Adhesive composition and separator containing same

Abstract

An adhesive composition comprising a polymer and ceramic particles, the polymer comprising structural units derived from a first class of monomers, a second class of monomers and a third class of monomers, and the molar ratio of the first class of monomers to the second class of monomers to the third class of monomers is 50-58:40-44:2-6, where the first class of monomers is one or more selected from compounds of formula I, the second class of monomers is one or more selected from compounds of formula II, and the third class of monomers is one or more selected from compounds of formula III. The adhesive increases the porosity of the separator, improves ionic conductivity and reduces internal resistance, and improves the cycle performance of the secondary battery.

Description

[Technical Field]

[0001] The present application relates to the technical field of lithium batteries, and in particular to an adhesive composition and a separator containing the same. The present application further relates to secondary batteries, battery modules, battery packs, and power consuming devices. [Background technology]

[0002] In recent years, the application range of secondary batteries has been expanding. Secondary batteries are widely used in energy storage power systems, such as hydroelectric power plants, thermal power plants, wind power plants, and solar power plants, as well as in multiple fields, such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, and aerospace. The remarkable development of secondary batteries has led to increasing requirements for their energy density, cycle performance, and safety performance. Secondary battery separators often use adhesives. However, conventional adhesives have poor viscosity and tend to clog the pores of the substrate, resulting in low separator porosity, poor ion mobility within the separator, and increased resistance within the separator, which affects the cycle performance of secondary batteries. Summary of the Invention

[0003] To achieve the above object, the present application provides an adhesive composition, and a separator, a secondary battery, a battery pack, and a power consuming device each including the composition.

[0004] A first aspect of the present application provides an adhesive composition, comprising a polymer and ceramic particles, wherein the polymer comprises structural units derived from a first class of monomers, a second class of monomers, and a third class of monomers, and the molar ratio of the first class of monomers to the second class of monomers to the third class of monomers is 50-58:40-44:2-6; The first class of monomers is one or more selected from compounds of formula I: [ka] wherein R1 is selected from a hydrogen atom and a linear or branched C1-6 alkyl group; R2 is selected from a substituted or unsubstituted linear or branched C1-15 alkyl group, a C3-6 cycloalkyl group, and an isobornyl group, and in the case of substitution, the substituent is selected from a hydroxyl group and a C1-6 chain alkyl group; The second class of monomers is one or more selected from compounds of formula II: [ka] wherein R3 is selected from a hydrogen atom and a linear or branched C1-6 alkyl group; The third class of monomers is one or more selected from compounds of formula III: [ka] wherein R4 is selected from a hydrogen atom and a linear or branched C1-6 alkyl group, and R5 is selected from a hydrogen atom, a hydroxy C1-6 alkyl group, and a C1-6 alkoxy group. The adhesive composition of the present application has good adhesion properties, and can also improve the porosity of the separator, improve ionic conductivity, reduce the internal resistance of the separator, and enhance the cycle performance of the secondary battery.

[0005] In any embodiment, R1 is selected from a hydrogen atom and a methyl group, and R2 is selected from a substituted or unsubstituted straight or branched chain C1-6 alkyl group, where if substituted, the substituent is a hydroxyl group, and / or R3 is selected from a hydrogen atom and a methyl group, and / or R4 is selected from a hydrogen atom and a methyl group, and R5 is selected from a hydrogen atom, a hydroxy C1-4 alkyl group, and a C1-4 alkoxy group.

[0006] In any embodiment, the first class of monomers is one or more selected from 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, 2-hydroxypropyl methacrylate; and / or the second class of monomers is acrylonitrile or methacrylonitrile; and / or the third class of monomers is one or more selected from acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide.

[0007] Further selection of monomers from the first, second and / or third groups, respectively, is advantageous in improving the ionic conductivity of the separator, thereby enhancing the cycling capacity retention of the battery.

[0008] In one embodiment, the molar ratio of the first type of monomer to the second type of monomer to the third type of monomer is 50-57:41-44:2-6. Using this molar ratio range, the adhesive composition is more advantageous in further improving the ionic conductivity of the separator, thereby improving the cycle capacity retention of the battery.

[0009] In one embodiment, the weight ratio of the polymer to the ceramic particles is 40-90:10-60, and optionally 50-80:20-50. The weight ratio of the polymer to the ceramic particles within this range ensures the adhesive, separator, and electrode plate adhesion, and also allows the separator to have appropriate porosity and good ionic conductivity.

[0010] In any embodiment, the weight average molecular weight of the polymer is 60,000-120,000, and optionally 63,300-118,800. When the weight average molecular weight of the polymer is within the above range, the polymer can have suitable fluidity when bonded with the adhesive composition of the present application, thereby achieving good adhesive effect and further improving the cycle performance of the secondary battery.

[0011] In any of the embodiments, the average particle size Dv50 of the ceramic particles is 40 nm-110 nm, optionally 45 nm-106 nm, further optionally 50 nm-100 nm, and further optionally 56 nm-89 nm. The average particle size of the ceramic particles can be further controlled to further improve ionic conductivity and capacity retention.

[0012] In any embodiment, the ceramic particles are porous particles, and the average pore size of the porous particles is 0.3 nm-6.0 nm, optionally 0.5 nm-5.7 nm, more preferably 1.0 nm-5.0 nm, and even more preferably 1.3 nm-3.8 nm. Selecting the porous particle material and controlling its average pore size is advantageous for ensuring the thermal stability of the separator, and further improving the porosity and ionic conductivity of the separator and the cycle capacity retention rate of the secondary battery.

