Battery pack, preparation method thereof and power utilization device

Abstract

The invention discloses a battery pack, a preparation method thereof and an electric device. The battery pack comprises single batteries and a box body, the box body defines an accommodating space, and the accommodating space is used for accommodating the single batteries; a coating is arranged on at least partial area of the outer surface of the box body, the coating comprises a polyurea material, micron-sized bulges are arranged on the surface of the coating, and nano-sized bulges are arranged on the surfaces of the micron-sized bulges. Therefore, the battery pack has relatively good hydrophobicity and relatively good impact resistance and wear resistance.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to battery packs, their preparation methods, and electrical devices. Background Technology

[0002] Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. However, taking electric vehicles as an example, because the battery pack is usually located at the bottom of the vehicle, the battery pack casing is easily contaminated by mud or damaged by sand and gravel impacts during vehicle use. Summary of the Invention

[0003] In view of the technical problems existing in the background art, this application provides a battery pack that aims to make the battery pack have both good hydrophobic properties and good impact resistance and wear resistance.

[0004] To achieve the above objectives, in a first aspect of this application, a battery pack is provided, comprising: a battery cell and a housing, the housing defining a receiving space for receiving the battery cell; at least a portion of the outer surface of the housing is provided with a coating comprising a polyurea material, the surface of the coating having micron-level protrusions, and the surface of the micron-level protrusions having nanon-level protrusions.

[0005] The battery pack of the first aspect of this application has at least the following beneficial effects: it enables the coating to play a better protective role, and enables the battery pack to have good hydrophobicity, impact resistance and wear resistance.

[0006] In some embodiments of this application, the micron-sized protrusions comprise fluorocarbon materials and inorganic nanoparticles. This further improves the hydrophobicity of the coating, making the battery pack less susceptible to sludge contamination or icing.

[0007] In some embodiments of this application, the fluorocarbon material includes fluorocarbon resin.

[0008] In some embodiments of this application, the inorganic nanoparticles include one or more of aluminum oxide, silicon dioxide, silicon nitride, copper sulfide, iron oxide, zinc oxide, titanium oxide, zirconium oxide, iron(II,III) oxide, and ferric oxide.

[0009] In some embodiments of this application, the inorganic nanoparticles include one or more of alumina, zirconium oxide, silicon dioxide, and silicon nitride. This can further improve the wear resistance of the coating and reduce the risk of the coating's hydrophobicity decreasing during battery pack use.

[0010] In some embodiments of this application, the coating comprises a covalent bond -HNCOO-M1, wherein M1 is an element present in the inorganic nanoparticles. This is beneficial for improving the bonding strength between the inorganic nanoparticles and other organic components, and enhancing the structural stability of the coating.

[0011] In some embodiments of this application, the coating and the housing are covalently bonded, and the covalent bond includes -SiO-M2, where M2 is an element present on the surface of the housing. This further improves the bonding strength between the coating and the housing surface, and enhances the coating's adhesion, abrasion resistance, and stone chip resistance.

[0012] In some embodiments of this application, the coating comprises a covalent bond -SiO-M1, wherein M1 is an element present in the inorganic nanoparticles. This is beneficial for improving the compatibility and dispersibility of the inorganic nanoparticles with other organic components in the coating, and for improving the uniformity of the micro / nano structure on the coating surface.

[0013] In some embodiments of this application, the contact angle of the coating is ≥120°. This achieves good hydrophobicity.

[0014] In some embodiments of this application, the contact angle of the coating is ≥150°. This further improves hydrophobicity.

[0015] In some embodiments of this application, the roll-off angle of the coating is ≤10°. This achieves good hydrophobicity.

[0016] In some embodiments of this application, the roll-off angle of the coating is ≤5°. This further improves hydrophobicity.

[0017] In some embodiments of this application, the coating thickness is 60 μm to 130 μm. This allows the coating to achieve a good balance between hydrophobic properties, impact resistance, and abrasion resistance, while also being cost-effective.

[0018] In some embodiments of this application, the thickness of the coating is 60 μm to 100 μm.

[0019] In some embodiments of this application, the coating includes a primer layer and a topcoat layer. The primer layer is located on at least a portion of the outer surface of the casing and comprises a polyurea material. The topcoat layer is located on the surface of the primer layer away from the casing, and the surface of the topcoat layer has micron-level protrusions, the surface of which has nano-level protrusions. This further enhances the protective effect of the coating, giving the battery pack good hydrophobicity, impact resistance, and abrasion resistance.

[0020] In some embodiments of this application, the thickness of the primer layer is 50μm to 100μm, and the thickness of the topcoat layer is 10μm to 30μm. Therefore, while taking cost into consideration, the coating can further enhance its protective effect, enabling the battery pack to possess good hydrophobicity, impact resistance, and abrasion resistance.

[0021] In some embodiments of this application, the primer layer and the casing are covalently bonded, and the covalent bonds include -SiO-M2, where M2 is an element present on the surface of the casing. This improves the bonding strength between the primer layer and the casing, enhances the adhesion of the coating, and further improves the battery pack's wear resistance and stone impact resistance.

[0022] In some embodiments of this application, the micron-sized protrusions comprise fluorocarbon materials and inorganic nanoparticles, and the primer layer and the topcoat layer are covalently bonded, the covalent bonds comprising -HNCOO-M1, wherein M1 is an element present in the inorganic nanoparticles. This improves the bonding strength between the topcoat layer and the primer layer, enhances the stability of the entire coating structure, and further improves the wear resistance and stone impact resistance of the battery pack.

[0023] In some embodiments of this application, the topcoat layer comprises covalent bonds -SiO-M1, wherein M1 is an element present in the inorganic nanoparticles. This is beneficial for improving the compatibility and dispersibility of the inorganic nanoparticles with other organic components in the coating, and for improving the uniformity of the micro-nano structure on the coating surface.

[0024] A second aspect of this application provides a method for manufacturing a battery pack, comprising: forming a coating on at least a portion of the outer surface of a casing, the coating comprising a polyurea material, the surface of the coating having micron-level protrusions, and the surface of the micron-level protrusions having nanon-level protrusions; and placing a battery cell within a receiving space of the casing. This allows the resulting battery pack to possess good hydrophobicity, impact resistance, and abrasion resistance.

[0025] In some embodiments of this application, the method for preparing a battery pack includes: mixing a first component and a second component and spraying the mixture onto at least a portion of the outer surface of the casing to form a primer layer comprising a polyurea material, wherein the first component comprises a terminal amino compound; the second component comprises isocyanate and / or isocyanate prepolymer; mixing inorganic nanoparticles and fluorocarbon material with a first solvent and spraying the mixture onto the surface of the primer layer away from the casing to form a topcoat layer, wherein the surface of the topcoat layer has micron-level protrusions, and the surface of the micron-level protrusions has nano-level protrusions. This not only facilitates obtaining the primer layer and topcoat layer within the desired thickness range, but also facilitates the micro / nano structure design of the topcoat layer, while improving the stability of the coating structure. Furthermore, this allows the coating to exert a better protective effect, enabling the battery pack to possess good hydrophobicity, impact resistance, and abrasion resistance.

[0026] In some embodiments of this application, the first component or the second component further includes a first coupling agent. This facilitates the formation of covalent bonds between the primer layer and the housing, further improving the bonding strength between the primer layer and the housing, and enhancing the adhesion of the coating.

