Hot melt adhesive tape, preparation method and application thereof, and lithium ion battery

Abstract

The invention belongs to the field of batteries, and particularly relates to a hot melt adhesive tape, a preparation method and application thereof and a lithium ion battery. The hot melt adhesive tape comprises a base film and hot melt adhesive layers arranged on the upper side and the lower side of the base film. The hot melt adhesive layer comprises hot melt adhesive strips and air channel gaps formed between the hot melt adhesive strips; and the hot melt adhesive tapes on the upper and lower sides are staggered. The invention provides a hot-melt adhesive tape coated at intervals in a staggered manner, a bubble discharge channel and a physical channel are reserved during hot-pressing lamination of a battery to replace chemical / process improvement, regular air channel gaps are formed through intermittent coating, and bubbles are directionally discharged along the gaps; by adopting the method provided by the invention, an original rubberizing process (a production line is not changed) is kept in a cell factory, and meanwhile, energy density loss caused by increase of the appearance and thickness of the battery due to bubbles of the hot melt adhesive tape can be prevented. The staggered coating reduces the thickness of the adhesive tape by 50%, and increases the energy density of the battery.

Description

Technical Field

[0001] This invention belongs to the field of batteries, specifically relating to a hot melt adhesive tape, its preparation method and application, and lithium-ion batteries. Background Technology

[0002] In the manufacturing process of lithium-ion batteries, hot melt adhesive tape is typically applied to the surface of the electrode assembly to prevent drop failure. This adhesion between the electrode assembly and the battery casing increases the pass rate of tests such as battery rolling and drop tests. However, traditional continuously coated hot melt adhesive tape is prone to trapping air during pressing, resulting in residual air bubbles. This not only reduces the effective adhesion area of ​​the tape, causing a decrease in bond strength and leading to drop failure, but the protruding air bubbles also increase the battery thickness, affecting its appearance. Furthermore, the increased thickness of the hot melt adhesive tape contributes to a loss in battery energy density.

[0003] In existing technologies, for continuous hot melt adhesive tapes that generate air bubbles during battery casing lamination, traditional solutions require adding a pre-pressurization and venting station (equipment modification cost ≥ 200,000 RMB / line); using highly breathable special adhesive tapes (material costs increase by 3-5 times); some use microsphere foaming agents to form venting channels, but this leads to a 30% decrease in adhesion; multi-station segmented lamination solutions reduce production line speed by 40%; and some use multi-layer composite structures (such as PE breathable membrane + adhesive layer), which require specialized lamination equipment and reduce production efficiency by 50%. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hot melt adhesive tape, its preparation method and application, and a lithium-ion battery.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A hot melt adhesive tape includes a base film and hot melt adhesive layers disposed on the upper and lower sides of the base film; the hot melt adhesive layers include hot melt adhesive strips and air passages disposed between the hot melt adhesive strips; the upper and lower hot melt adhesive strips are staggered.

[0007] The airway gap width D is related to the viscosity of the hot melt adhesive strip and the hot pressing pressure during battery manufacturing.

[0008]

[0009] In the formula, k is a constant, 10 -7 The units include the reciprocals of length, time, and temperature to balance the dimensions; d is the minimum airway gap width, in mm; P is the hot-pressing pressure, in Pa; η is the adhesive viscosity, in Pa·s, which is temperature-dependent; T is the temperature, in °C.

[0010] Preferably, the width of the hot melt adhesive strip is equal to the width of the airway gap.

[0011] Preferably, the single-sided thickness of the hot melt adhesive strip is t (in mm); the effective bonding area is A (in mm²). 2 The single-sided thickness and effective adhesive area satisfy the following formula:

[0012]

[0013] In the formula, τi is the interfacial shear strength, and is the adhesion force between the tape and the aluminum-plastic shell and the electrode assembly, with units of Pa (N / m). 2 σ represents the cohesive strength of the adhesive layer, in Pa (N / m). 2 The viscosity depends on the properties of the adhesive itself; η(T) is the viscosity of the adhesive, which is strongly correlated with temperature and is measured in Pa·s; γ is the shear rate, measured in s. -1 F represents the adhesive force, in N.

[0014] Preferably, the single-sided thickness of the hot melt adhesive strip is t, which is 5-50 μm, and more preferably 12 μm; the effective bonding area A ≥ 50% A0, where A0 is the initial full film area of ​​the adhesive strip.

