Adhesive and manufacturing method thereof, separator, electrode plate, electrode assembly, battery cell, battery, and power consumption device

Abstract

This application discloses an adhesive and its manufacturing method, a separator, an electrode plate, an electrode assembly, a battery cell, a battery, and a power consumption device, and relates to the field of battery technology. The adhesive includes a polyacrylate copolymer and a lithium-containing compound. The adhesive includes a polyacrylate copolymer and a lithium-containing compound, which allows the polymer to have very good swelling resistance, and exhibits good adhesion, improves ionic conductivity, and contributes to controlling the molecular weight and glass transition temperature of the polymer, thereby improving the adhesive performance. The adhesive further includes a lithium-containing compound, which allows the adhesive to have two functions of adhesive and lithium supplement at the same time, and eliminates the need to install an independent metallic lithium layer or lithium supplement layer in the lithium ion battery, and can improve the dynamic performance of the lithium ion battery, reduce the electrochemical impedance, and improve the cycle performance and power supply performance of the lithium ion battery.

Description

[Technical Field]

[0001] The present application relates to the field of battery technology, and more particularly to adhesives and methods for manufacturing the same, separators, plates, electrode assemblies, battery cells, batteries, and power consuming devices.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202310009976.4, proposed on January 4, 2023, for "Adhesive and manufacturing method thereof, separator, electrode plate, electrode assembly, battery cell, battery, and power consumption device," the entire contents of which are incorporated herein by reference. [Background technology]

[0003] Batteries are widely used in automotive power, electrical energy storage, portable electronic products, power tools, etc. During the initial charge / discharge process of a battery, problems such as the formation of an SEI film on the surface of the negative electrode, the presence of some dead lithium and other foreign substance side reactions in the positive electrode material, etc. reduce the efficiency of the initial charge / discharge and affect the cycle performance and power supply performance of the battery. Summary of the Invention

[0004] The present application has been made in view of the above-mentioned problems, and aims to provide an adhesive having good adhesive performance, which further has a lithium replenishment effect, thereby contributing to reducing electrochemical impedance and improving the cycle performance and power consumption performance of lithium ion batteries.

[0005] To achieve the above object, the present application provides an adhesive and a manufacturing method thereof, a separator, a plate, an electrode assembly, a battery cell, a battery, and a power consuming device.

[0006] According to a first aspect, an embodiment of the present application provides an adhesive, the adhesive including a polyacrylate-based copolymer and a lithium-containing compound.

[0007] Therefore, in the technical solutions of the embodiments of this application, the adhesive comprises a polyacrylate copolymer and a lithium-containing compound, which provides the polymer with excellent swelling resistance and excellent adhesion, improves ionic conductivity, and helps control the molecular weight and glass transition temperature of the polymer, thereby improving the adhesive performance. Furthermore, the adhesive further comprises a lithium-containing compound, which allows the adhesive to function as both an adhesive and a lithium replenisher, eliminating the need for a separate lithium metal layer or lithium replenisher layer in the lithium ion battery and allowing the consumed lithium ions to be quickly replenished, increasing the ion transmission rate and improving the structural stability of the lithium ion battery during cycling. When this adhesive is coated on a separator or electrode plate and used in a lithium ion battery, it can improve the dynamic performance of the lithium ion battery, reduce electrochemical impedance, and improve the cycle performance and power consumption performance of the lithium ion battery.

[0008] In any embodiment, the monomers of the polyacrylate copolymer include an acrylate monomer, an acrylonitrile monomer, and an acrylamide monomer.

[0009] The acrylate monomer improves the polymer's swelling resistance and, as a flexible monomer chain segment in the molecular chain, adjusts the polymer's glass transition temperature, improving the adhesive's toughness during application and contributing to its excellent adhesive properties. The acrylonitrile monomer contains a highly polar cyano group, improving ionic conductivity. The acrylamide monomer adjusts the molecular weight. The simultaneous presence of these three monomers controls the polymer's molecular weight and glass transition temperature, thereby improving the adhesive's adhesive properties.

[0010] In any embodiment, the molar ratio of the acrylate monomer to the acrylonitrile monomer to the acrylamide monomer is 1:(0.01-0.8):(0.01-0.15), or optionally 1:(0.05-0.7):(0.05-0.12). By controlling the molar ratio of the three monomers within the above ranges, the molecular weight and glass transition temperature of the polymer can be further controlled, thereby improving the adhesive performance of the adhesive.

[0011] In any embodiment, the acrylate monomer is methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, The acrylonitrile-based monomer includes at least one of acrylonitrile, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; the acrylonitrile-based monomer includes at least one of acrylonitrile and methacrylonitrile; and the acrylamide-based monomer includes at least one of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide. Experiments have shown that the above-mentioned three monomers have good lithium replenishment and adhesion effects, and further improve the cycle performance and power consumption performance of lithium-ion batteries.

[0012] In any embodiment, the mass ratio of lithium to the polyacrylate copolymer is 1:(10-1000), optionally 1:(100-600), and at this blending ratio, the adhesive simultaneously has excellent lithium replenishment and adhesive effects.

[0013] In any embodiment, the adhesive has a volume average particle size Dv50≦50 μm, and optionally Dv50 is 7 to 8 μm. In the above particle size range, the adhesive and lithium replenishment effects are good.

[0014] According to a second aspect, an embodiment of the present application provides a method for producing an adhesive, the method including the steps of adding a monomer of a polyacrylate copolymer to a first emulsifier solution to obtain a preliminary emulsion, adding an initiator to the preliminary emulsion to react with the initiator to obtain a reaction solution, and adding a lithium-containing material to the reaction solution, adjusting the pH value of the reaction solution to 7-8, and filtering the reaction solution to obtain the adhesive.

[0015] Emulsion polymerization has a fast polymerization rate and is advantageous for heat conduction and temperature control. After the reaction reaches a high conversion rate, the viscosity of the emulsion polymerization system remains very low, and the dispersion is stable, easy to control, and allows for continuous operation. Furthermore, the use of lithium-containing materials as pH adjusters saves on pH adjusters, reduces the amount of chemicals added, and reduces the likelihood of side reactions. It also increases the Li content of the adhesive, allowing it to quickly replenish consumed lithium ions in lithium batteries, increasing the ion transfer rate and improving the structural stability of lithium-ion batteries during cycling. When this adhesive is coated on a separator and used in lithium-ion batteries, it improves the kinetic performance of the lithium-ion battery, reduces electrochemical impedance, and improves the cycle performance and power consumption of the lithium-ion battery.

[0016] In any of the embodiments, in the step of adding monomers of a polyacrylate copolymer to the first emulsifier solution to obtain a pre-emulsion, the monomers of the polyacrylate copolymer include an acrylate monomer, an acrylonitrile monomer, and an acrylamide monomer.

