Battery box sealing coating and preparation method thereof

Abstract

The invention relates to the field of sealing coating preparation, in particular to a battery box sealing coating and a preparation method thereof, and the battery box sealing coating comprises an acetone bonding layer and an epoxy resin layer. The epoxy resin layer comprises the following components in parts by weight: 100-120 parts of epoxy resin, 8-12 parts of benzyl alcohol, 30-35 parts of silica powder, 12-18 parts of a toughening agent, 1-3 parts of a silane coupling agent, 0.3-2 parts of water and 33-38 parts of an aromatic amine curing agent. The toughening agent and the silane coupling agent are added during preparation of the epoxy resin layer, so that the toughness of the coating is improved, stress is absorbed to prevent crack propagation, the compatibility of the epoxy resin and the battery box is improved, interface defects are reduced, and the interface peel strength of the battery box sealing coating is synergistically improved in two directions; therefore, the battery box sealing coating with excellent interface peel strength is prepared.

Description

Technical Field

[0001] This application relates to the field of sealing coating preparation, and in particular to a battery box sealing coating and a method for preparing the same. Background Technology

[0002] Currently, battery packaging technology primarily uses flame-retardant polymers such as PC / ABS for the casing, but their surface properties result in poor adhesion to conventional sealing materials (such as epoxy resin). The industry commonly faces issues like easy peeling of the encapsulation layer and insufficient airtightness, directly impacting the battery's explosion-proof performance and lifespan. With the increasing use of underwater robots, the demand for higher battery box density has made packaging reliability a key factor restricting battery safety. While attempts have been made in recent years to modify resins or add mechanical clips, these methods suffer from either complex processes or excessively high costs.

[0003] Currently, many people use acetone to pretreat the surface of PC / ABS housings to form an acetone adhesive layer, and then coat the acetone adhesive layer with epoxy resin, which can effectively improve the interfacial peel strength of the sealing coating. However, the interfacial peel strength of the above materials still has considerable room for improvement to meet current application requirements. Summary of the Invention

[0004] To improve the interfacial peel strength of the battery box sealing coating, this application provides a battery box sealing coating and its preparation method.

[0005] Firstly, this application provides a battery box sealing coating, which adopts the following technical solution: A battery box sealing coating includes an acetone adhesive layer and an epoxy resin layer, wherein the epoxy resin layer comprises the following components in parts by weight: 100-120 parts epoxy resin, 8-12 parts benzyl alcohol, 30-35 parts silica powder, 12-18 parts toughening agent, 1-3 parts silane coupling agent, 0.3-2 parts water, and 33-38 parts aromatic amine curing agent.

[0006] By employing the above technical solution, the presence of the acetone adhesive layer facilitates the wetting and penetration of the subsequent epoxy resin layer, and helps with the physical anchoring of the epoxy resin layer to the battery box. Furthermore, by adding a toughening agent during the preparation of the epoxy resin layer, stress absorption is aided, preventing cracks from easily propagating along the interface or within the coating. The addition of a silane coupling agent acts as a "molecular bridge," with one end hydrolyzing into silanol, forming a strong -Si-OM covalent bond with the hydroxyl groups on the acetone-treated surface of the battery box, while the other end chemically reacts with the epoxy resin matrix, effectively reducing interfacial defects. This results in a battery box sealing coating with excellent interfacial peel strength.

[0007] This application improves the coating toughness by adding toughening agents and silane coupling agents during the preparation of the epoxy resin layer, thereby absorbing stress to prevent crack propagation and improving the compatibility between the epoxy resin and the battery box, and reducing interface defects. This synergistically improves the interfacial peel strength of the battery box sealing coating, thus preparing a battery box sealing coating with excellent interfacial peel strength.

[0008] Preferably, the toughening agent is at least one of terminal isocyanate-based liquid rubber, nitrile rubber, and EMA-grafted glycidyl methacrylate.

[0009] Preferably, the toughening agent is a terminal isocyanate-based liquid rubber.

