Ultraviolet curing ink, battery shell, preparation method of battery shell, battery monomer, secondary battery and electric device

Abstract

The invention provides ultraviolet curing ink, a battery shell, a preparation method of the battery shell, a battery monomer, a secondary battery and an electric device, and belongs to the technical field of batteries. The ultraviolet curing ink comprises 10 wt%-30 wt% of acrylic resin, 40 wt%-80 wt% of an active monomer and 2 wt%-10 wt% of a photoinitiator. Wherein the viscosity of the active monomer at 50 DEG C is less than or equal to 10cps. On the premise that the viscosity of the active monomer at 50 DEG C is less than or equal to 10cps and the ratio of the raw materials is met, the viscosity of the ultraviolet light curing ink at 50 DEG C can be less than or equal to 100cps, so that the ultraviolet light curing ink can form an insulating layer precursor on the outer side of the battery shell main body part in a spraying or printing manner and the like; and the insulating layer precursor forms an insulating layer through ultraviolet curing, so that the problem of poor insulating property of the surface of the battery monomer is solved, and the use safety of the power battery and / or the energy storage battery is improved.

Description

Ultraviolet curing ink, battery shell and preparation method thereof, battery cell, secondary battery and power-consuming device Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a UV-curable ink, a battery casing and a preparation method thereof, a battery cell, a secondary battery and an electrical device. Background Art

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become a crucial component of this industry's sustainable development. Battery technology is a crucial factor in the development of electric vehicles. Power batteries and / or energy storage batteries comprise multiple cells. Poor insulation performance on the surface of these cells can affect the safety of the power and / or energy storage batteries.

[0003] Summary of the Invention

[0004] In view of the above problems, the present application provides a UV-curable ink, a battery casing and its preparation method, a battery cell, a secondary battery and an electrical device, which can improve the problem of poor insulation performance on the surface of the battery cell and improve the safety of power batteries and / or energy storage batteries.

[0005] The embodiment of the present application is implemented as follows:

[0006] In a first aspect, the present application provides a UV-curable ink comprising: 10 wt% to 30 wt% acrylic resin, 40 wt% to 80 wt% reactive monomer, 2 wt% to 10 wt% photoinitiator, ≤15 wt% hydrophobic monomer, ≤5 wt% coupling agent, and ≤10 wt% pigment. The reactive monomer has a viscosity of ≤10 cps at 50°C.

[0007] In the technical solution of the embodiment of the present application, under the premise that the active monomer satisfies the viscosity of ≤10cps at 50°C and meets the above-mentioned raw material ratio, the UV-curable ink can achieve a viscosity of ≤100cps at 50°C, so that the UV-curable ink can form an insulating layer precursor on the outside of the main body of the battery shell by spraying or printing, and the insulating layer precursor is cured by UV light to form an insulating layer, thereby improving the problem of poor insulation performance on the surface of the battery cell and improving the safety of the power battery and / or energy storage battery.

[0008] In some embodiments, the reactive monomers include any one or more of isobornyl acrylate, tetrahydrofuran acrylate, bisphenol α dimethacrylate, 2-ethyl acrylate, β-hydroxyethyl methacrylate, 2-methoxyethyl acrylate, tripropylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, dimethylolethane triacrylate, trimethylolpropane triacrylate, 3-ethoxylated trimethylolpropane triacrylate, pentaerythritol pentaacrylate, and dipentaerythritol pentaacrylate. The viscosity of the reactive monomers at 50° C. is ≤10 cps, enabling the resulting UV-curable ink to have a viscosity of ≤100 cps at 50° C., thereby enabling the UV-curable ink to meet spraying or printing requirements.

[0009] In some embodiments, the active monomer includes a first monomer, which is a monofunctional monomer and can improve the toughness of the insulating layer formed by the UV-curable ink after UV-curing.

[0010] In some embodiments, the first monomer includes any one or more of isobornyl acrylate, tetrahydrofuran acrylate, bisphenol α dimethacrylate, 2-ethyl acrylate, β-hydroxyethyl methacrylate, and 2-methoxyethyl acrylate. These monomers are monofunctional monomers and can improve the toughness of the insulating layer formed by UV-curable inks after UV curing.

[0011] In some embodiments, the reactive monomer further comprises a second monomer, wherein the functionality of the second monomer is ≥ 2, and the mass of the second monomer is 30% to 50% of the mass of the first monomer. The second monomer can increase the degree of crosslinking during curing of the UV-curable ink, and when the mass of the second monomer is 30% to 50% of the mass of the first monomer, the insulating layer can maintain both high mechanical properties and good toughness.

[0012] In some embodiments, the second monomer includes any one or more of tripropylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, dimethylolethane triacrylate, trimethylolpropane triacrylate, 3-ethoxylated trimethylolpropane triacrylate, pentaerythritol pentaacrylate, and dipentaerythritol pentaacrylate. The functionality of these monomers is ≥ 2, which can increase the degree of crosslinking during curing of the UV-curable ink and ensure that the insulating layer maintains both high mechanical properties and good toughness.

[0013] In some embodiments, the UV-curable ink includes 0.1 wt% to 15 wt% of a hydrophobic monomer, wherein the hydrophobic monomer has a contact angle with water of ≥90°. The hydrophobic monomer can improve the heat and humidity aging resistance and water resistance of the insulating layer formed by UV-curable ink after UV curing.

[0014] In some embodiments, the hydrophobic monomer includes any one or more of trifluoroethyl (meth)acrylate, hexafluorobutyl (meth)acrylate, dodecafluoroheptyl methacrylate, tetrafluoropropanol methacrylate, γ-methacryloyloxypropyltrimethoxysilane, α-methacryloyloxymethyltrimethylsilane, and trimethylsilyl methacrylate. These monomers are hydrophobic monomers and can improve the wet-heat aging resistance and water resistance of the insulating layer formed by UV-curable inks after UV curing.