[0017] The acrylate monomer improves the polymer's swelling resistance and, as a flexible monomer chain segment in the molecular chain, adjusts the polymer's glass transition temperature, improving the adhesive's toughness during application and contributing to its excellent adhesive properties. The acrylonitrile monomer contains a highly polar cyano group, improving ionic conductivity. The acrylamide monomer adjusts the molecular weight. The simultaneous presence of these three monomers controls the polymer's molecular weight and glass transition temperature, thereby improving the adhesive's adhesive properties.

[0018] In any embodiment, the molar ratio of the acrylate monomer to the acrylonitrile monomer to the acrylamide monomer is 1:(0.01-0.8):(0.01-0.15), or optionally 1:(0.05-0.7):(0.05-0.12). By controlling the molar ratio of the three monomers within the above ranges, the molecular weight and glass transition temperature of the polymer can be further controlled, thereby improving the adhesive performance of the adhesive.

[0019] In any embodiment, the acrylate monomer is methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, The acrylonitrile-based monomer includes at least one of acrylonitrile, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; the acrylonitrile-based monomer includes at least one of acrylonitrile and methacrylonitrile; and the acrylamide-based monomer includes at least one of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide. Experiments have shown that the above-mentioned three monomers have good lithium replenishment and adhesion effects, and further improve the cycle performance and power consumption performance of lithium-ion batteries.

[0020] In any embodiment, the mass ratio of lithium to the polyacrylate copolymer is 1:(10-1000), optionally 1:(100-600), and at this blending ratio, the adhesive simultaneously has excellent lithium replenishment and adhesive effects.

[0021] In any one of the embodiments, the step of adding an initiator to the preliminary emulsion to react with the initiator to obtain a reaction liquid includes: The preliminary emulsion is added to a second emulsifier solution under heating and refluxing conditions, and an initiator is added to react with the second emulsifier solution to obtain a reaction solution.

[0022] The first and second emulsifiers allow the reactants to mix more uniformly, react more thoroughly, and distribute the product more uniformly.

[0023] In any embodiment, the reaction temperature is 20 to 90°C, and the reaction time is 20 to 40 minutes. Experiments have shown that the reaction temperature and time described above result in a more complete reaction and fewer side reactions.

[0024] In any one of the embodiments, in the step of adding a lithium-containing substance to the reaction solution, adjusting the pH value of the reaction solution to 7 to 8, and filtering the reaction solution to obtain the adhesive, The lithium-containing material includes at least one of lithium hydroxide, lithium oxide, lithium carbonate, and elemental lithium. The lithium-containing material is used as a pH adjuster, which on the one hand saves the pH adjuster, reduces the amount of chemicals added, and reduces the probability of side reactions occurring; on the other hand, it can increase the Li content of the adhesive, quickly replenish lithium ions consumed in the lithium battery, increase the ion transmission rate, and improve the structural stability of the lithium-ion battery during cycling.

[0025] The mass ratio of lithium to the polyacrylate copolymer is 1:(10-1000), and optionally 1:(100-600), and this blending ratio improves the pH value adjustment and lithium supplementation effects.

[0026] According to a third aspect, an embodiment of the present application provides a separator, the separator comprising an adhesive according to an embodiment of the first aspect of the present application or an adhesive produced by a method for producing an adhesive according to an embodiment of the second aspect of the present application.

[0027] According to a fourth aspect, an embodiment of the present application provides a plate, the plate comprising an adhesive according to an embodiment of the first aspect of the present application or an adhesive produced by the method for producing an adhesive according to an embodiment of the second aspect of the present application.

[0028] According to a fifth aspect, an embodiment of the present application provides an electrode assembly, the electrode assembly including at least one of the adhesive of the embodiment of the first aspect of the present application, the adhesive manufactured by the adhesive manufacturing method described in the embodiment of the second aspect, the separator of the embodiment of the third aspect, and the electrode plate of the embodiment of the fourth aspect.

[0029] According to a sixth aspect, an embodiment of the present application provides a battery cell, the battery cell including the electrode assembly of the embodiment of the fifth aspect of the present application.

[0030] According to a seventh aspect, an embodiment of the present application provides a battery, the battery including a battery cell according to an embodiment of the sixth aspect of the present application.

[0031] According to an eighth aspect, an embodiment of the present application provides a power consuming device, the power consuming device comprising a battery cell according to an embodiment of the sixth aspect of the present application or a battery according to an embodiment of the seventh aspect. [Brief explanation of the drawings]

[0032] In order to more clearly explain the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the embodiments or prior art description. It is obvious that the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can also obtain other related drawings based on these drawings without exerting any creative efforts. [Figure 1] 1 is a schematic diagram of a battery cell according to one embodiment of the present application; [Figure 2] FIG. 2 is an exploded view of the battery cell shown in FIG. 1 according to the embodiment of the present application. [Figure 3] 1 is a schematic diagram of a battery module according to an embodiment of the present application; [Figure 4] 1 is a schematic diagram of a battery pack according to an embodiment of the present application; [Figure 5] FIG. 5 is an exploded view of the battery pack according to the embodiment of the present application shown in FIG. 4. [Figure 6]1 is a schematic diagram of a power consumption device powered by a secondary battery according to an embodiment of the present application; [Figure 7] 1 is an SEM image of the adhesive of Example 1 of the present application. The realization of the objects, functional features and advantages of the present invention will be further explained with reference to the drawings in conjunction with the examples. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, with appropriate reference to the drawings, embodiments specifically disclosing the adhesive, separator, electrode plate, electrode assembly, battery cell, battery, and power consumption device of the present application will be described in detail. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of structures that are actually the same may be omitted. This is to avoid unnecessarily lengthening the following description and to facilitate understanding by those skilled in the art. Note that the drawings and the following description are provided to enable those skilled in the art to fully understand the present application, and are not intended to limit the subject matter described in the claims.

[0034] The "ranges" disclosed in this application are defined in the form of lower and upper limits. A given range is defined by selecting one lower limit and one upper limit, and the selected lower and upper limits define the boundaries of the particular range. Such defined ranges may be inclusive or exclusive of the end values ​​and are combinable; i.e., any lower limit can be combined with any upper limit to form a single range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if 1 and 2 are listed as minimum range values ​​and 3, 4, and 5 are listed as maximum range values, the ranges 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5 are all contemplated. In this application, unless otherwise specified, the numerical range "ab" represents a shorthand notation for any combination of real numbers from a to b, where a and b are both real numbers. For example, the numerical range "0-5" represents a list of all real numbers between "0-5" and is merely a shorthand for combinations of these numbers. Also, expressing a parameter as an integer ≧2 is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0035] Unless otherwise stated, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0036] Unless otherwise stated, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0037] Unless otherwise specified, all steps in this application may be performed in order or randomly, and are preferably performed in order. For example, when the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed in order, or steps (b) and (a) performed in order. For example, when the method mentioned above may further include step (c), it means that step (c) may be added to the method in any order, and for example, the method may include steps (a), (b), and (c), or may include steps (a), (c), and (b), or may include steps (c), (a), and (b), etc.