[0027] In some embodiments of this application, 30-70 parts by weight of a terminal amino compound, 1-8 parts by weight of a first coupling agent, 2-10 parts by weight of a filler, 0-30 parts by weight of an amine chain extender, 0-5 parts by weight of a pigment, and a second solvent are mixed to obtain the first component. This is beneficial for further improving the impact resistance of the primer layer.

[0028] In some embodiments of this application, 50-85 parts by weight of isocyanate, 5-25 parts by weight of polyol, 0.1-1 parts by weight of catalyst, and a third solvent are mixed to obtain the second component. This yields an isocyanate prepolymer with a relatively high molecular weight, enabling a polyurea reaction between the second and first components to obtain a polyurea material.

[0029] In some embodiments of this application, 10-80 parts by weight of the inorganic nanoparticles, 30-70 parts by weight of the fluorocarbon material, 0-40 parts by weight of the second coupling agent, and the first solvent are mixed and sprayed onto the surface of the primer layer away from the housing. This further facilitates obtaining a coating with better hydrophobicity.

[0030] In some embodiments of this application, the terminal amino compound includes one or more of polyetheramine, butanediamine, hexanediamine, decanediamine, dialiphatic diamine, and 4,4′-diaminodicyclohexylmethane.

[0031] In some embodiments of this application, the filler includes one or more of calcium carbonate, silicon dioxide, talc, silicate, and alumina.

[0032] In some embodiments of this application, the amine chain extender includes one or more of diethyltoluenediamine, dimethylthiotoluenediamine, N,N-dialkylmethyldiphenylamine, ethylenediamine, triethylenetetramine, diethylenetriamine, and N-isopropylethylenediamine.

[0033] In some embodiments of this application, the isocyanate includes one or more of TDI, MDI, PAPI, LMDI, HDI, IPDI, and XDI.

[0034] In some embodiments of this application, the polyol includes polyether polyols and / or polyester polyols.

[0035] In some embodiments of this application, the catalyst includes one or more of dimethyltin dilaurate, stannous octoate, succinic acid, N,N-dimethylethanolamine, and bis(dimethylaminomethyl)benzene.

[0036] In some embodiments of this application, the fluorocarbon material includes fluorocarbon resin.

[0037] In some embodiments of this application, the first coupling agent and the second coupling agent independently comprise one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

[0038] In some embodiments of this application, the first solvent, the second solvent, and the third solvent each independently include one or more of N,N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, toluene, methyl chloride, and ethyl acetate.

[0039] In some embodiments of this application, the mixing volume ratio of the first component and the second component is 1:(1~1.3).

[0040] In some embodiments of this application, the first component and the second component are mixed and then sprayed onto at least a portion of the outer surface of the casing. The spraying pressure is 0.4 MPa to 0.8 MPa, and the spraying distance is 20 cm to 100 cm. This facilitates thorough mixing of the terminal amino compound in the first component and the isocyanate prepolymer in the second component after spraying, forming a uniform primer layer on the outer surface of the casing.

[0041] In some embodiments of this application, the inorganic nanoparticles and the fluorocarbon material are mixed with the first solvent and then sprayed onto the surface of the primer layer away from the housing. The spraying pressure is 0.4 MPa to 0.8 MPa, the spraying distance is 20 cm to 100 cm, and the number of sprays is 3 to 5. This facilitates the embedding of the fluorocarbon material and inorganic nanoparticles into the primer layer and the formation of a topcoat layer with a micro-nano structure on the surface of the primer layer.

[0042] A third aspect of this application provides a battery device comprising: the battery pack described in the first aspect of this application, or a battery pack prepared using the method described in the second aspect of this application. Attached Figure Description

[0043] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0044] Figure 1 This is a schematic diagram of the structure of a battery cell according to one embodiment of this application.

[0045] Figure 2 This is a schematic diagram of the structure of a battery module according to one embodiment of this application.

[0046] Figure 3 This is a schematic diagram of the structure of a battery pack according to one embodiment of this application.

[0047] Figure 4 yes Figure 3 The exploded diagram.

[0048] Figure 5 This is a schematic diagram of one embodiment of the battery device used as a power source in this application.

[0049] Figure 6 This is the infrared spectrum of the coating obtained in Example 1 of this application.

[0050] Figure 7 This is a scanning electron microscope image of the coating obtained in Example 1 of this application.

[0051] Figure 8 This application Figure 7 A magnified view of a portion of the image.

[0052] Explanation of reference numerals in the attached figures:

[0053] 1: Battery cell; 2: Battery module; 3: Battery pack; 4: Upper casing; 5: Lower casing. Detailed Implementation

[0054] The present application will be further described below with reference to specific embodiments. It should be understood that these specific embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0055] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0056] The "range" disclosed in this application is defined in the form of a lower limit and / or an upper limit. A given range is defined by selecting a lower limit and / or an upper limit, which defines the boundary of the particular range. Ranges defined in this way may or may not include endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form an undefined range, and any lower limit can be combined with other lower limits to form an undefined range. Similarly, any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, each individually disclosed point or single value can itself serve as a lower limit or upper limit, combined with any other point or single value, or combined with other lower limits or upper limits to form an undefined range.

[0057] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0058] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0059] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps S1 and S2, indicating that the method may include steps S1 and S2 performed sequentially, or it may include steps S2 and S1 performed sequentially. For example, the method may also include step S3, indicating that step S3 may be added to the method in any order. For example, the method may include steps S1, S2, and S3, or it may include steps S1, S3, and S2, or it may include steps S3, S1, and S2, etc.

[0060] Unless otherwise specified, in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0061] In this application, the terms "multiple" or "various" refer to two or more kinds of things.

[0062] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit this application; the terms "comprising" and "having," and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion. Unless otherwise stated, the terms used in this application have their commonly understood meanings as understood by one of ordinary skill in the art. Unless otherwise stated, the numerical values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0063] With the continuous advancement of green and environmentally friendly themes, the application of batteries has penetrated into all aspects of life, including vehicles, electronic devices, and energy storage devices. A battery pack consists of individual battery cells and a housing for storing these cells, used to store and provide electrical energy. In vehicles, battery packs are typically located at the bottom, either mounted on the chassis or serving as part of the chassis itself. Due to this design, the battery pack housing is easily contaminated with mud during vehicle use, especially in low-temperature environments where mud can freeze, making battery swapping difficult. Furthermore, it is susceptible to impacts from road debris, and the housing is prone to dragging, bumping, and abrasion, leading to corrosion from acids, alkalis, and salts. Currently, high-pressure water jets are used to remove mud from the car chassis and battery pack housing surface, heating is used to remove ice from the battery pack housing surface, and underbody protection plates are added to prevent dragging, bumping, and abrasion. A PVC coating is also added to the underbody protection plates for corrosion protection. However, these methods do not improve the battery pack's inherent protective performance.

[0064] This application proposes a battery pack that utilizes a coating on the outer surface of the battery pack casing. The coating comprises a polyurea material, taking advantage of the fact that urea groups in the polyurea material readily form hydrogen bonds, and that breaking these hydrogen bonds requires energy absorption. This achieves good impact resistance and abrasion resistance. Furthermore, the inherent properties of the polyurea material also improve the coating's waterproof and abrasion-resistant properties. Simultaneously, the coating surface features micron-level protrusions, and these micron-level protrusions have a nano-level structure. Utilizing this micro-nano structure, similar to that of a lotus leaf surface, good hydrophobicity is achieved, preventing the battery pack casing from being contaminated by mud or ice. The hydrophobic design also further improves the casing's corrosion resistance. Therefore, the coating provides excellent protection, resulting in a battery pack that combines good hydrophobicity, impact resistance, and abrasion resistance.