[0015] In some embodiments, the UV curable ink includes 0.2 wt% to 5 wt% of a coupling agent, which can enhance the adhesion of the insulating layer formed by UV curing of the UV curable ink to the battery housing body and the structural adhesive.

[0016] In some embodiments, the coupling agent includes any one or more of 3-aminopropyltriethoxysilane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane. These coupling agents can enhance the adhesion of the insulating layer formed by UV-curable ink after UV curing to the main body of the battery housing and the structural adhesive.

[0017] In some embodiments, the UV curable ink includes 1 wt% to 10 wt% of a pigment. The pigment can dye the insulating layer to obtain an insulating layer of a target color.

[0018] In a second aspect, the present application provides a battery housing comprising a main body and an insulating layer, wherein the insulating layer is disposed on at least a portion of an outer surface of the main body and is formed from the aforementioned UV curable ink.

[0019] In the technical solution of the embodiment of the present application, an insulating layer formed by ultraviolet light curing ink is provided on at least part of the outer surface of the main body, thereby improving the problem of poor insulation performance on the surface of the battery cell and improving the safety of the power battery and / or energy storage battery.

[0020] In a third aspect, the present application provides a method for preparing a battery casing, which includes: providing a main body of the battery casing; using the ultraviolet light-curing ink of the above-mentioned embodiment as a raw material, inkjet printing on at least part of the outer surface of the main body to form an insulating layer precursor; curing the insulating layer precursor by ultraviolet light irradiation to form an insulating layer, thereby obtaining the battery casing of the above-mentioned embodiment.

[0021] In the technical solution of the embodiment of the present application, the preparation method of the battery shell of the present application is simple, and the insulating layer precursor can be cured by ultraviolet light to form an integrally formed insulating layer, thereby improving the integrity of the entire insulating layer and the smoothness of the edge position, thereby avoiding or reducing the liquid infiltration of the power battery and / or energy storage battery into the insulating layer conductive shell and other external structures during use, and improving the insulation and water resistance of the power battery and / or energy storage battery under harsh working conditions.

[0022] In a fourth aspect, the present application provides a battery cell, which includes the battery housing in the above embodiment, and the thickness of at least part of the insulating layer is 32.5 μm to 210 μm.

[0023] In a fifth aspect, the present application provides a battery comprising the battery cell in the above embodiment.

[0024] In a sixth aspect, the present application provides an electrical device, which includes the battery cell or battery in the above embodiment, and the battery is used to provide electrical energy.

[0025] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0027] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0028] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0029] FIG3 is a schematic structural diagram of a first battery housing according to some embodiments of the present application;

[0030] FIG4 is a cross-sectional view of a first battery housing according to some embodiments of the present application;

[0031] FIG5 is a partial schematic diagram of FIG4;

[0032] FIG6 is a schematic structural diagram of a second battery housing according to some embodiments of the present application;

[0033] FIG7 is a schematic structural diagram of a third battery housing according to some embodiments of the present application;

[0034] FIG8 is a schematic structural diagram of a fourth battery housing according to some embodiments of the present application;

[0035] FIG9 is a top view of a first battery housing according to some embodiments of the present application;

[0036] FIG10 is a top view of a fourth battery housing according to some embodiments of the present application;

[0037] FIG11 is a perspective view of a battery cell provided in some embodiments of the present application.

[0038] The figure numbers in the specific implementation manner are as follows: 1000-vehicle; 100-battery; 200-controller; 300-motor; 10-housing; 11-first part; 12-second part; 20-battery cell; 21-battery casing; 211-main body; 2111-shell; 2112-end cover; 212-insulating layer; 2121-first insulating layer; 2122-second insulating layer; 22-electrode assembly. DETAILED DESCRIPTION

[0039] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0041] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0042] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0043] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0044] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0045] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0046] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0047] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0048] Power batteries and / or energy storage batteries include multiple battery cells, which are arranged and assembled in a predetermined pattern. To ensure the battery cells' resistance to external impact and rapid heat dissipation, the battery casing is typically made of metal. This can lead to safety issues such as short circuits in the battery cell casing.

[0049] To alleviate safety issues like battery short circuits, insulating films such as PET film are typically used to adhere and coat the outer surface of the battery casing. However, wrinkles and bubbles are prone to forming during the coating process. Furthermore, insulating films such as PET film are inherently weak and easily break, affecting the insulation performance between the battery cell and the exterior. Furthermore, wrapping PET film around the edges and corners of the battery cell requires repeated lamination, affecting the subsequent module assembly dimensions. Condensation easily forms on power batteries and / or energy storage batteries during use, and this dew can easily penetrate through the splicing areas of the PET film, connecting the aluminum shell and the external structure, causing the PET film and other insulating films to lose their insulation properties.

[0050] Based on the above considerations, in order to further improve the safety of power batteries and / or energy storage batteries, the embodiment of the present application designs a UV-curable ink. Under the premise that the active monomer satisfies the viscosity of ≤10cps at 50°C and meets the preset raw material ratio, the UV-curable ink can achieve a viscosity of ≤100cps at 50°C, so that the UV-curable ink can form an insulating layer precursor on the outside of the main body of the battery shell by spraying or printing, and the insulating layer precursor is cured by UV light to form an insulating layer, thereby improving the problem of poor insulation performance on the surface of the battery cell and improving the safety of power batteries and / or energy storage batteries.

[0051] The battery referred to in the embodiments of this application refers to a single physical module that includes multiple battery cells to provide higher voltage and capacity. The battery generally includes a battery box for enclosing multiple battery cells. The battery box can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0052] Each battery cell is a secondary battery; it can be a lithium-ion battery, a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. Battery cells can be cylindrical, flat, rectangular, or other shapes. Battery cells are generally categorized into three types based on packaging: cylindrical, prismatic, and pouch-type.