[0013] In any embodiment, the ceramic particles are porous silicon dioxide particles, which further improve the porosity and ionic conductivity of the separator, reduce the internal resistance of the separator, and improve the cycling performance of the secondary battery.

[0014] In any of the embodiments, the polymer coats the ceramic particles, which is advantageous in that the adhesive composition can be uniformly applied to the substrate at an ideal blend ratio, thereby improving heat resistance, porosity, and achieving a good adhesive effect.

[0015] A second aspect of the present application provides a separator including a base layer and a coating layer disposed on at least one surface of the base layer, the coating layer comprising the adhesive composition of the first aspect of the present application. The separator of the present application can stably adhere to an electrode plate, has an increased porosity, improves ionic conductivity, reduces the internal resistance of the separator, and enhances the cycle performance of a secondary battery.

[0016] A third aspect of the present application provides a secondary battery, which includes the adhesive composition according to the first aspect of the present application and / or the separator according to the second aspect of the present application.

[0017] A fourth aspect of the present application provides a battery module, which includes the secondary battery of the third aspect of the present application.

[0018] A fifth aspect of the present application provides a battery pack, which includes the battery module of the fourth aspect of the present application.

[0019] A sixth aspect of the present application provides a power consumption device, the power consumption device including at least one selected from the secondary battery of the third aspect of the present application, the battery module of the fourth aspect of the present application, or the battery pack of the fifth aspect of the present application.

[0020] The adhesive of the present application has good adhesive performance, and furthermore, can improve the porosity of the separator, reduce the internal resistance of the separator, and enhance the cycle performance of the secondary battery. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic diagram of a secondary battery according to an embodiment of the present application; [Figure 2] FIG. 2 is an exploded view of the secondary battery 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 shown in FIG. 4 according to an embodiment of the present application. [Figure 6] 1 is a schematic diagram of a power consumption device in which a secondary battery according to an embodiment of the present application is used as a power source; DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, with appropriate reference to the drawings, embodiments specifically disclosing the adhesive composition, separator, secondary battery, battery module, battery pack, and power consumption device of the present application will be described in detail. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or redundant description of actually identical structures may be omitted. This is to avoid the following description becoming unnecessarily long 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.

[0023] The "ranges" disclosed herein 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 endpoints and may be arbitrarily combined, i.e., any lower limit may 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, a numerical range "ab" represents a shorthand notation for any combination of real numbers ab, where a and b are both real numbers. For example, the numerical range "0-5" represents that the present specification has already listed all real numbers between "0-5," and "0-5" is merely a shorthand representation of combinations of these numbers. Also, expressing a parameter as an integer ≧2 is equivalent to disclosing that this parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0024] Unless otherwise stated, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0025] 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.

[0026] 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.

[0027] 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 indicate that other components not listed may be further included or included, or that only the listed components may be included or included.

[0028] 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).

[0029] In recent years, the range of applications for secondary batteries has expanded. They are widely used in energy storage power systems, such as hydroelectric power plants, thermal power plants, wind power plants, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, and other fields. The rapid development of secondary batteries has led to increasing demands for their energy density, cycle performance, and safety. As an important component of secondary batteries, the separator has naturally become one of the key components that engineers focus on. Conventional technologies often involve coating the separator substrate with ceramic particles (e.g., inorganic oxide particles, such as silicon dioxide, aluminum oxide, and boehmite) to improve the separator's heat resistance and puncture resistance. The ceramic particle-coated separator is then coated with an adhesive and bonded to electrodes to produce a secondary battery. However, this method has its drawbacks. First, the ceramic particles tend to penetrate into the pores of the substrate, reducing the porosity of the separator and making it unfavorable for ion migration. Second, the adhesive effect of conventional adhesives is weak.

[0030] To solve the above problems, the present application proposes an adhesive composition containing a polymer that performs adhesive functions and ceramic particles that improve safety performance, reducing and even avoiding the occurrence of pore clogging and achieving good adhesion. Furthermore, the polymer in the adhesive composition of the present application is advantageous for improving ionic conductivity by selecting and controlling the ratio of its monomers. In summary, the adhesive composition of the present application can improve the porosity of the separator, improve ionic conductivity, and improve the cycle performance of secondary batteries.

[0031] <Adhesive> In one embodiment of the present application, the present application proposes an adhesive composition, which comprises a polymer and ceramic particles, wherein the polymer comprises structural units derived from a first class of monomers, a second class of monomers, and a third class of monomers, and the molar ratio of the first class of monomers to the second class of monomers to the third class of monomers is 50-58:40-44:2-6; The first class of monomers is one or more selected from compounds of formula I: [ka] wherein R1 is selected from a hydrogen atom and a linear or branched C1-6 alkyl group; and R2 is selected from a substituted or unsubstituted linear or branched C1-15 alkyl group, a C3-6 cycloalkyl group, and an isobornyl group, and in the case of substitution, the substituent is selected from a hydroxyl group and a C1-6 chain alkyl group; The second class of monomers is one or more selected from compounds of formula II: [ka] wherein R3 is selected from a hydrogen atom and a linear or branched C1-6 alkyl group; The third class of monomers is one or more selected from compounds of formula III: [ka] wherein R4 is selected from a hydrogen atom and a straight or branched C1-6 alkyl group, and R5 is selected from a hydrogen atom, a hydroxy C1-6 alkyl group, and a C1-6 alkoxy group.

[0032] The adhesive composition of the present application has a good adhesive effect, and can also improve the porosity of the separator, improve the ionic conductivity, reduce the internal resistance of the separator, and enhance the cycle performance of the secondary battery.