[0038] Unless otherwise specified, the terms "comprise" and "include" used in this application may be open-ended or closed-ended. For example, the terms "comprise" and "include" may further include or include other components not listed, or may include or include only the listed components.

[0039] Unless otherwise stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, "A or B" is satisfied when A is true (or exists) and B is false (or does not exist), when A is false (or does not exist) but B is true (or exists), or when both A and B are true (or exist).

[0040] Lithium-ion batteries are widely used in applications such as automotive power, energy storage, portable electronics, and power tools. During the initial charge / discharge process of lithium-ion batteries, an SEI film forms on the surface of the negative electrode, and some dead lithium and other foreign side reactions occur in the positive electrode material, reducing the efficiency of the initial charge / discharge. The primary method for replenishing lithium on the separator is to prefabricate a lithium-layer separator. The lithium-replenishing separator includes multiple stacked separator layers, each consisting of a polymer film, a metallic lithium layer, and a protective layer. The lithium-coated separator is produced by coating one side of a base film with a liquid adhesive and the other side with a lithium-replenishing slurry, followed by drying in an oven to obtain a lithium-replenishing composite separator. The ceramic composite separator has a ceramic layer and a ceramic-lithium replenishing layer on both sides of the base film, respectively, allowing for timely replenishment of consumed lithium ions, increasing the ion transmission rate and improving the structural stability of the lithium battery during cycling. These methods all involve the presence of an independent metallic lithium layer or a lithium supplementary layer, which can improve kinetics, but affect the adhesion between the separator and the electrode plate, which in turn affects the cycle performance and power rating of the battery.

[0041] In other words, the inventors discovered that in actual operation, the lithium replenisher for batteries used in conventional technology affects the adhesive strength between the separator and the electrode plate, and affects the cycle performance and power rating of the battery.

[0042] Based on this, the applicant has examined a large amount of data and conducted a large number of experiments and believes that if the two components, the lithium replenisher and the adhesive, can be combined into one material, there will be no need to provide an extra lithium replenisher layer, which will solve the problem of affecting the adhesive strength between the separator and the electrode plate, and thus affecting the cycle performance and power supply performance of the battery.

[0043] Furthermore, after extensive experimentation, the inventors discovered that organic polymers obtained by polymerizing polymer monomers containing specific functional groups in a certain weight ratio have good adhesive properties and are suitable for fully demonstrating their adhesive properties under battery operating conditions, thereby contributing to improving the dynamic and safety performance of secondary batteries. Furthermore, when the adhesive is used in a separator, it reduces the separator's resistance and contributes to increasing the separator's ionic conductivity, thereby improving battery performance.

[0044] Considering the development of the market situation, the application of power batteries will become more and more widespread. Power batteries are not only used in energy storage power systems such as hydroelectric power, thermal power, wind power and solar power plants, but also widely used in electric transportation tools such as electric bicycles, electric motorcycles and electric cars, as well as in military equipment and aerospace, etc. With the continuous expansion of the application fields of power batteries, the market demand for them is also continuously increasing.

[0045] Based on this, the present application provides adhesives, separators, plates, electrode assemblies, battery cells, batteries, and power consuming devices.

[0046] According to a first aspect, an embodiment of the present application provides an adhesive, the adhesive including a polyacrylate-based copolymer and a lithium-containing compound.

[0047] Polyacrylate copolymers are a general term for polymers produced through copolymerization reactions using acrylates as raw materials. Acrylates have active double bonds and are prone to spontaneous polymerization and copolymerization. The copolymerization monomers may be one or more, and may include other acrylic acid compounds or other unsaturated compounds with double bonds, such as styrene, acrylonitrile, vinyl acetate, and vinyl chloride.

[0048] The lithium-containing compound is a compound containing lithium, and may be organic or inorganic, and any of them falls within the scope of protection of the present application as long as they contain lithium element.

[0049] Therefore, in the technical solutions of the embodiments of this application, the adhesive comprises a polyacrylate copolymer and a lithium-containing compound, which provides the polymer with excellent swelling resistance and excellent adhesion, improves ionic conductivity, and helps control the molecular weight and glass transition temperature of the polymer, thereby improving the adhesive performance. Furthermore, the adhesive further comprises a lithium-containing compound, which allows the adhesive to function as both an adhesive and a lithium replenisher, eliminating the need for a separate lithium metal layer or lithium replenisher layer in the lithium ion battery and allowing the consumed lithium ions to be quickly replenished, increasing the ion transmission rate and improving the structural stability of the lithium ion battery during cycling. When this adhesive is coated on a separator or electrode plate and used in a lithium ion battery, it can improve the dynamic performance of the lithium ion battery, reduce electrochemical impedance, and improve the cycle performance and power consumption performance of the lithium ion battery.

[0050] In any embodiment, the monomers of the polyacrylate copolymer include an acrylate monomer, an acrylonitrile monomer, and an acrylamide monomer.

[0051] The acrylate monomer is a monomer containing an acrylate group, and its structural formula is as follows: TIFF0007829030000001.tif30129 Here, R1 includes a hydrogen atom or an alkyl group of 1 to 6 carbon atoms, and R2 includes a substituted or unsubstituted alkyl group of 1 to 15 carbon atoms, a cycloalkyl group of 3 to 6 carbon atoms, or an isobornyl group, and in the case of substitution, the substituent includes a hydroxyl group or an alkyl group of 1 to 6 carbon atoms.

[0052] The acrylonitrile-based monomer is a monomer containing an acrylonitrile group, and its structural formula is as follows: TIFF0007829030000002.tif30129 Here, R3 comprises a hydrogen atom or an alkyl group of 1 to 6 carbon atoms.

[0053] The acrylamide monomer is a monomer containing an acrylamide group, and its structural formula is as follows: TIFF0007829030000003.tif30129 Here, R4 includes a hydrogen atom or an alkyl group of 1 to 6 carbon atoms, and R5 includes a hydrogen atom, an alkyl group of 1 to 6 carbon atoms substituted with a hydroxyl group, or an alkoxy group of 1 to 6 carbon atoms.

[0054] The acrylate monomer improves the polymer's swelling resistance and, as a flexible monomer chain segment in the molecular chain, adjusts the polymer's glass transition temperature, improving the adhesive's toughness during application and contributing to its excellent adhesive properties. The acrylonitrile monomer contains a highly polar cyano group, improving ionic conductivity. The acrylamide monomer adjusts the molecular weight. The simultaneous presence of these three monomers controls the polymer's molecular weight and glass transition temperature, thereby improving the adhesive's adhesive properties.

[0055] It is understood that the present application does not limit the numbering method of each monomer in the polyacrylate copolymer, and the acrylate monomer, the acrylonitrile monomer and the acrylamide monomer may be arranged in order, or may be arranged randomly, and all of the above methods fall within the scope of protection of the present application.

