CN116144264B

CN116144264B - Coating composition, top cover and preparation method thereof, secondary battery and battery module

Info

Publication number: CN116144264B
Application number: CN202310400637.9A
Authority: CN
Inventors: 万云霄; 毕汉戎; 曹桂; 孟齐德
Original assignee: Jiangsu Contemporary Amperex Technology Ltd
Current assignee: Jiangsu Contemporary Amperex Technology Ltd
Priority date: 2023-04-14
Filing date: 2023-04-14
Publication date: 2023-09-01
Anticipated expiration: 2043-04-14
Also published as: CN116144264A

Abstract

The application relates to a coating composition, which comprises aminopropyl trimethoxy silane and a low surface energy substance, wherein a coating formed by the aminopropyl trimethoxy silane has a rough surface structure with micro-nano size and has lower surface energy, so that the coating has excellent electrolyte-thinning performance, and after electrolyte drops are dropped on the surface of a battery outer package provided with the coating, spherical drops can be formed to roll and fall off, thereby protecting the battery outer package from being polluted by electrolyte, and avoiding the electrolyte from corroding two-dimensional codes and polluting polar posts.

Description

Coating composition, top cover and preparation method thereof, secondary battery and battery module

Technical Field

The application relates to the technical field of batteries, in particular to a coating composition, a top cover, a preparation method of the top cover, a secondary battery, a battery module, a battery pack and an electric device.

Background

The secondary battery industry is rapidly developed, and particularly, a power battery is increasingly receiving attention. Secondary batteries generally include a positive electrode tab, a negative electrode tab, an electrolyte, and an exterior package (mostly an aluminum case) for packaging them. The outer package generally comprises a shell and a top cover, wherein a pole is arranged on the top cover and is carved with a two-dimensional code. In the manufacturing process of the secondary battery, electrolyte is usually required to be injected, liquid spraying, liquid dripping, liquid leakage and the like can occur during liquid injection, and liquid spraying and liquid dripping can also occur during infiltration and formation. The flowing electrolyte can pollute and corrode the outer package of the secondary battery, so that the two-dimensional code on the top cover is corroded, the pole is polluted, and the battery is scrapped. Therefore, how to prevent the electrolyte from polluting the battery outer package and avoid the electrolyte from corroding the two-dimensional code and polluting the polar column becomes an important research subject at the present stage.

Disclosure of Invention

In view of the problems existing in the background art, the application provides a coating composition which can prevent electrolyte from polluting the battery outer package and avoid the electrolyte from corroding two-dimensional codes and polluting polar posts.

The coating composition provided by the first aspect of the application comprises a component A and a component B, wherein the component A is amino propyl trimethoxysilane, and the component B is a low surface energy substance. Wherein the mass ratio of the component A to the component B is 1 (1-10).

Component a of the present application helps to impart micro-nano sized rough surface structure to the formed coating; component B is beneficial to lower the surface energy of the coating. The components A and B are used in a combined mode according to a specific proportion, the formed coating has a rough surface structure with micro-nano size and has lower surface energy, so that the coating has excellent electrolyte-thinning performance, and when electrolyte drops onto the surface of the battery outer package provided with the coating, spherical drops can be formed to roll and drop, so that the battery outer package is protected from being polluted by the electrolyte, and the two-dimensional code and the polar post are prevented from being corroded by the electrolyte.

In some embodiments, according to the first aspect, a first example of the first aspect is presented, the mass ratio of component a to component B being 1 (2-10).

The mass ratio of the component A to the component B is optimized, so that the contact angle between the electrolyte drop and the surface of the battery outer package modified by the coating is further increased, and the electrolyte-thinning performance of the coating is further improved.

In some embodiments, according to the first aspect, a second example of the first aspect is presented, the coating composition further comprising: component C, which is cage polysilsesquioxane or salt thereof containing amino group. The mass ratio of the component A to the component B to the component C is 1 (1-10) to 0.5-5.

The component C of the application is beneficial to improving the corrosion resistance of the coating, improving the bonding strength between the components and improving the adhesive force between the coating and the battery outer package, so that the coating is not easy to peel off. The application can provide continuous antifouling and anti-corrosion protection for the battery outer package by combining the component A, the component B and the component C with specific proportions. In addition, the coating of the application has no corrosiveness to the surface of the battery outer package, and has good combination with the top patch (the top patch is required to be stuck on the top cover during the coating), and the coating is not required to be cleaned in the subsequent manufacturing process.

In some embodiments, according to the first aspect, a third example of the first aspect is presented, the mass ratio of component A, component B, and component C being 1 (2-10): 0.5-2.

The antifouling property, the anticorrosion property and the adhesive property of the coating are further improved by optimizing the mass ratio of the component A to the component B to the component C.

In some embodiments, according to a fourth example of the first aspect, the amino group-containing cage polysilsesquioxane or salt thereof comprises one or more of an aminopropyl heptyl cage polysilsesquioxane, an octaaniline propyl cage polysilsesquioxane, a tetramethyl ammonium cage polysilsesquioxane.

The amino group-containing cage polysilsesquioxane or the salt thereof is optimized, so that the corrosion resistance and the adhesion performance of the coating are further improved.

In some embodiments, according to the first aspect, a fifth example of the first aspect is presented, the low surface energy substance having a carbon chain. The length of the carbon chain is more than 6 carbon atoms.

The application adopts low surface energy substance with long carbon chain, which is beneficial to further increasing the contact angle between the electrolyte drop and the surface of the top cover modified by the coating, thereby further improving the electrolyte-thinning performance of the coating.

In some embodiments, according to the first aspect, which provides a sixth example of the first aspect, the low surface energy substance comprises one or more of heptadecafluorodecyl trimethoxysilane, dodecafluoroheptyl propyl trimethyl silane, 1h,2 h-perfluorooctyl trimethoxysilane, trimethyl (tridecafluorohexyl) silane.