[0065] The battery pack disclosed in this application can be used in electrical devices that use the battery pack as a power source or in various energy storage systems that use individual battery packs as energy storage elements. Electrical devices may include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

[0066] A first aspect of this application provides a battery pack comprising: a battery cell and a housing, the housing defining a receiving space for accommodating the battery cell; at least a portion of the outer surface of the housing is provided with a coating comprising a polyurea material, the surface of the coating having micron-level protrusions, and the surface of the micron-level protrusions having nanon-level protrusions (see reference). Figure 7 and Figure 8 understand).

[0067] In this application, by applying a coating to the outer surface of the battery pack and simultaneously designing the material and structure of the coating, the coating can provide better protection, enabling the battery pack to have good hydrophobicity, impact resistance and wear resistance.

[0068] The coating on the outer surface of the battery pack uses a polyurea material comprising urea-HN-CO-NH-. The H atoms on the urea group, bonded to the electronegative N atoms with small radius, readily form hydrogen bonds with adjacent electronegative O atoms with small radius. Breaking these hydrogen bonds requires energy absorption, thus achieving good impact resistance without the need for a protective plate. This improved impact resistance also enhances the coating's wear resistance. Furthermore, the inherent properties of polyurea also contribute to improved water resistance and wear resistance. Simultaneously, the coating surface features micron-level protrusions, which in turn contain nano-level protrusions. These micro / nano structures can be filled with air to form numerous small air chambers, causing water droplets and sludge to form spheres on the coating instead of spreading out. This achieves good hydrophobicity, preventing the battery pack from becoming contaminated with sludge or ice. The hydrophobic design further improves the battery pack's corrosion resistance. Therefore, the coating provides excellent protection, resulting in a battery pack that combines good hydrophobicity, impact resistance, and wear resistance.

[0069] Therefore, the battery pack of the first aspect of this application has at least the following beneficial effects: it can have both good hydrophobic properties and good impact resistance and wear resistance.

[0070] For example, the coating may be applied to all areas of the outer surface of the enclosure.

[0071] For example, the coating may be applied to the outer surface area at the bottom of the housing and the lower outer surface area on the side of the housing.

[0072] For example, the housing may include an upper housing and a lower housing, the upper housing may cover the lower housing and form a receiving space for accommodating individual battery cells, and the coating may be applied to all areas of the outer surface of the lower housing.

[0073] In this application, the coating can be characterized using common characterization methods such as infrared spectroscopy (IR) or nuclear magnetic resonance (NMR) to detect chemical bonds and functional groups in the coating, determine the presence of urea groups, and thus determine the presence of polyurea materials in the coating. For example, if the infrared spectrum obtained from the infrared spectroscopy test of the coating shows both the stretching vibration absorption peak of NH (belonging to urea groups) and the stretching vibration absorption peak of C=O (belonging to urea groups), it indicates the presence of polyurea materials in the coating. Furthermore, scanning electron microscopy can be used to observe the microstructure of the coating surface, determining whether the coating surface has micron-sized protrusions, and whether the surface of the micron-sized protrusions has nano-sized protrusions.

[0074] In some embodiments of this application, the micron-sized protrusions may include fluorocarbon materials and inorganic nanoparticles. Introducing fluorocarbon materials into the coating surface helps reduce the surface energy of the coating, further improving its hydrophobicity; while using inorganic nanoparticles helps form nanoscale protrusions on both the coating surface and the surface of the micron-sized protrusions, thereby enabling the coating to achieve superhydrophobic properties. This further improves the hydrophobicity of the coating, making the battery pack casing less susceptible to sludge contamination or icing.

[0075] In some embodiments of this application, the fluorocarbon material may include fluorocarbon resin. Optionally, the fluorocarbon resin may include one or more of PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), FEVE (fluoroolefin-vinyl ether copolymer), and PVF (polyvinyl fluoride).

[0076] In some embodiments of this application, the inorganic nanoparticles may include one or more of alumina, silicon dioxide, silicon nitride, copper sulfide, iron oxide, zinc oxide, titanium oxide, zirconium oxide, iron(II,III) oxide, and ferric oxide. Optionally, the inorganic nanoparticles may include one or more of alumina, zirconium oxide, silicon dioxide, and silicon nitride. The given types of inorganic nanoparticles have relatively good wear resistance, which can further improve the wear resistance of the coating and reduce the degree of wear on the micro-nano structure of the coating surface due to friction, collision, etc. during the use of the battery pack, thereby reducing the risk of the hydrophobicity of the coating decreasing during the use of the battery pack.

[0077] In this application, one or more characterization methods, such as infrared spectroscopy, nuclear magnetic resonance, energy dispersive spectroscopy (EDS), and inductively coupled plasma atomic emission spectrometry (ICP), can be combined to confirm whether the micron-sized protrusions include fluorocarbon materials and inorganic nanoparticles, and to identify the types of inorganic nanoparticles. For example, EDS can be used to obtain the types, contents, and distribution regions of elements in the micron-sized protrusions. Based on the relative contents and distribution regions of fluorine and carbon, as well as the composition and distribution regions of other elements, it can be confirmed whether the micron-sized protrusions include fluorocarbon materials and inorganic nanoparticles, and the types of inorganic nanoparticles can be qualitatively analyzed.

[0078] In some embodiments of this application, the coating may include a covalent bond -HNCOO-M1, where M1 is an element present in the inorganic nanoparticles. Polyurea materials are typically prepared using a polyurethane prepolymer with isocyanate end groups and a terminal amino compound. Inorganic nanoparticles usually contain hydroxyl groups on their surface. During the formation of the polyurea material, the polyurethane prepolymer can be in relative excess. In this case, the polyurethane prepolymer with isocyanate end groups can react with the hydroxyl groups on the surface of the inorganic nanoparticles to form a covalent bond -HNCOO-M1. This not only improves the compatibility and dispersibility of the inorganic nanoparticles with other organic components in the coating, but also enhances the bonding strength between the inorganic nanoparticles and other organic components, thereby improving the stability of the micro / nano structures formed by micron-scale and nano-scale protrusions and the overall stability of the coating structure.

[0079] In some embodiments of this application, the coating and the housing can be covalently bonded, and the covalent bond can include -SiO-M2, where M2 is an element present on the surface of the housing. This can further improve the bonding strength between the coating and the housing surface, and improve the coating's adhesion, wear resistance, and stone impact resistance. Taking a metal housing as an example, the housing surface typically also has hydroxyl groups. During coating preparation, a silane coupling agent can be added to the coating raw material, allowing the silane coupling agent to react with the hydroxyl groups on the housing surface to form a covalent bond -SiO-M2, thereby improving the coating's adhesion, wear resistance, and stone impact resistance.

[0080] In some embodiments of this application, the coating may include covalent bonds -SiO-M1, where M1 is an element present in the inorganic nanoparticles. When preparing the coating, the inorganic nanoparticles in the micron-scale protrusions may be inorganic nanoparticles modified with a silane coupling agent, the modified inorganic nanoparticles having covalent bonds -SiO-M1 on their surface. Using inorganic nanoparticles modified with a silane coupling agent is beneficial for improving the compatibility and dispersibility of the inorganic nanoparticles with other organic components in the coating, and for improving the uniformity of the micro / nano structure on the coating surface.