[0056] In any embodiment, the molar ratio of the acrylate monomer to the acrylonitrile monomer to the acrylamide monomer is 1:(0.01-0.8):(0.01-0.15). For example, the molar ratio may be any one of the following values ​​or a range between any two of 1:0.01:0.01, 1:0.01:0.15, 1:0.8:0.01, 1:0.8:0.15, 1:0.4:0.01, 1:0.4:0.15, 1:0.01:0.08, and 1:0.8:0.08, but is not limited thereto. Controlling the molar ratio of the three monomers within the above ranges further controls the molecular weight and glass transition temperature of the polymer, thereby improving the adhesive performance of the adhesive.

[0057] In any embodiment, the acrylate monomer is methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, The acrylonitrile-based monomer includes at least one of acrylonitrile, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; the acrylonitrile-based monomer includes at least one of acrylonitrile and methacrylonitrile; and the acrylamide-based monomer includes at least one of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide. Experiments have shown that the above-mentioned three monomers have good lithium replenishment and adhesion effects, and further improve the cycle performance and power consumption performance of lithium-ion batteries.

[0058] In any embodiment, the mass ratio of lithium to the polyacrylate copolymer is 1:(10 to 1000), and may be, for example, but not limited to, any one of 1:10, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900, and 1:1000, or a range between any two of these. This blending ratio allows the adhesive to simultaneously exhibit excellent lithium replenishment and adhesive effects.

[0059] Lithium refers to lithium in a lithium-containing compound, and as can be understood, in the examples of the present application, lithium is connected to the polyacrylate copolymer by way of a polymer ionic bond, and lithium is present in the adhesive in the form of a compound.

[0060] In any embodiment, the volume average particle diameter Dv50 of the adhesive is 50 μm or less, and in the examples of the present application, Dv50 is 7 to 8 μm. Within this particle diameter range, the adhesive and lithium replenishment effects are good.

[0061] In the examples of the present application, the particle size corresponding to when the cumulative particle size distribution percentage of the adhesive particles reaches 50% is Dv50, and the test method is as follows:

[0062] Refer to the GB / T 19077-2016 / ISO 13320:2009 laser diffraction particle size distribution standard. Test using a laser particle sizer (Malvern 3000, MasterSizer 3000) with a helium-neon red light source as the primary light source. Add 1g of the sample to a clean, small beaker, add one drop of surfactant, and add 20ml of deionized water (ensure the sample concentration is 8-12% opacity). Sonicate at 53KHz / 120W for 5 minutes to ensure the sample is completely dispersed. Turn on the laser particle sizer and clean the optical path system before automatically testing the background. Stir the already sonicated sample to disperse it evenly. Add it to the sample pool as required and begin measuring the particle size. The measurement results can be read from the instrument.

[0063] According to a second aspect, an embodiment of the present application provides a method for producing an adhesive, the method including the steps of adding a monomer of a polyacrylate copolymer to a first emulsifier solution to obtain a preliminary emulsion, adding an initiator to the preliminary emulsion to react with the initiator to obtain a reaction solution, and adding a lithium-containing material to the reaction solution, adjusting the pH value of the reaction solution to 7-8, and filtering the reaction solution to obtain the adhesive.

[0064] Emulsifiers are organic compounds that form incompatible liquids into a stable emulsion. They are all surface-active substances that can reduce the interfacial tension between liquids, making it easier to emulsify incompatible liquids. During emulsification, the dispersed phase is uniformly distributed in the continuous phase in the form of very small liquid beads (with diameters ranging from 0.1 microns to several tens of microns), and the emulsifier forms a film or double electric layer on the surface of these liquid beads to prevent them from coagulating with each other and maintain the stability of the emulsion. In the examples of this application, the emulsifier used is sodium dodecyl sulfonate.

[0065] The pre-emulsion is a solution formed after emulsifying the monomers of the polyacrylate copolymer to form a stable emulsion of each monomer.

[0066] The initiator, also called a radical initiator, refers to a compound that easily decomposes into radicals (i.e., primary radicals) when exposed to heat, and can be used to initiate the radical polymerization and copolymerization of ene and diene monomers, as well as the crosslinking and curing of unsaturated polyesters and polymer crosslinking reactions. In the examples of this application, the initiator used is potassium persulfate.

[0067] The value of the hydrogen ion concentration index is commonly called the "pH value." The value that represents the degree of acidity or alkalinity of a solution is the negative value of the common logarithm of the hydrogen ion concentration contained. The pH value can be measured using pH test paper or a pH meter.

[0068] Emulsion polymerization has a fast polymerization rate and is advantageous for heat conduction and temperature control. After the reaction reaches a high conversion rate, the viscosity of the emulsion polymerization system remains very low, and the dispersion is stable, easy to control, and allows for continuous operation. Furthermore, the use of lithium-containing materials as pH adjusters saves on pH adjusters, reduces the amount of chemicals added, and reduces the likelihood of side reactions. It also increases the Li content of the adhesive, allowing it to quickly replenish consumed lithium ions in lithium batteries, increasing the ion transfer rate and improving the structural stability of lithium-ion batteries during cycling. When this adhesive is coated on a separator and used in lithium-ion batteries, it improves the kinetic performance of the lithium-ion battery, reduces electrochemical impedance, and improves the cycle performance and power consumption of the lithium-ion battery.

[0069] As can be understood by those skilled in the art, in the above method of the specific embodiment, the order of making each step does not mean to perform it in strict order and constitute any limitation on the implementation process, and the specific order of performing each step should be determined by its function and possible underlying logic.

[0070] In any of the embodiments, in the step of adding monomers of a polyacrylate copolymer to the first emulsifier solution to obtain a pre-emulsion, the monomers of the polyacrylate copolymer include an acrylate monomer, an acrylonitrile monomer, and an acrylamide monomer.

[0071] The acrylate monomer improves the polymer's swelling resistance and, as a flexible monomer chain segment in the molecular chain, adjusts the polymer's glass transition temperature, improving the adhesive's toughness during application and contributing to its excellent adhesive properties. The acrylonitrile monomer contains a highly polar cyano group, improving ionic conductivity. The acrylamide monomer adjusts the molecular weight. The simultaneous presence of these three monomers controls the polymer's molecular weight and glass transition temperature, thereby improving the adhesive's adhesive properties.

[0072] In any embodiment, the molar ratio of the acrylate-based monomer to the acrylonitrile-based monomer to the acrylamide-based monomer is 1:(0.01 to 0.8):(0.01 to 0.15).

[0073] The molar ratio of the monomers is the ratio of the mole numbers of the monomers, and may be, for example, but is not limited to, any one of the following values ​​or a range between any two of 1:0.01:0.01, 1:0.01:0.15, 1:0.8:0.01, 1:0.8:0.15, 1:0.4:0.01, 1:0.4:0.15, 1:0.01:0.08, and 1:0.8:0.08. Controlling the molar ratios of the three monomers within the above ranges further controls the molecular weight and glass transition temperature of the polymer, thereby improving the adhesive performance of the adhesive.