[0010] By employing the above technical solution, nitrile rubber is dispersed in an epoxy resin matrix as micron-sized elastomer particles, forming an "island structure." When the coating is subjected to external force, the resin surrounding the particles undergoes localized plastic deformation, absorbing mechanical energy. Furthermore, the nitrile groups in the nitrile rubber molecular chain enhance interfacial adhesion with the epoxy resin through hydrogen bonds or dipole interactions. Simultaneously, the rubber particles, acting as physical crosslinking points, prevent crazes from propagating into macroscopic cracks.

[0011] The epoxy groups in EMA grafted with glycidyl methacrylate can react with amine curing agents to form a covalent network, strengthening interfacial bonding and reducing interfacial delamination caused by stress concentration. Simultaneously, the ethylene-methyl acrylate backbone of EMA provides a flexible phase, absorbing impact energy through elastic deformation and inhibiting crack propagation.

[0012] The isocyanate-terminated liquid rubber can react with the hydroxyl groups in the acetone adhesive layer or the amine groups in the hardener to form chemical bonds, effectively improving interlayer adhesion. When blended with epoxy resin, the isocyanate-terminated liquid rubber forms an "island structure" or interpenetrating network during curing through the reaction of isocyanate groups with epoxy or hydroxyl groups. This physical entanglement increases interlayer mechanical interlocking, thereby enhancing the interfacial peel strength of the sealing coating. Simultaneously, the flexible segments of the rubber phase in the isocyanate-terminated liquid rubber are dispersed within the rigid epoxy resin matrix, absorbing impact energy and preventing crack propagation, effectively improving the impact resistance of the sealing coating. Furthermore, the cured product of the isocyanate-terminated liquid rubber contains urethane hard segments, which effectively improve the chemical corrosion resistance of the sealing coating, making it suitable for applications in underwater robot battery boxes.

[0013] Preferably, the amount of the terminal isocyanate-based liquid rubber added is 12-15 parts.

[0014] By adopting the above technical solution, when the amount of terminal isocyanate-based liquid rubber added is too small, the rubber phase provided by the terminal isocyanate-based liquid rubber is insufficient, lacking a flexible buffer layer, and stress cannot be effectively dispersed, thus weakening the interfacial bonding of the coating. When the amount of terminal isocyanate-based liquid rubber added is too large, the excessive terminal isocyanate-based liquid rubber will dilute the rigid skeleton of the epoxy resin. At the same time, the excessive terminal isocyanate-based liquid rubber will form a continuous phase or a large-size "island structure," further weakening the interfacial bonding.

[0015] Preferably, a processing aid is also added, wherein the processing aid is at least one of glass fiber and graphene oxide.

[0016] Preferably, the processing aid is a mixture of glass fiber and graphene oxide.

[0017] By adopting the above technical solution, the surface of the glass fiber has a micro-rough structure. After being embedded in the epoxy resin matrix, it forms physical anchor points, realizes mechanical interlocking, and prevents the propagation of cracks. Furthermore, the glass fiber is randomly or directionally distributed in the epoxy resin to form a three-dimensional network structure. Through the "skeleton support" effect, it restricts the separation of the interface. Moreover, the polar hydroxyl groups on the surface of the glass fiber are combined with the polar groups in the epoxy resin through hydrogen bonds or van der Waals forces, thereby improving the interfacial peel strength of the sealing coating.

[0018] The two-dimensional sheet structure of graphene oxide can be embedded in the interface region between the sealing coating and the battery box. Furthermore, the surface of graphene oxide is rich in active groups such as hydroxyl, epoxy, and carboxyl groups, which can form strong chemical bonds with the polar groups on the epoxy resin matrix or the surface of the battery box, increasing the interfacial bonding of the sealing coating. In addition, graphene oxide can act as a "molecular bridge," with one end bonded to the siloxane bond of the silane coupling agent and the other end crosslinked with the epoxy resin to form a denser interfacial network.