The fluorine-containing low-surface-energy substance is beneficial to further increasing the contact angle between the electrolyte drop and the surface of the top cover modified by the coating, so that the electrolyte-repellent performance of the coating is further improved.

In some embodiments, according to the first aspect, a seventh example of the first aspect is presented, the coating composition further comprising: component D, which is a solvent.

The viscosity and the brushing performance of the paint are improved by optimizing the type of the solvent and the dosage ratio of the solute to the solvent, so that the paint is easy to coat.

A second aspect of the application provides a top cover. The top cover surface is provided with a coating. The coating is made using the coating composition of the first aspect of the present application.

The coating has excellent electrolyte-thinning performance, and after electrolyte drops on the surface of the battery outer package provided with the coating, spherical drops can be formed to roll and drop, so that the battery outer package is protected from being polluted by electrolyte, and the electrolyte is prevented from corroding the two-dimensional code and the pollution pole on the top cover. In addition, the coating of the present application is transparent and insulating. The transparent coating does not influence the scanning of the two-dimensional code. The insulating coating can not lead to the conduction of the pole and the shell to cause poor shell pressure.

In some embodiments, according to the second aspect, a first example of the second aspect is presented, where the contact angle of the electrolyte droplet with the surface of the top cover modified by the coating is 90 ° or more.

The larger the contact angle between the electrolyte drop and the surface of the top cover is, the more excellent the electrolyte-repellent performance is, and the top cover is protected from being polluted by electrolyte.

The third aspect of the present application provides a method for manufacturing a top cover, comprising the steps of:

mixing amino propyl trimethoxy silane, a low surface energy substance and a solvent to obtain a coating composition; wherein the mass ratio of the amino propyl trimethoxy silane to the low surface energy substance is 1 (1-10);

the coating composition is applied to the top surface and dried.

The coating obtained by the preparation method has excellent electrolyte-thinning performance, and is transparent and insulating.

In some embodiments, according to a third aspect, which proposes a first example of the third aspect, a cage polysilsesquioxane or salt thereof containing an amino group is mixed together with an aminopropyl trimethoxysilane, a low surface energy material, a solvent; wherein the mass ratio of the amino propyl trimethoxy silane to the low surface energy substance to the amino group-containing cage polysilsesquioxane or the salt thereof is 1 (1-10) (0.5-5).

The application can provide continuous antifouling and anticorrosion protection for the battery outer package by combining the amino propyl trimethoxy silane (component A), the low surface energy substance (component B) and the cage-shaped polysilsesquioxane containing amino or the salt thereof (component C) in a specific proportion. In addition, the coating of the application has no corrosiveness to the surface of the battery outer package, and has good combination with the top patch on the top cover, and the coating does not need to be cleaned in the subsequent manufacturing process.

In some embodiments, according to the third aspect, a second example of the third aspect is presented, the drying temperature being 25 ℃ to 120 ℃. The drying time is 2-72h.

The drying temperature and the drying time of the coating are optimized, so that the contact angle between the electrolyte drops and the surface of the top cover modified by the coating is improved, and the electrolyte-repellent performance of the coating is further improved.

A fourth aspect of the application provides a housing. The surface of the shell is provided with a coating. The coating is made using the coating composition of the first aspect of the present application.

The manufacturing method of the shell is the same as that of the top cover, and will not be described here.

A fifth aspect of the present application provides a secondary battery including a case, a battery cell, and a top cap. The surface of the shell and/or the surface of the top cover is provided with a coating. The coating is made using the coating composition of the first aspect of the present application.

A sixth aspect of the application provides a battery module comprising the secondary battery of the fifth aspect of the application.

A seventh aspect of the present application provides a battery pack comprising the secondary battery of the fifth aspect of the present application or the battery module of the sixth aspect of the present application.

An eighth aspect of the application provides an electric device comprising at least one of the secondary battery of the fifth aspect of the application, the battery module of the sixth aspect of the application, and the battery pack of the seventh aspect of the application.

The foregoing description is only an overview of the present application, and is intended to provide a better understanding of the technical means of the present application, as it is embodied in the present specification, and is intended to provide a better understanding of the above and other objects, features and advantages of the present application, as it is embodied in the following description.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

fig. 1 is a flow chart of a conventional secondary battery manufacturing process.

Fig. 2 is a schematic view of a secondary battery according to an embodiment of the present application.

Fig. 3 is an exploded view of the secondary battery according to an embodiment of the present application shown in fig. 2.

Fig. 4 is a schematic view of a battery module according to an embodiment of the present application.

Fig. 5 is a schematic view of a battery pack according to an embodiment of the present application.

Fig. 6 is an exploded view of the battery pack of the embodiment of the present application shown in fig. 5.

Fig. 7 is a schematic view of an electric device in which a secondary battery according to an embodiment of the present application is used as a power source.

Fig. 8 is a graph comparing contact angles of electrolyte droplets with a top cover surface provided with a coating and without a coating.

Fig. 9 is a graph comparing corrosion conditions of two-dimensional codes on a top cover with a coating and without a coating.

Fig. 10 is a graph comparing the contamination of the negative electrode column on the top cap with and without the coating.

Fig. 11 is a comparative plot of the shell pressure after anode column contamination on top caps with and without coating.

Reference numerals illustrate:

1, a battery pack; 2, upper box body; 3, lower box body; 4, a battery module; 5 a secondary battery; 51 a housing; 52 electrode assembly; 53 top cover.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The terms "comprising" and "having" and any variations thereof in the description of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.

