A protective adhesive tape for a power battery shell and a preparation method thereof

Abstract

The application belongs to the technical field of adhesive tapes, and particularly relates to a protective adhesive tape for power battery shell and a preparation method thereof. The protective adhesive tape for power battery shell comprises a release layer, a substrate layer and an adhesive layer arranged in sequence, and the substrate layer comprises the following raw materials in parts by weight: PET resin 30-40 parts, modified halloysite nanotube 3-5 parts, heat stabilizer 1-4 parts, coupling agent 0.5-1 part, antioxidant 0.3-0.5 part and pigment 0.5-1 part. The modified halloysite nanotube contained in the adhesive tape can improve the overall mechanical properties of the adhesive tape, and the heat stabilizer can improve the thermal stability of the adhesive tape.

Description

Technical Field

[0001] This invention belongs to the field of adhesive tape technology, specifically relating to a protective adhesive tape for power battery casing and its preparation method. Background Technology

[0002] With the development of technology and the increasing awareness of environmental protection, new energy vehicles are gradually playing an important role in people's lives. The power battery, which provides the power source, is the core component of new energy vehicles, and its safety plays a crucial role in the overall safety of these vehicles. During the manufacturing process of power batteries, adhesive tape is typically used to wrap the battery casing to secure the internal components.

[0003] Furthermore, adhesive tape can separate battery cells to prevent the failure of a single cell from affecting other cells. Therefore, adhesive tape plays a crucial role in the manufacturing process of power batteries. With the rapid development of the new energy vehicle industry, the demand for power batteries has increased significantly, leading to a greater market demand for protective tapes used in battery casings. However, this also places higher demands on the performance of these protective tapes. Currently available tapes often suffer from poor thermal stability and mechanical properties, potentially causing safety issues such as battery short circuits and even spontaneous combustion. Therefore, it is necessary to further explore and improve the performance of protective tapes used in power battery casings. Summary of the Invention

[0004] The primary objective of this invention is to provide a protective tape for the casing of a power battery, which has excellent mechanical properties and thermal stability.

[0005] The second objective of this invention is to provide a method for preparing a protective tape for a power battery casing, which is simple and easy to implement.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A protective tape for a power battery casing, the protective tape comprising a release layer, a substrate layer and an adhesive layer arranged sequentially, wherein the substrate layer comprises the following raw materials in parts by weight: 30-40 parts PET resin, 3-5 parts modified halloysite nanotubes, 1-4 parts heat stabilizer, 0.5-1 part coupling agent, 0.3-0.5 parts antioxidant, and 0.5-1 part pigment;

[0008] The preparation process of the modified halloysite nanotubes is as follows:

[0009] (1) Halloysite nanotubes were added to Tris-dopamine hydrochloride solution and stirred to react. After the reaction was completed, the pretreated halloysite nanotubes were obtained by purification.

[0010] (2) Disperse sodium alginate in anhydrous ethanol, then add sodium periodate to react. After the reaction is completed, purify and dry to obtain oxidized sodium alginate.

[0011] (3) Add the pretreated halloysite nanotubes from step (1) to water, then add sodium oxidized alginate to react. After the reaction is completed, the modified halloysite nanotubes are obtained by purification.

[0012] Further, in step (1), the solid-liquid ratio of halloysite nanotubes and Tris-dopamine hydrochloride solution is (0.1-0.2) mg: 1 mL; the concentration of dopamine hydrochloride in the Tris-dopamine hydrochloride solution is 2-3 mg / mL; the temperature of the stirring reaction is 40-60℃, and the stirring reaction time is 24-36 h.

[0013] Further, in step (2), the mass ratio of sodium alginate to sodium periodate is 1:(2-4); the molecular weight of sodium alginate is 10-20KD; and the reaction is specifically carried out at room temperature in the dark for 8-12 hours.

[0014] Further, in step (3), the mass ratio of oxidized sodium alginate to pretreated halloysite nanotubes is 1:(0.1-0.5); the reaction time is 10-12h.

[0015] Furthermore, the preparation process of the heat stabilizer is as follows:

[0016] The graphene is obtained by adding hydroxylated graphene to an aqueous solution of polyacrylic acid and heating it.

[0017] Furthermore, the molar ratio of the hydroxylated graphene to polyacrylic acid is 1:(2-5); the heating reaction temperature is 60-70℃, and the heating reaction time is 6-8h.

[0018] Furthermore, the coupling agent is a silane coupling agent, the antioxidant is a hindered phenolic antioxidant, and the pigment is cobalt blue pigment.