[0081] In this application, the coating can be characterized by commonly used characterization methods such as infrared spectroscopy or nuclear magnetic resonance to determine whether covalent bonds -HNCOO-M1, -SiO-M2 or -SiO-M1 exist in the coating.

[0082] In some embodiments of this application, the contact angle of the coating can be ≥120°. Exemplary examples include contact angles of ≥120°, ≥130°, ≥140°, ≥150°, ≥155°, or ≥160°, etc. The contact angle of the coating can be tested using ultrapure water, referring to ASTM D7334.8. A larger contact angle indicates better hydrophobicity. Coatings meeting the aforementioned contact angle range exhibit superhydrophobic properties, further preventing the battery pack casing surface from being contaminated with sludge or ice. Optionally, the contact angle of the coating can be ≥150°.

[0083] In some embodiments of this application, the roll-off angle of the coating can be ≤10°. Exemplary examples include roll-off angles of ≤10°, ≤9°, ≤8°, ≤7°, ≤6°, ≤5°, ≤4°, or ≤3°, etc. The roll-off angle of the coating can be determined using the following tilting plate method: place a droplet on the sample surface, then slowly tilt the sample surface while tracking changes in the droplet's shape and position. When the droplet begins to slide, record the tilt angle at this point as the roll-off angle. The smaller the roll-off angle of the coating, the better its hydrophobicity. Coatings meeting the stated roll-off angle range exhibit superhydrophobic properties, further preventing the battery pack casing surface from being contaminated with sludge or icing. Optionally, the roll-off angle of the coating can be ≤5°.

[0084] In some embodiments of this application, the coating thickness can be 60 μm to 130 μm. For example, the coating thickness can be 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, or 130 μm, etc. The coating thickness can be measured using conventional instruments such as a thickness gauge. Increasing the coating thickness is beneficial for improving the coating's protective effect on the battery pack housing. Achieving a coating thickness within the aforementioned range allows the coating to balance good hydrophobic properties, good impact resistance and abrasion resistance, while also considering cost.

[0085] In some embodiments of this application, the coating may include a primer layer and a topcoat layer. The primer layer may be located on at least a portion of the outer surface of the casing, and the primer layer comprises a polyurea material; the topcoat layer may be located on the surface of the primer layer away from the casing, and the surface of the topcoat layer has micron-level protrusions, and the surface of the micron-level protrusions has nano-level protrusions. Optionally, the primer layer and the topcoat layer may be formed independently by spraying. This not only allows the primer layer to have a denser structure, further improving the impact resistance and abrasion resistance of the coating, but also facilitates the micro-nano structure design of the topcoat layer. Simultaneously, it also improves the bonding strength between the topcoat layer and the casing, enhancing the stability of the coating. Furthermore, it allows the coating to exert a better protective effect, enabling the battery pack to possess good hydrophobicity, impact resistance, and abrasion resistance.

[0086] In some embodiments of this application, the thickness of the primer layer can be 50μm to 100μm, such as 50μm, 60μm, 70μm, 80μm, 90μm, or 100μm, etc.; the thickness of the topcoat layer can be 10μm to 30μm, such as 10μm, 15μm, 20μm, 25μm, or 30μm, etc. Ensuring the primer layer thickness meets the given range is beneficial for achieving good impact resistance and abrasion resistance while considering cost. Ensuring the topcoat layer thickness meets the given range is beneficial for the topcoat layer to have suitable density and form micro / nano structures, improving the hydrophobicity of the coating and reducing the risks of low coating density due to a small topcoat layer thickness and the difficulty of forming micro / nano structures due to a large topcoat layer thickness. Therefore, the coating can further exert a better protective effect, enabling the battery pack to have good hydrophobicity, impact resistance, and abrasion resistance.

[0087] In some embodiments of this application, the primer layer and the casing may be covalently bonded, and the covalent bond may include -SiO-M2, where M2 is an element present on the surface of the casing. This can improve the bonding strength between the primer layer and the casing, enhance the adhesion of the coating, and further improve the wear resistance and stone impact resistance of the battery pack.

[0088] In some embodiments of this application, the micron-sized protrusions may include fluorocarbon materials and inorganic nanoparticles, and the primer layer and topcoat layer may be covalently bonded, wherein the covalent bond may include -HNCOO-M1, where M1 is an element present in the inorganic nanoparticles. This improves the bonding strength between the topcoat layer and the primer layer, enhances the stability of the entire coating structure, and further improves the wear resistance and stone impact resistance of the battery pack.

[0089] In some embodiments of this application, the topcoat layer may include covalent bonds -SiO-M1, where M1 is an element present in the inorganic nanoparticles. When preparing the topcoat layer, inorganic nanoparticles modified with a silane coupling agent can be used; the modified inorganic nanoparticles have covalent bonds -SiO-M1 on their surface. Using inorganic nanoparticles modified with a silane coupling agent is beneficial for improving the compatibility and dispersibility of the inorganic nanoparticles with other organic components in the coating, and for improving the uniformity of the micro / nano structure on the coating surface.

[0090] In some embodiments of this application, referring to standard ISO20567-1, a plate sample with dimensions of 150mm × 70mm was placed in a stone impact tester to test the coating's resistance to stone impact. The stones used were rhombic quartz sand with a size of 1mm to 2mm. Each impact cycle used 1kg of stones, the air pressure was 5 bar, and the impact time was 10s. After the impact test, the area of ​​coating lifting and peeling was ≤1cm². 2Furthermore, the hydrophobicity meets the HC1 standard. The hydrophobicity is tested using the water spray grading method (HC grading method), which includes seven grades: HC1, HC2, HC3, HC4, HC5, HC6, and HC7, with HC1 exhibiting the best hydrophobicity. Coatings meeting these conditions demonstrate excellent adhesion, abrasion resistance, impact resistance, and hydrophobicity, providing good protective performance.

[0091] In some embodiments of this application, the coating was subjected to abrasion resistance testing using 1 kg of CS-17 friction medium, according to standard ASTM D4060, at a rate of 45 cycles / minute for 1000 cycles. After the abrasion resistance test, the coating showed no bare substrate, no cracks, no peeling, and its hydrophobicity met the HC1 standard. Coatings meeting these conditions exhibit excellent abrasion resistance and hydrophobicity, providing good protective performance.

[0092] In some embodiments of this application, referring to standard GB / T 9286, the sample was placed in an environment of 25°C and 50% humidity for 24 hours and then immediately subjected to an adhesion test. The adhesion test showed that the coating's adhesion was grade 0. The adhesion test method for the coating was performed according to GB / T 9286. The coating meeting the above conditions exhibited excellent adhesion and bonding strength between the coating and the enclosure, thus providing good protective performance.

[0093] In some embodiments of this application, the coating was subjected to salt spray testing according to test method 6 in standard GB / T 2423.18. After the test, the coating showed no softening, swelling, blistering, lifting, discoloration, exposure of the substrate, cracking, or peeling. Furthermore, the hydrophobicity met HCl, and the adhesion was grade 0-1. Coatings meeting these conditions exhibit excellent corrosion resistance, hydrophobicity, and adhesion, thus providing good protective effects.

