Binders and associated separators, plates, batteries, battery modules, battery packs, and power consuming devices

Abstract

The present application provides a binder, and a separator, an electrode plate, a related secondary battery, a battery module, a battery pack, and a power consumption device, each containing the binder. The binder includes an organic polymer and an inorganic material, and the organic polymer is obtained by polymerizing a first polymerizable monomer having an ester bond, a second polymerizable monomer having a nitrile bond, and a third polymerizable monomer having an amide bond, and the weight ratio of the first polymerizable monomer: the second polymerizable monomer: the third polymerizable monomer is 1:0-0.8:0-0.15, and optionally 1:0.05-0.2:0.05-0.1. When the binder is applied to a separator, it helps to reduce the resistance of the separator and improve the ionic conductivity of the separator, thereby improving the battery performance.

Description

[Technical Field]

[0001] The present application relates to the technical field of lithium batteries, and in particular to binders and separators containing the same, electrode plates, related secondary batteries, battery modules, battery packs, and power consuming devices. [Background technology]

[0002] In recent years, the application range of lithium-ion batteries has become increasingly broad, and they have been widely used in energy storage power systems such as hydroelectric, thermal, wind, and solar power plants, as well as in many fields such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, and aerospace. However, battery binders used in conventional technologies have drawbacks such as high melting points and poor adhesive properties, which in turn prevent effective adhesion of battery components, deteriorating the dynamic characteristics of the battery and causing safety issues. Therefore, how to develop binders suitable for battery systems remains a pressing issue for researchers. Summary of the Invention [Problem to be solved by the invention]

[0003] The present application has been made in view of the above-mentioned problems, and aims to provide a binder that provides good adhesive performance under conditions suitable for battery processing and can help improve the dynamic characteristics and safety performance of batteries. [Means for solving the problem]

[0004] To achieve the above object, the present application provides a binder and a separator containing the binder, an electrode plate, a related secondary battery, a battery module, a battery pack, and a power consuming device.

[0005] A first aspect of the present application provides a binder comprising an organic polymer and an inorganic substance, wherein the organic polymer comprises at least: a first polymerizable monomer having at least one ester linkage and selectively one or more of methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl 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, vinyl acetate, trifluoroethyl methacrylate, glycidyl methacrylate or trimethylolpropane triacrylate, more selectively one or more of methyl methacrylate, lauryl acrylate, lauryl methacrylate or trimethylolpropane triacrylate; a second polymerizable monomer having at least one nitrile bond and selectively one or more of acrylonitrile, methacrylonitrile, ethacrylonitrile, more selectively one or more of acrylonitrile, methacrylonitrile; and a third polymerizable monomer having at least one amide bond and selectively one or more of acrylamide, N-methylolacrylamide, N-butoxymethylacrylamide, more selectively one or more of acrylamide, N-methylolacrylamide, The weight ratio of the first polymerizable monomer: the second polymerizable monomer: the third polymerizable monomer is 1:0-0.8:0-0.15, and optionally 1:0.05-0.2:0.05-0.1.

[0006] When the organic polymer is polymerized using the above polymerizable monomer, the binder produced has good adhesive properties and a low glass transition temperature, which is suitable for fully demonstrating its adhesive properties under the processing conditions of the battery, and further helps improve the dynamic properties and safety performance of the battery.

[0007] In any embodiment, optionally, the content of the first polymerizable monomer is 60 to 100 wt %, optionally 60 to 90 wt %, based on the total weight of the organic polymer; The content of the second polymerizable monomer is 0 to 30% by weight, and optionally 5 to 15% by weight; The content of the third polymerizable monomer is 0 to 40% by weight, and optionally 0 to 25% by weight.

[0008] In any embodiment, optionally, the volume average particle diameters D10, D50, and D90 of the binder satisfy (D90-D10) / D50<2.5, optionally <2, more preferably <1.8.

[0009] In any embodiment, optionally, the content of the organic polymer particles is 50 to 99.9%, optionally 60 to 99%, more optionally 70 to 99%, based on the total dry weight of the binder; Based on the total dry weight of the binder, the content of the inorganic material is 0.1 to 50%, preferably 1 to 40%, more preferably 1 to 30%.

[0010] In any embodiment, optionally, the weight ratio of the organic polymer to the inorganic material is 99:1 to 1:1, optionally 70:30 to 1:1.