[0074] In any embodiment, the acrylate monomer is methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, The acrylonitrile-based monomer includes at least one of acrylonitrile, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; the acrylonitrile-based monomer includes at least one of acrylonitrile and methacrylonitrile; and the acrylamide-based monomer includes at least one of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide. Experiments have shown that the above-mentioned three monomers have good lithium replenishment and adhesion effects, and further improve the cycle performance and power consumption performance of lithium-ion batteries.

[0075] In any embodiment, the mass ratio of lithium to the polyacrylate copolymer is 1:(10 to 1000), and may be, for example, but not limited to, any one of 1:10, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900, and 1:1000, or a range between any two of these. This blending ratio allows the adhesive to simultaneously exhibit excellent lithium replenishment and adhesive effects.

[0076] In any one of the embodiments, the step of adding an initiator to the preliminary emulsion to react with the initiator to obtain a reaction liquid includes: The preliminary emulsion is added to a second emulsifier solution under heating and refluxing conditions, and an initiator is added to react with the second emulsifier solution to obtain a reaction solution.

[0077] The first and second emulsifiers allow the reactants to mix more uniformly, react more thoroughly, and distribute the product more uniformly.

[0078] As can be understood, in the embodiments of the present application, the first emulsifier and the second emulsifier may be common emulsifiers in the art, such as sodium dodecyl sulfonate, and the present application is not limited thereto; furthermore, the first emulsifier and the second emulsifier may be the same or different, and the present application is also not limited thereto.

[0079] In any embodiment, the reaction temperature is 20 to 90°C, and may be, for example, but is not limited to, any one of 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, or 90°C, or a range between any two of these. The reaction time is 20 to 40 minutes, and may be, for example, but is not limited to, any one of 20 minutes, 22 minutes, 25 minutes, 28 minutes, 30 minutes, 33 minutes, 35 minutes, 37 minutes, or 40 minutes, or a range between any two of these. Experiments have shown that the reaction temperature and time described above result in more complete reactions and fewer side reactions.

[0080] As can be understood, the above-mentioned reaction temperature and reaction time limitations may be satisfied either alone or simultaneously, but in the examples of the present application, both are satisfied simultaneously to make the reaction more complete and reduce side reactions.

[0081] In any one of the embodiments, in the step of adding a lithium-containing substance to the reaction solution, adjusting the pH value of the reaction solution to 7 to 8, and filtering the reaction solution to obtain the adhesive, The lithium-containing material includes at least one of lithium hydroxide, lithium oxide, lithium carbonate, and elemental lithium. All of the lithium-containing materials are alkaline and can adjust the pH of the reaction solution. Using the lithium-containing material as a pH adjuster saves the pH adjuster, reduces the amount of chemicals added, and reduces the probability of side reactions. It also increases the Li content of the adhesive, allowing the lithium ions consumed in the lithium battery to be quickly replenished, increasing the ion transmission rate and improving the structural stability of the lithium ion battery during cycling.

[0082] The mass ratio of lithium to the polyacrylate copolymer is 1:(10 to 1000), and may be, for example, but not limited to, any one of 1:10, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900, and 1:1000, or a range between any two of these values. The above blending ratio improves the pH value adjustment and lithium supplementation effects.

[0083] According to a third aspect, an embodiment of the present application provides a separator, the separator comprising an adhesive according to an embodiment of the first aspect of the present application or an adhesive produced by a method for producing an adhesive according to an embodiment of the second aspect of the present application.

[0084] When the adhesive of the first aspect of the present application is used in a separator, it contributes to reducing the resistance of the separator and increasing the ionic conductivity of the separator, thereby improving battery performance and further serving to effectively replenish lithium.

[0085] The present application does not particularly limit the type of separator substrate, and any known porous structure separator substrate having good chemical stability and mechanical stability can be selected.

[0086] In some embodiments, the separator substrate may be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, without any particular limitation. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, without any particular limitation.

[0087] The separator of the present application can be manufactured using conventional methods for separators in the art, such as dissolving the adhesive described in the first embodiment of the present application in an organic solvent to obtain a slurry, coating the slurry on a separator material, and then drying to remove the organic solvent, thereby obtaining the separator of the present application.

[0088] In some embodiments, the adhesive has a coating density on the separator substrate of 0.3-1.0 g / m 2 and even 0.3-0.8 g / m 2 is.

[0089] According to a fourth aspect, the present application provides an electrode plate, the electrode plate comprising an adhesive manufactured by the adhesive manufacturing method described in the examples of the first aspect of the present application or the adhesive manufacturing method described in the examples of the second aspect of the present application. It comprises an adhesive manufactured by the adhesive manufacturing method described in the examples of the first aspect of the present application or the adhesive manufacturing method described in the examples of the second aspect of the present application. The electrode plate can be manufactured by a method commonly used in the art.

[0090] It should be explained that the electrode plate of the present application may be a positive electrode plate or a negative electrode plate.

[0091] The positive electrode plate includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, and the positive electrode film layer includes the adhesive of the first aspect of the present application.

[0092] For example, the positive electrode current collector has two surfaces that face each other in the thickness direction thereof, and the positive electrode film layer is disposed on either one or both of the two facing surfaces of the positive electrode current collector.

[0093] In some embodiments, the positive electrode current collector may be a metal foil sheet or a composite current collector. For example, aluminum foil may be used as the metal foil sheet. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base layer. The composite current collector may be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0094] In some embodiments, the positive electrode active material may be any positive electrode active material known in the art. For example, the positive electrode active material may include at least one of a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide, and a modified compound of each. However, the present application is not limited to these materials, and other conventional materials usable as positive electrode active materials in batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Here, examples of lithium transition metal oxides include lithium cobalt oxide (e.g., LiCoO), lithium nickel oxide (e.g., LiNiO), lithium manganese oxide (e.g., LiMnO, LiMnO), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 (may be abbreviated as "LiNi") 0.5 Co 0.3 Mn 0.2 O2(NCM 523 (may be abbreviated as "LiNi")0.5 Co 0.25 Mn 0.25 O2(NCM 211 (may be abbreviated as "LiNi") 0.6 Co 0.2 Mn 0.2 O2(NCM 622 (may be abbreviated as "LiNi") 0.8 Co 0.1 Mn 0.1 O2(NCM 811 Lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05 Examples of the lithium-containing phosphate having an olivine structure may include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which may be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.

[0095] In some embodiments, a positive electrode plate can be manufactured in the following manner: Components for manufacturing the positive electrode plate, such as a positive electrode active material, a conductive agent, an adhesive described in the examples of the first aspect of the present application, and any other components, are dispersed in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry, which is then coated onto a positive electrode current collector, and the positive electrode plate is obtained after processes such as drying and cold pressing.

[0096] In some embodiments, the amount of the adhesive used in the positive electrode plate according to the examples of the first aspect of the present application is 1-3%, calculated based on the total weight of the positive electrode membrane layer.