For simplicity, only a few numerical ranges are explicitly disclosed herein. However, any lower limit may be combined with any upper limit to form a range not explicitly recited; and any lower limit may be combined with any other lower limit to form a range not explicitly recited, and any upper limit may be combined with any other upper limit to form a range not explicitly recited. Furthermore, each point or individual value between the endpoints of the range is included within the range, although not explicitly recited. Thus, each point or individual value may be combined as a lower or upper limit on itself with any other point or individual value or with other lower or upper limit to form a range that is not explicitly recited.

In the description herein, unless otherwise indicated, "above" and "below" are intended to include the present number, and the meaning of "multiple" in "one or more" is two or more (including two).

In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, and indicates that three relationships may exist, for example, a and/or B may indicate: there are three cases, a, B, a and B simultaneously.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like should be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; or may be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to specific circumstances.

The above summary of the present application is not intended to describe each disclosed embodiment or every implementation of the present application. The following description more particularly exemplifies illustrative embodiments. Guidance is provided throughout this application by a series of embodiments, which may be used in various combinations. In the various examples, the list is merely a representative group and should not be construed as exhaustive.

The secondary battery industry is rapidly developed, and particularly, a power battery is increasingly receiving attention. Secondary batteries generally include a positive electrode tab, a negative electrode tab, an electrolyte, and an exterior package (mostly an aluminum case) for packaging them. The outer package generally comprises a shell and a top cover, wherein a pole is arranged on the top cover and is carved with a two-dimensional code. In the manufacturing process of the secondary battery, electrolyte is generally required to be injected, as shown in fig. 1, liquid spraying, liquid dripping, liquid leakage and the like may occur during liquid injection, and liquid spraying and liquid dripping may also occur during infiltration and formation. The discharged electrolyte can pollute and corrode the battery outer package, so that the battery is scrapped due to bad coating. In addition, the flowing electrolyte can erode the two-dimensional code on the top cover, so that the battery can not sweep the code and is scrapped. In addition, the flowing electrolyte can pollute the battery pole, and poor contact and even safety accidents can be caused in the formation and capacity charge and discharge processes; particularly, when the electrolyte pollutes the negative electrode column, the electrolyte can conduct the aluminum shell and the negative electrode column, and a primary battery consisting of the aluminum shell and the negative electrode forms a complete closed loop, wherein the aluminum shell is used as a positive electrode, and the negative electrode plate is used as a negative electrode. Lithium ions in the electrolyte are continuously intercalated into the aluminum shell to form lithium aluminum alloy (corrosion product), at the moment, the electrode potential of the aluminum shell is rapidly reduced, and the potential difference between the aluminum shell and the negative electrode is greatly reduced. The lithium aluminum alloy has loose structure, and the aluminum shell can be corroded and perforated after long-time reaction. The general manufacturer can measure the potential difference between the negative pole post and the shell in the battery test procedure, and when the potential difference is smaller than the specified value of 1.5V, the lithium intercalation reaction of the aluminum shell is carried out to produce the lithium aluminum alloy, namely the short circuit between the negative pole of the battery and the shell is indicated, and the battery must be scrapped. Therefore, how to prevent the electrolyte from polluting the battery outer package and avoid the corrosion of the two-dimensional code and the polar post on the top cover becomes an important research subject at the present stage.

In order to prevent the battery outer package from being polluted and corroded, researchers usually apply a coating on the surface of the outer package, however, most of the existing coatings are hydrophobic coatings, do not have the function of electrolyte-repellent, and are difficult to prevent the electrolyte from polluting and corroding the battery outer package.

In order to solve the above problems, the inventors have conducted intensive studies to design a coating composition comprising aminopropyl trimethoxysilane and a low surface energy substance in a specific ratio. The coating composition can enable the formed coating to have a rough surface structure with micro-nano size and low surface energy, so that the coating has excellent electrolyte-thinning performance, and after electrolyte drops on the surface of the battery outer package provided with the coating, spherical drops can be formed to roll and drop, thereby protecting the battery outer package from being polluted by the electrolyte, and avoiding the electrolyte from corroding the two-dimensional code and polluting the polar post. The application can effectively prevent the secondary battery from being scrapped caused by pollution of electrolyte in the manufacturing process, and improves the product quality.

The technical scheme described in the embodiment of the application is applicable to a coating composition, and is also applicable to a top cover provided with a coating layer, a preparation method of the top cover, a secondary battery using the top cover, a battery module using the secondary battery, a battery pack using the secondary battery or the battery module, and an electric device using at least one of the secondary battery, the battery module and the battery pack.

In a first aspect, according to some embodiments of the present application, the present application provides a coating composition. The material comprises a component A and a component B, wherein the component A is aminopropyl trimethoxysilane, and the component B is a low-surface-energy substance. Wherein the mass ratio of the component A to the component B is 1 (1-10).

The structural formula of the aminopropyl trimethoxysilane is shown as follows:

。

component a of the present application helps to impart micro-nano sized rough surface structure to the formed coating; component B is beneficial to lower the surface energy of the coating. The combination of the component A and the component B in a specific proportion can lead the formed coating to have a rough surface structure with micro-nano size and simultaneously have lower surface energy, thereby leading the coating to have excellent electrolyte-thinning performance.

In addition, the coating formed by the coating composition has excellent electrolyte-repellent performance, and is transparent and insulating. The transparent coating does not influence the scanning of the two-dimensional code. The insulating coating can not lead to the conduction of the pole and the shell to cause poor shell pressure.

In some embodiments, the mass ratio of component A to component B may be 1 (2-10).

In some embodiments, the mass ratio of component a to component B may be 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10. The mass ratio of component a to component B may be within a range of values defined by any two of the values listed above as endpoints.

In some embodiments, the coating composition may further comprise: component C, which is cage polysilsesquioxane or salt thereof containing amino group. The mass ratio of the component A to the component B to the component C can be 1 (1-10): 0.5-5.