[0011] In any embodiment, optionally, the inorganic material is selected from one or more of oxides of silicon, aluminum, calcium, zinc, magnesium, and sodium sulfate, sodium benzoate, calcium carbonate and modified materials thereof, optionally one or more of silica, silica sol, aluminum oxide, zinc oxide, magnesium oxide, sodium benzoate, more optionally one or more of fumed silica, silicon fine powder, aluminum oxide, sodium benzoate.

[0012] In any embodiment, the binder particles optionally have an uneven surface, and inorganic oxide clusters having a particle size of 10 to 200 nm are uniformly distributed on the surface.

[0013] In any embodiment, optionally, the glass transition temperature of the binder is -20°C to 30°C.

[0014] A second aspect of the present application provides a separator comprising the binder according to the first aspect of the present application.

[0015] A third aspect of the present application provides an electrode plate comprising the binder according to the first aspect of the present application.

[0016] A fourth aspect of the present application provides a secondary battery including at least one of the binder according to the first aspect of the present application, the separator according to the second aspect of the present application, or the electrode plate according to the third aspect of the present application.

[0017] A fifth aspect of the present application provides a battery module including the secondary battery according to the third aspect of the present application.

[0018] A sixth aspect of the present application provides a battery pack including the battery module according to the fifth aspect of the present application.

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

[0020] In the binder of the present application, the organic polymer is obtained by polymerizing a first polymerizable monomer, a second polymerizable monomer, and a third polymerizable monomer having different functional groups in a certain ratio. The resulting organic polymer fully utilizes the advantages of each polymerizable monomer. The binder polymer containing the organic polymer has good adhesive properties and a low glass transition temperature, making it suitable for fully utilizing its adhesive properties under battery processing conditions and further contributing to improving the dynamic properties and safety performance of secondary batteries. Furthermore, when the binder is applied to a separator, it helps reduce the separator's resistance and improve the separator's ionic conductivity, thereby improving battery performance.

[0021] The battery module, battery pack, and power consumption device of the present application include the secondary battery provided by the present application, and therefore have at least the same advantages as the secondary battery. [Brief explanation of the drawings]

[0022] [Figure 1] 1A-1C are scanning electron microscope images at different magnifications of the binder produced in Example 1 of the present application. [Figure 2] 1 is a schematic diagram of a secondary battery according to an embodiment of the present application; [Figure 3] FIG. 3 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 2. [Figure 4] 1 is a schematic diagram of a battery module according to an embodiment of the present application; [Figure 5] 1 is a schematic diagram of a battery pack according to an embodiment of the present application. [Figure 6] FIG. 6 is an exploded view of the battery pack shown in FIG. 5 according to an embodiment of the present application. [Figure 7] 1 is a schematic diagram of a power consuming device that uses a secondary battery as a power source according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, with appropriate reference to the drawings, embodiments specifically disclosing the binder of the present application and the related separator, electrode plate, secondary battery, battery module, battery pack, and power consumption device will be described in detail. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially the same structures may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate easy understanding by those skilled in the art. Furthermore, 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 scope of the claims.

[0024] The "ranges" disclosed herein are defined in the form of lower and upper limits, and a given range is defined by selecting one lower limit and one upper limit, with the selected lower and upper limits defining the boundaries of the given range. Such defined ranges may be inclusive or exclusive of both 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 to 120 and 80 to 110 are recited for a given parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if 1 and 2 are recited as minimum range values ​​and 3, 4, and 5 are recited as maximum range values, then the ranges of 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 are all contemplated. Unless otherwise specified herein, a numerical range "a to b" is shorthand for any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0 to 5" means that all real numbers between "0 and 5" are listed herein, and "0 to 5" is simply shorthand for combinations of these numbers. Note that describing 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.

[0025] Unless otherwise stated, all embodiments and alternative embodiments in the present application can be combined with each other to form new technical solutions.

[0026] Unless otherwise stated, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0027] Unless otherwise specified, all steps herein may be performed in sequence or randomly, preferably in sequence. For example, when the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed in sequence, or may include steps (b) and (a) performed in sequence. For example, when it is stated that the method may further include step (c), it means that step (c) can be added to the method in any order; 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).

[0028] Unless otherwise specified, the terms "comprise" and "comprises" used herein may be open-ended or closed-ended. For example, the terms "comprise" and "comprises" may indicate that the compound may further include or include other components not listed, or may include or include only the listed components.

[0029] Unless otherwise stated, the term "or" in this application is inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition that A is true (or exists) and B is false (or does not exist), the condition that A is false (or does not exist) and B is true (or exists), or the condition that both A and B are true (or exist) all satisfy the condition "A or B."