[0094] In some embodiments of this application, the coating was subjected to an impact resistance test at an impact energy of 10J, in accordance with standard GB / T 1732. After the impact test, the coating showed no substrate exposure, no cracks, no peeling, and its hydrophobicity met the HCl standard. The coating meeting these conditions exhibited excellent impact resistance and hydrophobicity, thus providing good protective performance.

[0095] This application does not impose any particular limitation on the shape of the battery cell. For example, in some embodiments of this application, the battery cell can be a pouch cell, a prismatic cell, or a cylindrical cell. Figure 1 Here is a square-structured battery cell 1 as an example.

[0096] In some embodiments of this application, multiple battery cells can be placed directly in the housing space of the casing, or multiple battery cells can be assembled into a battery module and then placed in the housing space of the casing. Figure 2This is battery module 2 as an example. (See reference...) Figure 2 In battery module 2, multiple battery cells 1 can be arranged sequentially along the length of battery module 2. Of course, they can also be arranged in any other manner. Furthermore, the multiple battery cells 1 can be secured with fasteners. Battery module 2 may also include a housing with a receiving space in which the multiple battery cells 1 are housed. Figure 3 and 4 This is battery pack 3 as an example. (See reference...) Figure 3 and 4 The battery pack 3 may include a housing, which consists of an upper housing 4 and a lower housing 5. The upper housing 4 covers the lower housing 5 and forms a space for housing. Multiple battery modules 2, assembled from individual battery cells 1, can be arranged in the housing in any manner. The specific number of individual battery cells or battery modules in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0097] Based on the same inventive concept, a second aspect of this application provides a method for manufacturing a battery pack, comprising: forming a coating on at least a portion of the outer surface of the casing, the coating comprising a polyurea material, the surface of the coating having micron-level protrusions, and the surface of the micron-level protrusions having nanon-level protrusions; and placing a battery cell within the receiving space of the casing. This allows the resulting battery pack to possess good hydrophobicity, impact resistance, and abrasion resistance.

[0098] In some embodiments of this application, forming a coating on at least a portion of the outer surface of the housing may include the following steps:

[0099] The first component and the second component are mixed and sprayed onto at least a portion of the outer surface of the casing to form a primer layer comprising a polyurea material, wherein the first component comprises a terminal amino compound; and the second component comprises an isocyanate and / or an isocyanate prepolymer.

[0100] Inorganic nanoparticles and fluorocarbon materials are mixed with a first solvent and then sprayed onto the surface of the primer layer away from the box to form a topcoat layer. The surface of the topcoat layer has micron-level protrusions, and the surface of the micron-level protrusions has nanon-level protrusions.

[0101] This approach facilitates obtaining primer and topcoat layers within the desired thickness ranges, enables the micro / nano structure design of the topcoat layer, and improves the stability of the coating structure. Consequently, it allows the coating to provide better protection, resulting in a battery pack with superior hydrophobicity, impact resistance, and abrasion resistance. It should be noted that the individual thickness ranges of the primer and topcoat layers, the total thickness range of the coating, and the beneficial effects achieved by meeting these thickness ranges have been described in the preceding sections and will not be repeated here.

[0102] In some embodiments of this application, the first component or the second component may further include a first coupling agent. Optionally, the first coupling agent may be a silane coupling agent. Introducing a coupling agent into the first component or the second component helps to form a covalent bond between the primer layer and the casing, further improving the bonding strength between the primer layer and the casing, improving the adhesion of the coating, and thus further improving the wear resistance and stone impact resistance of the battery pack.

[0103] In some embodiments of this application, 30-70 parts by weight of a terminal amino compound, 1-8 parts by weight of a first coupling agent, 2-10 parts by weight of a filler, 0-30 parts by weight of an amine chain extender, 0-5 parts by weight of a pigment, and a second solvent can be mixed to obtain a first component. Exemplarily, the weight percentage of the terminal amino compound can be 30, 35, 40, 45, 50, 55, 60, 65, or 70, etc.; the weight percentage of the first coupling agent can be 1, 2, 3, 4, 5, 6, 7, or 8, etc.; the weight percentage of the filler can be 2, 3, 4, 5, 6, 7, 8, 9, or 10, etc.; the weight percentage of the amine chain extender can be 0, 5, 10, 15, 20, 25, or 30, etc.; and the weight percentage of the pigment can be 0, 1, 2, 3, 4, or 5, etc. Optionally, the first component may include 20 to 100 parts by weight of a second solvent, such as 20, 30, 40, 50, 60, 70, 80, 90, or 100 parts by weight. Introducing fillers helps to further improve the impact resistance of the primer layer; introducing amine chain extenders helps to further increase the molecular weight of the polyurea material, which in turn helps to further improve the density and impact resistance of the primer layer; introducing pigments helps to achieve the desired appearance color. Comprehensively controlling the raw material composition and dosage of the first component within the given range helps to further improve the impact resistance of the primer layer.

[0104] In some embodiments of this application, 50-85 parts by weight of isocyanate, 5-25 parts by weight of polyol, 0.1-1 parts by weight of catalyst, and a third solvent can be mixed to obtain a second component. Exemplarily, the weight percentage of isocyanate can be 50, 55, 60, 65, 70, 75, 80, or 85, etc.; the weight percentage of polyol can be 5, 10, 15, 20, or 25, etc.; and the weight percentage of catalyst can be 0.1, 0.3, 0.5, 0.8, or 1 part by weight, etc. Optionally, the second component may include 50-200 parts by weight of a third solvent, such as 50, 60, 70, 80, 90, 100, 120, 150, 180, or 200 parts by weight of the third solvent. Introducing a polyol allows the isocyanate to react with hydroxyl groups to obtain an isocyanate prepolymer, thereby further increasing the molecular weight of the polyurea material and improving the density and impact resistance of the primer layer. Introducing a catalyst can further promote the reaction between isocyanate and polyol, increasing the molecular weight of the isocyanate prepolymer. The isocyanate prepolymer includes isocyanate prepolymers containing isocyanate end groups. By comprehensively controlling the raw material composition and dosage of the second component within a given range, an isocyanate prepolymer with a relatively high molecular weight can be obtained, enabling the polyurea reaction between the second and first components to obtain a polyurea material.

[0105] In some embodiments of this application, when the first component and the second component are mixed, the isocyanate in the second component can be in relative excess relative to the terminal amino compound in the first component. This is also beneficial for the isocyanate prepolymer obtained in the second component to react with the inorganic nanoparticles in the topcoat layer to form covalent bonds during the preparation of the topcoat layer, thereby improving the bonding strength between the topcoat layer and the primer layer and improving the structural stability of the coating.

[0106] In some embodiments of this application, 10-80 parts by weight of inorganic nanoparticles, 30-70 parts by weight of fluorocarbon material, 0-40 parts by weight of a second coupling agent, and a first solvent can be mixed and sprayed onto the surface of the primer layer away from the housing. For example, the weight percentage of the inorganic nanoparticles can be 10, 20, 30, 40, 50, 60, 70, or 80, etc.; the weight percentage of the fluorocarbon resin can be 30, 35, 40, 45, 50, 55, 60, 65, or 70, etc.; and the weight percentage of the second coupling agent can be 0, 5, 10, 15, 20, 25, 30, 35, or 40, etc. Optionally, in the mixture, the weight percentage of the first solvent can be 50-300, such as 50, 60, 70, 80, 90, 100, 120, 150, 180, 200, 220, 250, 280, or 300, etc. Optionally, the second coupling agent can be a silane coupling agent. Optionally, the fluorocarbon material can include a fluorocarbon resin. Introducing the fluorocarbon material not only reduces the surface energy of the topcoat layer but also encapsulates inorganic nanoparticles, reducing their water absorption and improving the hydrophobicity of the topcoat layer. Introducing the second coupling agent can hydrophobically modify the inorganic nanoparticles, improving their compatibility and dispersibility with the fluorocarbon resin. This further facilitates obtaining a coating with better hydrophobicity.