[0015] The substrate is made of at least one of biaxially oriented polypropylene (BOPP), polyester film (PET), polyvinyl chloride (PVC), polyethylene (PE), polytetrafluoroethylene (PTFE), polyimide (PI), EVA foam substrate, or PE foam substrate; preferably, the thickness of the substrate is 5–50 μm; more preferably, it is 7–15 μm.

[0016] The hot melt adhesive strip is made of at least one of the following: rubber-based, acrylic-based, polyurethane (PUR) adhesive-based, polyamide-type hot melt adhesive (PA), hydrogenated petroleum resin adhesive-based, polyolefin-based adhesive-based, and epoxy resin adhesive-based.

[0017] The present invention also includes a method for preparing the hot melt adhesive tape, comprising the following steps:

[0018] 1) First, the substrate is pretreated by corona treatment to achieve a dyne value ≥38 and a temperature resistance requirement of ≥120℃.

[0019] 2) Prepare adhesive for coating hot melt adhesive strips; preferably, the adhesive comprises 50-70% polyacrylate, 10-28% hydrogenated rosin ester, 2-10% terpene phenolic resin, 1-3% silica, 2-5% dioctyl phthalate, 3-8% hydroxyethyl acrylate and 0.1-0.3% crosslinking agent;

[0020] 3) Coating is applied to both sides of the substrate, which are side A and side B respectively; side A is the adhesive side and side B is the non-adhesive side.

[0021] A-side is coated with an intermittent layer of hot melt adhesive, which is applied at intervals with a set air channel gap to obtain multiple hot melt adhesive strips on A-side, while simultaneously forming an uncoated air channel gap area; heating is used to semi-cur the hot melt adhesive strips; preferably, the heating temperature is 80-100℃ and the time is 30s.

[0022] Side B is offset from side A and coated with layers at intervals. Side B is coated in the air passage gap of side A to obtain multiple hot melt adhesive strips on side B. At the same time, the uncoated areas formed between the hot melt adhesive strips on side B correspond to the hot melt adhesive strip areas on side A.

[0023] 4) Post-cur the hot melt adhesive strips on sides A and B.

[0024] The present invention also includes an application of the aforementioned hot melt adhesive tape for bonding battery electrode groups.

[0025] The present invention also includes a lithium-ion battery, comprising an electrode assembly, a battery casing, and the hot melt adhesive tape disposed between the battery casing and the electrode assembly.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] This invention provides a staggered, intermittently coated hot melt adhesive tape that leaves air gaps, i.e., channels for air bubble discharge, during battery hot-press bonding. Physical channels replace chemical / process improvements. The regular air gaps formed by intermittent coating enable air bubbles to be discharged directionally along the air gaps without the need for additional pressure / temperature. This solves the problem in the prior art where, if the energy density of the battery is increased by reducing the thickness, the adhesion of the hot melt adhesive strip must be improved, which makes it impossible to effectively remove air bubbles from the hot melt adhesive tape.

[0028] Using the method described in this application, battery cell manufacturers can maintain their existing adhesive application process with zero changes to the production line. Simultaneously, it prevents energy density loss caused by increased battery appearance and thickness due to hot melt adhesive bubbles. The staggered coating reduces the adhesive tape thickness by 50%, thereby increasing battery energy density. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the intermittent coating method in Embodiment 1 of the present invention;

[0030] Figure 2 This is a schematic diagram of the cross-section of the staggered interval coating in Embodiment 1 of the present invention;

[0031] Figure 3 This is a schematic diagram of the cross-section of the staggered interval coating in Embodiment 3 of the present invention;

[0032] Figure 4 This is a schematic diagram of the cross-section of the staggered interval coating in Embodiment 4 of the present invention;

[0033] Figure 5This is a schematic diagram of the coating process in Comparative Example 1 of this embodiment. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments.