[0030] During the inventor's work, he found that some battery binders used in the prior art have poor adhesive properties, and some have high melting points, making it difficult for them to fully exert their adhesive properties under the working conditions of the battery. This makes it difficult to effectively bond battery components, and the components may separate or fall off during use, deteriorating the dynamic characteristics of the battery and posing safety risks.

[0031] Unexpectedly, after extensive experimentation, the inventors discovered that an organic polymer obtained by polymerizing polymerizable monomers containing specific functional groups in a certain weight ratio has good adhesive properties and is suitable for fully demonstrating its adhesive properties under battery operating conditions, thereby helping to improve the dynamic characteristics and safety performance of secondary batteries. Furthermore, when this binder is applied to a separator, it helps to reduce the separator's resistance and improve the separator's ionic conductivity, thereby improving battery performance.

[0032] [Binder] A first aspect of the present application provides a binder comprising an organic polymer and an inorganic substance, wherein the organic polymer comprises at least: a first polymerizable monomer having at least one ester linkage and selectively one or more of methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl 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, vinyl acetate, trifluoroethyl methacrylate, glycidyl methacrylate or trimethylolpropane triacrylate, more selectively one or more of methyl methacrylate, lauryl acrylate, lauryl methacrylate or trimethylolpropane triacrylate; a second polymerizable monomer having at least one nitrile bond and selectively one or more of acrylonitrile, methacrylonitrile, ethacrylonitrile, more selectively one or more of acrylonitrile, methacrylonitrile; and a third polymerizable monomer having at least one amide bond and selectively one or more of acrylamide, N-methylolacrylamide, N-butoxymethylacrylamide, more selectively one or more of acrylamide, N-methylolacrylamide, The weight ratio of the first polymerizable monomer: the second polymerizable monomer: the third polymerizable monomer is 1:0-0.8:0-0.15, and optionally 1:0.05-0.2:0.05-0.1.

[0033] The binder of the present application includes an organic polymer obtained by polymerizing a first polymerizable monomer having an ester bond, a second polymerizable monomer having a nitrile bond, and a third polymerizable monomer having an amide bond in a certain weight ratio. This contributes to fully utilizing the synergistic effects of each monomer, and the resulting organic polymer has good adhesive properties and an appropriate glass transition temperature, making it suitable for fully utilizing its adhesive properties under battery operating conditions and improving the dynamic characteristics and safety performance of secondary batteries. The binder of the present application further includes an inorganic material, which helps improve the flame retardancy of the binder and the safety performance of secondary batteries. Furthermore, when the binder is applied to a separator, it helps reduce the separator's resistance and improve the separator's ionic conductivity, thereby improving battery performance.

[0034] In some embodiments, optionally based on the total weight of the organic polymer, the content of the first polymerizable monomer is 60 to 100 wt %, optionally 60 to 90 wt %, the content of the second polymerizable monomer is 0 to 30 wt %, optionally 5 to 15 wt %, and the content of the third polymerizable monomer is 0 to 40 wt %, optionally 0 to 25 wt %.

[0035] When the content of each polymerizable monomer is within the above range, it contributes to the improvement of the adhesion performance of the binder. At the same time, the organic polymer produced by the polymerizable monomer within the above range has an appropriate glass transition temperature and helps to provide sufficient adhesion force under the processing conditions of the battery.

[0036] In some embodiments, optionally, the volume average particle size D50 of the binder satisfies 3 < D50 ≤ 10 μm, and is optionally 5 - 8 μm.

[0037] If the particle size of the binder is too small, when applied to the separator, it may prevent the pores of the separator, increase the internal resistance of the battery, and deteriorate the kinetic properties. If the particle size of the binder is too large, the binder may not be applicable to the manufacture of the cell.

[0038] In some embodiments, optionally, the volume average particle sizes D10, D50 and D90 of the binder satisfy (D90 - D10) / D50 < 2.5, and are optionally < 2, and more optionally < 1.8.

[0039] The narrower the particle size distribution of the binder, the more uniform the size of the produced binder, which helps to fully exert the adhesion effect of the binder.

[0040] In some embodiments, optionally, based on the total dry weight of the binder, the content of the organic polymer particles is from 50% to 99.9%, optionally from 60% to 99%, and more optionally from 70% to 99%. Based on the total dry weight of the binder, the content of the inorganic substance is from 0.1% to 50%, optionally from 1% to 40%, and more optionally from 1% to 30%.