[0053] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive electrode collector. The uncoated positive electrode collector protrudes from the coated positive electrode collector, and the uncoated positive electrode collector serves as the positive electrode tab. For lithium-ion batteries, for example, the positive electrode current collector can be made of aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative electrode collector. The uncoated negative electrode collector protrudes from the coated negative electrode collector, and the uncoated negative electrode collector serves as the negative electrode tab. The negative electrode current collector can be made of copper, and the negative electrode active material can be carbon or silicon. To ensure that high current can pass without melting, the positive electrode tabs are multiple and stacked together, and the negative electrode tabs are multiple and stacked together. The separator can be made of polypropylene (PP) or polyethylene (PE). In addition, the electrode assembly can be a wound structure or a laminated structure, but the embodiments of the present application are not limited to this.

[0054] The battery cell also includes a current collecting component, which is used to electrically connect the tabs and electrode terminals of the battery cell to transmit electrical energy from the electrode assembly to the electrode terminals, and then to the outside of the battery cell through the electrode terminals; multiple battery cells are electrically connected through the current collecting component to realize series, parallel or mixed connection of multiple battery cells.

[0055] The battery also includes sampling terminals and a battery management system. The sampling terminals are connected to the busbar and are used to collect information about the battery cells, such as voltage or temperature. The sampling terminals transmit the collected battery cell information to the battery management system. If the battery management system detects that the battery cell information is outside the normal range, it will limit the battery's output power for safety protection.

[0056] It will be appreciated that the electrical devices applicable to the batteries described in the embodiments of the present application may be in various forms, for example, mobile phones, portable devices, laptop computers, electric vehicles, electric cars, ships, spacecraft, electric toys and electric tools, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc. Electric toys include fixed or mobile electric toys, for example, game consoles, electric car toys, electric ship toys and electric airplane toys, etc. Electric tools include metal cutting power tools, grinding power tools, assembly power tools and railway power tools, for example, electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers.

[0057] The battery cells and batteries described in the embodiments of the present application are not limited to the electrical devices described above, but can also be applied to all electrical devices using battery cells and batteries. However, for the sake of simplicity, the following embodiments are described using electric vehicles as an example.

[0058] Please refer to Figure 1, which is a structural diagram of a vehicle provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0059] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0060] Please refer to Figure 2, which is an exploded view of a battery provided in some embodiments of the present application. Battery 100 includes a housing 10 and battery cells 20, with battery cells 20 housed within housing 10. Housing 10 provides storage space for battery cells 20 and can have various structures. In some embodiments, housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for battery cells 20. Second portion 12 can be a hollow structure with one end open. First portion 11 can be a plate-like structure, with first portion 11 overlapping the open side of second portion 12, so that the first and second portions 11 and 12 together define a storage space. Alternatively, first portion 11 and second portion 12 can each be a hollow structure with one end open, with the open side of first portion 11 overlapping the open side of second portion 12. Housing 10 formed by first portion 11 and second portion 12 can have various shapes, such as a cylinder or a rectangular parallelepiped.

[0061] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0062] Each battery cell 20 is a secondary battery, which may be a lithium-ion battery, a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0063] According to some embodiments of the present application, a UV-curable ink is provided, comprising: 10 wt% to 30 wt% acrylic resin, 40 wt% to 80 wt% reactive monomer, 2 wt% to 10 wt% photoinitiator, ≤15 wt% hydrophobic monomer, ≤5 wt% coupling agent, and ≤10 wt% pigment. The reactive monomer has a viscosity of ≤10 cps at 50°C.

[0064] Among them, the acrylic resin is selected from any one or more of EBECRYL 572 (functionality 3, number average molecular weight 1500) of the United States, EBECRYL 800 (functionality 4, number average molecular weight 780) of the United States, EBECRYL 837 (functionality 6, number average molecular weight 2700) of the United States, AgiSyn 707 (functionality 4, number average molecular weight 4700) of the Netherlands, AgiSyn 720 (functionality 4, number average molecular weight 1000) of the Netherlands and NeoRad P-56 (functionality 6, number average molecular weight 1800) of the Netherlands.

[0065] The photoinitiator is selected from any one or more of 1-hydroxycyclohexylphenyl ketone, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 2-isopropylthioxanthone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone and 2-hydroxy-2-methyl-1-phenylpropanone.

[0066] On the premise that the active monomer satisfies the viscosity of ≤10cps at 50°C and meets the above-mentioned raw material ratio, the UV-curable ink can achieve a viscosity of ≤100cps at 50°C, so that the UV-curable ink can form an insulating layer precursor on the outside of the main body of the battery shell by spraying or printing. The insulating layer precursor is cured by UV light to form an insulating layer, thereby improving the problem of poor insulation performance on the surface of the battery cell and improving the safety of the power battery and / or energy storage battery.

[0067] Optionally, the viscosity of the reactive monomer at 50° C. is ≤ 8 cps.

[0068] On the premise that the active monomer satisfies the viscosity of ≤8cps at 50°C and meets the above raw material ratio, the UV-curable ink can achieve a viscosity of ≤80cps at 50°C.

[0069] According to some embodiments of the present application, optionally, the active monomer includes any one or more of isobornyl acrylate, tetramethylene acrylate, bisphenol α dimethacrylate, 2-ethyl acrylate, β-hydroxyethyl methacrylate, 2-methoxyethyl acrylate, tripropylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, dimethylolethane triacrylate, trimethylolpropane triacrylate, 3-ethoxylated trimethylolpropane triacrylate, pentaerythritol pentaacrylate and dipentaerythritol pentaacrylate.

[0070] The viscosity of the reactive monomer at 50° C. is ≤10 cps, which can make the viscosity of the prepared UV-curable ink at 50° C. ≤100 cps, thereby making the UV-curable ink meet the requirements of spraying or printing.

[0071] The viscosity of the reactive monomer and the prepared external light curing ink at 50°C can be obtained by testing with reference to the GB / T 2794 method.