[0033] In the polymer of this application, the first type of monomer is an acrylate-based monomer, which can improve the anti-swelling ability of the adhesive and, as a flexible monomer chain segment in the molecular chain, can adjust the glass transition temperature of the polymer, thereby favoring good adhesive properties of the adhesive composition. The second type of monomer is an acrylonitrile-based monomer, which has a strongly polar cyano group, which is advantageous for improving ionic conductivity. The third type of monomer is an acrylamide-based monomer, the main function of which is the amide group, which serves as a crosslinking function and is advantageous for adjusting the molecular weight of the polymer. By controlling the molar ratio of the above three types of monomers within a certain range, the polymer will have an ideal molecular weight and glass transition temperature, thereby ensuring the adhesive performance of the adhesive and favorably improving ionic conductivity.

[0034] In some embodiments, R1 is selected from a hydrogen atom and a methyl group, and R2 is selected from a substituted or unsubstituted straight or branched chain C1-6 alkyl group, where if substituted, the substituent is a hydroxyl group. In some embodiments, R3 is selected from a hydrogen atom and a methyl group. In some embodiments, R4 is selected from a hydrogen atom and a methyl group, and R5 is selected from a hydrogen atom, a hydroxy C1-4 alkyl group, and a C1-4 alkoxy group.

[0035] In some embodiments, the first class of monomers is one or more selected from 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. In some embodiments, the second class of monomers is acrylonitrile or methacrylonitrile. In some embodiments, the third class of monomers is selected from one or more of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide.

[0036] Further selection from the monomers of the first, second and / or third classes is advantageous in improving the ionic conductivity of the separator, thereby improving the cycle capacity retention rate of the battery.

[0037] In some embodiments, the molar ratio of the first type of monomer to the second type of monomer to the third type of monomer is 50-57:41-44:2-6. By adopting a molar ratio in this range, the adhesive composition is more advantageous in further improving the ionic conductivity of the separator, thereby improving the cycle capacity retention rate of the battery.

[0038] In some embodiments, the molar percentage content of the first group of monomers is 50-58 mol%, alternatively 50-57 mol%, and alternatively 50 mol%, 51 mol%, 52 mol%, 53 mol%, 54 mol%, 55 mol%, 56 mol%, 57 mol%, or 58 mol%, or any range consisting of any two of the foregoing values, based on the total molar amount of the first group of monomers, the second group of monomers, and the third group of monomers. In some embodiments, the molar percentage content of the second group of monomers is 40-44 mol%, alternatively 41-44 mol%, and alternatively 40 mol%, 41 mol%, 42 mol%, 43 mol%, or 44 mol%, or any range consisting of any two of the foregoing values, based on the total molar amount of the first group of monomers, the second group of monomers, and the third group of monomers. In some embodiments, based on the total molar amount of the first type monomer, the second type monomer, and the third type monomer, the molar percentage content of the third type monomer is 2-6 mol%, and optionally the molar percentage content of the third type monomer is 2 mol%, 3 mol%, 4 mol%, 5 mol%, or 6 mol%, or within a range consisting of any two of the foregoing values.

[0039] In some embodiments, the weight ratio of the polymer to the ceramic particles is 40-90:10-60, and optionally 50-80:20-50. The weight ratio of the polymer to the ceramic particles within this range can further ensure the adhesive between the adhesive, the separator, and the electrode plates, and also ensure that the separator has appropriate porosity and good ionic conductivity.

[0040] In some embodiments, the weight average molecular weight of the polymer is 60,000-120,000, and optionally 63,300-118,800. When the weight average molecular weight of the polymer is within this range, the polymer can have suitable fluidity when bonded with the adhesive composition of the present application, thereby achieving good adhesive properties and further improving the cycle performance of the secondary battery.

[0041] In some embodiments, the ceramic particles have an average particle size Dv50 of 40-110 nm, optionally 45-106 nm. Alternatively, the ceramic particles have an average particle size Dv50 of 40 nm, 45 nm, 50 nm, 56 nm, 70 nm, 89 nm, 100 nm, 106 nm, or 110 nm, or any range consisting of any two of these values. Alternatively, the ceramic particles have an average particle size Dv50 of 50-100 nm, and more preferably 56-89 nm. Further, controlling the average particle size of the ceramic particles can further improve ionic conductivity and capacity retention.

[0042] In the present application, the material of the ceramic particles may be any applicable conventional material in the art, in some embodiments, the ceramic particles are selected from aluminum oxide, boehmite, titanium dioxide, and silicon dioxide.

[0043] In some embodiments, the ceramic particles may be porous or solid (i.e., non-porous). In some embodiments, the ceramic particles are porous. The porous particles have an average pore size of 0.3 nm-6.0 nm, and optionally, the average pore size is 0.5 nm, 1 nm, 1.3 nm, 3 nm, 3.8 nm, 5 nm, or 5.7 nm, or within a range consisting of any two of these values. Optionally, the average pore size is 0.5 nm-5.7 nm, more optionally, 1.0 nm-5.0 nm, and even more optionally, 1.3 nm-3.8 nm. Furthermore, selecting a porous particle material and preferably controlling its average pore size can be advantageous in ensuring the thermal stability of the separator, improving the porosity and ionic conductivity of the separator, and improving the cycle capacity retention of the secondary battery.

[0044] In some embodiments, the ceramic particles are porous silicon dioxide particles, which can further improve the porosity and ionic conductivity of the separator, reduce the internal resistance of the separator, and improve the cycling performance of the secondary battery.