[0041] If the content of the organic polymer is too low or the content of the inorganic substance is too high, the adhesion performance of the whole binder may be insufficient, and as a result, the organic polymer and the inorganic substance may not be maintained as a whole. If the content of the inorganic substance is too low, the flame retardant performance of the binder may be inferior.

[0042] In some embodiments, optionally, the weight ratio of the organic polymer to the inorganic material is 99:1 to 1:1, optionally 70:30 to 1:1.

[0043] When the weight ratio of the organic polymer to the inorganic material is within the above range, the synergistic effect between the organic polymer and the inorganic material is fully exerted, and the binder has good adhesive properties and flame retardant properties.

[0044] In some embodiments, the inorganic material is optionally selected from one or more of oxides of silicon, aluminum, calcium, zinc, magnesium, and sodium sulfate, sodium benzoate, calcium carbonate, and modified materials thereof, optionally one or more of silica, silica sol, aluminum oxide, zinc oxide, magnesium oxide, sodium benzoate, and more preferably one or more of fumed silica, silicon fine powder, aluminum oxide, and sodium benzoate.

[0045] In some embodiments, the binder particles optionally have an uneven surface, and inorganic oxide clusters having a particle size of 10 to 200 nm are uniformly distributed on the surface.

[0046] During the research, the inventors found that if the surfaces of the binder particles satisfy the above conditions, it helps the organic polymer to be dispersed uniformly, and further improves the adhesive performance of the binder.

[0047] In some embodiments, the weight-average molecular weight of the organic polymer is optionally 500,000 to 1.2 million, and optionally 800,000 to 1 million. The molecular weight of the organic polymer can be measured using a method commonly used in the art, for example, by gel permeation chromatography in accordance with GB / T 21863-2008.

[0048] In some embodiments, the glass transition temperature of the binder is optionally −20° C. to 30° C. The glass transition temperature can be measured by a method commonly used in the art, for example, by differential scanning calorimetry in accordance with GB / T 19466.2.

[0049] When the glass transition temperature of the binder is within the above range, the binder can fully exhibit its adhesive performance and provide sufficient adhesive strength to the battery components under the operating conditions of the battery, thereby avoiding the deterioration of the dynamic characteristics of the battery due to separation or detachment of the components and resulting in safety issues.

[0050] The present application further provides a method for producing the binder according to the first aspect of the present application, including at least the following steps 1 to 4: Step 1: Provide a first polymerizable monomer, a second polymerizable monomer, and a third polymerizable monomer, and the weight ratio of the first polymerizable monomer: the second polymerizable monomer: the third polymerizable monomer is 1:0-0.8:0-0.15, optionally 1:0.05-0.2:0.05-0.1. Step 2: Polymerize the polymerizable monomer to obtain an organic polymer. Step 3: Add an organic solvent and an inorganic substance to the organic polymer from step 2, and after stirring, obtain a mixed slurry. Step 4: The mixed slurry from step 3 is dried, polished and crushed to obtain the binder described in the present application.

[0051] It should be noted that the polymerization of the polymerizable monomer can be carried out by a polymerization method commonly used in the art, for example, emulsion polymerization or suspension polymerization.

[0052] In some embodiments, additives such as an emulsifier such as sodium lauryl sulfate and a polymerization initiator such as ammonium persulfate may be optionally added to the polymerization system of the polymerizable monomer.

[0053] [Separator] A second aspect of the present application provides a separator including the binder according to the first aspect of the present application. When the binder according to the first aspect of the present application is applied to a separator, it helps to reduce the resistance of the separator and improve the ionic conductivity of the separator, thereby improving battery performance.

[0054] In the present application, there is no particular limitation on the type of separator substrate, and any separator substrate having a known porous structure and having good chemical stability and mechanical stability can be selected.

[0055] In some embodiments, the separator substrate can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, and is not particularly limited. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, and are not particularly limited.

[0056] The separator described in the present application can be manufactured by adopting a conventional separator manufacturing method in the art. For example, the binder described in the first aspect of the present application is dissolved in an organic solvent to obtain a slurry, and then the slurry is applied to a separator material, followed by drying to remove the organic solvent, thereby obtaining the separator described in the present application.

[0057] In some embodiments, the binder may have a coating density of 0.3 to 1.0 g / m on the separator substrate. 2 and selectively 0.3 to 0.8 g / m 2 is.

[0058] [Pole plate] A third aspect of the present application provides an electrode plate comprising the binder according to the first aspect of the present application. The electrode plate can be manufactured by a method commonly used in the art.