[0107] In some embodiments of this application, the terminal amino compound in the first component may be one or more of polyetheramine, butanediamine, hexamethylenediamine, decanediamine, diammonium diamine (priamine 1074), and 4,4′-diaminodicyclohexylmethane.

[0108] In some embodiments of this application, the filler in the first component may include, but is not limited to, one or more of calcium carbonate, silica, talc, silicates, and alumina. Optionally, the silica may be fumed silica. The calcium carbonate may be light calcium carbonate.

[0109] In some embodiments of this application, the amine chain extender in the first component may be one or more of diethyltoluenediamine, dimethylthiotoluenediamine, N,N-dialkylmethyldiphenylamine, ethylenediamine, triethylenetetramine, diethylenetriamine, and N-isopropylethylenediamine.

[0110] In some embodiments of this application, the isocyanate in the second component may be one or more of TDI, MDI, PAPI, LMDI, HDI, IPDI, and XDI, including but not limited to TDI, MDI, PAPI, LMDI, HDI, IPDI, and XDI.

[0111] In some embodiments of this application, the polyol in the second component may include, but is not limited to, polyether polyols and / or polyester polyols. For example, the polyether polyol may include one or more of the following brands: 210 polyether, 220 polyether, 330E polyether, 347 polyether, and 466H polyether. For example, the polyester polyol may include one or more of the following brands: PDA-1000, PDA-2000, PEA-1000, PEA-2000, PEA-3000, PBA-580, PBA-1000, PBA-2000, PEBA-1000, PEBA-2000, PEDA-2000, and PEPA-2000.

[0112] In some embodiments of this application, the catalyst in the second component may include, but is not limited to, one or more of dimethyltin dilaurate, stannous octoate, succinic acid, N,N-dimethylethanolamine, and bis(dimethylaminomethyl)benzene.

[0113] In some embodiments of this application, the fluorocarbon material may include fluorocarbon resin. Exemplary examples include one or more of PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), FEVE (fluoroolefin-vinyl ether copolymer), and PVF (polyvinyl fluoride).

[0114] In some embodiments of this application, the first coupling agent and the second coupling agent may be, independently including but not limited to, one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

[0115] In some embodiments of this application, the first solvent, the second solvent, and the third solvent may be, independently, including but not limited to, one or more of N,N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, toluene, methane chloride, and ethyl acetate.

[0116] In some embodiments of this application, the mixing volume ratio of the first component and the second component can be 1:(1 to 1.3). For example, the range can be 1:1, 1 / 1.1, 1 / 1.2, or 1 / 1.3, etc.

[0117] In some embodiments of this application, the first component and the second component are mixed and sprayed onto at least a portion of the outer surface of the casing. The spraying pressure can be 0.4 MPa to 0.8 MPa, and the spraying distance can be 20 cm to 100 cm. For example, the spraying pressure can be 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, or 0.8 MPa, etc. For example, the spraying distance can be 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, or 100 cm, etc. This facilitates thorough mixing of the terminal amino compound in the first component and the isocyanate prepolymer in the second component after spraying, forming a uniform primer layer on the outer surface of the casing.

[0118] In some embodiments of this application, inorganic nanoparticles and fluorocarbon materials can be mixed with a first solvent and sprayed onto the surface of the primer layer away from the housing. The spraying pressure can be 0.4 MPa to 0.8 MPa, the spraying distance can be 20 cm to 100 cm, and the number of sprays can be 3 to 5. For example, the spraying pressure can be 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, or 0.8 MPa, etc. For example, the spraying distance can be 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, or 100 cm, etc. For example, the number of sprays can be 3, 4, or 5. Multiple sprayings also help improve the drying efficiency of the topcoat layer. Therefore, it is beneficial for the fluorocarbon materials and inorganic nanoparticles to embed into the primer layer and form a topcoat layer with a micro-nano structure on the surface of the primer layer.

[0119] It should be noted that the method for preparing the battery pack described in the second aspect of this application is based on the same inventive concept as the battery pack in the first aspect of this application. The features and effects described for the battery pack in the first aspect of this application are also applicable to the method for preparing the battery pack in the second aspect of this application, and will not be repeated here.

[0120] A third aspect of this application provides an electrical device comprising: a battery pack according to the first aspect of this application, or a battery pack prepared using the method described in the second aspect of this application. The battery pack is used to provide electrical energy.

[0121] Specifically, the battery pack can serve as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks), electric trains, ships and satellites, and energy storage systems. Figure 5This is an example of an electrical device. The electrical device includes pure electric vehicles, hybrid electric vehicles, or plug-in hybrid electric vehicles.

[0122] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0123] Example 1

[0124] Forming a coating on the surface of aluminum sheet:

[0125] First component: by weight, it includes: 60 parts of terminal amino compound polyetheramine, 5 parts of coupling agent N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 8 parts of filler nano calcium carbonate, 25 parts of N,N-dialkylmethyldiphenylamine, and 30 parts of solvent N-methylpyrrolidone.

[0126] The second component, by weight, includes: 80 parts isocyanate TDI, 20 parts polyether polyol, 0.5 parts catalyst dimethyl dilaurate tin, and 100 parts solvent toluene;

[0127] The third component, by weight, includes: 40 parts by weight of silica, 10 parts by weight of alumina, 40 parts by weight of fluorocarbon resin PEVE, 10 parts by weight of coupling agent γ-aminopropyltriethoxysilane, and 150 parts by weight of solvent ethyl acetate.

[0128] The first and second components were mixed in a volume ratio of 1:1 and then sprayed onto the substrate surface. The spraying pressure was 0.5 MPa and the spraying distance was 30 cm, forming a primer layer with a thickness of 70 μm.

[0129] The third component was sprayed onto the substrate surface at a pressure of 0.7 MPa, a distance of 20 cm, and four times to form a topcoat layer with a thickness of 20 μm.

[0130] Example 2

[0131] The difference from Example 1 is that no coupling agent is added to the first component.

[0132] Example 3

[0133] The difference from Example 1 is that the weight of TDI isocyanate in the second component is 55.

[0134] Example 4

[0135] The difference from Example 1 is that the inorganic nanoparticles in the third component include 50 parts by weight of silicon dioxide and do not contain aluminum oxide.

[0136] Example 5

[0137] The difference from Example 1 is that the fluorocarbon resin used is a silicone resin.

[0138] Example 6

[0139] The difference from Example 1 is that no coupling agent is added to the third component.

[0140] Example 7

[0141] The difference from Example 1 is as follows:

[0142] First component: by weight, it includes: 70 parts of terminal amino compound polyetheramine, 8 parts of coupling agent N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 2 parts of filler nano calcium carbonate, 30 parts of N,N-dialkylmethyldiphenylamine, and 30 parts of solvent N-methylpyrrolidone.