[0045] In some embodiments, the polymer coats the ceramic particles. Coating the ceramic particles with the polymer before application reduces or prevents the particles from falling into the separator pores and blocking the pores, while ensuring that the polymer and ceramic particles are uniformly applied to the substrate in an ideal ratio, thereby improving heat resistance, porosity, and achieving good adhesion. In some embodiments, the polymer coats the porous silicon dioxide particles.

[0046] <Separator> Another aspect of the present application provides a separator including a base layer and a coating layer disposed on at least one surface of the base layer, the coating layer including the adhesive of the present application.

[0047] The present application does not particularly limit the type of material for the separator base layer, but any known porous structure base layer having good chemical stability and mechanical stability may be selected.

[0048] In some embodiments, the separator base layer may be made of at least one material selected from the group consisting of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, but is not limited thereto. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, but are not limited thereto.

[0049] <Secondary battery, battery module, battery pack and power consuming device> A third aspect of the present application provides a secondary battery, which includes the adhesive of the present application and / or the separator of the present application.

[0050] A fourth aspect of the present application provides a battery module, which includes the secondary battery of the third aspect.

[0051] A fifth aspect of the present application provides a battery pack, which includes the battery module of the fourth aspect.

[0052] A sixth aspect of the present application provides a power consumption device, which includes at least one selected from the secondary battery of the third aspect, the battery module of the fourth aspect, and the battery pack of the fifth aspect.

[0053] The secondary battery, battery module, battery pack, and power consumption device of the present application will be described below with appropriate reference to the drawings.

[0054] In one embodiment of the present application, a secondary battery is provided, in some embodiments, the secondary battery is a lithium ion secondary battery.

[0055] Generally, a secondary battery includes a positive electrode plate, a negative electrode plate, an electrolyte, and a separator. During charging and discharging, active ions are absorbed and released between the positive and negative electrodes. The electrolyte functions to conduct ions between the positive and negative electrodes. The separator, located between the positive and negative electrodes, primarily prevents short-circuiting and allows ions to pass through.

[0056] [Positive electrode plate] 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 a positive electrode active material.

[0057] 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.

[0058] 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)).

[0059] 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 an olivine-structured lithium-containing phosphate, a lithium transition metal oxide and its modified compound, a sodium transition metal oxide, a polyanion-type compound, and a Prussian blue-based compound. However, the present application is not limited to these materials, and other conventional materials usable as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. 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 0.2 Mn 0.3 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 0.05It may contain, but is not limited to, at least one of O2) and modified compounds thereof. Examples of lithium-containing phosphates having an olivine structure include at least one of lithium iron phosphate (e.g., LiFePO4, which may 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, but are not limited thereto.

[0060] In some embodiments, in the sodium transition metal oxide, the transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce. The sodium transition metal oxide is, for example, Na x M y O2, where M is one or more of Ti, V, Mn, Co, Ni, Fe, Cr, and Cu, 0 < x ≦ 1, and 0.5 < y ≦ 1.5. In some embodiments, the positive electrode active material may adopt Na 0.88 Cu 0.24 Fe 0.29 Mn 0.47 O2.

[0061] In some embodiments, the polyanion-type compound may be a kind of compound having sodium ions, transition metal ions, and tetrahedral (YO4) n- anion units. The transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce, Y may be at least one of P, S, and Si, and n represents the valence of (YO4) n- .

[0062] In some embodiments, the polyanion-type compound contains sodium ions, transition metal ions, tetrahedral (YO4) n-The anion unit may be a compound having a halogen anion, the transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce, Y may be at least one of P, S, and Si, and n may be (YO4) n- The halogen may be at least one of F, Cl, and Br.

[0063] In some embodiments, the polyanionic compound is a sodium ion, tetrahedral (YO4) n- Anionic unit, polyhedral unit (ZO y ) m+ and optionally a halogen anion. Y may be at least one of P, S, and Si, and n is (YO4) n- Z represents a transition metal and may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce, and m represents a valence of (ZO y ) m+ The halogen may be at least one of F, Cl, and Br.

[0064] In some embodiments, the polyanionic compounds include, for example, NaFePO4, Na3V2(PO4)3, NaM'PO4F (where M' is one or more of V, Fe, Mn, and Ni), and Na3(VO y )2(PO4)2F 3-2y At least one of (0≦y≦1).

[0065] In some embodiments, the Prussian blue-based compound contains sodium ions, transition metal ions, and cyanide ions (CN - The transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce. The Prussian blue compound may be, for example, Na a Me b Me' c(CN)6, where Me and Me' are each independently at least one of Ni, Cu, Fe, Mn, Co, and Zn; <a≦2、0<b<1、0<c<1である。

[0066] In some embodiments, the positive electrode membrane layer optionally further comprises an adhesive, which may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0067] In some embodiments, the positive electrode film layer optionally further comprises a conductive agent, for example, the conductive agent may comprise at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0068] In some embodiments, the positive electrode plate may be manufactured by the following method: components for manufacturing the positive electrode plate, such as a positive electrode active material, a conductive agent, an adhesive, 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 can be obtained after processes such as drying and cold pressing.

[0069] [Negative electrode plate] The negative electrode plate includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, the negative electrode film layer including a negative electrode active material.

[0070] For example, the negative electrode current collector has two surfaces facing 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.

[0071] In some embodiments, the negative electrode current collector may be a metal foil sheet or a composite current collector. For example, a copper 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 substrate. 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 substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0072] 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 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 at least one selected from a silicone monomer, a silicone oxide, a silicone carbon composite, a silicone nitrogen composite, and a silicone alloy. The tin-based material may be at least one selected from a tin monomer, a tin oxide, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials usable as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination.