[0019] The surface of graphene oxide contains abundant oxygen-containing groups (such as hydroxyl and carboxyl groups), which can chemically bond with the hydroxyl groups on the surface of glass fiber and the epoxy groups in epoxy resin, thereby enhancing the interfacial bonding force between glass fiber and epoxy resin, making the compatibility between the three better, and thus improving the interfacial peel strength of the sealing coating.

[0020] Meanwhile, the terminal isocyanate groups of the liquid rubber react with the hydroxyl and carboxyl groups on the surface of graphene oxide to form polyurethane bonds, and react with the epoxy groups or aromatic amine curing agents of epoxy resin to form a covalent network of "graphene oxide-terminated isocyanate liquid rubber-epoxy resin". Furthermore, the terminal isocyanate groups in the liquid rubber can also react with the hydroxyl groups on the surface of glass fiber or the active groups in epoxy resin to form chemical bonds, which enhances the interfacial adhesion between glass fiber and epoxy resin matrix, effectively reduces stress concentration, allows glass fiber to be uniformly dispersed, delays crack propagation, and further improves the interfacial peel strength of the sealing coating.

[0021] Preferably, the mixing ratio of glass fiber and graphene oxide is 9-19:1.

[0022] By employing the above technical solutions, when the proportion of glass fiber is too high, the functional groups on the surface of graphene oxide are insufficient to fully bond with epoxy resin, resulting in limited improvement in the interfacial adhesion of the sealing coating. Furthermore, excessive glass fiber reduces the proportion of epoxy resin matrix between the glass fibers, leading to decreased epoxy resin fluidity and increased localized stress concentration, thus increasing the brittleness of the sealing coating. When the proportion of graphene oxide is too high, the graphene sheets tend to stack and agglomerate, forming microscopic defects. This reduces the density and barrier properties of the sealing coating, and the interfacial adhesion between the agglomerated graphene oxide and the epoxy resin matrix decreases, resulting in a decrease in the interfacial peel strength of the sealing coating.

[0023] Preferably, the amount of the processing aid added is 15-25 parts.

[0024] By adopting the above technical solution, when the amount of processing aid added is too small, the processing aid cannot form an effective reinforcing network, the impact resistance of the sealing coating decreases significantly, and it is prone to cracking due to vibration or external force, resulting in a decrease in the interfacial peel strength of the sealing coating. When the amount of processing aid added is too large, the epoxy resin matrix will be excessively diluted, making it difficult to apply the epoxy resin layer uniformly. Furthermore, excessive processing aid is prone to agglomeration, forming local enrichment areas, which increases the brittleness of the sealing coating, thereby reducing the interfacial peel strength of the sealing coating.

[0025] Secondly, this application provides a method for preparing a battery box sealing coating, which adopts the following technical solution: A method for preparing a battery case sealing coating includes the following steps: S1: After wiping the surface of the battery box with acetone, let it air dry at room temperature to form a slightly etched active surface, i.e., an acetone adhesive layer. S2: Mix epoxy resin, benzyl alcohol, silica powder, toughening agent, silane coupling agent, water, and aromatic amine curing agent according to the formula, and cover the resulting mixture onto the acetone adhesive layer to obtain an epoxy resin layer. After the epoxy resin layer solidifies, a sealing coating is formed.

[0026] By adopting the above technical solution, an epoxy resin layer is formed by spraying acetone onto the surface of the PC / ABS shell to form a transition interface layer, and an epoxy resin layer is formed on top of the acetone adhesive layer to form a main sealing layer. The epoxy resin layer is then cured by cross-linking it with other raw materials in the epoxy resin layer using an aromatic amine curing agent. This process yields a battery box sealing coating with excellent interfacial peel strength.

[0027] Preferably, in step S2, the processing aid is first soaked in silane coupling agent to obtain modified processing aid, and then the modified processing aid is mixed with epoxy resin, benzyl alcohol, silica powder, toughening agent, silane coupling agent, water, and aromatic amine curing agent according to the formula amount.