[0019] Furthermore, the silane coupling agent is trimethoxy(propyl)silane, and the hindered phenolic antioxidant is 3,5-di-tert-butyl-4-hydroxybenzoic acid.

[0020] Further, the thickness of the release layer is 0.5-1.5 μm, the thickness of the substrate layer is 20-40 μm, and the thickness of the adhesive layer is 15-35 μm. A method for preparing the above-mentioned protective tape for a power battery casing includes the following steps:

[0021] i. According to the stated weight ratio, the raw materials of the substrate layer are mixed evenly, and then calendered after melt extrusion to obtain the substrate layer;

[0022] ii. A non-silicone release agent solution is coated on one side of the substrate layer in step i, and then cured in an oven to obtain a release layer;

[0023] iii. Apply polyacrylate adhesive to the other side of the substrate layer in step i, cure it in an oven to obtain an adhesive layer, and then cut and roll it up after cooling.

[0024] Furthermore, in step ii, the curing temperature is 70-80℃ and the curing time is 10-15 min; in step iii, the curing temperature is 80-90℃ and the curing time is 45-50 min.

[0025] The beneficial technical effects of this invention are as follows:

[0026] This invention obtains polydopamine-coated halloysite nanotubes, or pretreated halloysite nanotubes, through dopamine self-polymerization. The surface of the pretreated halloysite nanotubes contains abundant amino functional groups, which can react with the aldehyde functional groups in sodium alginate oxide, thereby improving the overall mechanical properties of the tape. Heat stabilizers can improve the compatibility of graphene in the substrate, thus improving the thermal stability of the substrate. Furthermore, the combined use of modified halloysite nanotubes and heat stabilizers can further enhance the thermal stability of the substrate. Detailed Implementation

[0027] The following is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0028] The preparation process of hydroxylated graphene in this invention is as follows:

[0029] Take 1 L of 1.5 g / L graphene oxide aqueous solution, sonicate for 30 min, add ammonia and adjust the pH of the solution to 7.5 to obtain a mixed solution; add 2.0 g of hydrazine hydrate to the mixed solution, transfer to a 90℃ oil bath, reflux for 32 h, then adjust the oil bath temperature to 80℃, add 2.0 g of aminophenylethanol and 2.5 g of isoamyl nitrite to the mixed solution, reflux for 36 h, filter to neutral, and then freeze-dry for 5 days to obtain hydroxylated graphene.

[0030] The non-silicone release agent solution involved in this invention is PEELOIL 1010.

[0031] 1. Example

[0032] Example 1

[0033] A protective tape for a power battery casing, the protective tape comprising a release layer, a substrate layer and an adhesive layer arranged sequentially, wherein the substrate layer comprises the following raw materials in parts by weight: 33 parts PET resin, 4 parts modified halloysite nanotubes, 2 parts heat stabilizer, 0.7 parts trimethoxy(propyl)silane, 0.4 parts 3,5-di-tert-butyl-4-hydroxybenzoic acid, and 0.8 parts cobalt blue pigment.

[0034] The preparation process of the modified halloysite nanotubes is as follows:

[0035] (1) According to the solid-liquid ratio of halloysite nanotubes to Tris-dopamine hydrochloride solution of 0.15 mg: 1 mL, halloysite nanotubes were added to Tris-dopamine hydrochloride solution. The concentration of dopamine hydrochloride in Tris-dopamine hydrochloride solution was 2.4 mg / mL. The mixture was stirred at 50 °C for 30 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain pretreated halloysite nanotubes.

[0036] (2) Sodium alginate (molecular weight 12KD) was dispersed in anhydrous ethanol at a mass ratio of 1:3 to sodium periodate, and then sodium periodate was added. The reaction was carried out at room temperature in the dark for 10 hours. After the reaction was completed, the sodium alginate was purified and dried to obtain oxidized sodium alginate.

[0037] (3) According to the mass ratio of sodium oxidized alginate to pretreated halloysite nanotubes of 1:0.4, the pretreated halloysite nanotubes from step (1) were added to water, and then sodium oxidized alginate was added and reacted for 11 hours. After the reaction was completed, the modified halloysite nanotubes were obtained by purification.

[0038] The preparation process of the above heat stabilizer is as follows:

[0039] The hydroxylated graphene and polyacrylic acid were added to an aqueous solution of polyacrylic acid at a molar ratio of 1:3, and reacted at 65°C for 7 hours to obtain the final product.