[0059] It should be noted that the electrode plates described herein can be positive or negative plates.

[0060] The positive electrode plate includes a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector, and the positive electrode film layer includes the binder according to the first aspect of the present application.

[0061] As an example, the positive electrode current collector has two surfaces facing each other in the thickness direction thereof, and the positive electrode film layer is provided on either one or both of the two facing surfaces of the positive electrode current collector.

[0062] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, the metal foil may be an aluminum foil. The composite current collector may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material base layer. The composite current collector may be formed by forming a metal material (such as aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, or a silver alloy) on a polymeric material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0063] In some embodiments, the positive electrode active material may be any positive electrode active material known in the art for batteries. For example, the positive electrode active material may include at least one of materials such as lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and modified compounds thereof. However, the present application is not limited to these materials, and other conventional materials used 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. 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 / 3Co 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 0.05 O2) and modified compounds thereof, etc. 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.

[0064] In some embodiments, the positive electrode film layer may further include a conductive agent, such as one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0065] In some embodiments, a positive electrode plate can be manufactured by the following method. The components for manufacturing the positive electrode plate described above, such as the positive electrode active material, conductive agent, binder described in 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. The positive electrode slurry is applied to a positive electrode current collector, and after steps such as baking and cold pressing, a positive electrode plate can be obtained.

[0066] In some embodiments, the amount of the binder according to the first aspect of the present application used in the positive electrode plate is optionally 1 to 3% based on the total weight of the positive electrode membrane layer.

[0067] Similarly, the electrode plate described herein may be a negative electrode plate, which includes a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector, and the negative electrode film layer includes the binder described in the first aspect of the present application.

[0068] As an example, the negative electrode current collector has two surfaces facing each other in the thickness direction thereof, and the negative electrode film layer is provided on either one or both of the two facing surfaces of the negative electrode current collector.

[0069] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, the metal foil may be a copper foil. The composite current collector may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material 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 polymeric material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0070] 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, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of tin, tin-oxygen compounds, and tin alloys. However, the present application is not limited to these materials, and other conventional materials used as negative electrode active materials in batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0071] In some embodiments, the negative electrode film layer optionally further comprises a conductive agent, which may be selected from one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0072] In some embodiments, the negative electrode membrane layer optionally further comprises other additives, such as a thickener (eg, carboxymethylcellulose sodium (CMC-Na)).

[0073] In some embodiments, a negative electrode plate can be manufactured by the following method. The components for manufacturing the negative electrode plate described above, such as the negative electrode active material, the conductive agent, the binder described in 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. The negative electrode slurry is applied to a negative electrode current collector, and after steps such as baking and cold pressing, a negative electrode plate can be obtained.

[0074] In some embodiments, the amount of the binder according to the first aspect of the present application used in the negative electrode plate is 1 to 3%, optionally based on the total weight of the negative electrode membrane layer.

[0075] [Secondary battery] A fourth aspect of the present application provides a secondary battery including at least one of the binder according to the first aspect of the present application, the separator according to the second aspect of the present application, or the electrode plate according to the third aspect of the present application.

[0076] Typically, a secondary battery comprises a positive electrode plate, a negative electrode plate, an electrolyte, and a separator. During the charge and discharge process of the battery, active ions are repeatedly inserted and removed between the positive and negative electrodes. The electrolyte serves to conduct ions between the positive and negative electrodes. The separator, located between the positive and negative electrodes, serves mainly to prevent short circuits between the positive and negative electrodes while also allowing ions to pass through.

[0077] The secondary battery can be manufactured by a method commonly used in the art. For example, a positive electrode plate, a negative electrode plate, and a separator are manufactured as an electrode assembly by a winding process or a lamination process, and then an electrolyte solution is injected into the electrode assembly and sealed to manufacture a secondary battery.

[0078] [Electrolyte] The electrolyte serves to conduct ions between the positive and negative electrodes. In this application, the type of electrolyte is not specifically limited and can be selected according to needs. For example, the electrolyte may be liquid, gel-like, or all solid.

[0079] In some embodiments, the electrolyte is an electrolytic solution, which includes an electrolyte salt and a solvent.

[0080] In some embodiments, the electrolyte salt can 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 difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0081] In some embodiments, the solvent can be chosen 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, methyl ethyl sulfone, and diethyl sulfone.

[0082] In some embodiments, the electrolyte solution may further optionally contain additives, such as additives for improving the overcharge performance of the battery, additives for improving the high-temperature or low-temperature performance of the battery, or additives for improving the overcharge performance of the battery, such as additives for improving the high-temperature or low-temperature performance of the battery.