[0028] By adopting the above technical solution, the processing aid is modified before being mixed with other raw materials, which helps to improve the compatibility of the processing aid with the epoxy resin matrix and enhance its interfacial bonding force with the epoxy resin matrix and silica fume filler.

[0029] In summary, this application includes at least one of the following beneficial technical effects: 1. This application improves the coating toughness by adding toughening agents and silane coupling agents during the preparation of the epoxy resin layer. This enhances the coating's toughness, absorbs stress to prevent crack propagation, and improves the compatibility between the epoxy resin and the battery box, reducing interface defects. These two aspects synergistically improve the interfacial peel strength of the battery box sealing coating, thus preparing a battery box sealing coating with excellent interfacial peel strength. 2. This application selects isocyanate-terminated liquid rubber as a toughening agent. The isocyanate-terminated liquid rubber can form chemical bonds with acetone and directional amine curing agents, effectively improving interlayer adhesion. Simultaneously, the flexible segments of the rubber phase in the isocyanate-terminated liquid rubber are dispersed in the rigid epoxy resin matrix, absorbing impact energy, preventing crack propagation, and effectively improving the impact resistance of the sealing coating. Furthermore, the cured product of the isocyanate-terminated liquid rubber contains urethane hard segments, which can effectively improve the chemical corrosion resistance of the sealing coating. 3. This application selects a mixture of glass fiber and graphene oxide as a processing aid. The surface of graphene oxide contains abundant oxygen-containing groups (such as hydroxyl and carboxyl groups), which can chemically bond with the hydroxyl groups on the surface of glass fiber and the epoxy groups in epoxy resin, thereby enhancing the interfacial bonding force between glass fiber and epoxy resin, making the compatibility between the three better, and thus improving the interfacial peel strength of the sealing coating. Detailed Implementation

[0030] The raw materials in this application include the following: Fiberglass: Commercially available products with CAS number 65997-17-3; Graphene oxide: A commercially available product with CAS number 7782-42-5; Isocyanate-terminated liquid rubber: TY-IRⅡ type isocyanate-terminated butadiene rubber from Tianyuan Aviation Materials (Yingkou) Technology Co., Ltd. Nitrile rubber: Commercially available products with CAS number 68891-50-9; EMA-grafted glycidyl methacrylate: EMA-grafted glycidyl methacrylate of brand name HT-022 from Dongguan Zhangmutou Hengtai Plastic Raw Materials Business Department; Aromatic amine curing agents: selected from m-phenylenediamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane, etc. This application takes m-phenylenediamine with CAS number 108-45-2 as an example; Silane coupling agent: selected from KH-550, KH-570, etc. This application takes KH-550 with CAS number 919-30-2 as an example.

[0031] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0032] Example 1 A battery box sealing coating includes an acetone adhesive layer, an epoxy resin layer, and a curing layer. The epoxy resin layer comprises the following components: 110g epoxy resin, 10g benzyl alcohol, 33g silica powder, 14g isocyanate-terminated liquid rubber, 2g silane coupling agent, 1g water, and 36g aromatic amine curing agent.

[0033] A method for preparing a battery case sealing coating includes the following steps: S1: After lightly wiping the surface of the battery box 3-5 times with 90% acetone, let it air dry at room temperature to form a slightly etched active surface, i.e., an acetone adhesive layer. S2: Mix epoxy resin, benzyl alcohol, silica powder, toughening agent, silane coupling agent, water, and aromatic amine curing agent according to the formula, and cover the resulting mixture onto the acetone adhesive layer to obtain an epoxy resin layer. After the epoxy resin layer solidifies, a sealing coating is formed.

[0034] Example 2-3 Examples 2-3 are based on the preparation method of Example 1, but the composition ratio of the epoxy resin layer is adjusted as shown in Table 1.

[0035] Comparative Examples 1-2 Comparative Examples 1-2 were prepared based on the method in Example 1, but the composition ratio of the epoxy resin layer was adjusted as shown in Table 1.