[0073] In some embodiments, the negative electrode membrane layer optionally further comprises an adhesive, which may be at least one selected from styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0074] In some embodiments, the negative electrode film layer further optionally includes a conductive agent, which may be at least one selected from superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0075] In some embodiments, the negative electrode membrane layer optionally further comprises other additives, such as a thickener (eg, carboxymethylcellulose sodium (CMC-Na)).

[0076] In some embodiments, the negative electrode plate may be manufactured by the following method: components for manufacturing the negative electrode plate, such as a negative electrode active material, a conductive agent, an adhesive, 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 can be obtained after processes such as drying and cold pressing.

[0077] [Electrolyte] 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.

[0078] In some embodiments, the electrolyte is an electrolytic solution, which includes an electrolyte salt and a solvent.

[0079] In some embodiments, the electrolyte salt is selected from the group consisting 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, sodium hexafluorophosphate (NaPF), sodium hexafluoroborate (NaBF), NaN(SOF) (abbreviated as NaFSI), NaClO, NaAsF, NaB(CO) (abbreviated as NaBOB), NaBF(CO) (abbreviated as NaDFOB), NaN(SOR) F )2 and NaN(SO2F)(SO2R F ), where R F is C b F 2b+1 wherein b is an integer in the range of 1-10, optionally an integer in the range of 1-3, and further optionally R F is -CF3, -C2F5 or -CF2CF2CF3.

[0080] In some embodiments, the solvent may be at least one selected from 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.

[0081] 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 performance of the battery, 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.

[0082] In some embodiments, the positive and negative electrodes and the separator can be fabricated into an electrode assembly by a winding or lamination process.

[0083] [Exterior body] In some embodiments, the secondary battery may include an outer casing for packaging the positive electrode plate, the negative electrode plate, and the electrolyte. For example, the positive electrode plate, the negative electrode plate, and the separator may be stacked or wound to form a stacked or wound battery core, and the battery core is packaged in the outer casing. The electrolyte may be the electrolyte solution described in the first aspect of the present application, and the electrolyte solution may be impregnated into the battery core. The number of battery cores in the secondary battery may be one or more, and can be adjusted according to needs.

[0084] In one embodiment, the present application provides an electrode assembly. In some embodiments, the positive electrode plate, the negative electrode plate, and the separator can be fabricated into the electrode assembly by a winding process or a lamination process. An outer package can be used to package the electrode assembly and the electrolyte.

[0085] In some embodiments, the exterior of the secondary battery may be a pouch, such as a bag-like pouch. The material of the pouch may be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), etc. In some embodiments, the exterior of the secondary battery may be a hard case, such as a hard plastic case, an aluminum case, a steel case, etc.

[0086] The present application does not particularly limit the shape of the secondary battery, which may be cylindrical, rectangular, or any other shape. For example, Figure 1 shows an example of a rectangular secondary battery 5.

[0087] 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 side plates connected to the bottom plate, which together form a surrounding accommodating cavity. The case 51 has an opening communicating with the accommodating cavity, and the cover plate 53 may be installed over 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 within the accommodating cavity. An electrolyte is impregnated into the electrode assembly 52. ​​The number of electrode assemblies 52 included in the secondary battery 5 may be one or more, and this can be selected by those skilled in the art according to actual needs.

[0088] In some embodiments, the secondary batteries can be assembled into a battery module, and the number of secondary batteries included in the battery module can be one or more, with the specific number being selectable by those skilled in the art depending on the application and capacity of the battery module.

[0089] FIG. 3 shows an example of a battery module 4. Referring to FIG. 3, in the battery module 4, a plurality of secondary batteries 5 may be arranged in order along the longitudinal direction of the battery module 4. Of course, they may be arranged in any other manner. Furthermore, the plurality of secondary batteries 5 may be fixed by fasteners.

[0090] Optionally, the battery module 4 may further include a housing having an accommodating space, and the plurality of secondary batteries 5 are accommodated in this accommodating space.

[0091] In some embodiments, the battery modules may be further assembled into a battery pack, and the number of battery modules included in the battery pack may be one or more, the specific number of which can be selected by those skilled in the art depending on the application and capacity of the battery pack.

[0092] 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 is attached to the lower housing 3 as a lid 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.

[0093] The present application also provides a power consuming device, the power consuming device including at least one of a secondary battery, a battery module, or a battery pack according to the present application. The secondary battery, the battery module, or the battery pack may be used as a power source for the power consuming device or as an energy storage unit for the power consuming device. The power consuming device may include, but is 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, satellites, energy storage systems, etc.

[0094] The power consumption device can select a secondary battery, a battery module, or a battery pack according to its usage needs.

[0095] 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 and high energy density from secondary batteries in the power consuming device, a battery pack or battery module can be employed.

[0096] 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 employ a secondary battery as a power source. [Example]

[0097] Examples of the present application are described below. The examples described below are illustrative and are intended only to interpret the present application and should not be understood as limitations on the present application. If specific techniques or conditions are not specified in the examples, they are carried out according to techniques or conditions described in literature in the field or according to product specifications. The reagents or instruments used are not specified by manufacturer and are all ordinary products that are commercially available.

[0098] 1. Polymer production <Production Example 1> At room temperature, 60.92 g of methyl acrylate, 33.04 g of acrylonitrile, and 6.04 g of acrylamide were weighed in a molar ratio of 50:44:6 and added to a 500 mL four-neck flask equipped with a mechanical stirrer, thermometer, and condenser. 3 g of sodium lauryl sulfate emulsifier, 1 g of ammonium persulfate initiator, and 120 g of deionized water were then added. The mixture was emulsified by stirring at 1600 rpm for 30 minutes, and then heated to 75°C under nitrogen gas protection and reacted for 4 hours. The pH was adjusted to 6-8, and the mixture was immediately cooled to below 40°C and discharged to obtain Polymer 1.