[0072] According to some embodiments of the present application, optionally, the active monomer includes a first monomer, and the first monomer is a monofunctional monomer.

[0073] The functionality of the monofunctional monomer, ie, the first monomer, is 1.

[0074] The first monomer can improve the toughness of the insulating layer formed by the ultraviolet curing ink through ultraviolet curing.

[0075] According to some embodiments of the present application, optionally, the first monomer includes any one or more of isobornyl acrylate, tetramethylene acrylate, bisphenol α dimethacrylate, 2-ethyl acrylate, β-hydroxyethyl methacrylate and 2-methoxyethyl acrylate.

[0076] The above monomer is a monofunctional monomer, which can improve the toughness of the insulating layer formed by the ultraviolet curing ink through ultraviolet curing.

[0077] According to some embodiments of the present application, optionally, the active monomer further includes a second monomer, the functionality of the second monomer is ≥2, and the mass of the second monomer is 30% to 50% of the mass of the first monomer.

[0078] As an example, the weight of the second monomer is 30%, 35%, 40%, 45%, or 50% of the weight of the first monomer.

[0079] The second monomer can improve the crosslinking degree of the UV-curable ink during curing, and when the mass of the second monomer is 30% to 50% of the mass of the first monomer, the insulating layer can maintain both high mechanical properties and good toughness.

[0080] According to some embodiments of the present application, optionally, the second monomer includes any one or more of tripropylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, dimethylolethane triacrylate, trimethylolpropane triacrylate, 3-ethoxylated trimethylolpropane triacrylate, pentaerythritol pentaacrylate and dipentaerythritol pentaacrylate.

[0081] The functionality of the above monomers is ≥2, which can improve the cross-linking degree of the UV-curable ink during curing and enable the insulating layer to maintain both high mechanical properties and good toughness.

[0082] According to some embodiments of the present application, optionally, the UV-curable ink includes 0.1 wt % to 15 wt % of a hydrophobic monomer, and the contact angle of the hydrophobic monomer with water is ≥90°.

[0083] The hydrophobic monomer can improve the moisture-heat aging resistance and water resistance of the insulating layer formed by UV-curable ink through UV curing.

[0084] Optionally, the contact angle of the hydrophobic monomer with water is ≥135°.

[0085] According to some embodiments of the present application, optionally, the hydrophobic monomer includes any one or more of trifluoroethyl (meth)acrylate, hexafluorobutyl (meth)acrylate, dodecafluoroheptyl methacrylate, tetrafluoropropanol methacrylate, γ-methacryloyloxypropyltrimethoxysilane, α-methacryloyloxymethyltrimethylsilane and trimethylsilyl methacrylate.

[0086] The above monomer is a hydrophobic monomer, which can improve the moisture-heat aging resistance and water resistance of the insulating layer formed by UV-curable ink through UV curing.

[0087] According to some embodiments of the present application, optionally, the UV curable ink includes 0.2 wt % to 5 wt % of a coupling agent.

[0088] The coupling agent can enhance the adhesion of the insulating layer formed by UV-curing ink through UV curing to the main body of the battery shell and the structural adhesive.

[0089] According to some embodiments of the present application, optionally, the coupling agent includes any one or more of 3-aminopropyltriethoxysilane (KH-550), γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH-560) and γ-methacryloxypropyltrimethoxysilane (KH-570).

[0090] The coupling agent can enhance the adhesion of the insulating layer formed by UV-curable ink through UV-curing to the main body of the battery shell and the structural adhesive.

[0091] According to some embodiments of the present application, optionally, the UV curable ink includes 1 wt% to 10 wt% of pigment.

[0092] The pigment can dye the insulation layer to obtain an insulation layer of a target color.

[0093] Target colors include benzidine yellow, phthalocyanine blue, permanent red, pink, ruby ​​red, or light-fast crimson.

[0094] The pigment includes any one or more of azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, isoindolinone pigments, benzimidazolone pigments, dioxazine pigments, perylene pigments, perinone pigments, anthraquinone pigments, anthrapyrimidine pigments and indanthrene pigments.

[0095] According to some embodiments of the present application, optionally, please refer to Figures 3 to 10. Figure 3 is a schematic structural diagram of a first battery housing 21 in some embodiments of the present application, Figure 4 is a cross-sectional view of the first battery housing 21 in some embodiments of the present application, Figure 5 is a partial schematic diagram of Figure 4, Figure 6 is a schematic structural diagram of a second battery housing 21 in some embodiments of the present application, Figure 7 is a schematic structural diagram of a third battery housing 21 in some embodiments of the present application, Figure 8 is a schematic structural diagram of a fourth battery housing 21 in some embodiments of the present application, Figure 9 is a top view of the first battery housing 21 in some embodiments of the present application, and Figure 10 is a top view of the fourth battery housing 21 in some embodiments of the present application. The present application also provides a battery housing, comprising: a main body 211 and an insulating layer 212. The insulating layer 212 is provided on at least a portion of the outer surface of the main body 211, and the insulating layer 212 is formed by the above-mentioned UV curable ink.

[0096] The main body 211 is the main part of the battery shell. The main body 211 can isolate the electrode assembly in the battery shell from the external environment, and the main body 211 can be mainly made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the main body 211 is not easily deformed when squeezed or collided, so that the battery cell made of the battery shell can have higher structural strength and improved safety performance.

[0097] Furthermore, the main body 211 may be of various shapes and sizes. For example, the main body 211 may be in the shape of a cuboid, a cylinder, a hexagonal prism, etc., and the embodiments of the present application do not impose any special restrictions on this.

[0098] Furthermore, the main body 211 can be made of various materials. For example, the main body 211 can be made of copper, iron, aluminum, stainless steel, aluminum alloy, etc., and the embodiments of the present application do not impose any special restrictions on this.