[0083] [Battery modules, battery packs and power consumption devices] A fifth aspect of the present application provides a battery module including the secondary battery according to the fourth aspect of the present application. The battery module can be manufactured by employing a method commonly used in the art.

[0084] A sixth aspect of the present application provides a battery pack including the battery module according to the fifth aspect of the present application. The battery pack can be manufactured by employing a method commonly used in the art.

[0085] A seventh aspect of the present application provides a power consumption device including at least one selected from the secondary battery according to the fourth aspect of the present application, the battery module according to the fifth aspect of the present application, or the battery pack according to the sixth aspect of the present application.

[0086] 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.

[0087] In some embodiments, the secondary battery may include an exterior body that can be used to encapsulate the electrode assembly and electrolyte.

[0088] In some embodiments, the exterior of the secondary battery may be a hard case such as a hard plastic case, an aluminum case, or a steel case. The exterior of the secondary battery may be a soft pack such as a bag-type soft pack. The soft pack may be made of plastic, such as polypropylene, polybutylene terephthalate, or polybutylene succinate.

[0089] In the present application, the shape of the secondary battery is not particularly limited, and may be cylindrical, rectangular, or any other shape. For example, Fig. 2 shows a secondary battery 5 having a rectangular structure as an example.

[0090] In some embodiments, as shown in FIG. 3 , the exterior body may include a case 51 and a cover plate 53. The case 51 may include a bottom plate and side plates connected to the bottom plate, which surround the chamber to form a storage chamber. The case 51 may have an opening communicating with the storage chamber, and the cover plate 53 may cover the opening to seal the storage chamber. 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 sealed in the storage chamber. An electrolyte solution permeates the electrode assembly 52. ​​The number of electrode assemblies 52 included in the lithium-ion battery 5 may be one or more, and can be selected by those skilled in the art according to specific actual needs.

[0091] In some embodiments, the secondary battery can be assembled into a battery module, and the number of secondary batteries included in the battery module 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 module.

[0092] Fig. 4 shows an example of a battery module 3. As shown in Fig. 4, in the battery module 4, the 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 fastening members.

[0093] Optionally, the battery module 4 may further include a housing having an accommodating space, and the plurality of secondary batteries 5 are accommodated in the accommodating space.

[0094] 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 according to the application and capacity of the battery pack.

[0095] 5 and 6 show an example of a battery pack 1. As shown in FIGS. 5 and 6, the battery pack 1 may include a battery box and a plurality of battery modules 4 provided in the battery box. The battery box may include an upper box 2 and a lower box 3, and the upper box 2 may cover the lower box 3 to form an enclosed space for accommodating the battery modules 4. The plurality of battery modules 4 may be arranged in the battery box in any manner.

[0096] The present application also provides a power consuming device including at least one of the secondary battery, battery module, or battery pack provided herein. The secondary battery, battery module, or 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, notebook computers, etc.), electric vehicles (e.g., rechargeable battery electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric cars, ships and satellites, energy storage systems, etc.

[0097] The power consumption device can be selected as a secondary battery, a battery module, or a battery pack depending on the needs of the device.

[0098] 7 shows an example of a power consuming device, such as a secondary battery electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. A battery pack or a battery module can be employed to meet the high power and high energy density requirements of the secondary battery of the power consuming device.

[0099] Other example devices may be mobile phones, tablets, laptops, etc. Such devices typically require light weight and thinness, and can employ secondary batteries as their power source.

[0100] Example Examples of the present application are described below. The examples described below are illustrative and are intended merely to interpret the present application and should not be understood as limiting the present application. If specific techniques or conditions are not specified in the examples, they are performed according to the techniques or conditions described in the literature in the field or according to the product specifications. If the manufacturers of the reagents or equipment used are not specified, they are all conventional products that are commercially available.

[0101] 1. Separator Comparative Example 1 Preparation of organic polymer 1-1 The required monomers (50% by weight, 2-hydroxyethyl acrylate, 40% by weight, n-butyl acrylate, 5% by weight, methyl methacrylate, and 5% by weight, trimethylolpropane triacrylate) were mixed uniformly at room temperature by stirring. 100 g of the mixed monomers, 3 g of emulsifier sodium lauryl sulfate, 1 g of initiator ammonium persulfate, and 120 g of deionized water were added to a 500 mL four-neck flask equipped with a mechanical stirrer, thermometer, and condenser. The mixture was emulsified by stirring at 1600 rpm for 30 minutes. The mixture was then heated to 75°C under nitrogen gas protection and reacted for 4 hours. After that, the pH was adjusted to 6-8, and the temperature was immediately lowered to below 40°C and discharged to obtain the emulsion-state organic polymer 1-1, which had a solids content of approximately 45%.