[0097] Similarly, the electrode plate of the present application may be a negative electrode plate, which includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, and the negative electrode film layer includes the adhesive described in the first aspect of the present application.

[0098] For example, the negative electrode current collector has two surfaces that face each other in the thickness direction thereof, and the negative electrode film layer is disposed on either one or both of the two facing surfaces of the negative electrode current collector.

[0099] In some embodiments, the negative electrode current collector may be a metal foil sheet or a composite current collector. For example, the metal foil sheet may be copper foil. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base. The composite current collector may be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymer base material (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0100] In some embodiments, the negative electrode active material may be any negative electrode active material known in the art. For example, the negative electrode active material may include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicone-based material, a tin-based material, and lithium titanate. The silicone-based material may be selected from at least one of a silicone element, a silicone oxide, a silicone carbon composite, a silicone nitrogen composite, and a silicone alloy. The tin-based material may be selected from at least one of a tin element, a tin oxide, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials usable as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination.

[0101] In some embodiments, the negative electrode film layer optionally further comprises a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0102] In some embodiments, the negative electrode membrane layer optionally further comprises other additives, such as a thickener (eg, carboxymethylcellulose sodium (CMC-Na)).

[0103] In some embodiments, a negative electrode plate can be manufactured in the following manner: Components for manufacturing the negative electrode plate, such as a negative electrode active material, a conductive agent, an adhesive described in the examples of the first aspect of the present application, and any other components, are dispersed in a solvent (e.g., deionized water) to form a negative electrode slurry, which is then coated onto a negative electrode current collector, and the negative electrode plate is obtained after processes such as drying and cold pressing.

[0104] In some embodiments, the amount of the adhesive described in the examples of the first aspect of the present application used in the negative electrode plate is 1-3%, calculated based on the total weight of the negative electrode membrane layer.

[0105] According to a fifth aspect, an embodiment of the present application provides an electrode assembly, which includes at least one of the adhesive of the embodiment of the first aspect of the present application, the adhesive manufactured by the adhesive manufacturing method described in the embodiment of the second aspect, the separator of the embodiment of the third aspect, and the electrode plate of the embodiment of the fourth aspect. The electrode assembly proposed in the present application has all the beneficial effects of the adhesive, and will not be further described here.

[0106] According to a sixth aspect, an embodiment of the present application provides a battery cell, the battery cell including the electrode assembly of the embodiment of the fifth aspect of the present application.

[0107] Generally, a battery cell includes a positive electrode plate, a negative electrode plate, an electrolyte, and a separator. During charging and discharging, active ions move back and forth between the positive and negative electrodes, absorbing and releasing ions. The electrolyte functions to conduct ions between the positive and negative electrodes. The separator, located between the positive and negative electrodes, primarily prevents short circuits between the positive and negative electrodes and allows ions to pass through.

[0108] The battery cell can be manufactured by a method commonly used in the art. For example, a positive electrode plate, a negative electrode plate, and a separator can be manufactured into an electrode assembly by a winding process or a stacking process, and an electrolyte solution is injected into the electrode assembly and sealed to manufacture the battery cell.

[0109] The electrolyte serves to conduct ions between the positive and negative electrodes. The present application does not specifically limit the type of electrolyte, and it can be selected according to needs. For example, the electrolyte may be liquid, gel, or all solid.

[0110] In some embodiments, the electrolyte is an electrolytic solution, which includes an electrolyte salt and a solvent.

[0111] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluorobis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0112] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, ethyl methyl sulfone, and diethyl sulfone.

[0113] In some embodiments, the electrolyte solution may further optionally contain additives, such as an additive for forming a negative electrode film or a positive electrode film, and may further include additives that can improve some battery performance, such as an additive for improving the overcharge performance of the battery or an additive for improving the high-temperature or low-temperature performance of the battery.

[0114] In some embodiments, the positive and negative electrodes and the separator can be fabricated into an electrode assembly by a winding or lamination process.

[0115] In some embodiments, the battery cell may include an outer casing, which may be used to package the electrode assembly and electrolyte.

[0116] In some embodiments, the battery cell exterior may be a hard case, such as a hard plastic case, an aluminum case, a steel case, etc. The battery cell exterior may be a pouch, such as a bag-like pouch. The pouch may be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0117] The present application does not particularly limit the shape of the battery cell, which may be cylindrical, rectangular, or any other shape. For example, Figure 1 shows an example of a battery cell 5 with a rectangular structure.

[0118] In some embodiments, referring to FIG. 2 , the exterior body may include a case 51 and a cover plate 53. Here, the case 51 may include a bottom plate and a side plate connected to the bottom plate, where the bottom plate and the side plate together form a surrounding accommodating cavity. The case 51 has an opening communicating with the accommodating cavity, and the cover plate 53 may cover the opening to seal the accommodating cavity. The positive electrode plate, the negative electrode plate, and the separator may be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is packaged in the accommodating cavity. An electrolyte is impregnated into the electrode assembly 52. ​​The number of electrode assemblies 52 included in the battery cell 5 may be one or more, and this can be selected by those skilled in the art according to specific actual needs.

[0119] According to a seventh aspect, an embodiment of the present application provides a battery, which includes the battery cell of the embodiment of the sixth aspect of the present application. The specific form of the battery may be a battery module or a battery pack, and the number of battery cells included in the battery module may be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0120] Fig. 3 shows an example of a battery module 4. Referring to Fig. 3, in the battery module 4, a plurality of battery cells 5 may be arranged in order along the longitudinal direction of the battery module 4. Of course, the battery cells 5 may be arranged in any other manner. Furthermore, the plurality of battery cells 5 may be fixed by fasteners.

[0121] In either embodiment, the battery module 4 may further include a housing having an accommodating space, and the plurality of battery cells 5 are accommodated in this accommodating space.

[0122] In some embodiments, the battery modules can be further assembled into a battery pack, and the number of battery modules included in the battery pack can be one or more, and the specific number can be selected by those skilled in the art depending on the application and capacity of the battery pack.

[0123] 4 and 5 show an example of a battery pack 1. Referring to FIGS. 4 and 5, the battery pack 1 may include a battery box and a plurality of battery modules 4 installed in the battery box. The battery box includes an upper housing 2 and a lower housing 3, and the upper housing 2 can cover the lower housing 3 to form a sealed space for accommodating the battery modules 4. The plurality of battery modules 4 may be arranged in the battery box in any manner.

[0124] According to an eighth aspect, an embodiment of the present application provides a power consuming device, the power consuming device comprising a battery cell according to an embodiment of the sixth aspect of the present application or a battery according to an embodiment of the seventh aspect.

[0125] The battery cells and batteries may be used as a power source for the power consuming devices, or as an energy storage unit for the power consuming devices, which may include, but are not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0126] The power consumption device can be selected from a secondary battery, a battery module, or a battery pack depending on its usage needs.