[0036] Performance testing The battery box sealing coatings of Examples 1-3 and Comparative Examples 1-2 were analyzed using the following specific testing methods: The interfacial peel strength test involves rigidly fixing the battery box coated with a sealant in a special fixture, separating the sealant and the battery box at a constant rate of 300 mm / min, measuring the average peel force required for a 25 mm width, and ensuring that no less than 90% of the interface is destroyed.

[0037] Based on the above detection method, the test results of Examples 1-3 and Comparative Examples 1-2 were obtained, as shown in Table 1 below.

[0038] Table 1. Epoxy resin layer composition ratios and performance tests for Examples 1-3 and Comparative Examples 1-2 Referring to Table 1, comparing Examples 1-3 and Comparative Examples 1-2, it can be seen that the interfacial peel strength of the battery sealing coatings obtained in Examples 1-3 is higher than that of the battery sealing coatings obtained in Comparative Examples 1-2. This may be because the addition of isocyanate-terminated liquid rubber as a toughening agent can disperse in the epoxy resin matrix to form an "island structure". By absorbing impact energy, it prevents cracks from easily propagating along the interface or inside the coating. The addition of silane coupling agent can connect the battery box and the epoxy resin, thereby effectively improving the interfacial peel strength of the battery box sealing coating.

[0039] Examples 4-5 Examples 4-5 are based on the preparation method of Example 1, but the type of toughening agent is adjusted, as shown in Table 2.

[0040] Performance testing: The battery box sealing coatings of Examples 1 and 4-5 were analyzed using the following specific testing methods: Chemical corrosion resistance is tested according to the method specified in HG / T4759-2014. The battery box sealing coating is immersed in a 20wt% sodium hydroxide aqueous solution, and the corrosion of the sealing coating is observed. The number of days required for the corrosion area of ​​the sealing coating to be greater than 30% is determined.

[0041] Based on the above detection method, the test results of Examples 1 and 4-5 were obtained, as shown in Table 2 below.

[0042] Table 2. Types of toughening agents and performance test results for Examples 1 and 4-5. Referring to Table 2, a comparison of Examples 1 and 4-5 shows that the interfacial peel strength and chemical corrosion resistance of the battery box sealing coating obtained in Example 1 are superior to those obtained in Examples 4-5. This may be because the terminal isocyanate groups in the terminal isocyanate-based liquid rubber can react with the hydroxyl groups in the acetone adhesive layer or the amine groups in the aromatic amine curing agent to form chemical bonds, effectively improving interlayer adhesion. Therefore, the resulting structure is more stable, effectively enhancing the interfacial peel strength of the battery box sealing coating. Furthermore, the cured product of the terminal isocyanate-based liquid rubber contains urethane hard segments, thereby improving the chemical corrosion resistance of the battery box sealing coating.

[0043] Examples 6-8 Examples 6-8 are based on the preparation method of Example 1, but the amount of isocyanate-terminated liquid rubber added is adjusted, as shown in Table 3.

[0044] Comparative Examples 3-4 Comparative Examples 3-4 were prepared using the same method as in Example 1, but with adjustments made to the amount of isocyanate-terminated liquid rubber added. The specific adjustments are shown in Table 3.

[0045] The battery box sealing coatings of Examples 6-8 and Comparative Examples 3-4 were subjected to the above performance tests, and the test results are shown in Table 3.

[0046] Table 3. Addition amount and performance test results of terminal isocyanate-based liquid rubbers in Examples 1, 6-8 and Comparative Examples 3-4. Referring to Table 3, comparing Examples 1, 6-8, and Comparative Examples 3-4, it can be seen that when the amount of terminal isocyanate-based liquid rubber added is between 12-18g, especially when the amount of terminal isocyanate-based liquid rubber added is 14g, the resulting battery box sealing coating has the best interfacial peel strength. This may be because when the amount of terminal isocyanate-based liquid rubber added is too low, the rubber phase provided by the terminal isocyanate-based liquid rubber is insufficient, lacking a flexible buffer layer, so that the stress cannot be dispersed. When the amount of terminal isocyanate-based liquid rubber added is too high, the rigid skeleton of the epoxy resin is diluted, and the excessive amount of terminal isocyanate-based liquid rubber will form a continuous phase or a large-size "island structure", which weakens the interfacial bonding force of the sealing coating.

