperature peel force between the non-adhesive layer and the non-adhesive film in the above samples is greater than that between the hot-pressed adhesive layer and the cover film at room temperature (approximately 5 g / inch). Removing the cover film before using the tape has virtually no impact on the structure of the non-adhesive film and the adhesive layer. Furthermore, after hot pressing, the adhesion between the hot-pressed adhesive layer and the adhered object (e.g., aluminum foil) is much greater than the peel force between the non-adhesive layer and the non-adhesive film. Therefore, the non-adhesive film can be easily peeled off from the surface of the non-adhesive layer with minimal impact on the structure of the adhesive layer. Moreover, due to the non-adhesive nature of the non-adhesive film, it does not stick to the electrode active layer material when peeled off after hot pressing, thus having no negative impact on the battery. In addition, based on the swelling and dissolution tests of the non-adhesive layer and the hot-pressed adhesive layer in the electrolyte, as well as the immersion adhesion test results, it is evident that the tape exhibits minimal swelling and dissolution in the electrolyte and has strong electrolyte resistance. In summary, this utility model, through the design of the structure and adhesive strength of each layer of the double-sided non-adhesive tape, enables the double-sided non-adhesive tape to better meet the construction process and effectively protect the electrode tab solder marks.

[0111] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the present invention. Clearly, those skilled in the art can make various alterations and modifications to the present invention without departing from its spirit and scope. Thus, if such modifications and modifications fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include such modifications and modifications.

Claims

1. A double-sided non-adhesive tape, characterized in that, Includes an adhesive layer and a non-adhesive membrane disposed on an outer side of the adhesive layer (4); The adhesive layer includes a substrate layer (1), and a non-adhesive layer (2) and a hot-press adhesive layer (3) respectively stacked on both sides of the substrate layer (1). The substrate layer (1) is connected to the non-adhesive carrier film (4) through the non-adhesive layer (2). The room temperature peeling force between the non-adhesive layer (2) and the non-adhesive film (4) is less than the hot-press adhesive layer (3) and the adhesive object.

2. The double-sided non-adhesive tape as described in claim 1, characterized in that, A cover film (5) is provided on the other outer side of the adhesive layer, and the substrate layer (1) is connected to the cover film (5) by a hot-press adhesive layer (3).

3. The double-sided non-adhesive tape as described in claim 2, characterized in that, The room temperature peel force of the non-adhesive layer (2) and the non-adhesive film (4) is greater than that of the hot-pressed adhesive layer (3) and the cover film (5).

4. The double-sided non-adhesive tape as described in claim 1, characterized in that, The thickness of the substrate layer (1) is 1-25 μm, and the substrate layer (1) includes at least one of PP film layer, PI film layer, PE film layer, PET film layer and PPS film layer.

5. The double-sided non-adhesive tape as described in claim 1, characterized in that, The thickness of the non-adhesive layer (2) is 0.5-12 μm, and the non-adhesive layer (2) contains a hot melt adhesive layer.

6. The double-sided non-adhesive tape as described in claim 1, characterized in that, The thickness of the hot-pressed adhesive layer (3) is 2-15 μm, and the hot-pressed adhesive layer (3) includes a hot melt adhesive layer.

7. The double-sided non-adhesive tape as described in any one of claims 1-6, characterized in that, The non-adhesive membrane (4) is a single-sided release membrane or a double-sided release membrane with a thickness of 19-100 μm.

8. The double-sided non-adhesive tape as described in claim 2 or 3, characterized in that, The cover film (5) is a release film or an electrostatic film with a thickness of 10-40 μm.

9. The double-sided non-adhesive tape as described in any one of claims 1-6, characterized in that, The adhesive layer includes multiple adhesive units (10), which are spaced apart on the non-adhesive film (4).

10. The double-sided non-adhesive tape as described in claim 9, characterized in that, In the direction perpendicular to the extension of the tape, the length (L) of the adhesive unit (10) is less than the width (W) of the non-adhesive film (4).

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