The component C of the application is beneficial to improving the corrosion resistance of the coating, improving the bonding strength between the components and improving the adhesive force between the coating and the battery outer package, so that the coating is not easy to peel off. The application can provide continuous antifouling and anti-corrosion protection for the battery outer package by combining the component A, the component B and the component C with specific proportions.

In some embodiments, the mass ratio of component A, component B, and component C may be 1 (2-10): 0.5-2.

In some embodiments of the present application, in some embodiments, the mass ratio of component a, component B, and component C may be 1:2:0.5, 1:3:0.5, 1:4:0.5, 1:5:0.5, 1:6:0.5, 1:7:0.5, 1:8:0.5, 1:9:0.5, 1:10:0.5, 1:2:0.75, 1:3:0.75, 1:4:0.75, 1:5:0.75, 1:6:0.75, 1:7:0.75, 1:8:0.75, 1:9:0.75, 1:10:0.75, 1:2:1, 1:1:1, 1:4:1, 1:5:1, 1:6:1, 1:7:1, 1:8:1, 1:9:1, 1:1: 1:10:1, 1:2:1.1, 1:3:1.1, 1:4:1.1, 1:5:1.1, 1:6:1.1, 1:7:1.1, 1:8:1.1, 1:9:1.1, 1:10:1.1, 1:2:1.2, 1:3:1.2, 1:4:1.2, 1:5:1.2, 1:6:1.2, 1:7:1.2, 1:8:1.2, 1:9:1.2, 1:10:1.2, 1:2:1.3, 1:3:1.3, 1:4:1.3, 1:5:1.3, 1:6:1.3, 1:7:1.3, 1:8:1.3, 1:9:1.3, 1:10:1.3, 1:2:4:1.2, 1:4:1.2, 1.2, 1:1.3, 1:2, 1:2:1.3.3. 1:10:1, 1:2:1.1, 1:3:1.1, 1:4:1.1, 1:5:1.1, 1:6:1.1, 1:7:1.1, 1:8:1.1, 1:9:1.1, 1:10:1.1, 1:2:1.2, 1:3:1.2, 1:4:1.2, 1:5:1.2, 1:6:1.2: 1:7:1.2, 1:8:1.2, 1:9:1.2, 1:10:1.2, 1:2:1.3, 1:3:1.3, 1:4:1.3, 1:5:1.3, 1:6:1.3, 1:7:1.3, 1:8:1.3, 1:9:1.3, 1:10:1.3, 1:2:1.4, 1:3:1.4. The mass ratio of the component a, the component B and the component C may be within a range of values constituted by any two of the above-listed values as the end values.

In some embodiments, the amino-containing cage polysilsesquioxane or salt thereof may comprise one or more of an aminopropyl heptyl cage polysilsesquioxane, an octaaniline propyl cage polysilsesquioxane, a tetramethyl ammonium cage polysilsesquioxane.

The structural formula of the aminopropyl heptyl cage polysilsesquioxane is shown as follows:

the structural formula of the octa-phenylpropyl cage-shaped polysilsesquioxane is shown as follows:

the structural formula of the tetramethyl ammonium cage polysilsesquioxane is shown as follows:

In some embodiments, the amino-containing cage polysilsesquioxane or salt thereof comprises an aminopropyl heptyl cage polysilsesquioxane and a tetramethyl ammonium cage polysilsesquioxane.

In some embodiments, the low surface energy substance may have a carbon chain. The carbon chain length may be more than 6 carbon atoms.

The surface energy of the long carbon chain substance is lower, and the application adopts the low surface energy substance with long carbon chain, which is beneficial to further increasing the contact angle between the electrolyte drop and the surface of the top cover modified by the coating, thereby further improving the electrolyte-thinning performance of the coating.

In some embodiments, the length of the carbon chain may be 6 carbon atoms, 7 carbon atoms, 8 carbon atoms, 9 carbon atoms, 10 carbon atoms, 11 carbon atoms, 12 carbon atoms, 13 carbon atoms, 14 carbon atoms, 15 carbon atoms, 16 carbon atoms, 17 carbon atoms, 18 carbon atoms, 19 carbon atoms, or 20 carbon atoms. The length of the carbon chain may be within a range of values defined by any two of the values listed above as the endpoints.

In some embodiments, the low surface energy species may include one or more of heptadecafluorodecyl trimethoxysilane, dodecafluoroheptyl propyl trimethyl silane, 1H, 2H-perfluorooctyl trimethoxysilane, trimethyl (tridecyl) silane.

The structural formula of heptadecafluorodecyl trimethoxysilane is shown as follows:

。

the fluorine-substituted long carbon chain substance has lower surface energy, and the fluorine-containing low surface energy long carbon chain substance is favorable for further increasing the contact angle between the electrolyte drop and the surface of the top cover modified by the coating, so that the electrolyte-thinning performance of the coating is further improved.

In some embodiments, the coating composition may further comprise, in addition to component a and component B: component D, which is a solvent.

By optimizing the type of solvent and the ratio of solute to solvent, it is advantageous to better disperse component a and component B in the solvent, making it easier to coat.

In some embodiments, the solvent may include one or more of ethanol, propanol, isopropanol. In some embodiments, the solvent may comprise a mixture of ethanol and propanol. The volume ratio of ethanol to propanol may be (6.5-7.5): (2.5-3.5), for example 6.5:3.5, 6.8:3.2, 7:3, 7.2:2.8 or 7.5:2.5.