[0047] Example 9 In Example 9, based on the preparation method of Example 1, in S2, 20g of a mixture of glass fiber and graphene oxide is first soaked in silane coupling agent for 3-5 minutes to obtain a modified processing aid. Then, the modified processing aid is mixed with epoxy resin, benzyl alcohol, silica powder, toughening agent, silane coupling agent water, and aromatic amine curing agent according to the formula amount. The mixing ratio of glass fiber to graphene oxide is 15:1.

[0048] Examples 10-11 Examples 10-11 are based on the preparation method of Example 9, but the components of the processing aid are adjusted as shown in Table 4.

[0049] The battery box sealing coatings of Examples 9-11 were subjected to the above-mentioned performance tests, and the test results are shown in Table 4.

[0050] Table 4. Processing aid components and performance test results for Examples 1 and 9-11. Referring to Table 4, a comparison of Examples 1 and 9-11 shows that the interfacial peel strength of Examples 9-11 is higher than that of Example 1, and the interfacial peel strength of the battery box sealing coating obtained in Example 9 is the best. This may be because after the glass fiber is embedded in the epoxy resin matrix, it forms physical anchoring points, achieving mechanical interlocking. Furthermore, the polar hydroxyl groups on the surface of the glass fiber can bond with the polar groups in the epoxy resin through hydrogen bonds or van der Waals forces, thereby improving the interfacial peel strength of the battery box sealing coating. The two-dimensional sheet structure of graphene oxide can be embedded in the interface region between the sealing coating and the battery box, and the active groups on the surface of graphene oxide can form strong chemical bonds with the polar groups on the epoxy resin matrix or the surface of the battery box, enhancing the interfacial bonding of the battery box sealing coating. At the same time, the oxygen-containing groups on the surface of graphene oxide can chemically bond with the hydroxyl groups on the surface of the glass fiber and the epoxy groups on the epoxy resin, enhancing the interfacial bonding force between the glass fiber and the epoxy resin, making the compatibility among the three better, thereby improving the interfacial peel strength of the battery box sealing coating.

[0051] Meanwhile, the terminal isocyanate groups of the liquid rubber can react with the hydroxyl and carboxyl groups on the surface of graphite oxide, the hydroxyl groups on the surface of glass fiber, and the epoxy groups of epoxy resin to form chemical bonds, further improving the interfacial peel strength of the battery box sealing coating.

[0052] Examples 12-13 Examples 12-13 are based on the preparation method of Example 9, but the mixing ratio of glass fiber and graphene oxide is adjusted as shown in Table 5.

[0053] Comparative Examples 5-6 Comparative Examples 5-6 are based on the preparation method of Example 9, but the mixing ratio of glass fiber and graphene oxide is adjusted as shown in Table 5.

[0054] The battery box sealing coatings of Examples 12-13 and Comparative Examples 5-6 were subjected to the above performance tests, and the test results are shown in Table 5.

[0055] Table 5. Mixing ratios and performance tests of glass fiber and graphene oxide in Examples 9, 12-13, and Comparative Examples 5-6. Referring to Table 5, comparing Examples 9, 12-13, and Comparative Examples 5-6, it can be seen that when the mixing ratio of glass fiber and graphene oxide is between 9 and 19:1, especially when the mixing ratio of glass fiber and graphene oxide is 15:1, the resulting battery box sealing coating exhibits the best interfacial peel strength. This may be because when the proportion of glass fiber is too high, the functional groups on the surface of graphene oxide are insufficient to fully bond with the epoxy resin, and excessive glass fiber reduces the proportion of epoxy resin matrix between glass fibers, easily leading to local stress concentration and increased brittleness of the battery box sealing coating. When the proportion of graphene oxide is too high, the graphene oxide sheets are prone to stacking and agglomeration, resulting in a decrease in the interfacial bonding between graphene oxide and the epoxy resin matrix, thus reducing the interfacial peel strength of the battery box sealing coating.