[0099] The insulating layer 212 is a layered structure made of an insulating material. The insulating layer 212 has a certain insulating capacity. The insulating capacity refers to the ability of the insulating layer 212 to withstand a test voltage without being broken down and losing its insulating properties. The insulating layer 212 can be applied to at least a portion of the outer surface of the main body 211 by spraying or other methods.

[0100] The insulating layer 212 may include one or more layers.

[0101] The outer surface of the main body 211 is the surface of the main body 211 facing the external environment, and the outer surface of the main body 211 forms the outer contour of the main body 211 .

[0102] In the technical solution of the embodiment of the present application, an insulating layer 212 formed of ultraviolet light curing ink is provided on at least part of the outer surface of the main body 211, thereby improving the problem of poor insulation performance on the surface of the battery cell and improving the safety of the power battery and / or energy storage battery.

[0103] Optionally, the insulating layer 212 includes a first insulating layer 2121 arranged on at least a portion of the outer surface of the main body 211, and the thickness of the first insulating layer 2121 is H, where H satisfies: H = (F / A) × 1000 + B; wherein F is the detection voltage, A is the dielectric strength of the first insulating layer 2121, and B is the reserved thickness; and 0.5kV≤F≤6kV, 20μm≤B≤60μm, the unit of the detection voltage is kV, and the unit of the dielectric strength is kV / mm.

[0104] The first insulating layer 2121 is a region where the insulating layer 212 is disposed on at least a portion of the outer surface of the main body 211 .

[0105] The detection voltage is a test voltage applied to the insulating layer 212 , and under the test voltage, the insulating layer 212 is not broken down and the leakage current is less than 0.1 mA.

[0106] The detection voltage can be obtained by the following methods:

[0107] Gradually increase the test voltage and record the voltage when the coating is broken down. This voltage is the detection voltage.

[0108] As an example, the value of F may be 0.5 kV, 0.8 kV, 1 kV, 1.5 kV, 2 kV, 2.5 kV, 3 kV, 3.5 kV, 4 kV, 4.5 kV, 5 kV, 5.5 kV, or 6 kV.

[0109] The detection voltage F of power batteries and energy storage batteries is between 0.5kV and 6kV.

[0110] Among them, the detection voltage of the power battery is 0.5kV~3kV, and the detection voltage of the energy storage battery is 0.5kV~6kV.

[0111] The dielectric strength is a measure of the ability of the insulating layer 212 to withstand high voltage without dielectric breakdown, and the dielectric strength is related to the thickness of the insulating layer 212 .

[0112] The dielectric strength can be measured according to the method of GB / T 1408.2.

[0113] Wherein, dielectric strength=breakdown voltage / thickness of insulating layer 212 .

[0114] The reserved thickness is a thickness value that ensures that the insulating layer 212 has insulating capability. The reserved thickness can avoid thickness fluctuation of the insulating layer 212 during the manufacturing process that may reduce the insulating capability, thereby providing redundancy in the insulating capability of the insulating layer 212 .

[0115] Optionally, the dielectric strength A is ≥ 40 kV / mm.

[0116] As an example, the value of B may be 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, or 60 μm.

[0117] The unit of the insulating layer 212 may be micrometer (μm), the unit of the detection voltage may be kilovolt (kV), the unit of the dielectric strength may be kilovolt per millimeter (KV / mm), and the unit of the reserved thickness may be micrometer (μm).

[0118] If the dielectric strength A of the material of the selected first insulating layer 2121 is 45 kV / mm, the detection voltage F is 2.7 kV, and the reserved thickness B ranges from 20 μm to 60 μm, it can be calculated that the thickness range of the first insulating layer 2121 is 80 μm to 120 μm.

[0119] Controlling the thickness of the insulating layer 212 can not only ensure that the insulating layer 212 has sufficient insulation capability under a specified detection voltage, but also improve material utilization.

[0120] Optionally, referring to Figures 3 to 8, the main body 211 includes a shell 2111 and at least one end cover 2112, the shell 2111 includes at least one opening, the end cover 2112 covers the opening, the outer surface of the shell 2111 is provided with a first insulating layer 2121, and there is a connection between at least one end cover 2112 and the shell 2111. The insulating layer 212 also includes a second insulating layer 2122, and the second insulating layer 2122 covers the connection and is connected to the first insulating layer 2121.

[0121] The end cap 2112 refers to a component that covers the opening of the shell 2111 to isolate the internal environment of the battery cell from the external environment. Without limitation, the shape of the end cap 2112 can be adapted to the shape of the shell 2111 to match the shell 2111. Optionally, the end cap 2112 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 2112 is not easily deformed when squeezed and collided, so that the battery cell can have a higher structural strength and the safety performance can also be improved. Functional components such as electrode terminals can be provided on the end cap 2112. The electrode terminal can be used to electrically connect to the electrode assembly for outputting or inputting electrical energy of the battery cell. In some embodiments, the end cap 2112 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell reaches a threshold.

[0122] Furthermore, the end cap 2112 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular limitations on this. In some embodiments, an insulating member can be provided inside the end cap 2112 to isolate the electrical connection components within the housing 2111 from the end cap 2112 to reduce the risk of short circuits. Exemplary materials include plastic, rubber, etc.

[0123] The shell 2111 is a component used to cooperate with the end cap 2112 to form the internal environment of the battery cell, wherein the formed internal environment can be used to accommodate the electrode assembly, electrolyte, and other components. The shell 2111 and the end cap 2112 can be independent components. An opening can be set on the shell 2111, and the end cap 2112 is made to cover the opening to form the internal environment of the battery cell. Without limitation, the end cap 2112 and the shell 2111 can also be integrated. Specifically, the end cap 2112 and the shell 2111 can form a common connection surface before other components are inserted into the shell. When the interior of the shell 2111 needs to be encapsulated, the end cap 2112 is made to cover the shell 2111.