[0102] Manufacturing of Binder 1-1 1 kg of organic polymer 1 was added to 450 g of silica (dry weight) and 1 kg of deionized water, and the mixture was stirred for 1 hour to thoroughly mix. The mixture was then spray-dried to remove the solvent and produce binder powder. The mixture was then ground and pulverized to obtain binder 1-1, which had a D50 particle size of 6 μm and a particle size distribution of 1.78.

[0103] Manufacturing of separator 1-1 A commercially available PP-PE copolymer microporous film (Model 20 available from Zhuoguang Electronics Technology Co., Ltd.) with a thickness of 20 μm and an average pore size of 80 nm was used as the separator substrate. The prepared binder 1 was dissolved in N-methylpyrrolidone (i.e., NMP) and stirred to homogeneously mix to obtain a slurry. The slurry was then applied to a PP-PE copolymer microporous separator. The binder 1 was then applied to the separator at a coating density of 0.5 g / m. 2 The organic solvent was removed by drying so as to obtain Separator 1-1.

[0104] Comparative Example 2 and Examples 1 to 8 Except for the types and amounts of polymerizable monomers and inorganic substances used, the other steps of Comparative Example 2 and Examples 1 to 8 are the same as those of Comparative Example 1, see Table 1 for details.

[0105] 2. Secondary battery Positive electrode plate manufacturing The positive electrode active material, lithium iron phosphate (LiFePO4), the conductive agent, acetylene black, and the binder, PVDF, were mixed in a mass ratio of 96.5:2:1.5, dissolved in the solvent, N-methylpyrrolidone (i.e., NMP), and thoroughly stirred to obtain a uniform mixture, resulting in a positive electrode slurry. The positive electrode slurry was then uniformly applied to an aluminum foil, baked, cold-pressed, and cut to obtain a positive electrode plate. The resulting positive electrode active material layer had an areal density of 19.5 mg / cm. 2 and the compressed density is 2.4 g / cm 3 It was.

[0106] Negative electrode plate manufacturing Graphite, conductive black, PVDF binder, and carboxymethylcellulose sodium (CMC) thickener were dissolved in deionized water in a mass ratio of 96.5:0.7:1.8:1 part by weight and thoroughly stirred to obtain a negative electrode slurry. The negative electrode slurry was uniformly applied to the copper foil of the negative electrode current collector, baked, cold pressed, and cut to obtain a negative electrode plate. The resulting negative electrode active material layer had an areal density of 9.8 mg / cm. 2 and the compressed density is 1.65 g / cm 3 It was.

[0107] Electrolyte production The organic solvents ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed uniformly in a weight ratio of 50 / 50, and LiPF6 was added to and dissolved in the organic solvent. The mixture was stirred uniformly so that the LiPF6 concentration became 1.1 mol / L, thereby obtaining an electrolyte solution.

[0108] Separator The separator 2-1 produced in Example 1 of the present application was used as a separator for a secondary battery.

[0109] secondary battery The positive electrode plate, separator 2-1, and negative electrode plate were stacked in this order, and a separator was placed between the positive and negative electrodes to serve as an insulator. The stack was then wound up to obtain a bare cell. The bare cell was placed in an outer casing, and the above-mentioned electrolyte solution was poured into the exterior, followed by packaging to obtain a secondary battery.

[0110] Test methods for relevant parameters 1. Scanning electron microscope examination A suitable amount of sample of the lithium iron phosphate particles to be tested is prepared, and the morphology of the sample is observed using a ZEISS sigma 300 scanning electron microscope with reference to standard JY / T010-1996.

[0111] 2. Volume average particle size test Refer to the GB / T 19077-2016 / ISO 13320:2009 laser diffraction particle size distribution standard. The test is performed using a laser particle size analyzer (Malvern 3000, MasterSizer 3000) with a helium-neon red light source as the primary light source. Add 1 g of test sample to a clean small beaker, add one drop of surfactant, and add 20 ml of deionized water (ensuring a light-blocking level of 8-12% relative to the sample concentration). Sonicate at 53 kHz / 120 W for 5 minutes to ensure complete dispersion. Turn on the laser particle size analyzer and clean the optical path system, then automatically test the background. Stir the sonicated test solution until uniformly dispersed. If necessary, add it to the sample cell and begin particle size measurement. The measurement results can be read from the instrument.