[0056] Examples 14-15 Examples 14-15 are based on the preparation method of Example 9, but the amount of processing aids (glass fiber and graphene oxide) added is adjusted, as shown in Table 6.

[0057] Comparative Examples 7-8 Comparative Examples 7-8 are based on the preparation method of Example 9, but the amount of processing aids (glass fiber and graphene oxide) added is adjusted, as shown in Table 6.

[0058] The battery box sealing coatings of Examples 14-15 and Comparative Examples 7-8 were subjected to the above performance tests, and the test results are shown in Table 6.

[0059] Table 6. Processing aid dosage and performance test results for Examples 9, 14-15, and Comparative Examples 7-8. Referring to Table 6, comparing Examples 9, 14-15, and 7-8, it can be seen that when the amount of processing aid added is between 15-25g, especially when the amount of processing aid added is 20g, the interfacial peel strength of the resulting battery box sealing coating is optimal. This may be because when the amount of processing aid added is too small, the processing aid cannot form an effective reinforcing network, resulting in a decrease in the interfacial peel strength of the battery box sealing coating. When the amount of processing aid added is too large, the epoxy resin matrix will be excessively diluted, making it difficult for the epoxy resin layer to form a uniform film by coating. Furthermore, excessive processing aid is prone to agglomeration, forming local enrichment areas, which leads to a decrease in the interfacial peel strength of the battery box sealing coating.

[0060] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A battery case sealing coating, comprising an acetone adhesive layer and an epoxy resin layer, characterized in that, The epoxy resin layer comprises the following components in parts by weight: 100-120 parts epoxy resin, 8-12 parts benzyl alcohol, 30-35 parts silica powder, 12-18 parts toughening agent, 1-3 parts silane coupling agent, 0.3-2 parts water, and 33-38 parts aromatic amine curing agent.

2. The battery box sealing coating according to claim 1, characterized in that, The toughening agent is at least one of terminal isocyanate-based liquid rubber, nitrile rubber, and EMA-grafted glycidyl methacrylate.

3. The battery box sealing coating according to claim 2, characterized in that, The toughening agent is a terminal isocyanate-based liquid rubber.

4. The battery box sealing coating according to claim 3, characterized in that, The amount of the terminal isocyanate-based liquid rubber added is 12-15 parts.

5. The battery box sealing coating according to claim 3, characterized in that, It also contains processing aids, which are at least one of glass fiber and graphene oxide.

6. The battery case sealing coating according to claim 5, characterized in that, The processing aid is a mixture of glass fiber and graphene oxide.

7. The battery case sealing coating according to claim 6, characterized in that, The mixing ratio of glass fiber and graphene oxide is 9-19:

1.

8. The battery box sealing coating according to claim 5, characterized in that, The amount of the processing aid added is 15-25 parts.

9. A method for preparing a battery case sealing coating according to any one of claims 1-8, characterized in that, Includes the following steps: S1: After wiping the surface of the battery box with acetone, let it air dry at room temperature to form a slightly etched active surface, i.e., an acetone adhesive layer. S2: Mix epoxy resin, benzyl alcohol, silica powder, toughening agent, silane coupling agent, water, and aromatic amine curing agent according to the formula, and cover the resulting mixture onto the acetone adhesive layer to obtain an epoxy resin layer. After the epoxy resin layer solidifies, a sealing coating is formed.

10. The method for preparing a battery case sealing coating according to claim 9, characterized in that, In S2, the processing aid is first soaked in silane coupling agent to obtain modified processing aid, and then the modified processing aid is mixed with epoxy resin, benzyl alcohol, silica powder, toughening agent, silane coupling agent, water and aromatic amine curing agent according to the formula amount.

Images