In some embodiments, the coating composition includes component a, component B, and component D. The ratio of the total mass of component A, component B to the volume of component D may be (0.1 g-20 g): 100mL. For example, the ratio of the total mass of component A, component B, and the volume of component D may be 0.1g to 100mL, 0.5g to 100mL, 1g to 100mL, 2g to 100mL, 3g to 100mL, 4g to 100mL, 5g to 100mL, 6g to 100mL, 7g to 100mL, 8g to 100mL, 9g to 100mL, 10g to 100mL, 11g to 100mL, 12g to 100mL, 13g to 100mL, 14g to 100mL, 15g to 100mL, 16g to 100mL, 17g to 100mL, 18g to 100mL, 19g to 100mL, or 20g to 100mL. The ratio of the total mass of the component a, the component B, and the volume of the component D may be within a range of values constituted by any two of the above-listed values as the end values.

In some embodiments, the coating composition includes component a, component B, component C, and component D. The ratio of the total mass of component A, component B and component C to the volume of component D was (0.1 g-20 g): 100mL. For example, the ratio of the total mass of component A, component B and component C to the volume of component D may be 0.1 g: 100mL, 0.5 g: 100mL, 1 g: 100mL, 2 g: 100mL, 3 g: 100mL, 4 g: 100mL, 5 g: 100mL, 6 g: 100mL, 7 g: 100mL, 8 g: 100mL, 9 g: 100mL, 10 g: 100mL, 11 g: 100mL, 12 g: 100mL, 13 g: 100mL, 14 g: 100mL, 15 g: 100mL, 16 g: 100mL, 17 g: 100mL, 18 g: 100mL, 19 g: 100mL or 20 g: 100mL. The ratio of the total mass of the component a, the component B and the component C to the volume of the component D may be within a range of values constituted by any two of the above-listed values as the end values.

In some embodiments, the contact angle of the electrolyte drop with the surface of the top cover modified by the coating can be more than 90 °.

In some embodiments, the contact angle of the electrolyte drop with the coating-modified cap surface may be 90 °, 95 °, 100 °, 105 °, 110 °, 115 °, 120 °, 125 °, 130 °, 135 °, 140 °, 145 °, 150 °, 151 °, 152 °, 153 °, 154 °, 155 °, 156 °, 157 °, 158 °, 159 °, 160 °, 161 °, 162 °, 163 °, 164 °, 165 °, 166 °, 167 °, 168 °, 169 °, or 170 °.

In some embodiments, the coating thickness may be 0.1-500 μm, for example, 1-100 μm, 100-200 μm, 200-300 μm, 300-400 μm, or 400-500 μm. The coating has a micron-sized thickness and is very thin, and the scanning of the two-dimensional code is not influenced by the thin transparent coating.

The thickness of the coating is optimized, so that the antifouling property and the corrosion resistance of the coating are further improved, and the transparency of the coating is ensured.

Of course, the coating composition of the present application can be used not only to coat the upper surface of the battery top cover, but also to coat the outer surface of the case to form an electrolyte-repellent coating to prevent the contamination of the outer surface of the case by the electrolyte.

The specific structure of the battery top cover and the case is not particularly limited in the present application, and the coating composition of the present application may be applied as long as it can be used for a top cover and a case of a secondary battery.

the coating composition is applied to the top surface and dried.

In some embodiments, the amino-containing cage polysilsesquioxane or salt thereof is mixed with the aminopropyl trimethoxysilane, the low surface energy material, and the solvent; wherein the mass ratio of the amino propyl trimethoxy silane to the low surface energy substance to the amino group-containing cage polysilsesquioxane or the salt thereof is 1 (1-10) (0.5-5).

。

In some embodiments, the solvent may include one or more of ethanol, propanol, isopropanol.

In some embodiments, the drying temperature may be 25 ℃ -120 ℃, for example may be 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃, or 120 ℃. The drying time may be 2-72h, for example 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, 36h, 48h, 60h or 72h. The drying temperature and the drying time may be within a range of values constituted by any two of the above-listed values as the end values.

In some embodiments, the coating composition may be applied to the cap surface using spraying, brushing, or spin-coating. For example, the coating composition may be uniformly sprayed onto the cap using a spray coating process. The thickness of the coating can be controlled by controlling the spraying time and flow, and then the coating is dried, so that the top cover achieves an excellent electrolyte-thinning effect.

The secondary battery, the battery module, the battery pack, and the electric device of the present application are described below with appropriate reference to the accompanying drawings.

In general, a secondary battery includes a positive electrode tab, a negative electrode tab, an electrolyte, and a separator. During the charge and discharge of the battery, active ions are inserted and extracted back and forth between the positive electrode plate and the negative electrode plate. The electrolyte plays a role in ion conduction between the positive electrode plate and the negative electrode plate. The isolating film is arranged between the positive pole piece and the negative pole piece, and mainly plays a role in preventing the positive pole piece and the negative pole piece from being short-circuited, and meanwhile ions can pass through the isolating film.

[ Positive electrode sheet ]

In a secondary battery, the positive electrode tab generally includes a positive electrode current collector and a positive electrode film layer disposed on the positive electrode current collector, the positive electrode film layer including a positive electrode active material.

The positive electrode current collector can adopt a conventional metal foil or a composite current collector (a metal material can be arranged on a high polymer base material to form the composite current collector). As an example, the positive electrode current collector may employ aluminum foil.

The specific kind of the positive electrode active material is not limited, and active materials known in the art to be capable of being used for a positive electrode of a secondary battery may be used, and those skilled in the art may select according to actual demands.

As an example, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxide, olivine-structured lithium-containing phosphate, and their respective modified compounds. Examples of the lithium transition metal oxide may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt aluminum oxide, and modified compounds thereof. Examples of olivine structured lithium-containing phosphates may include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate-carbon composites, lithium manganese phosphate-carbon composites, lithium manganese phosphate-iron, lithium manganese phosphate-carbon composites, and modified compounds thereof. These materials are commercially available.