[0035] Example 1: A method for preparing hot melt adhesive tape, comprising the following steps:

[0036] 1) First, the substrate is pretreated by selecting 12um ultra-thin PET, with surface corona treatment (dyne value ≥38), and temperature resistance requirement: ≥120℃;

[0037] 2) Adhesive preparation: 65% polyacrylate, 25% hydrogenated rosin ester (tackifying resin), 2% silica, and 3% dioctyl phthalate (DOP) by mass fraction were added to a reactor and heated to 150-160℃ for melting and mixing (under nitrogen protection). High-speed dispersion (2000 rpm, 30 min) was performed; the mixture was then cooled to 120℃, and 4.8% hydroxyethyl acrylate (HEA) and 0.2% crosslinking agent (dicumyl peroxide) were added. The mixture was stirred and reacted for 2 hours (controlling the degree of crosslinking); the mixture was then filtered through a 200-mesh filter and degassed under vacuum (-0.08 MPa, 30 min).

[0038] 3) Coating: The viscosity of the adhesive obtained in step 1) is around 1 Pa·s, and the hot-pressing pressure is 0.2 MPa. Based on the formula, the preferred coating gap is calculated to be 2 mm (d = 10). -7 *0.2*10 6 *100 / 1), A-side is coated with an intermittent layer of hot melt adhesive. The hot melt adhesive layer on A-side is applied with an intermittent blade coating at 2mm air channel gaps and 2mm adhesive width (hot melt adhesive strip width). The thickness of the adhesive layer (hot melt adhesive strip) is controlled at 12um, forming the first air channel gap area without adhesive. It is then rapidly cured by a cooling roller (5-10℃), and the winding tension is controlled at 7N / cm. Then, the B-side is coated with an offset layer. The hot melt adhesive layer on B-side is applied to the first air channel gap area with an adhesive width (hot melt adhesive strip width) of 2mm and an adhesive layer (hot melt adhesive strip) thickness of 12um. The adhesive layer area on A-side is left uncoated on B-side, forming the second air channel gap area without adhesive. CCD visual positioning (accuracy ±0.1mm) is used to ensure the misalignment of the patterns on A / B sides.

[0039] The adhesive strength is used to determine the airway gap. The effective area and single-layer thickness together confirm that the adhesive strength meets the requirements. The final requirement is an adhesive strength ≥ 12 gf per unit weight (g) of battery. The adhesive strength of the hot melt adhesive tape in the battery is calculated as t · A · F, where t represents the single-sided thickness of the hot melt adhesive tape in μm, and A represents the effective bonding area in mm. 2F represents the viscosity of the hot melt adhesive per unit volume, which is related to the surface tension of the adhesive, hot pressing pressure, temperature, time, contact angle, and surface roughness of the substrate.

[0040] 4) Post-curing: Curing at 50℃ for 24 hours to promote complete cross-linking reaction. Cutting and slitting into rolls of adhesive tape with a total width of 40mm, which are the hot melt adhesive tapes. Figure 1-2 (As shown) includes a base film 003 and hot melt adhesive layers disposed on the upper and lower sides of the base film; the hot melt adhesive layers include hot melt adhesive strips 001 and air passage gaps 002 disposed between the hot melt adhesive strips; the upper and lower hot melt adhesive strips are staggered.

[0041] Example 2: A method for preparing hot melt adhesive tape, comprising the following steps:

[0042] 1) First, the substrate is pretreated by selecting 12um ultra-thin PET, with surface corona treatment (dyne value ≥38), and temperature resistance requirement: ≥120℃;

[0043] 2) Adhesive preparation: 65% polyacrylate, 20% hydrogenated rosin ester (tackifying resin), 5% terpene phenolic resin (replacing part of the rosin ester), 2% silica, and 3% dioctyl phthalate (DOP) by mass fraction were added to a reactor and heated to 150-160℃ for melting and mixing (under nitrogen protection). High-speed dispersion (2000 rpm, 30 min); cooling to 120℃, 4.8% hydroxyethyl acrylate (HEA) and 0.2% crosslinking agent (dicumyl peroxide) were added, and the mixture was stirred for 1-2 hours (controlling the degree of crosslinking); the mixture was then filtered through a 200-mesh filter and degassed under vacuum (-0.08 MPa, 30 min).