[0112] 3. Ionic conductivity test The separator was cut into 40 mm x 20 mm x 9 μm test pieces, and four layers of the cut separators were stacked together. After completely wetting the separators with commercially available electrolyte, they were assembled into a symmetrical test battery in a glove box. The separator impedance (R) was measured using an electrochemical workstation, with a measurement range of 1 Hz to 100,000 Hz and an applied AC signal with a polarization of 5 mV. From the AC impedance test results, the ionic conductivity could be calculated using the following formula: δ=1000L / RA where δ represents ionic conductivity in mS / cm, and A represents the area of ​​the separator under test in cm. 2 where L represents the thickness of the separator under test in μm, and R represents the resistance of the separator under test.

[0113] 4. Glass transition temperature test The glass transition temperature is measured by differential scanning calorimetry (DSC) with reference to standard GB / T 19466.2.

[0114] 5.Solids content test The solid content can be tested by referring to GB / T 1725-2007 "Paints, varnishes and plastics - Determination of non-volatile matter content."

[0115] [Table 1]

[0116] As can be seen from the above results, the separators produced with the binders of Examples 1 to 8 have higher ionic conductivities than the separators produced with the binders of Comparative Examples 1 and 2. In particular, the ionic conductivity of the separator can be further improved by adjusting the proportion of each polymerizable monomer and the ratio of the dry weight of the organic polymer to the dry weight of the inorganic material.

[0117] It should be noted that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and all embodiments that have substantially the same configuration as the technical idea and exhibit the same functions and effects within the scope of the technical solution of the present application are encompassed within the technical scope of the present application. Furthermore, various modifications that can be conceived by a person skilled in the art to the embodiments and other forms configured by combining some of the components of the embodiments are also encompassed within the scope of the present application, as long as they do not deviate from the gist of the present application. [Explanation of symbols]

[0118] 1 battery pack 2 Upper Box 3 Lower Box 4 Battery Module 5 Secondary battery 51 Housing 52 Electrode assembly 53 Top cover assembly

Claims

1. A binder for a separator comprising an organic polymer and an inorganic material, The organic polymer comprises at least a first polymerizable monomer that is one or more of methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, lauryl methacrylate, or trimethylolpropane triacrylate; a second polymerizable monomer that is acrylonitrile; and and a third polymerizable monomer which is acrylamide, a weight ratio of the first polymerizable monomer: the second polymerizable monomer: the third polymerizable monomer is 1:0.8 or less:0.15 or less; Based on the total dry weight of the binder, the content of the organic polymer particles is 50 to 99.9%; A binder for a separator, wherein the content of the inorganic substance is 0.1 to 50% based on the total dry weight of the binder.

2. based on the total weight of the organic polymer, the content of the first polymerizable monomer is 60 to 100% by weight, the content of the second polymerizable monomer is 30% by weight or less; 2. The binder for a separator according to claim 1, wherein the content of the third polymerizable monomer is 40% by weight or less.

3. 3. The binder for a separator according to claim 1, wherein the volume average particle diameters D10, D50 and D90 of the binder satisfy (D90-D10) / D50<2.

5.

4. 4. The binder for a separator according to claim 1, wherein a weight ratio of the organic polymer to the inorganic material is 99:1 to 1:

1.

5. 5. The binder for a separator according to claim 1, wherein the inorganic substance is selected from one or more of oxides of silicon, aluminum, calcium, zinc, and magnesium, as well as sodium sulfate, sodium benzoate, calcium carbonate, and modified materials thereof.

6. 6. The binder for separators according to claim 1, wherein the surfaces of the binder particles are uneven, and inorganic oxide clusters having particle sizes of 10 to 200 nm are uniformly distributed thereon.

7. 7. The binder for a separator according to claim 1, wherein the binder has a glass transition temperature of -20°C to 30°C.

8. A separator comprising the binder for a separator according to any one of claims 1 to 7.

9. An electrode plate comprising the binder for a separator according to any one of claims 1 to 7.

10. A secondary battery comprising at least one of the binder for a separator according to any one of claims 1 to 7, the separator according to claim 8, or the electrode plate according to claim 9.

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

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

13. A power consumption device comprising at least one selected from the group consisting of the secondary battery according to claim 10, the battery module according to claim 11, and the battery pack according to claim 12.

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