[0099] <Production Examples 2 to 5> The production steps of Production Examples 2 to 5 are the same as those of Production Example 1, except that the molar ratios of the three monomers are 51:43:6, 52:42:6, 53:41:6, and 54:40:6, respectively, and the total mass of the three monomers is 100 g, and polymers 2 to 5 are obtained by production.

[0100] <Production Examples 6 to 10> In Preparation Example 6, 69.71 g of n-butyl acrylate, 24.90 g of acrylonitrile and 5.39 g of N-methylolacrylamide were weighed at room temperature according to a molar ratio of 51:44:5, and the other steps were the same as in Preparation Example 1 to obtain Polymer 6.

[0101] In Preparation Examples 7 to 10, the molar ratios of the three monomers were 52:43:5, 53:42:5, 54:41:5, and 55:40:5, respectively, and the total mass of the three monomers was 100 g. The other steps were the same as in Preparation Example 1, and polymers 7 to 10 were obtained.

[0102] <Production Examples 11 to 15> In Preparation Example 11, 68.42g of ethyl methacrylate, 26.91g of acrylonitrile and 4.66g of N-methylolacrylamide were weighed at room temperature according to a molar ratio of 52:44:4, and the other steps were the same as in Preparation Example 1 to obtain Polymer 11.

[0103] In Production Examples 12 to 15, the molar ratios of the three monomers were 53:43:4, 54:42:4, 55:41:4, and 56:40:4, respectively, and the total mass of the three monomers was 100 g. The other steps were the same as in Production Example 1, and polymers 12 to 15 were obtained.

[0104] <Production Examples 16-20> In Preparation Example 16, 67.94g of 2-hydroxyethyl methacrylate, 29.08g of methacrylonitrile and 2.99g of N-butoxymethacrylamide were weighed at room temperature according to a molar ratio of 53:44:3, and the other steps were the same as in Preparation Example 1 to obtain Polymer 16.

[0105] In Production Examples 17 to 20, the molar ratios of the three monomers were 54:43:3, 55:42:3, 56:41:3, and 57:40:3, respectively, and the total mass of the three monomers was 100 g. The other production steps were the same as in Production Example 1, and polymers 17 to 20 were obtained.

[0106] <Production Examples 21-25> In Preparation Example 21, 70.44g of 2-hydroxypropyl methacrylate, 26.71g of methacrylonitrile and 2.85g of N-butoxymethacrylamide were weighed at room temperature according to a molar ratio of 54:44:2, and the other preparation steps were the same as those in Preparation Example 1 to obtain Polymer 21.

[0107] In Production Examples 22 to 25, the molar ratios of the three monomers were 55:43:2, 56:42:2, 57:41:2, and 58:40:2, respectively, and the total mass of the three monomers was 100 g. The other production steps were the same as in Production Example 1, and polymers 22 to 25 were obtained.

[0108] <Production Example 26> In Preparation Example 26, 75.13 g of cyclohexyl acrylate, 20.88 g of acrylonitrile, and 4.00 g of acrylamide were weighed at room temperature according to a molar ratio of 52:42:6, and other preparation steps were the same as those in Preparation Example 1 to obtain Polymer 26.

[0109] <Production Example 27> In Preparation Example 27, 80.07 g of isobornyl methacrylate, 16.95 g of methacrylonitrile, and 2.98 g of N-butoxymethacrylamide were weighed at room temperature according to a molar ratio of 57:40:3, and the other preparation steps were the same as those in Preparation Example 1 to obtain Polymer 27.

[0110] <Comparative Manufacturing Example 1> At room temperature, 69.50 g of methyl acrylate, 22.85 g of acrylonitrile and 7.65 g of acrylamide were weighed according to a molar ratio of 60:32:8, and the other steps were the same as in Preparation Example 1 to obtain Polymer C1.

[0111] <Comparative Manufacturing Example 2> At room temperature, 74.42 g of 2-hydroxyethyl methacrylate and 25.58 g of methacrylonitrile were weighed out according to a molar ratio of 60:40, and the other steps were the same as in Preparation Example 1 to obtain Polymer C2.

[0112] The weight average molecular weights of Polymer 1-27 and Comparative Polymer 1-2 obtained in the above Preparation Example and Comparative Preparation Example were measured using a Waters 1515 gel permeation chromatograph. The flow phase was N,N-dimethylformamide, the standard sample was a linear polymethyl methacrylate polymer with a narrow molecular weight distribution, and the solvent flow rate was 1.0 ml / min.

[0113] Table 1 shows the monomers and their molar ratios in Production Example 1-27 and Comparative Production Example 1-2, as well as the weight average molecular weights of the final polymers obtained.

[0114] [Table 1-1] [Table 1-2]

[0115] In this application, the ceramic particles in the following examples are all commercially available. The average particle size Dv50 of the ceramic particles was measured using a laser particle size analyzer (deionized water as a dispersant), and the average pore size of the ceramic particles was measured using a gas adsorption-desorption isotherm method. The average particle size and average pore size are shown in Table 2 below.

[0116] Example 1 1. Preparation of adhesive composition According to a polymer to porous silicon dioxide particle mass ratio of 75:25, 750 g of Polymer 1 obtained in Preparation Example 1 was added to 250 g of porous silicon dioxide particles and 1 kg of deionized water, and the mixture was stirred at room temperature for 1 hour, sprayed, and dried so that the polymer uniformly coated the surface of the porous silicon dioxide particles, and then ball milled to obtain the adhesive composition of the present application. As shown in Table 2, the porous silicon dioxide particles used above had an average particle size Dv50 of 70 nm and an average pore size of 2.5 nm.