[0044] 3) Coating: The viscosity of the adhesive obtained in step 1) is around 1.5 Pa·s, and the hot-pressing pressure is 0.2 MPa. For comparison with Example 1, the A side is coated with an intermittent layer. The hot melt adhesive layer on the A side is applied with an intermittent gap of 2 mm and an adhesive width of 2 mm using a scraper, and the adhesive layer thickness is controlled at 12 μm, forming the first gap area without adhesive. It is then rapidly cured by a cooling roller (5-10℃), and the winding tension is controlled at 7 N / cm. Then, the B side is coated with a staggered layer. The hot melt adhesive layer on the B side is applied to the first gap area with an adhesive width of 2 mm and an adhesive layer thickness of 12 μm. The adhesive layer area on the A side is left uncoated on the B side, forming the second gap area without adhesive. CCD visual positioning (accuracy ±0.1 mm) is used to ensure that the patterns on the A / B sides are misaligned.

[0045] 4) Post-curing: Curing at 50℃ for 24 hours to promote complete cross-linking reaction. Cutting and slitting into rolls of tape with a total width of 40mm.

[0046] Example 3: A method for preparing hot melt adhesive tape, comprising the following steps:

[0047] 1) First, the substrate is pretreated by selecting 12um ultra-thin PET, with surface corona treatment (dyne value ≥38), and temperature resistance requirement: ≥120℃;

[0048] 2) Adhesive preparation: 65% polyacrylate, 15% hydrogenated rosin ester (tackifying resin), 10% terpene phenolic resin (replacing part of the rosin ester), 2% silica, and 3% dioctyl phthalate (DOP) by mass fraction were added to a reactor and heated to 150-160℃ for melting and mixing (under nitrogen protection). High-speed dispersion (2000 rpm, 30 min); cooling to 120℃, 4.8% hydroxyethyl acrylate (HEA) and 0.2% crosslinking agent (dicumyl peroxide) were added, and the mixture was stirred for 1 hour (controlling the degree of crosslinking); the mixture was then filtered through a 200-mesh filter and degassed under vacuum (-0.08 MPa, 30 min).

[0049] 3) Coating: The obtained adhesive viscosity is around 2 Pa·s, and the hot-pressing pressure is 0.2 MPa. Based on the formula, the preferred coating gap is 1 mm. With a 1 mm coating gap, the A-side is coated intermittently. The hot melt adhesive layer on the A-side is applied with an intermittent squeegee application at 1 mm gaps and 1 mm widths, with the adhesive layer thickness controlled at 12 μm, forming the first uncoated gap area. It is then rapidly cured using a cooling roller (5-10℃), with the winding tension controlled at 7 N / cm. Then, the B-side is coated with a staggered pattern. The hot melt adhesive layer on the B-side is applied to the first gap area with a 1 mm width and a thickness of 12 μm. The A-side adhesive area is left uncoated on the B-side, forming the second uncoated gap area. CCD visual positioning (accuracy ±0.1 mm) is used to ensure the A / B side pattern is misaligned.

[0050] 4) Post-curing: Curing at 50℃ for 24 hours to promote complete cross-linking reaction. Cutting and slitting into rolls of tape with a total width of 40mm.

[0051] Example 4

[0052] The difference between Example 4 and Example 1 is that the width C of the hot melt adhesive strip is 2mm, and the air passage gap width D is 1mm. Figure 3 (as shown).

[0053] Example 5

[0054] The difference between Example 5 and Example 1 is that the width C of the hot melt adhesive strip is 2mm, and the air passage gap width D is 3mm. Figure 4 (as shown).

[0055] Comparative Example 1

[0056] The preparation methods for the hot melt adhesive tape and lithium-ion battery are similar to those in Example 1, with the substrate thickness, adhesive coating thickness, and tape width being the same as in Example 1; both sides of the substrate are fully coated, and no air passage gaps are provided. Figure 5 (as shown).

[0057] Comparative Example 2

[0058] The preparation methods of hot melt adhesive tape and lithium-ion battery are similar to those in Example 1, with the substrate thickness and tape width being the same as in Example 1; both sides of the substrate are fully coated without air channel gaps; the difference is that the coating thickness is halved, i.e., the adhesive layer thickness is controlled at 6 μm.

[0059] One hundred lithium-ion batteries each from Examples 1-5 and the comparative example assembled with adhesive tape were subjected to battery thickness, drop tests, and bubble counts, as detailed below:

[0060] 1. Battery thickness test: The thickness of the different hot melt adhesive tape lithium-ion batteries after they were manufactured was tested using a 500gf PPG.