[0040] The specific method for preparing the protective tape for the aforementioned power battery casing is as follows:

[0041] i. According to the weight ratio, the raw materials of the substrate layer are mixed evenly and placed in a twin-screw extruder. The screw speed is set to 120 rpm and the die temperature is set to 160°C. After melt extrusion and calendering, a substrate layer with a thickness of 30 μm is obtained.

[0042] ii. Apply a non-silicone release agent solution to one side of the substrate layer in step i, and cure it in an oven at 75°C for 12 minutes to obtain a release layer with a thickness of 1 μm;

[0043] iii. Apply polyacrylate adhesive to the other side of the substrate layer in step i, and cure it in an oven at 85°C for 48 minutes to obtain an adhesive layer with a thickness of 20 μm. After cooling, cut and roll it up.

[0044] Example 2

[0045] A protective tape for a power battery casing, the protective tape comprising a release layer, a substrate layer and an adhesive layer arranged sequentially, wherein the substrate layer comprises the following raw materials in parts by weight: 40 parts PET resin, 5 parts modified halloysite nanotubes, 4 parts heat stabilizer, 1 part trimethoxy(propyl)silane, 0.5 parts 3,5-di-tert-butyl-4-hydroxybenzoic acid, and 1 part cobalt blue pigment.

[0046] The preparation process of the modified halloysite nanotubes is as follows:

[0047] (1) According to the solid-liquid ratio of halloysite nanotubes and Tris-dopamine hydrochloride solution of 0.2 mg: 1 mL, halloysite nanotubes were added to Tris-dopamine hydrochloride solution. The concentration of dopamine hydrochloride in Tris-dopamine hydrochloride solution was 3 mg / mL. The reaction was stirred at 60 °C for 24 h. After the reaction was completed, the pretreated halloysite nanotubes were obtained by filtration, washing and drying.

[0048] (2) Sodium alginate (molecular weight 20KD) was dispersed in anhydrous ethanol at a mass ratio of 1:4 to sodium periodate, and then sodium periodate was added. The reaction was carried out at room temperature in the dark for 12 hours. After the reaction was completed, the sodium alginate was purified and dried to obtain oxidized sodium alginate.

[0049] (3) According to the mass ratio of sodium oxidized alginate to pretreated halloysite nanotubes of 1:0.5, the pretreated halloysite nanotubes from step (1) were added to water, and sodium oxidized alginate was added to react for 12 hours. After the reaction was completed, the modified halloysite nanotubes were obtained by purification.

[0050] The preparation process of the above heat stabilizer is as follows:

[0051] The hydroxylated graphene and polyacrylic acid were added to an aqueous solution of polyacrylic acid at a molar ratio of 1:5, and reacted at 70°C for 6 hours to obtain the final product.

[0052] The specific method for preparing the protective tape for the aforementioned power battery casing is as follows:

[0053] i. According to the weight ratio, the raw materials of the substrate layer are mixed evenly and placed in a twin-screw extruder. The screw speed is set to 120 rpm and the die head temperature is set to 160°C. After melt extrusion and calendering, a substrate layer with a thickness of 20 μm is obtained.

[0054] ii. Apply a non-silicone release agent solution to one side of the substrate layer from step i, and cure it in an oven at 80°C for 10 minutes to obtain a release layer with a thickness of 0.5 μm;

[0055] iii. Apply polyacrylate adhesive to the other side of the substrate layer in step i, and cure it in a 90°C oven for 45 minutes to obtain an adhesive layer with a thickness of 15 μm. After cooling, cut and roll it up.

[0056] Example 3

[0057] A protective tape for a power battery casing, the protective tape comprising a release layer, a substrate layer and an adhesive layer arranged sequentially, wherein the substrate layer comprises the following raw materials in parts by weight: 30 parts PET resin, 3 parts modified halloysite nanotubes, 1 part heat stabilizer, 0.5 parts trimethoxy(propyl)silane, 0.3 parts 3,5-di-tert-butyl-4-hydroxybenzoic acid, and 0.5 parts cobalt blue pigment.

[0058] The preparation process of the modified halloysite nanotubes is as follows:

[0059] (1) According to the solid-liquid ratio of halloysite nanotubes and Tris-dopamine hydrochloride solution of 0.1 mg: 1 mL, halloysite nanotubes were added to Tris-dopamine hydrochloride solution. The concentration of dopamine hydrochloride in Tris-dopamine hydrochloride solution was 2 mg / mL. The reaction was stirred at 40 °C for 36 h. After the reaction was completed, the pretreated halloysite nanotubes were obtained by filtration, washing and drying.