[0117] 2. Separator manufacturing A commercially available PP-PE copolymer microporous film (manufactured by Zhuoga Electronics Technology Co., Ltd., Model No. 20) with a thickness of 20 μm and an average pore size of 80 nm was used as the substrate. The adhesive composition prepared above was uniformly mixed and stirred in N-methylpyrrolidone (NMP) to obtain a slurry (solid content 20%). The slurry was uniformly coated on both surfaces of the substrate, and the organic solvent was removed by drying. The adhesive composition was coated on the substrate at a coating density of 0.5 g / m². 2 Thus, a separator was obtained.

[0118] 3. Manufacturing of positive electrode plates Polyvinylidene fluoride (PVDF), lithium iron phosphate (LFP), conductive carbon black, and N-methylpyrrolidone (NMP) were mixed in a mass ratio of 1.2:58.38:0.42:40 and thoroughly and uniformly stirred to prepare a positive electrode slurry. 2 The coated aluminum foil was then dried, cold pressed, and slit to obtain a positive electrode plate.

[0119] 4. Manufacturing of negative electrode plates Artificial graphite, conductive agent acetylene black, adhesive styrene butadiene rubber (SBR), and thickener sodium carboxymethyl cellulose (CMC-Na) were added to deionized water in a mass ratio of 96.2:1.0:1.6:1.2, and the mixture was thoroughly and uniformly stirred to prepare anode slurry (solid content 63%). This anode slurry was prepared at 98 g / m 2 The coated copper foil was then dried, cold pressed and slit to obtain a negative electrode plate.

[0120] 5. Electrolyte Production At a temperature of 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 with a LiPF6 concentration of 1 mol / L.

[0121] 6. Secondary battery manufacturing The positive electrode plate, separator, and negative electrode plate were stacked in this order and wound, and then pre-press-molded (in this process, the separator is bonded to the electrode plate) to obtain an electrode assembly. The electrode assembly was then placed in an outer casing, and the above-prepared electrolyte solution was added. After packaging, leaving it to stand, chemical conversion, aging, and other processes, a secondary battery was obtained.

[0122] <Example 2> As shown in Table 2 below, 600 g of Polymer 11 obtained in Preparation Example 11 was mixed with 400 g of porous silicon dioxide particles and 1 kg of deionized water in a 60:40 weight ratio of polymer to silicon dioxide. The mixture was stirred at room temperature for 1 hour, sprayed, dried, and then ball milled to obtain an adhesive composition in which the polymer was uniformly coated on the surface of the porous silicon dioxide particles. The porous silicon dioxide particles had an average particle size of 80 nm and an average pore size of 3.0 nm. The other steps were the same as in Example 1.

[0123] <Examples 3 to 5> The other steps of Examples 3 to 5 were the same as those of Example 1, except that the polymers were Polymer 24 obtained in Production Example 24, Polymer 26 obtained in Production Example 26, and Polymer 27 obtained in Production Example 27, respectively.

[0124] <Examples 6 to 11> The other steps of Examples 6 to 11 are the same as those of Example 1, except that the average particle diameter of the porous silicon dioxide particles is changed to 45 nm, 50 nm, 56 nm, 89 nm, 100 nm and 106 nm, respectively.

[0125] <Examples 12 to 17> The other steps of Examples 12 to 17 are the same as those of Example 2, except that the average pore diameter of the porous silicon dioxide particles is changed to 0.5 nm, 1 nm, 1.3 nm, 3.8 nm, 5 nm and 5.7 nm, respectively.

[0126] <Examples 18 to 21> The other steps of Examples 18 to 21 are the same as those of Example 3, except that the mass ratio of the polymer to the porous silicon dioxide particles is changed to 40:60, 50:50, 75:25, 80:20, and 90:10, respectively.

[0127] <Examples 22 to 27> Other steps of Examples 22 to 27 are the same as Example 1, except that the porous silicon dioxide particles are replaced with solid (non-porous) silicon dioxide particles of different particle sizes.

[0128] <Comparative Examples 1 and 2> The other steps of Comparative Examples 1 and 2 were the same as those of Example 1, except that the polymer used was changed from that of Production Example 1 to that of Comparative Production Example 1 and Comparative Production Example 2.

[0129] <Comparative Examples 3 and 4> The other steps of Comparative Examples 3 and 4 were the same as those of Example 2, except that the polymer used was changed from that of Production Example 11 to that of Comparative Production Example 1 and Comparative Production Example 2.

[0130] <Comparative Example 5> The other steps of Comparative Example 5 are the same as those of Example 1, except that the polymer is changed from that of Preparation Example 1 to that of Comparative Preparation Example C1, and the particles are changed from porous particles to solid (non-porous) particles with the same average particle size.

[0131] <Test Method> 1.Separator ionic conductivity test (1) Preparation of a test 2025 button battery: In a vacuum glove box, a lithium sheet was placed in the battery negative electrode housing, 150 μL of the above electrolyte was added, and the separator (with an area of ​​3.14 cm) prepared above was placed in the negative electrode housing. 2 A 12 μm thick battery was placed in the battery and attached to the lithium sheet. 25 μL of the electrolyte was then added, and the positive electrode plate was placed on top of the battery and packaged. The assembled button battery was removed from the vacuum glove box and left to stand for 24 hours before the next test.