[0061] 2. Hot melt adhesive tape tensile test: The completed lithium-ion battery was discharged at 0.2C to 3.0V, dissected, and the adhesion between the aluminum-plastic shell and the hot melt adhesive tape was tested. The tensile speed was 50mm / min, the test length was 100m, and the average tensile test value was recorded.

[0062] 3. Number of air bubbles: Under the same preparation conditions, observe the surface of the battery with the hot melt adhesive tape attached and calculate the number of batteries with air bubbles.

[0063] 4. Drop Test: The lithium-ion battery was coated with backing adhesive using an extrusion jig (excluding the hot melt adhesive strip side) with an extrusion tool. The battery was then extruded at 3.0 kgf for 5 seconds. The battery was then placed in a drop fixture and subjected to a drop test using an automatic drop device after 24 hours. The drop test conditions were 36 drops from a height of 1.8 m, including drops from the top, bottom, and four corners. After the test, the battery leakage, surface temperature, voltage, and internal resistance were observed, and the battery drop pass rate was recorded.

[0064] Table 1 shows the test results of Examples 1-5 and the comparative examples.

[0065] Table 1

[0066]

[0067] The test results in Example 1 show that, under the existing hot melt adhesive strip formulation, increasing the air channel gap can overcome the bubble problem, but its adhesion (tensile strength in Table 1) may be insufficient. Therefore, it can be adjusted by F = min(τi·A, σ·A, η(T)·A / t·γ). For example, by partially replacing hydrogenated rosin ester with terpene phenolic resin in Example 2, the properties of the material can be changed, thereby improving the adhesion while keeping A and t constant, ensuring sufficient adhesion without the generation of bubbles. The single-sided thickness of the hot melt adhesive strip is t (mm); the effective bonding area is A (mm). 2 τi represents the interfacial shear strength (adhesion between the tape and the aluminum-plastic shell / electrode assembly), in Pa (N / m). 2 σ represents the cohesive strength of the adhesive layer, in Pa (N / m). 2 The viscosity depends on the properties of the adhesive itself; η(T) is the viscosity of the adhesive (strongly correlated with temperature), in Pa·s; γ is the shear rate, in s. -1 F represents the adhesive force, in N.

[0068] Multiple experimental results show that the airway gap width D is related to the viscosity of the hot melt adhesive strip and the hot pressing pressure during battery manufacturing.

[0069]

[0070] In the formula, k is a constant (10 -7 The units include the reciprocals of length, time, and temperature to balance the dimensions; d is the minimum airway gap width (unit: mm); P is the hot-pressing pressure (unit: Pa); η is the adhesive viscosity (unit: Pa·s), which is temperature-dependent; T is the temperature (°C). More preferably, the width of the hot melt adhesive strip is equal to the airway gap width.

[0071] Meanwhile, the test results above reflect that, by comparing Examples 1-3 and Comparative Example 1, it can be seen that the hot melt adhesive tape used in this invention can significantly reduce the battery thickness, thereby increasing the battery energy density. Furthermore, compared to Examples 1 and Comparative Example 1, the bubble ratio can be reduced from 11% to 0%, indicating that the gas channels in the hot melt adhesive tape can significantly reduce the bubble ratio on the battery surface. Examples 2, 1, and Comparative Example 1 demonstrate that the adhesion between the hot melt adhesive tape and the aluminum-plastic shell can be controlled by the viscosity of the adhesive system, without affecting the battery's drop performance. The reduction in the effective area of ​​the hot melt adhesive tape used in this invention can be completely compensated for by using high-viscosity hot melt adhesive to improve adhesion. Example 3 shows that under optimal air channel size conditions, the adhesive strength of the tape can be doubled. In Example 4, due to the air channel size causing some overlap between the A and B sides of the tape, a 1mm air channel still exists, and the bubble ratio is reduced from 11% to 2%, indicating that a smaller gap size also reduces the bubble size on the battery surface, but does not improve the battery thickness. In Example 5, the gap is larger, the effective area is reduced, and there is a pure base film area, resulting in poor battery manufacturing process and battery drop performance. By comparing Comparative Examples 1 and 2 with Example 1, it is found that simply reducing the adhesive layer thickness results in a worse hot melt adhesive tape adhesion, no improvement in the bubble ratio, and a worse drop performance. Therefore, the above examples and comparative examples prove that the separator described in this invention can not only reduce the bubble ratio on the battery surface from 11% to 0%, but also achieve the purpose of thinning the battery thickness through staggered coating.