In some embodiments, the modifying compound of each of the above materials may be a doping modification and/or a surface coating modification of the material.

The positive electrode film layer also typically optionally includes a binder, a conductive agent, and other optional adjuvants.

As an example, the conductive agent may be one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, super P (SP), graphene, and carbon nanofibers.

As an example, the binder may be one or more of styrene-butadiene rubber (SBR), aqueous acrylic resin (water-based acrylic resin), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB).

[ negative electrode sheet ]

The negative electrode plate comprises a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, wherein the negative electrode film layer comprises a negative electrode active material.

As an example, the anode current collector has two surfaces opposing in its own thickness direction, and the anode film layer is provided on either one or both of the two surfaces opposing the anode current collector.

In some embodiments, the negative electrode current collector may employ a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used. The composite current collector may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material base material. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

In some embodiments, the anode active material may employ an anode active material for a battery, which is well known in the art. As an example, the anode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like. The silicon-based material may include at least one of elemental silicon, a silicon oxygen compound, a silicon carbon compound, a silicon nitrogen compound, and a silicon alloy. The tin-based material may include at least one of elemental tin, a tin oxide, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery anode active material may be used. These negative electrode active materials may be used alone or in combination of two or more.

In some embodiments, the negative electrode film layer further optionally includes a binder. The binder may include at least one of Styrene Butadiene Rubber (SBR), polyacrylic acid (PAA), sodium Polyacrylate (PAAs), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium Alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

In some embodiments, the negative electrode film layer further optionally includes a conductive agent. The conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

In some embodiments, the negative electrode film layer may optionally further include other adjuvants, such as thickening agents (e.g., sodium carboxymethyl cellulose (CMC-Na)), and the like.

In some embodiments, the negative electrode sheet may be prepared by: dispersing the above components for preparing the negative electrode sheet, such as a negative electrode active material, a conductive agent, a binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; and coating the negative electrode slurry on a negative electrode current collector, and obtaining a negative electrode plate after the procedures of drying, cold pressing and the like.

[ electrolyte ]

The electrolyte plays a role in ion conduction between the positive electrode plate and the negative electrode plate. The application is not particularly limited in the kind of electrolyte, and may be selected according to the need. For example, the electrolyte may be liquid, gel, or all solid.

In some embodiments, the electrolyte is an electrolyte. The electrolyte includes an electrolyte salt and a solvent.

In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalato borate, lithium difluorodioxaato phosphate, and lithium tetrafluorooxalato phosphate.

In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1, 4-butyrolactone, sulfolane, dimethyl sulfone, methyl sulfone, and diethyl sulfone.

In some embodiments, the electrolyte further optionally includes an additive. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives capable of improving certain properties of the battery, such as additives that improve the overcharge performance of the battery, additives that improve the high or low temperature performance of the battery, and the like.

[ isolation Membrane ]

In some embodiments, a separator is further included in the secondary battery. The type of the separator is not particularly limited, and any known porous separator having good chemical stability and mechanical stability can be used.

In some embodiments, the material of the isolation film may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multilayer composite film, and is not particularly limited. When the separator is a multilayer composite film, the materials of the respective layers may be the same or different, and are not particularly limited.

In some embodiments, the positive electrode tab, the negative electrode tab, and the separator may be manufactured into an electrode assembly through a winding process or a lamination process.

In some embodiments, the secondary battery may include an outer package. The outer package may be used to encapsulate the electrode assembly and electrolyte described above.

In some embodiments, the outer package of the secondary battery may be a hard case, such as a hard plastic case, an aluminum case, a steel case, or the like. The exterior package of the secondary battery may also be a pouch type pouch, for example. The material of the flexible bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

The shape of the secondary battery is not particularly limited in the present application, and may be cylindrical, square, or any other shape. For example, fig. 2 is a secondary battery 5 of a square structure as one example.

In some embodiments, referring to fig. 3, the outer package may include a housing 51 and a top cover 53. The housing 51 may include a bottom plate and a side plate connected to the bottom plate, where the bottom plate and the side plate enclose a receiving chamber. The housing 51 has an opening communicating with the accommodation chamber, and the top cover 53 can be provided to cover the opening to close the accommodation chamber. The positive electrode tab, the negative electrode tab, and the separator may be formed into the electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is enclosed in the accommodating chamber. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 included in the secondary battery 5 may be one or more, and those skilled in the art may select according to specific practical requirements.

In some embodiments, the secondary batteries may be assembled into a battery module, and the number of secondary batteries included in the battery module may be one or more, and the specific number may be selected by one skilled in the art according to the application and capacity of the battery module.

Fig. 4 is a battery module 4 as an example. Referring to fig. 4, in the battery module 4, a plurality of secondary batteries 5 may be sequentially arranged in the longitudinal direction of the battery module 4. Of course, the arrangement may be performed in any other way. The plurality of secondary batteries 5 may be further fixed by fasteners.

Alternatively, the battery module 4 may further include a case having an accommodating space in which the plurality of secondary batteries 5 are accommodated.

In some embodiments, the above battery modules may be further assembled into a battery pack, and the number of battery modules included in the battery pack may be one or more, and a specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.

Fig. 5 and 6 are battery packs 1 as an example. Referring to fig. 5 and 6, a battery case and a plurality of battery modules 4 disposed in the battery case may be included in the battery pack 1. The battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be covered on the lower box body 3 and forms a closed space for accommodating the battery module 4. The plurality of battery modules 4 may be arranged in the battery box in any manner.

In addition, the application also provides an electric device which comprises at least one of the secondary battery, the battery module or the battery pack. The secondary battery, the battery module, or the battery pack may be used as a power source of the power consumption device, and may also be used as an energy storage unit of the power consumption device. The power utilization device may include mobile devices (e.g., cell phones, notebook computers, etc.), electric vehicles (e.g., electric-only vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but is not limited thereto.