[0060] (2) Sodium alginate (molecular weight of 10KD) was dispersed in anhydrous ethanol at a mass ratio of 1:2 to sodium periodate, and then sodium periodate was added. The reaction was carried out at room temperature in the dark for 8 hours. After the reaction was completed, the sodium alginate was purified and dried to obtain oxidized sodium alginate.

[0061] (3) According to the mass ratio of sodium oxidized alginate to pretreated halloysite nanotubes of 1:0.1, the pretreated halloysite nanotubes from step (1) were added to water, and sodium oxidized alginate was added to react for 10 hours. After the reaction was completed, the modified halloysite nanotubes were obtained by purification.

[0062] The preparation process of the above heat stabilizer is as follows:

[0063] The hydroxylated graphene and polyacrylic acid were added to an aqueous solution of polyacrylic acid at a molar ratio of 1:2, and reacted at 60°C for 8 hours to obtain the final product.

[0064] The specific method for preparing the protective tape for the aforementioned power battery casing is as follows:

[0065] i. According to the weight ratio, the raw materials of the substrate layer are mixed evenly and placed in a twin-screw extruder. The screw speed is set to 120 rpm and the die temperature is set to 160°C. After melt extrusion and calendering, a substrate layer with a thickness of 40 μm is obtained.

[0066] ii. Apply a non-silicone release agent solution to one side of the substrate layer from step i, and cure it in a 70°C oven for 15 minutes to obtain a release layer with a thickness of 1.5 μm;

[0067] iii. Apply polyacrylate adhesive to the other side of the substrate layer in step i, and cure it in an oven at 80°C for 50 minutes to obtain an adhesive layer with a thickness of 35μm. After cooling, cut and roll it up.

[0068] 2. Comparative Example

[0069] Comparative Example 1

[0070] The difference between Comparative Example 1 and Example 1 is that halloysite nanotubes were used instead of modified halloysite nanotubes.

[0071] Comparative Example 2

[0072] The difference between Comparative Example 2 and Example 1 is that polydopamine and halloysite nanotubes were used instead of modified halloysite nanotubes, and the mass ratio of halloysite nanotubes to polydopamine was 0.15:2.4. The other preparation conditions were the same as in Example 1.

[0073] Comparative Example 3

[0074] The difference between Comparative Example 3 and Example 1 is that the preparation process of the modified halloysite nanotubes was changed. Specifically:

[0075] Steps (2)-(3) are omitted, i.e., pretreated halloysite nanotubes are used instead of modified halloysite nanotubes, and the remaining preparation conditions are the same as in Example 1.

[0076] Comparative Example 4

[0077] The difference between Comparative Example 4 and Example 1 is that graphene is used instead of a heat stabilizer.

[0078] 3. Test Case

[0079] Tensile strength and elongation at break: The tensile strength and elongation at break of the tapes prepared in Examples 1-3 and Comparative Examples 1-4 were tested using a universal tensile testing machine. The test temperature was room temperature, the effective test length for each sample was 100 mm, and the test speed was 10 m / min. The results are shown in Table 1.

[0080] Heat resistance: The tapes prepared in Examples 1-3 and Comparative Examples 1-4 were pasted onto a clean stainless steel plate and baked in a constant temperature oven at 150°C for 4 hours. While still hot, the tapes were peeled off in the oven, and the stainless steel plate was observed for any residual adhesive residue. The heat resistance of each tape was evaluated, and the results are shown in Table 1.

[0081] Table 1

[0082] Tape / property Tensile strength (MPa) Elongation at break (%) Adhesive residue Example 1 196.2 116.8 No adhesive residue Example 2 195.0 116.1 No adhesive residue Example 3 193.8 115.6 No adhesive residue Comparative Example 1 163.3 92.4 Slight adhesive residue Comparative Example 2 169.6 100.2 Slight adhesive residue Comparative Example 3 178.1 103.7 Slight adhesive residue Comparative Example 4 191.7 114.3 Severe adhesive residue

[0083] As shown in Table 1, the tapes prepared in Examples 1-3 have excellent mechanical properties and high thermal stability.