[0143] The second component, by weight, comprises: 85 parts isocyanate TDI, 25 parts polyether polyol, 0.5 parts catalyst dimethyl dilaurate tin, and 100 parts solvent toluene.

[0144] The third component, by weight, includes: 8 parts by weight of silica, 2 parts by weight of alumina, 30 parts by weight of fluorocarbon resin PEVE, 20 parts by weight of coupling agent γ-aminopropyltriethoxysilane, and 150 parts by weight of solvent ethyl acetate.

[0145] The first and second components were mixed at a volume ratio of 1:1 and then sprayed onto the substrate surface. The spraying pressure was 0.5 MPa and the spraying distance was 30 cm, forming a primer layer with a thickness of 50 μm.

[0146] The third component was sprayed onto the substrate surface at a pressure of 0.7 MPa, a distance of 20 cm, and four spraying passes to form a topcoat layer with a thickness of 30 μm.

[0147] Example 8

[0148] The difference from Example 1 is as follows:

[0149] First component: by weight, it includes: 30 parts of terminal amino compound polyetheramine, 1 part of coupling agent N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 10 parts of filler nano calcium carbonate, 5 parts of N,N-dialkylmethyldiphenylamine, and 30 parts of solvent N-methylpyrrolidone.

[0150] The second component, by weight, includes: 50 parts isocyanate TDI, 5 parts polyether polyol, 0.5 parts catalyst dimethyl dilaurate tin, and 100 parts solvent toluene;

[0151] The third component, by weight, comprises: 64 parts by weight of silica, 16 parts by weight of alumina, 70 parts by weight of fluorocarbon resin PEVE, 40 parts by weight of coupling agent γ-aminopropyltriethoxysilane, and 150 parts by weight of solvent ethyl acetate.

[0152] The first and second components were mixed at a volume ratio of 1:1 and then sprayed onto the substrate surface. The spraying pressure was 0.5 MPa and the spraying distance was 30 cm, forming a primer layer with a thickness of 100 μm.

[0153] The third component was sprayed onto the substrate surface at a pressure of 0.7 MPa, a distance of 20 cm, and four spraying passes to form a topcoat layer with a thickness of 10 μm.

[0154] Example 9

[0155] The difference from Example 1 is as follows:

[0156] First component: by weight, it includes: 10 parts of filler nano calcium carbonate, 5 parts of N,N-dialkylmethyldiphenylamine, and other components are the same as in Example 1.

[0157] Example 10

[0158] The difference from Example 1 is as follows:

[0159] The first component, by weight, includes 40 parts of butanediamine and 8 parts of filler nano-calcium carbonate, with other components the same as in Example 1.

[0160] Example 11

[0161] The difference from Example 1 is as follows:

[0162] The first component, by weight, comprises 55 parts of hexamethylenediamine and 8 parts of silicon dioxide, with other components the same as in Example 1.

[0163] Comparative Example 1

[0164] The difference from Example 1 is as follows:

[0165] Without the third component, only the first and second components are mixed at a volume ratio of 1:1 and sprayed onto the substrate surface. The spraying pressure is 0.5 MPa and the spraying distance is 30 cm, forming a coating with a thickness of 90 μm.

[0166] Comparative Example 2

[0167] The difference from Example 1 is as follows:

[0168] A 70μm thick commercially available bisphenol A epoxy resin coating was sprayed onto the substrate surface. The third component was then sprayed onto the epoxy coating surface at a spraying pressure of 0.7MPa, a spraying distance of 20cm, and four spraying passes to form a 20μm thick topcoat layer.

[0169] Comparative Example 3

[0170] The first, second, and third components were mixed in a volume ratio of 1:1:0.5 and then sprayed onto the substrate surface. The spraying pressure was 0.5 MPa and the spraying distance was 30 cm, forming a primer layer with a thickness of 90 μm.

[0171] Performance testing:

[0172] Contact angle test: The test was conducted using ultrapure water, in accordance with ASTM D7334.8.

[0173] Impact resistance test: Refer to standard GB / T 1732, impact energy is 10J.

[0174] Stone impact resistance test: Referring to standard ISO20567-1, a plate sample with a length and width of 150mm×70mm was selected and placed in a stone impact tester to test the stone impact resistance of the coating. The stones used were rhombic quartz sand with a size of 1mm to 2mm. Each impact cycle used 1kg of stones, the air pressure was 5bar, and the impact time was 10s.

[0175] Abrasion resistance test: According to standard ASTM D4060, 1 kg of friction medium CS-17 was used for testing, 45 cycles / minute, 1000 cycles.

[0176] Adhesion test: Performed in accordance with GB / T 9286.

[0177] Microscopic morphology testing: The prepared sample was cut using ion beam sputtering to obtain the cross-section of the coating. The morphology of the coating cross-section was observed using scanning electron microscopy.

[0178] Characterization of chemical bonds and functional groups: Infrared spectroscopy analysis.

[0179] The coatings prepared in Examples 1-11 and Comparative Examples 1-3 were subjected to relevant tests, and the test results are detailed in Table 1. Figure 6 , Figure 7 and Figure 8 .

[0180] Table 1. Partial test results of Examples 1-11 and Comparative Examples 1-3

[0181]

[0182] Results and conclusions:

[0183] As can be seen from Examples 1-11, Comparative Examples 1-3, and Table 1, using polyurea material to prepare the coating, and forming micron-level protrusions on the coating surface, and further forming nano-level protrusions on the surface of the micron-level protrusions, can result in a coating that possesses good hydrophobicity, impact resistance, stone chip resistance, and abrasion resistance. Figure 6 The infrared spectrum of the coating obtained in Example 1 is shown, with values ​​at 3303 cm⁻¹. -1 The characteristic peak at 1636 cm⁻¹ is attributed to the NH stretching vibration absorption peak of the urea group. -1 The characteristic peak at this location is attributed to the C=O stretching vibration absorption peak of the urea group, indicating that the coating prepared in Example 1 contains polyurea material; furthermore... Figure 6 In the middle, at 1731cm -1 The characteristic peak at 1541 cm⁻¹ is attributed to the C=O absorption peak of carbamate. -1 The characteristic peak at that location is attributed to the NH absorption peak of carbamate. Figure 7 and Figure 8 The microstructure of the coating obtained in Example 1 is shown in the figure. Figure 7 and Figure 8 As can be seen, the coating surface prepared in Example 1 has obvious micron-level protrusions, and the surface of these micron-level protrusions also has nano-level protrusions. Furthermore, combining Examples 1 and 2, it is known that introducing a coupling agent on the side of the coating close to the substrate is beneficial for further improving the coating's adhesion, abrasion resistance, and stone impact resistance. Combining Examples 1 and 3, it is known that appropriately increasing the amount of isocyanate is beneficial for further improving the coating's adhesion, abrasion resistance, and stone impact resistance. The main reason for this is that the polyurethane prepolymer formed can react with the hydroxyl groups on the surface of inorganic particles in the substrate and / or coating to form covalent bonds. Combining Examples 1 and 4, it is known that introducing alumina into the coating forms micro / nano-structures on the surface. The structure is beneficial to further improve the wear resistance of the coating; as can be seen from Examples 1 and 5, the use of fluorocarbon resin and inorganic nanomaterials to form a micro-nano structure on the coating surface is beneficial to further improve the hydrophobicity of the coating; as can be seen from Examples 1 and 5, the introduction of coupling agent on the coating surface can also further improve the hydrophobicity, wear resistance, stone impact resistance and other properties of the coating; as can be seen from Examples 1 and Examples 1-11 and Comparative Examples 1-3, the coatings in the above embodiments of this application can obtain better hydrophobicity, impact resistance, stone impact resistance and wear resistance when used in the battery pack housing.