[0124] Furthermore, the housing 2111 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 2111 can be determined based on the specific shape and size of the electrode assembly. The housing 2111 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular limitations on this.

[0125] The connection point is the connection position between the shell 2111 and the end cover 2112 , which includes a gap, a groove or a protrusion formed between the shell 2111 and the end cover 2112 .

[0126] As an example, the housing 2111 and the end cap 2112 can be fixed together by welding. Therefore, when the housing 2111 and the end cap 2112 are welded, the connection between the housing 2111 and the end cap 2112 forms a weld. The position of the end cap 2112 near the housing 2111 is prone to contact with other conductive objects, resulting in the risk of short circuit. Therefore, the second insulating layer 2122 can be used to cover the weld, thereby reducing the risk of electrical connection between the weld and other conductive objects and ensuring the safety of the battery cell.

[0127] As an example, the connection may be a weld.

[0128] The second insulating layer 2122 is a region where the insulating layer 212 covers the connection and is connected to the first insulating layer 2121 .

[0129] It should be noted that, since the second insulating layer 2122 and the second insulating layer 2122 are cured simultaneously under light after spraying, the connection between the second insulating layer 2122 and the second insulating layer 2122 is smooth and seamless, thereby preventing water from penetrating into the battery cell.

[0130] The outer surface of the shell 2111 is insulated from other conductive objects by the first insulating layer 2121, and the connection between the end cover 2112 and the shell 2111 is insulated from other conductive objects by the second insulating layer 2122, thereby improving the safety of the power battery and / or energy storage battery.

[0131] Optionally, the connection is generally in the shape of a ring, and the second insulating layer 2122 is also in the shape of a ring and is arranged around the connection.

[0132] The position of the second insulating layer 2122 needs to be designed according to the shape of the entire main body 211 . A portion of the second insulating layer 2122 is disposed at the connection, and another portion is disposed on a portion of the outer surface of the end cover 2112 and / or the shell 2111 .

[0133] Optionally, please refer to Figure 3, the second insulating layer 2122 can be partially set at the connection, and the other part can be set on the partial outer surface of the end cover 2112; please refer to Figure 7, the second insulating layer 2122 can also be partially set at the connection, and the other part can be set on the partial outer surface of the shell 2111; please refer to Figure 8, the second insulating layer 2122 can also be partially set at the connection, part can be set on the partial outer surface of the end cover 2112, and the other part can be set on the partial surface of the shell 2111.

[0134] 3-4 and 7-8 , the main body 211 may include a shell 2111 and an end cover 2112 . One end of the shell 2111 has an opening, and the end cover 2112 covers the opening.

[0135] Please refer to FIG. 6 . The main body 211 may include a shell 2111 and two end covers 2112 . The shell 2111 has an opening at two opposite ends respectively, and the two end covers 2112 cover the two openings respectively.

[0136] Optionally, a ratio of the thickness of the second insulating layer 2122 to the thickness of the first insulating layer 2121 is 2-3.

[0137] As an example, the ratio of the thickness of the second insulating layer 2122 to the thickness of the first insulating layer 2121 can be 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 or 3.

[0138] Since the connection between the end cover 2112 and the shell 2111 may have a protrusion due to unevenness, the thickness of the second insulating layer 2122 is set to 2 to 3 times the thickness of the first insulating layer 2121, which is beneficial for the second insulating layer 2122 to better cover the connection between the end cover 2112 and the shell 2111 and reduce the waste of insulating materials.

[0139] If the thickness of the first insulating layer 2121 is in the range of 80 μm to 120 μm, it can be calculated that the thickness of the second insulating layer 2122 is in the range of 160 μm to 360 μm.

[0140] Optionally, referring to FIG. 9 , the width of the second insulating layer 2122 is W=P, where P is the creepage distance of the second insulating layer 2122 ; and 3 mm ≤ P ≤ 10 mm.

[0141] The creepage distance refers to the distance between two conductive parts measured along the surface of the second insulating layer 2122 . Under different usage conditions, the second insulating layer 2122 may be charged due to the polarization of the insulating material surrounding the conductor.

[0142] Creepage distance is determined by system voltage, pollution degree and material properties.

[0143] Creepage distance can be measured according to the method of IEC62368-1.

[0144] The second insulating layer 2122 may be arranged around the connection, and the width direction of the second insulating layer 2122 is perpendicular to the extension direction of the connection.

[0145] The unit of the width of the second insulating layer 2122 may be millimeter (mm), and the unit of the creepage distance may be millimeter (mm).

[0146] When the width W of the second insulating layer 2122 is P, it can prevent or improve the discharge of other objects to the single battery through the second outer surface, thereby improving the safety of the power battery and / or energy storage battery. In particular, when two or more battery cells with insulating layers 212 are in contact with each other and close to each other, the creepage distance requirements can be met.

[0147] If the creepage distance P of the second insulating layer 2122 is 10 mm, the width of the second insulating layer 2122 is 10 mm.

[0148] Optionally, at least part of the outer surface of the end cap 2112 is provided with an insulating layer 212 ; optionally, based on the total area of ​​the outer surface of the end cap 2112 , 5% to 30% of the outer surface of the end cap 2112 is provided with an insulating layer 212 .

[0149] As an example, based on the total area of ​​the outer surface of the end cap 2112 , 5%, 10%, 15%, 20%, 25% or 30% of the outer surface of the end cap 2112 is provided with the insulating layer 212 .

[0150] Part of the outer surface of the end cap 2112 is insulated from other conductive objects by the insulating layer 212, which can improve the safety of the power battery and / or energy storage battery while exposing special positions such as the pole, explosion-proof valve, barcode and liquid filling port.

[0151] Optionally, referring to FIG. 9 , the second insulating layer 2122 is provided only on the edge of the outer surface of the end cover 2112 .

[0152] Optionally, referring to FIG. 10 , except for special locations such as the pole, explosion-proof valve, barcode, and liquid filling port, the outer surface of the end cover 2112 is provided with a first insulating layer 2121 and a second insulating layer 2122 .