[0072] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hot melt adhesive tape, characterized in that, It includes a base film and hot melt adhesive layers disposed on the upper and lower sides of the base film; the hot melt adhesive layers include hot melt adhesive strips and air passage gaps disposed between the hot melt adhesive strips; the upper and lower hot melt adhesive strips are staggered.

2. The hot melt adhesive tape according to claim 1, characterized in that, The airway gap width D is related to the viscosity of the hot melt adhesive strip and the hot pressing pressure during battery manufacturing. In the formula, k is a constant, 10 -7 The units include the reciprocals of length, time, and temperature to balance the dimensions; d is the minimum airway gap width, in mm; P is the thermo-pressure, in Pa. η is the viscosity of the adhesive solution, in Pa·s, which is temperature-dependent; T is the temperature, in °C.

3. The hot melt adhesive tape according to claim 2, characterized in that, The width of the hot melt adhesive strip is equal to the width of the airway gap.

4. The hot melt adhesive tape according to claim 1, characterized in that, The single-sided thickness of the hot melt adhesive strip is t (in mm); the effective bonding area is A (in mm²). 2 The relationship between single-sided thickness, effective bonding area, and adhesive force must satisfy the following formula: In the formula, τ i The interfacial shear strength is the adhesion between the tape and the aluminum-plastic shell and the electrode assembly, measured in Pa (N / m). 2 σ represents the cohesive strength of the adhesive layer, in Pa (N / m). 2 The viscosity depends on the properties of the adhesive itself; η(T) is the viscosity of the adhesive, which is strongly correlated with temperature and is measured in Pa·s; γ is the shear rate, measured in s. -1 F represents the adhesive force, in N.

5. The hot melt adhesive tape according to claim 1, characterized in that, The single-sided thickness of the hot melt adhesive strip is t, which is 5-50 μm; the effective bonding area A is ≥ 50% A0, where A0 is the initial full film area of ​​the hot melt adhesive strip.

6. The hot melt adhesive tape according to claim 1, characterized in that, The substrate is made of at least one of the following materials: biaxially oriented polypropylene (BOPP), polyester film (PET), polyvinyl chloride (PVC), polyethylene (PE), polytetrafluoroethylene (PTFE), polyimide (PI), EVA foam substrate, or PE foam substrate; the thickness of the substrate is 5–50 μm.

7. The hot melt adhesive tape according to claim 1, characterized in that, The hot melt adhesive strip is made of at least one of the following materials: rubber, acrylic, polyurethane (PUR), polyamide (PA), hydrogenated petroleum resin, polyolefin, and epoxy resin.

8. A method for preparing the hot melt adhesive tape according to any one of claims 1-7, characterized in that, Includes the following steps: 1) First, the substrate is pretreated by corona treatment to achieve a dyne value ≥38 and a temperature resistance requirement of ≥120℃. 2) Prepare an adhesive for coating hot melt adhesive strips; the adhesive comprises 50-70% polyacrylate, 10-28% hydrogenated rosin ester, 2-10% terpene phenolic resin, 1-3% silica, 2-5% dioctyl phthalate, 3-8% hydroxyethyl acrylate and 0.1-0.3% crosslinking agent; 3) Coating is applied to both sides of the substrate, which are side A and side B, respectively; The hot melt adhesive layer on surface A is applied at intervals with a set air channel gap to obtain multiple hot melt adhesive strips on surface A, while forming an uncoated air channel gap area. The hot melt adhesive strips are then heated to semi-cured; the heating temperature is 80-100℃ and the time is 30s. Side B is offset from side A and coated with layers at intervals. Side B is coated in the air passage gap of side A to obtain multiple hot melt adhesive strips on side B. At the same time, the uncoated areas formed between the hot melt adhesive strips on side B correspond to the hot melt adhesive strip areas on side A. 4) Post-cur the hot melt adhesive strips on sides A and B.

9. The application of the hot melt adhesive tape according to any one of claims 1-7, characterized in that, Used for bonding battery electrode packs.

10. A lithium-ion battery, comprising an electrode assembly, a battery casing, and a hot melt adhesive tape as described in any one of claims 1-7 disposed between the battery casing and the electrode assembly.

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