As the electricity consumption device, a secondary battery, a battery module, or a battery pack may be selected according to the use requirements thereof.

Fig. 7 is an electrical device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or the like. In order to meet the high power and high energy density requirements of the secondary battery by the power consumption device, a battery pack or a battery module may be employed.

As another example, the device may be a cell phone, tablet computer, notebook computer, or the like. The device is generally required to be light and thin, and a secondary battery can be used as a power source.

In order to make the technical problems, technical schemes and beneficial effects solved by the application more clear, the following will be further described in detail with reference to the embodiments and the accompanying drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. All other embodiments, which can be made by a person skilled in the art based on the embodiments of the application without any inventive effort, are intended to fall within the scope of the application.

The materials used in the examples of the present application are all commercially available.

Preparation of coating compositions

Example 1

0.1g of aminopropyl trimethoxysilane (component A) and 0.8g of heptadecafluorodecyl trimethoxysilane (component B) were dissolved in 100mL of an ethanol-propanol mixed solution (volume ratio: 7:3), and mixed by ultrasonic waves for 30 minutes to prepare a dope composition stock solution.

Example 2-example 4

Examples 2-4 were conducted as described in example 1 except that the parameters set forth in Table 1 below were different from example 1.

Example 5

A dope composition stock solution was prepared by dissolving 0.1g of aminopropyl trimethoxysilane (component A), 0.8g of heptadecafluorodecyl trimethoxysilane (component B), 0.05g of tetramethylammonium cage polysilsesquioxane (component C) and 0.05g of aminopropyl heptyl cage polysilsesquioxane (component C) in 100mL of an ethanol-propanol mixed solution (volume ratio: 7:3), and mixing by ultrasonic waves for 30 minutes.

Example 6

A dope composition stock solution was prepared by dissolving 0.2g of aminopropyl trimethoxysilane (component A), 0.7g of heptadecafluorodecyl trimethoxysilane (component B), 0.1g of tetramethylammonium cage polysilsesquioxane (component C) and 0.05g of aminopropyl heptyl cage polysilsesquioxane (component C) in 100mL of an ethanol-propanol mixed solution (volume ratio 5:5) and ultrasonically mixing for 30 minutes.

Examples 7 to 26

Examples 7-26 were conducted as described in example 5 except that the parameters set forth in table 1 below were different from example 5.

Example 27

The procedure described in example 5 was followed, except that 0.1g of vinyltriethoxysilane was used in place of 0.05g of tetramethylammonium-based cage polysilsesquioxane (component C) and 0.05g of aminopropyl heptyl cage polysilsesquioxane (component C).

Comparative example 1

The procedure described in example 1 was followed, except that aminopropyl trimethoxysilane (component A) was not used.

Comparative example 2

The procedure described in example 1 was followed, except that heptadecafluorodecyl trimethoxysilane (component B) was not used.

Comparative example 3-comparative example 4

Comparative example 3-comparative example 4 was carried out according to the method described in example 1, except that the parameters listed in table 1 below were different from example 1.

Comparative example 5

The procedure described in example 5 was followed, except that heptadecafluorodecyl trimethoxysilane (component B) was not used.

TABLE 1

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Using the dope composition stock solutions prepared in example 1 to example 27 and comparative example 1 to comparative example 5, secondary batteries were prepared according to the following general preparation methods.

Preparation of secondary battery

Examples 1 a-27 a and comparative examples 1 a-5 a

First, provide battery top cap, it includes lamina tecti (the substrate is aluminum alloy 5052), anodal post subassembly, negative pole post subassembly, annotate liquid hole etc. the upper surface of lamina tecti is equipped with the two-dimensional code.

Then, pouring the prepared coating composition stock solution into a sprayer, and then uniformly spraying the coating composition stock solution onto the upper surface of the battery top cover; and drying the battery top cover at a certain temperature for a certain time to obtain the battery top cover with the electrolyte-repellent coating, wherein the drying temperature and the drying time are shown in the following table 2.

Finally, the electrode assembly (including the positive electrode sheet, the separator and the negative electrode sheet) was put into a case (the base material was aluminum alloy 5052), the opening of the case was sealed with the prepared battery top cover, and then baked to remove water, and then subjected to primary injection, infiltration, formation, secondary injection, sealing nail welding, capacity test, coating and the like to obtain finished secondary batteries (numbered example 1a-27a, comparative example 1 a-comparative example 5 a).

Comparative example 6a

A secondary battery was manufactured according to the above-described method, except that an electrolyte-repellent coating layer was not formed on the battery top cover.

Battery top cap antiseptic property characterization

Contact angle test:

the Contact Angle (CA) refers to the Angle between a tangent line and a solid-liquid interface when the whole system reaches the equilibrium of solid, liquid and gas phases and the tangent line is formed at the boundary of the three phases. The contact angle tester is just used to measure CA of liquids to solids, and thus to study the wettability of objects.

Specifically, 7 μl of the electrolyte was dropped on the battery top cap surfaces of the secondary batteries prepared in examples 1a to 27a, comparative examples 1a to 5a, and comparative example 6a, respectively. The contact angle of the electrolyte drop with the surface of the battery top cover was measured using a contact angle meter, and the results are shown in table 2 below.

Among them, the contact angle of the electrolyte droplet with the battery top cover (no coating) of the secondary battery prepared in comparative example 6a and the contact angle of the electrolyte droplet with the battery top cover (coated, drying temperature of coating was 60 ℃ C., drying time was 8 h) of the secondary battery prepared in example 5a were compared with those shown in FIG. 8 (obtained by using a contact angle meter).