[0184] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery pack, characterized in that, include: Battery cell; The housing defines a receiving space for accommodating the individual battery cells; At least a portion of the outer surface of the enclosure is provided with a coating, the coating comprising a polyurea material, the surface of the coating having micron-level protrusions, and the surface of the micron-level protrusions having nanon-level protrusions.

2. The battery pack according to claim 1, characterized in that, The micron-sized protrusions include fluorocarbon materials and inorganic nanoparticles.

3. The battery pack according to claim 2, characterized in that, The fluorocarbon material includes fluorocarbon resin; and / or, The inorganic nanoparticles include one or more of the following: aluminum oxide, silicon dioxide, silicon nitride, copper sulfide, iron oxide, zinc oxide, titanium oxide, zirconium oxide, iron(II,III) oxide, and ferric oxide.

4. The battery pack according to claim 2 or 3, characterized in that, The inorganic nanoparticles include one or more of the following: alumina, zirconium oxide, silicon dioxide, and silicon nitride.

5. The battery pack according to any one of claims 2 to 4, characterized in that, The coating comprises a covalent bond -HNCOO-M1, wherein M1 is an element present in the inorganic nanoparticles.

6. The battery pack according to any one of claims 1 to 5, characterized in that, The coating and the housing are covalently bonded, and the covalent bonds include -SiO-M2, where M2 is an element present on the surface of the housing.

7. The battery pack according to any one of claims 2 to 5, characterized in that, The coating comprises a covalent bond -SiO-M1, wherein M1 is an element present in the inorganic nanoparticles.

8. The battery pack according to any one of claims 1 to 7, characterized in that, The contact angle of the coating is ≥120°; and / or, the roll-off angle of the coating is ≤10°.

9. The battery pack according to any one of claims 1 to 8, characterized in that, The contact angle of the coating is ≥150°; and / or the roll-off angle of the coating is ≤5°.

10. The battery pack according to any one of claims 1 to 9, characterized in that, The thickness of the coating is 60μm to 130μm.

11. The battery pack according to any one of claims 1 to 10, characterized in that, The thickness of the coating is 60μm to 100μm.

12. The battery pack according to any one of claims 1 to 11, characterized in that, The coating comprises: A primer layer, the primer layer being located on at least a portion of the outer surface of the enclosure, the primer layer comprising a polyurea material; A topcoat layer, the topcoat layer being located on the surface of the primer layer away from the housing, the surface of the topcoat layer having the micron-level protrusions, and the surface of the micron-level protrusions having the nano-level protrusions.

13. The battery pack according to claim 12, characterized in that, The thickness of the primer layer is 50μm to 100μm, and the thickness of the topcoat layer is 10μm to 30μm.

14. The battery pack according to claim 12 or 13, characterized in that, The primer layer and the housing are connected by covalent bonds, and the covalent bonds include -SiO-M2, where M2 is an element present on the surface of the housing.

15. The battery pack according to any one of claims 12 to 14, characterized in that, The micron-sized protrusions comprise fluorocarbon materials and inorganic nanoparticles. The primer layer and the topcoat layer are covalently bonded, with the covalent bonds comprising -HNCOO-M1, where M1 is an element present in the inorganic nanoparticles; and / or, The topcoat layer comprises covalent bonds -SiO-M1, wherein M1 is an element present in the inorganic nanoparticles.

16. A method for preparing a battery pack, characterized in that, include: A coating is formed on at least a portion of the outer surface of the enclosure, the coating comprising a polyurea material, the surface of the coating having micron-level protrusions, and the surface of the micron-level protrusions having nanon-level protrusions; The individual battery cells are placed within the housing space of the casing.

17. The method according to claim 16, characterized in that, include: The first component and the second component are mixed and then sprayed onto at least a portion of the outer surface of the casing to form a primer layer comprising a polyurea material, wherein the first component comprises a terminal amino compound; and the second component comprises an isocyanate and / or an isocyanate prepolymer. Inorganic nanoparticles and fluorocarbon materials are mixed with a first solvent and then sprayed onto the surface of the primer layer away from the housing to form a topcoat layer. The surface of the topcoat layer has micron-level protrusions, and the surface of the micron-level protrusions has nanon-level protrusions.

18. The method according to claim 17, characterized in that, The first component or the second component further includes: a first coupling agent.

19. The method according to claim 17 or 18, characterized in that, At least one of the following conditions must be met: The first component is obtained by mixing 30-70 parts by weight of a terminal amino compound, 1-8 parts by weight of a first coupling agent, 2-10 parts by weight of a filler, 0-30 parts by weight of an amine chain extender, 0-5 parts by weight of a pigment and a second solvent. The second component is obtained by mixing 50-85 parts by weight of isocyanate, 5-25 parts by weight of polyol, 0.1-1 parts by weight of catalyst with a third solvent. The inorganic nanoparticles, 30-70 parts by weight of fluorocarbon material, 0-40 parts by weight of second coupling agent and first solvent are mixed and sprayed onto the surface of the primer layer away from the box body.

20. The method according to claim 19, characterized in that, At least one of the following conditions must be met: The terminal amino compound includes one or more of polyetheramine, butanediamine, hexanediamine, decanediamine, dimeric aliphatic diamine and 4,4′-diaminodicyclohexylmethane; The filler includes one or more of calcium carbonate, silicon dioxide, talc, silicate, and alumina; The amine chain extender includes one or more of diethyltoluenediamine, dimethylthiotoluenediamine, N,N-dialkylmethyldiphenylamine, ethylenediamine, triethylenetetramine, diethylenetriamine, and N-isopropylethylenediamine; The isocyanate includes one or more of TDI, MDI, PAPI, LMDI, HDI, IPDI, and XDI; The polyols include polyether polyols and / or polyester polyols; The catalyst includes one or more of dimethyltin dilaurate, stannous octoate, succinic acid, N,N-dimethylethanolamine, and bis(dimethylaminomethyl)benzene; The fluorocarbon material includes fluorocarbon resin; The first coupling agent and the second coupling agent each independently comprise one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane; The first solvent, the second solvent, and the third solvent each independently include one or more of N,N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, toluene, methyl chloride, and ethyl acetate.

21. The method according to any one of claims 17 to 20, characterized in that, At least one of the following conditions must be met: The mixing volume ratio of the first component and the second component is 1:(1~1.3); The first component and the second component are mixed and then sprayed onto at least a portion of the outer surface of the box, with a spraying pressure of 0.4 MPa to 0.8 MPa and a spraying distance of 20 cm to 100 cm. The inorganic nanoparticles and the fluorocarbon material are mixed with the first solvent and then sprayed onto the surface of the primer layer away from the box body. The spraying pressure is 0.4MPa to 0.8MPa, the spraying distance is 20cm to 100cm, and the number of spraying times is 3 to 5.

22. An electrical appliance, characterized in that, The battery pack includes any one of claims 1 to 15 or a battery pack prepared by any one of claims 16 to 21.

Images