[0084] Compared to Examples 1-3, Comparative Example 1 used halloysite nanotubes instead of modified halloysite nanotubes, and Comparative Examples 2-3 adjusted the preparation process of modified halloysite nanotubes, all of which resulted in a significant decrease in the mechanical properties of the obtained tapes. Analysis shows that this invention obtains polydopamine-coated halloysite nanotubes, i.e., pretreated halloysite nanotubes, through the self-polymerization of dopamine. The surface of the pretreated halloysite nanotubes contains abundant amino functional groups, which can react with the aldehyde functional groups in oxidized sodium alginate to form covalent bonds. This chemical bonding significantly enhances the interfacial bonding force between the halloysite nanotubes and the matrix material. Stronger interfacial bonding indicates that the halloysite nanotubes are less likely to detach from the matrix when the tape is subjected to external forces, thereby improving the overall mechanical properties of the tape.

[0085] Compared to Examples 1-3, the thermal stability of the tapes in Comparative Examples 1-3 was reduced, and the thermal stability of the tape in Comparative Example 4, which used graphene instead of a heat stabilizer, was significantly reduced. These results indicate that the heat stabilizer of the present invention can improve the compatibility of graphene in the substrate, thereby improving the thermal stability of the substrate. Furthermore, the combined use of modified halloysite nanotubes and the heat stabilizer can further enhance the thermal stability of the substrate.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A protective tape for a power battery casing, characterized in that, The protective tape comprises a release layer, a substrate layer, and an adhesive layer arranged sequentially. The substrate layer comprises the following raw materials in parts by weight: 30-40 parts PET resin, 3-5 parts modified halloysite nanotubes, 1-4 parts heat stabilizer, 0.5-1 part coupling agent, 0.3-0.5 parts antioxidant, and 0.5-1 part pigment. The adhesive layer is made of polyacrylate. The preparation process of the modified halloysite nanotubes is as follows: (1) Halloysite nanotubes were added to Tris-dopamine hydrochloride solution and stirred to react. After the reaction was completed, the pretreated halloysite nanotubes were obtained by purification. (2) Disperse sodium alginate in anhydrous ethanol, then add sodium periodate to react. After the reaction is completed, purify and dry to obtain oxidized sodium alginate. (3) Add the pretreated halloysite nanotubes from step (1) to water, then add sodium oxidized alginate to react. After the reaction is completed, the modified halloysite nanotubes are obtained by purification. The preparation process of the heat stabilizer is as follows: The graphene is obtained by adding hydroxylated graphene to an aqueous solution of polyacrylic acid and heating it.

2. The protective tape for the power battery casing according to claim 1, characterized in that, In step (1), the solid-liquid ratio of halloysite nanotubes and Tris-dopamine hydrochloride solution is (0.1-0.2) mg:1 mL; the concentration of dopamine hydrochloride in the Tris-dopamine hydrochloride solution is 2-3 mg / mL; the temperature of the stirring reaction is 40-60℃, and the stirring reaction time is 24-36 h.

3. The protective tape for the power battery casing according to claim 1, characterized in that, The mass ratio of sodium alginate to sodium periodate in step (2) is 1:(2-4); the molecular weight of sodium alginate is 10-20 kDa; the reaction is specifically carried out at room temperature in the dark for 8-12 hours.

4. The protective tape for the power battery casing according to claim 1, characterized in that, In step (3), the mass ratio of oxidized sodium alginate to pretreated halloysite nanotubes is 1:(0.1-0.5); the reaction time is 10-12 h.

5. The protective tape for the power battery casing according to claim 1, characterized in that, The molar ratio of the hydroxylated graphene to polyacrylic acid is 1:(2-5); the heating reaction temperature is 60-70℃, and the heating reaction time is 6-8h.

6. The protective tape for the power battery casing according to claim 1, characterized in that, The coupling agent is a silane coupling agent, the antioxidant is a hindered phenolic antioxidant, and the pigment is cobalt blue pigment.

7. The protective tape for the power battery casing according to claim 1, characterized in that, The thickness of the release layer is 0.5-1.5μm, the thickness of the substrate layer is 20-40μm, and the thickness of the adhesive layer is 15-35μm.

8. A method for preparing a protective tape for a power battery casing as described in claim 1, characterized in that, Includes the following steps: According to the stated weight ratio, the raw materials of the substrate layer are mixed evenly, and then melt-extruded and calendered to obtain the substrate layer; In the steps A non-silicone release agent solution is coated on one side of the substrate layer, and after curing in an oven, a release layer is obtained. In the steps Polyacrylate adhesive is applied to the other side of the substrate layer, cured in an oven to obtain the adhesive layer, and then cut and rolled up after cooling.

9. The method according to claim 8, characterized in that, step The curing temperature is 70-80℃, and the curing time is 10-15 minutes; Steps The curing temperature is 80-90℃, and the curing time is 45-50 minutes.

Images