[0153] According to some embodiments of the present application, optionally, the present application also provides a method for preparing a battery casing, comprising: providing a main body 211 of the battery casing; using the ultraviolet light-curing ink of the above-mentioned embodiment as a raw material, inkjet printing on at least a portion of the outer surface of the main body 211 to form an insulating layer 212 precursor; curing the insulating layer 212 precursor by ultraviolet light irradiation to form an insulating layer 212, thereby obtaining the battery casing of the above-mentioned embodiment.

[0154] The preparation method of the battery shell of the present application is simple, and the precursor of the insulating layer 212 can be cured by ultraviolet light to form an integrally formed insulating layer 212, thereby improving the integrity of the entire insulating layer 212 and the smoothness of the edge positions, thereby avoiding or reducing the liquid infiltration of the power battery and / or energy storage battery into the insulating layer 212 conductive shell 2111 and other external structures during use, thereby improving the insulation and water resistance of the power battery and / or energy storage battery under harsh working conditions.

[0155] Optionally, the UV light intensity is 2000 mW / cm 2 ~5000mW / cm 2 .

[0156] As an example, the UV light intensity can be 2000 mW / cm 2 , 2500mW / cm 2 3000mW / cm 2 、3500mW / cm 2 , 4000mW / cm 2 , 4500mW / cm 2 or 5000mW / cm 2 .

[0157] Optionally, the ultraviolet light irradiation time is 2s to 20s.

[0158] As an example, the UV light irradiation time can be 2s, 3s, 4s, 5s, 6s, 7s, 8s, 9s or 10s.

[0159] Optionally, the wavelength of the ultraviolet light is 350nm to 400nm.

[0160] As an example, the wavelength of the ultraviolet light may be 350 nm, 360 nm, 370 nm, 380 nm, 390 nm, or 400 nm.

[0161] According to some embodiments of the present application, optionally, please refer to Figure 11, which is a perspective view of a battery cell 20 provided in some embodiments of the present application. The present application also provides a battery cell 20, which includes the battery housing 21 in the above embodiment.

[0162] The battery cell 20 is the smallest unit of the battery. As shown in FIG11 , the battery cell 20 includes an end cap 2112 , a housing 2111 , an electrode assembly 22 , and other functional components.

[0163] The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 22 may be contained in the housing 2111. The electrode assembly 22 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly 22, and the parts of the positive and negative electrode sheets without active materials each constitute a tab. The positive and negative electrode tabs may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive active material and the negative active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0164] The thickness of the first insulating layer 2121 is 32.5 μm to 210 μm.

[0165] Optionally, the thickness of the first insulating layer 2121 is 80 μm to 120 μm, and the thickness of the second insulating layer 2122 is 160 μm to 240 μm.

[0166] Optionally, the thickness of the first insulating layer 2121 is 90 μm to 110 μm, and the thickness of the second insulating layer 2122 is 180 μm to 220 μm.

[0167] The UV curable ink and battery housing of the present application are further described in detail below with reference to the embodiments.

[0168] The amount of components used in the UV-curable inks of Examples 1 to 26 and Comparative Examples 1 to 3 is shown in Table 1, and the type of components used in the UV-curable inks of Examples 1 to 26 and Comparative Examples 1 to 3 is shown in Table 2.

[0169] Table 1 Component dosage of UV curable inks of Examples 1 to 26 and Comparative Examples 1 to 3

[0170] Table 2 Component types of UV curable inks of Examples 1 to 26 and Comparative Examples 1 to 3

[0171] Test Example 1

[0172] The properties of the UV-curable inks of Examples 1 to 26 and Comparative Examples 1 to 3 were measured and shown in Table 3.

[0173] The test methods for the properties of the insulating layers of Examples 1 to 26 and Comparative Examples 1 to 3 are as follows:

[0174] 1. Viscosity

[0175] Tested according to GB / T 2794 method.

[0176] 1. Shear strength

[0177] Standard aluminum sheets with insulation layers are overlapped with structural adhesive and tested according to the GB / T 7124 method.

[0178] 2. Insulation withstand voltage test

[0179] Cut the insulation layer into 5×5cm rectangular strips and attach them to the surface of the aluminum plate. Use an insulation withstand voltage tester to perform a 2700V, 60s withstand voltage test. If the leakage current is ≤0.1mA, it passes.

[0180] 3. Adhesion

[0181] Test according to GB / T 9286-1998. Adhere the insulation layer to the surface of a 150 x 100 mm aluminum plate and place it on a horizontal, rigid surface. Use a grid knife to cut perpendicular to the sample, ensuring all cuts penetrate the substrate surface. Then, make the same number of cuts at 90° angles to the original cut lines to form a grid. Then, use a soft brush to brush several times. Apply transparent tape over the grid, flatten it, and remove the tape. Refer to the Adhesion Grading Chart to determine the adhesion of the bonded insulation layer.

[0182] 4. Aging test

[0183] A standard aluminum sheet with an insulation layer was exposed to 85°C / 85% for 1000 hours to test the shear strength and adhesion of the insulation layer after aging.

[0184] 5. Water test

[0185] Place a standard aluminum sheet with an insulating layer in 85°C deionized water for 1000 hours, take it out, wipe off the moisture and let it dry, and test the adhesion and insulation withstand voltage performance of the insulating layer.

[0186] 6. Flexibility test

[0187] According to GB / T 6742, the test specimens coated with the insulating layer shall be bent 180° on mandrels of different diameters, and the minimum curvature diameter at which the insulating layer does not crack or peel off shall be reported.

[0188] Table 3 shows the properties of the UV-curable inks of Examples 1 to 26 and Comparative Examples 1 to 3.