[0132] (2) Test: 10 -1 ~10 6 The test was performed within a frequency range of 100 Hz, and the separator resistance Rb was obtained. The ionic conductivity σ (unit: S cm) was calculated using the following formula: -1 ) was calculated.

number

[0133] 2. Battery cycle performance / capacity retention test Taking Example 1 as an example, the battery capacity retention test process is as follows: At 25°C, the battery produced in Example 1 is charged to 4.3 V at a constant current of 1 / 3 C, then charged to a constant voltage of 4.3 V at a current of 0.05 C, left for 5 minutes, and discharged to 2.8 V at 1 / 3 C. The resulting discharge capacity is the initial capacity C0. The above steps are repeated for the same battery, and the discharge capacity C of the battery after the nth cycle is also measured. n The battery capacity retention rate (Pn) after each cycle is recorded as Pn = C n The battery capacity retention rate was calculated as / C0*100%, which means that the difference in cycle performance can be reflected by using the battery capacity retention rate at a specific number of cycles.

[0134] In Table 2, the battery capacity retention data corresponding to Example 1 is the data tested after 100 cycles under the above test conditions. The test process for the comparative example and other examples is the same as above.

[0135] The test results are shown in Table 2.

[0136] [Table 2-1] [Table 2-2]

[0137] As can be seen from each example shown in Table 2 above, the adhesive composition of the present application improves ionic conductivity and enhances the cycle performance (e.g., capacity retention) of secondary batteries. A comparison of Examples 6 to 30 with Comparative Examples 1 to 5 shows that by controlling the content ratio of polymer to ceramic particles, and the particle size and / or average pore size of the ceramic particles, the resulting separators had relatively high ionic conductivity and relatively good battery capacity retention.

[0138] It should be noted that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any embodiment that has substantially the same configuration as the technical idea within the scope of the technical solution of the present application and achieves the same effects is included within the technical scope of the present application. In addition, various modifications that a person skilled in the art can make to the embodiments without departing from the spirit of the present application, and other methods configured by combining some of the components of the embodiments, are also included within the scope of the present application. [Explanation of symbols]

[0139] 1 battery pack, 2 upper housing, 3 lower housing, 4 battery module, 5 secondary battery, 51 case, 52 electrode assembly, 53 cover plate

Claims

1. An adhesive composition comprising a polymer and ceramic particles, the polymer comprising structural units derived from a first class of monomers, a second class of monomers, and a third class of monomers, the molar ratio of the first class of monomers to the second class of monomers to the third class of monomers being 50-58:40-44:2-6; The first class of monomers is one or more selected from compounds of formula I: 【Chemistry 1】 Here, R １ is selected from a hydrogen atom and a straight or branched C1-6 alkyl group, and R ２ is selected from a substituted or unsubstituted linear or branched C1-15 alkyl group, a C3-6 cycloalkyl group, and an isobornyl group, and in the case of substitution, the substituent is selected from a hydroxyl group and a C1-6 linear alkyl group; The second class of monomers is one or more selected from compounds of formula II: 【Chemistry 2】 Here, R ３ is selected from a hydrogen atom and a straight or branched C1-6 alkyl group; The third class of monomers is one or more selected from compounds of formula III: 【Transformation 3】 Here, R ４ is selected from a hydrogen atom and a straight or branched C1-6 alkyl group, and R ５ is selected from a hydrogen atom, a hydroxy C1-6 alkyl group, and a C1-6 alkoxy group.

2. R １ is selected from a hydrogen atom and a methyl group, and R ２ is selected from substituted or unsubstituted straight or branched chain C1-6 alkyl groups, in which case the substituent is a hydroxyl group, and / or R ３ is selected from a hydrogen atom and a methyl group, and / or R ４ is selected from a hydrogen atom and a methyl group, and R ５ The adhesive composition according to claim 1, wherein is selected from a hydrogen atom, a hydroxy C1-4 alkyl group, and a C1-4 alkoxy group.

3. the first class of monomers are one or more selected from 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, 2-hydroxypropyl methacrylate; and / or the second type of monomer is acrylonitrile or methacrylonitrile, and / or 2. The adhesive composition according to claim 1, wherein the third type of monomer is one or more selected from the group consisting of acrylamide, N-methylolacrylamide, and N-(butoxymethyl)acrylamide.

4. 2. The adhesive composition according to claim 1, wherein the molar ratio of the first type of monomer to the second type of monomer to the third type of monomer is 50-57:41-44:2-6.

5. 2. The adhesive composition according to claim 1, wherein the weight ratio of the polymer to the ceramic particles is 40-90:10-60.

6. 2. The adhesive composition according to claim 1, wherein the weight average molecular weight of the polymer is 60,000 to 120,000.

7. 2. The adhesive composition according to claim 1, wherein the ceramic particles have an average particle size Dv50 of 40 nm to 110 nm.

8. 2. The adhesive composition according to claim 1, wherein the ceramic particles are porous particles, and the average pore size of the porous particles is 0.3 nm to 6.0 nm.

9. The adhesive composition of claim 1 , wherein the ceramic particles are porous silicon dioxide particles.

10. The adhesive composition of claim 1 , wherein the polymer coats the ceramic particles.

11. A separator for a secondary battery, comprising a base layer and a coating layer disposed on at least one surface of the base layer, wherein the coating layer comprises the adhesive composition according to claim 1 .

12. A secondary battery comprising the separator for a secondary battery according to claim 11.

13. A battery module comprising the secondary battery according to claim 12.

14. A battery pack comprising the battery module of claim 13.

15. A power consuming device comprising the secondary battery of claim 12.

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