[0127] 6 shows an example of a power consuming device, such as a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the demand for high power output and high energy density of the secondary battery of the power consuming device, a battery pack or battery module can be employed.

[0128] Other examples of the device may be a mobile phone, a tablet computer, a laptop computer, etc. These devices are generally required to be thin and can use a secondary battery as a power source.

[0129] The technical solution of the present invention will be described in more detail below with reference to specific examples and drawings. It should be understood that the following examples are only for the purpose of illustrating the present invention, and are not intended to limit the present invention.

[0130] The relevant parameters of the adhesives of Examples 1 to 17 and Comparative Examples 1 and 2 are shown in Table 1 below.

[0131] TIFF0007829030000004.tif244170

[0132] Example 1 [Adhesive manufacturing] (1) Add 150g of deionized water and 3.6g of sodium dodecylsulfonate to a 500ml three-neck flask, emulsify the mixture by stirring thoroughly for 15 minutes, and then add 75.24g of methyl acrylate, 18.55g of acrylonitrile, and 6.21g of acrylamide in that order, with a molar ratio of 1:0.4:0.1. Stir thoroughly for 60 minutes to obtain a preliminary emulsion of the monomers, which is then set aside for storage. (2) Add 100ml of deionized water and 0.15g of sodium dodecylbenzenesulfonate into a 500ml three-neck flask, heat to 80℃, emulsify at 2000r / min for 15 minutes until the system is fully emulsified, and then slowly add the preliminary emulsion prepared in step (1) and the initiator solution (0.2g of potassium persulfate as initiator dissolved in 30g of deionized water to form a solution). After the addition is complete, increase the temperature to 90℃ and keep the temperature for 0.5 hours to react, then cool to 40℃. (3) After adjusting the pH value to 7 with LiOH aqueous solution, the stirring was stopped, filtered, and the material was discharged.

[0133] [Separator manufacturing] A commercially available PP-PE copolymer microporous film (manufactured by Zhuoga Electronics Technology Co., Ltd., model number 20) with a thickness of 20 μm and an average pore diameter of 80 nm was used as the substrate. The adhesive prepared above was stirred with deionized water to obtain a slurry (solid content: 20%). The slurry was uniformly coated on both surfaces of the substrate and dried to remove the solvent. The coating density of the coating composition on the substrate was 1.0 g / m. 2 Thus, a separator was obtained.

[0134] [Production of positive electrode plates] Polyvinylidene fluoride (PVDF), lithium iron phosphate (LFP), carbon black (a conductive agent), and N-methylpyrrolidone (NMP) were mixed in a mass ratio of 1.2:58.38:0.42:40 and thoroughly stirred to homogeneity, followed by preparation of a positive electrode slurry. This positive electrode slurry was prepared at a concentration of 200 g / m 2 The coated aluminum foil positive electrode current collector was then dried, cold pressed and slit to obtain a positive electrode plate.

[0135] [Manufacturing of negative electrode plates] Artificial graphite, acetylene black as a conductive agent, styrene butadiene rubber (SBR) as an adhesive, and sodium carboxymethyl cellulose (CMC-Na) as a thickener were added to deionized water in a mass ratio of 96.2:1.0:1.6:1.2, and after thorough stirring to homogeneously mix, anode slurry was prepared (solid content: 63%). This anode slurry was prepared at 98 g / m 2 The resultant was then dried, cold pressed and slit to obtain a negative electrode plate.

[0136] [Electrolyte production] At 25°C, ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain a mixed solvent, and LiPF6 was dissolved in the mixed solvent to obtain an electrolyte solution, in which the concentration of LiPF6 was 1 mol / L.

[0137] [Secondary battery manufacturing] The positive electrode plate, separator, and negative electrode plate were stacked and wound in this order, and pre-pressurized (during this period, the separator was bonded to the electrode plate) to obtain an electrode assembly. The electrode assembly was then placed in an outer casing, and the prepared electrolyte solution was added. After going through processes such as packaging, standing, chemical conversion, and edging, a secondary battery was obtained.

[0138] The adhesives and separators, positive and negative electrode plates, electrolytes, and secondary battery preparations of Examples 2 to 17 and Comparative Examples 1 and 2 are the same as those of Example 1, except that they are prepared according to the parameters in Table 1.

[0139] The adhesive of Comparative Example 1 had no lithium, and the adhesive particle size of Comparative Example 2 exceeded 50 μm.

[0140] A scanning electron microscope image of the adhesive obtained in Example 1 was taken, and FIG. 7 shows that the adhesive produced in Example 1 of the present application is spherical in shape, with a particle size of approximately 8 μm.

[0141] The products of Examples 1 to 17 and Comparative Examples 1 and 2 were subjected to the following tests.

[0142] 1.Separator and electrode plate adhesion test: The battery electrode plate and separator were stacked together and placed in a heated press. The heated press parameters were set to 25°C, 10 T pressure, and 30 s time. A bonded separator / positive electrode sample was then produced and cut into a 150 x 20 mm rectangular bar. One side of the rectangular bar's electrode was attached to a steel plate with double-sided tape, and the separator and electrode were separated at one end of the rectangular bar by a 2 cm length along the length. This produced a test sample.

[0143] The steel plate was held horizontally and fixed using the lower fixture of a universal testing machine (Xieqiang Instrument Manufacturing (Shanghai) Co., Ltd., model CTM2100). The peeled end of the separator described above was fixed using the upper fixture of the universal testing machine and connected to a tensile machine. The test conditions were set at a tensile rate of 20 mm / min, and the sample was pulled horizontally for 10 cm. After the tensile force stabilized, the tensile force value was recorded, and the ratio of the tensile force value to the sample width was used to determine the adhesive strength between the separator and the electrode plate.

[0144] 2. EIS data (electrochemical impedance spectroscopy): Using Shanghai Chenhua's CHI660D electrochemical station, a small amplitude sinusoidal voltage signal with a frequency of W1 is applied to the battery system, and the system responds by generating a sinusoidal current with a frequency of W2. The change in the ratio of the excitation voltage to the response current is the AC impedance test of the impedance spectrum of the electrochemical system. The test frequency range is 10mHz to 100kHz, and the amplitude is 5mV. Information such as the real and imaginary parts of the impedance can be obtained at different frequencies through the test.

[0145] 3. Cycle performance of lithium-ion batteries: At 25°C, the battery produced in Example 1 was charged at a constant current of 1 / 3 C to 3.8 V, then charged at a constant voltage of 3.8 V until the current reached 0.05 C, allowed to stand for 5 minutes, and then discharged at 1 / 3 C to 2.0 V. The resulting discharge capacity was recorded as the initial capacity C0. The same battery was then subjected to the same steps, and the discharge capacity Cn of the battery after the nth cycle was recorded at the same time. The battery capacity retention rate Pn after each cycle was calculated as (Cn / C0) × 100%. In other words, the battery capacity retention rate after 500 cycles can represent the difference in cycle performance.