Two-dimensional code corrosion:

2 mL electrolyte was dripped onto the two-dimensional code of the battery top cap (coated) of the secondary battery prepared in example 5 a. In addition, 2 mL electrolyte was dropped onto the two-dimensional code of the battery top cover (uncoated) of the secondary battery prepared in comparative example 6 a. After being placed at 25 ℃ for one month, the two-dimensional code corrosion condition is indistinguishable from that the uncoated two-dimensional code is corroded, as shown in fig. 9, and the coated two-dimensional code is clearly visible.

Negative electrode column pollution:

10 mL electrolyte was dropped onto the negative electrode column of the battery top cap (coated) of the secondary battery prepared in example 6a (no electrolyte was dropped on the two-dimensional code). In addition, 10 mL electrolyte was dropped onto the negative electrode column (no coating) of the battery top cap (no electrolyte was dropped onto the two-dimensional code) of the secondary battery prepared in comparative example 6 a. The negative electrode column pollution condition pair is shown in fig. 10. After the electrolyte is dripped on the uncoated negative electrode column, residual crystallization appears on the negative electrode column and the vicinity thereof along with the evaporation of the solvent, and the negative electrode column is obviously polluted by the electrolyte. After the electrolyte is dripped on the coated cathode column, the electrolyte can roll off and cannot be left on the top cover, so that no crystallization residue exists, and the cathode column is not polluted by the electrolyte.

Potential difference between the negative electrode column and the case:

10 mL electrolyte was dropped onto the negative electrode column of the battery top cap (coated) of the secondary battery prepared in example 6a (no electrolyte was dropped on the two-dimensional code). In addition, 10 mL electrolyte was dropped onto the negative electrode column (no coating) of the battery top cap (no electrolyte was dropped onto the two-dimensional code) of the secondary battery prepared in comparative example 6 a. The change in potential difference (i.e., can pressure) between the anode stem and the casing was measured at intervals, and the result is shown in fig. 11. The testing method comprises the following steps: and testing by adopting a universal meter, wherein the positive electrode probe is contacted with the shell, the negative electrode probe is contacted with the negative electrode column of the battery, and the potential difference between the positive electrode probe and the negative electrode probe is the shell pressure. The results show that the potential difference between the coated anode stem and the casing remains stable. The potential difference between the uncoated negative electrode column and the shell is rapidly reduced, and after the electrode liquid and the peripheral electrolyte on the uncoated negative electrode column are removed, the potential difference cannot be recovered to be normal, so that irreversible damage is caused.

TABLE 2

As can be seen from the above examples and comparative examples, the coating layer formed from the coating composition of the present application has excellent electrolyte-repellent properties, and when an electrolyte drops onto the surface of the battery top cover provided with the coating layer, spherical drops are formed to roll off, thereby protecting the battery top cover from being contaminated by the electrolyte, and preventing the electrolyte from corroding the two-dimensional code and contaminating the post.

The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A coating composition comprising: the composition comprises a component A, a component B and a component C, wherein the component A is aminopropyl trimethoxysilane, the component B is a low surface energy substance, and the component C is cage-shaped polysilsesquioxane containing amino groups or a salt thereof; wherein the mass ratio of the component A to the component B to the component C is 1 (5-10): 0.5-5;

the low surface energy material comprises one or more of heptadecafluorodecyl trimethoxysilane, dodecafluoroheptyl propyl trimethyl silane, 1H, 2H-perfluoro octyl trimethoxysilane and trimethyl (tridecyl fluorohexyl) silane.

2. The coating composition according to claim 1, wherein the mass ratio of the component A, the component B and the component C is 1 (5-10): 0.5-2.

3. The coating composition of claim 1 or 2, wherein the amino group-containing cage polysilsesquioxane or salt thereof comprises one or more of an aminopropyl heptyl cage polysilsesquioxane, an octaaniline propyl cage polysilsesquioxane, and a tetramethyl ammonium cage polysilsesquioxane.

4. The coating composition of claim 1 or 2, further comprising: component D, wherein the component D is a solvent.

5. A cap, characterized in that the surface of the cap is provided with a coating, which is produced from the coating composition according to any one of claims 1 to 4.

6. The cap of claim 5, wherein the electrolyte drop has a contact angle of 90 ° or more with the surface of the cap modified with the coating.

7. The preparation method of the top cover is characterized by comprising the following steps of:

mixing cage-shaped polysilsesquioxane or salt thereof containing amino groups with amino propyl trimethoxy silane, a low surface energy substance and a solvent to obtain a coating composition; wherein the mass ratio of the amino propyl trimethoxy silane to the low surface energy substance to the amino-containing cage-shaped polysilsesquioxane or the salt thereof is 1 (5-10) (0.5-5); the low surface energy substance comprises one or more of heptadecafluorodecyl trimethoxysilane, dodecafluoroheptyl propyl trimethyl silane, 1H, 2H-perfluoro octyl trimethoxysilane and trimethyl (tridecyl fluorohexyl) silane;

The coating composition is applied to the top surface and dried.

8. The method according to claim 7, wherein the drying temperature is 25-120 ℃ and the drying time is 2-72h.

9. A housing, characterized in that the housing surface is provided with a coating, which is produced from the coating composition according to any one of claims 1 to 4.

10. A secondary battery comprising a case, a battery cell, and a top cover, wherein the surface of the case and/or the surface of the top cover is provided with a coating layer made of the coating composition according to any one of claims 1 to 4.

11. A battery module comprising the secondary battery according to claim 10.

12. A battery pack comprising the secondary battery according to claim 10 or the battery module according to claim 11.

13. An electric device comprising at least one of the secondary battery according to claim 10, the battery module according to claim 11, and the battery pack according to claim 12.