[0189] From the comparison of Examples 1 to 26 and Comparative Examples 1 to 3, it can be seen that the first monomer and the second monomer of Examples 1 to 26 are both active monomers with a viscosity of ≤10 cps at 50°C and meet the ratio relationship, and the viscosity of the obtained UV-curable ink at 50°C is ≤100 cps; the first monomer of Comparative Example 1 is an active monomer with a viscosity of >10 cps at 50°C (lauryl methacrylate, with a viscosity of 47 cps at 50°C), and the viscosity of the obtained UV-curable ink at 50°C is as high as 186 cps; the second monomer of Comparative Example 2 is an active monomer with a viscosity of >10 cps at 50°C. s active monomer (ethoxylated bisphenol A dimethacrylate, viscosity at 50°C is 39cps), the viscosity of the prepared UV-curable ink at 50°C is as high as 153cps; in Comparative Example 3, the first monomer is selected as an active monomer with a viscosity greater than 10cps at 50°C (lauryl methacrylate, viscosity at 50°C is 47cps), and the second monomer is selected as an active monomer with a viscosity greater than 10cps at 50°C (ethoxylated bisphenol A dimethacrylate, viscosity at 50°C is 39cps), and the viscosity of the prepared UV-curable ink at 50°C is as high as 357cps.

[0190] From the comparison between Example 1 and Example 23, it can be seen that Example 23 does not have the second monomer, and its insulation withstand voltage is worse than that of Example 1, and its shear strength is lower.

[0191] From the comparison between Example 1 and Example 24, it can be seen that Example 24 does not have the first monomer, and its flexibility is poorer than that of Example 1.

[0192] From the comparison between Example 1 and Example 25, it can be seen that Example 25 has no hydrophobic monomer, and its adhesion after immersion in water at 85°C is poorer than that of Example 1, and its insulation withstand voltage after immersion in water at 85°C is poorer.

[0193] From the comparison between Example 1 and Example 26, it can be seen that Example 26 does not have a coupling agent, and its adhesion after immersion in water at 85°C is poorer than that of Example 1, and its insulation withstand voltage after immersion in water at 85°C is poorer.

[0194] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A UV curable ink, wherein: The ultraviolet curing ink comprises: 10wt% to 30wt% acrylic resin, 40wt% to 80wt% active monomer, 2wt% to 10wt% photoinitiator, ≤15wt% hydrophobic monomer, ≤5wt% coupling agent and ≤10wt% pigment; Wherein, the viscosity of the active monomer at 50° C. is ≤10 cps.

2. The UV curable ink according to claim 1, wherein: The active monomers include any one or more of isobornyl acrylate, tetrahydrofuran acrylate, bisphenol α dimethacrylate, 2-ethyl acrylate, β-hydroxyethyl methacrylate, 2-methoxyethyl acrylate, tripropylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, dimethylolethane triacrylate, trimethylolpropane triacrylate, 3-ethoxylated trimethylolpropane triacrylate, pentaerythritol pentaacrylate and dipentaerythritol pentaacrylate.

3. The UV curable ink according to claim 1 or 2, wherein: The active monomer includes a first monomer, and the first monomer is a monofunctional monomer.

4. The UV curable ink according to claim 3, wherein: The first monomer includes any one or more of isobornyl acrylate, tetrahydrofuran acrylate, bisphenol α dimethacrylate, 2-ethyl ethyl acrylate, β-hydroxyethyl methacrylate and 2-methoxyethyl acrylate.

5. The UV curable ink according to claim 3 or 4, wherein: The active monomer further includes a second monomer, the functionality of the second monomer is ≥2, and the mass of the second monomer is 30% to 50% of the mass of the first monomer.

6. The UV curable ink according to claim 5, wherein: The second monomer includes any one or more of tripropylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, dimethylolethane triacrylate, trimethylolpropane triacrylate, 3-ethoxylated trimethylolpropane triacrylate, pentaerythritol pentaacrylate and dipentaerythritol pentaacrylate.

7. The UV curable ink according to any one of claims 1 to 6, wherein: The ultraviolet curable ink comprises 0.1wt% to 15wt% of a hydrophobic monomer, and the contact angle between the hydrophobic monomer and water is ≥90°.

8. The UV curable ink according to claim 7, wherein: The hydrophobic monomer includes any one or more of trifluoroethyl (meth)acrylate, hexafluorobutyl (meth)acrylate, dodecafluoroheptyl methacrylate, tetrafluoropropanol methacrylate, γ-methacryloxypropyltrimethoxysilane, α-methacryloxymethyltrimethylsilane and trimethylsilyl methacrylate.

9. The UV curable ink according to any one of claims 1 to 8, wherein: The ultraviolet curable ink includes 0.2 wt % to 5 wt % of a coupling agent.

10. The UV curable ink according to claim 9, wherein: The coupling agent includes any one or more of 3-aminopropyltriethoxysilane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

11. The UV curable ink according to any one of claims 1 to 10, wherein: The ultraviolet curable ink includes 1wt% to 10wt% of pigment.

12. A battery casing, wherein: The battery housing comprises: Main body; An insulating layer is provided on at least a portion of the outer surface of the main body, and the insulating layer is formed by the ultraviolet curable ink according to any one of claims 1 to 11.

13. A method for preparing a battery shell, wherein: The preparation method of the battery shell comprises: Providing a main body of a battery housing; Using the UV curable ink according to any one of claims 1 to 11 as a raw material, inkjet printing is performed on at least a portion of the outer surface of the main body to form an insulating layer precursor; The insulating layer precursor is cured by ultraviolet light to form an insulating layer, thereby obtaining the battery shell as claimed in claim 12.

14. A battery cell, wherein: The battery cell comprises the battery case according to claim 12, and the thickness of at least a portion of the insulating layer is 32.5 μm to 210 μm.

15. A secondary battery, wherein: The secondary battery includes the battery cell according to claim 14 .

16. An electrical device, wherein: The electrical device comprises the battery according to claim 15, and the battery is used for providing electrical energy.

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