[0146] 4. Lithium-ion battery multiplication performance: The test was performed using Wuhan King Nuo Electronics' CT-2001 A LAND battery test system. The test environment was a room temperature of 25°C, with a voltage range of 2.8 to 4.3V. Test batteries were assembled using electrode materials manufactured at rates of 0.2C, 0.5C, 1C, 2C, 5C, and 0.2C (1C=200 mAh / g), and were subjected to five constant-current charge-discharge cycles. The battery capacity after the first five constant-current charge-discharge cycles at 0.2C was recorded as C1, and the battery capacity after the second five constant-current charge-discharge cycles at 0.2C was recorded as C2. The performance ratio P was expressed as (C2 / C1) x 100%.

[0147] The test results are shown in Table 2 below.

[0148] TIFF0007829030000005.tif194165

[0149] As can be seen from Table 2, by comparing the comparative examples with the examples, it is clear that in Examples 1 to 25, the adhesive contains a polyacrylate copolymer, and the resulting adhesive has good adhesive properties, which are suitable for fully demonstrating its adhesive properties under battery operating conditions, further contributing to improving the dynamic performance and safety performance of the battery, and further improving the battery cycle capacity retention rate.

[0150] The adhesive in Comparative Example 1 had no lithium, and the adhesive particle size in Comparative Example 2 was greater than 50 μm. As can be seen from Comparative Example 1, no lithium was added to the adhesive, and the adhesive adhesion, battery impedance, cycle performance, and expansion rate performance were all relatively poor. As can be seen from Comparative Example 2, the adhesive particle size was too large, and the adhesive cycle performance and expansion rate performance were all relatively poor. The particle size was too large, which caused a decrease in adhesive strength, thereby affecting the cycle and expansion rate performance.

[0151] In summary, the adhesive proposed in this application comprises a polyacrylate copolymer and a lithium-containing compound, which provides the polymer with excellent swelling resistance and excellent adhesion, improves ionic conductivity, and controls the polymer's molecular weight and glass transition temperature, thereby improving the adhesive performance. Furthermore, the adhesive further comprises a lithium-containing compound, allowing the adhesive to function as both an adhesive and a lithium replenisher, eliminating the need for a separate lithium metal layer or lithium replenisher layer in the lithium ion battery. This allows the adhesive to quickly replenish consumed lithium ions in the lithium ion battery, increasing the ion transmission rate and improving the structural stability of the lithium ion battery during cycling. When this adhesive is coated on a separator or electrode plate and used in a lithium ion battery, it can improve the kinetic performance of the lithium ion battery, reduce electrochemical impedance, and improve the cycle performance and power consumption of the lithium ion battery.

[0152] The above is merely a preferred embodiment of the present invention, and is not intended to limit the scope of the patent of the present invention, and those skilled in the art can make various modifications and variations to the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the patent scope of the present invention. [Explanation of symbols]

[0153] 1 battery pack 2 Upper housing 3 Lower housing 4 Battery Module 5 battery cells 51 cases 52 Electrode Assembly 53 Cover plate

Claims

1. An adhesive comprising a polyacrylate copolymer and a lithium-containing compound; The monomers of the polyacrylate copolymer include an acrylate monomer, an acrylonitrile monomer, and an acrylamide monomer; the molar ratio of the acrylate-based monomer to the acrylonitrile-based monomer to the acrylamide-based monomer is 1:(0.01 to 0.8):(0.01 to 0.15); The acrylate monomer includes at least one of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; The volume average particle diameter of the adhesive is 0.5 μm≦Dv50≦50 μm An adhesive characterized by:

2. 2. The adhesive according to claim 1, wherein a molar ratio of the acrylate-based monomer to the acrylonitrile-based monomer to the acrylamide-based monomer is 1:(0.05 to 0.7):(0.05 to 0.12).

3. The acrylonitrile-based monomer includes at least one of acrylonitrile and methacrylonitrile, and / or 3. The adhesive according to claim 2, wherein the acrylamide-based monomer includes at least one of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide.

4. 2. The adhesive according to claim 1, wherein the mass ratio of lithium to the polyacrylate copolymer in the adhesive is 1:(10 to 1000).

5. 5. The adhesive according to claim 1, wherein the volume average particle diameter Dv50 of the adhesive is in the range of 7 to 8 μm.

6. A method for manufacturing an adhesive, comprising: adding a monomer of a polyacrylate copolymer to a first emulsifier solution to obtain a pre-emulsion; adding an initiator to the preliminary emulsion to react with it, thereby obtaining a reaction liquid; adding a lithium-containing material to the reaction solution, adjusting the pH value of the reaction solution to 7-8, and filtering the reaction solution to obtain the adhesive; The monomers of the polyacrylate copolymer include an acrylate monomer, an acrylonitrile monomer, and an acrylamide monomer; the molar ratio of the acrylate-based monomer to the acrylonitrile-based monomer to the acrylamide-based monomer is 1:(0.01 to 0.8):(0.01 to 0.15); The acrylate monomer includes at least one of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; The volume average particle diameter of the adhesive is 0.5 μm≦Dv50≦50 μm A method for producing an adhesive comprising the steps of:

7. 7. The method for producing an adhesive according to claim 6, wherein a molar ratio of the acrylate-based monomer to the acrylonitrile-based monomer to the acrylamide-based monomer is 1:(0.05 to 0.7):(0.05 to 0.12).

8. The acrylonitrile-based monomer includes at least one of acrylonitrile and methacrylonitrile, and / or 7. The method for producing an adhesive according to claim 6, wherein the acrylamide-based monomer includes at least one of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide.

9. The step of adding an initiator to the preliminary emulsion to react with the initiator to obtain a reaction liquid includes:

7. The method for producing an adhesive according to claim 6, further comprising adding the preliminary emulsion to a second emulsifier solution under heating and refluxing conditions, and then adding an initiator to react with the second emulsifier solution to obtain a reaction solution.

10. the temperature of the reaction is between 20 and 90°C, and / or The method for producing an adhesive according to any one of claims 6 to 9, wherein the reaction time is 20 to 40 minutes.

11. adding a lithium-containing material to the reaction solution, adjusting the pH value of the reaction solution to 7-8, and filtering the reaction solution to obtain the adhesive; The lithium-containing material includes at least one of lithium hydroxide, lithium oxide, lithium carbonate, and elemental lithium; and / or 10. The method for manufacturing an adhesive according to claim 6, wherein the mass ratio of lithium to the polyacrylate copolymer is 1:(10 to 1000).

12. A separator comprising the adhesive of any one of claims 1 to 4.

13. 5. A plate comprising an adhesive according to any one of claims 1 to 4.

14. An electrode assembly comprising the separator of claim 12.

15. A battery cell comprising the electrode assembly of claim 14.

16. A battery comprising the battery cell of claim 15.

17. 17. A power consuming device comprising a battery according to claim 16.

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