Adhesives and methods for manufacturing the same, as well as separators, electrode assemblies, battery cells, batteries, and power consumption devices.

Abstract

The present application relates to the field of battery technology, in particular to an adhesive and its manufacturing method, and a separator, an electrode assembly, a battery cell, a battery and a power consumption device containing the adhesive. The adhesive includes a core layer structure and a shell layer structure provided on the surface of the core layer structure, the core layer structure includes a polyvinylidene fluoride polymer, and the shell layer structure includes a polyacrylate-based polymer, and the polyvinylidene fluoride is a homopolymer with a crystallinity of about 50% and insufficient adhesive strength. Therefore, the present application improves the crystallinity of the polyvinylidene fluoride polymer in the adhesive with the core-shell structure by coating the polyvinylidene fluoride polymer with a polyacrylate-based polymer to obtain an adhesive with a core-shell structure, thereby realizing the improvement of the adhesive performance of the adhesive with the core-shell structure, and the adhesive improves the adhesive strength between the separator and the electrode plate.

Description

Cross-reference of related applications

[0001] This application claims priority to the Chinese patent application filed on January 4, 2023, with application number 202310010451.2, the entirety of which is incorporated into this application by reference. [Technical Field]

[0002] This application relates to the battery technology field, and more particularly to adhesives and methods for manufacturing the same, as well as separators, electrode assemblies, battery cells, batteries, and power consumption devices. [Background technology]

[0003] With the rapid increase in portable electronic devices and electric vehicles, the demand for power batteries is constantly growing. In this context, the electrochemical performance of batteries is attracting increasing attention.

[0004] Currently, the battery core of batteries has an opening problem; specifically, a gap easily forms between the electrode plate and the separator, which degrades the battery's cycle performance. [Overview of the project]

[0005] This application primarily aims to provide an adhesive that improves the adhesive strength between the separator and the electrode plate, thereby improving the battery's cycle performance.

[0006] To achieve the above objective, this application provides an adhesive comprising a core layer structure and a shell layer structure provided on the surface of the core layer structure, wherein the shell layer structure comprises a polyacrylate polymer and the core layer structure comprises a polyvinylidene fluoride polymer.

[0007] The adhesive of this application comprises a core layer structure and a shell layer structure provided on the surface of the core layer structure. The core layer structure comprises a polyvinylidene fluoride polymer, and the shell layer structure comprises a polyacrylate polymer. The polyvinylidene fluoride is a homopolymer with a crystallinity of approximately 50%, resulting in insufficient adhesive strength. Therefore, this application aims to improve the crystallinity of the polyvinylidene fluoride polymer in the core-shell adhesive by coating the polyvinylidene fluoride polymer with a polyacrylate polymer to obtain a core-shell adhesive, thereby improving the adhesive performance of the core-shell adhesive and improving the adhesive strength between the separator and the electrode plate.

[0008] Selectively, the shell layer structure includes a plurality of cases, which are spaced apart on the surface of the core layer structure.

[0009] The cases, made of polyacrylate polymer, do not continuously cover the surface of the core layer structure, but rather adhere to the surface of the core layer structure at intervals, resembling a raspberry-like structure. As can be understood, this corresponds to the shell layer structure being composed of multiple cases, with gaps between adjacent cases, allowing the surface of the core layer structure to be exposed at these gaps. Thus, the polyvinylidene fluoride polymer core layer structure is exposed, and because the core layer structure also possesses relatively good adhesion, the core layer structure exposed between the cases can also reinforce the adhesive performance. Furthermore, the raspberry-like core-shell structure has a larger specific surface area compared to a core layer structure that completely covers the shell layer, and thus, the surface structure with adhesive function can perform a greater degree of adhesion.

[0010] Selectively, the mass ratio of the polyvinylidene fluoride polymer to the polyacrylate-based polymer is (2-100):1, and selectively, (10-80):1.

[0011] To obtain the raspberry-like core-shell structure mentioned above, the mass of the polyvinylidene fluoride polymer is greater than the mass of the polyacrylate polymer, the mass of the core layer structure is greater than the mass of the shell layer structure, the surface of the core layer structure is not completely covered by the shell layer structure, and a portion of the structure is exposed on the surface of the core layer structure, thereby obtaining the raspberry-like core-shell structure. Here, the mass of the core layer structure is greater than the mass of the shell layer structure, and the mass ratio of the core layer structure to the shell layer structure may be (2~100):1, where (2~100):1 includes the minimum and maximum values ​​within this range, and the values ​​between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and 2:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, etc.

[0012] Selectively, the mass ratio of the polyvinylidene fluoride polymer to the polyacrylate-based polymer is (10-80):1.

[0013] To obtain the raspberry-like core-shell structure mentioned above, the mass of the polyvinylidene fluoride polymer is greater than the mass of the polyacrylate polymer, the mass of the core layer structure is greater than the mass of the shell layer structure, the surface of the core layer structure is not completely covered by the shell layer structure, and a portion of the structure is exposed on the surface of the core layer structure, thereby obtaining the raspberry-like core-shell structure. Here, the mass of the core layer structure is greater than the mass of the shell layer structure, and the mass ratio of the core layer structure to the shell layer structure may be (10~80):1, where (10~80):1 includes the minimum and maximum values ​​within this range, and the values ​​between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, etc.

[0014] Selectively, the volume-average particle size Dv50 of the adhesive is between 0.5 μm and 50 μm, and selectively between 7 μm and 8 μm.

[0015] Theoretically, the volume-average particle size Dv50 of the adhesive in this application may be less than 0.5 μm or greater than 50 μm. However, considering that the adhesive in this application is used in a separator, the volume-average particle size Dv50 of the adhesive cannot be too large or too small. If the adhesive is too small, it is likely to clog the holes in the separator, reducing the passability of lithium ions through the separator. If the adhesive is too large, a thick coating will be formed when the adhesive is applied to the separator. Therefore, to avoid affecting the energy density of batteries manufactured later, the volume-average particle size Dv50 of the adhesive is 0.5 μm-50 μm, and within the above 0.5 μm-50 μm range, the values ​​include the minimum and maximum values ​​within this range, and each value between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and 0.5 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc.

[0016] Selectively, the volume-average particle size Dv50 of the adhesive is 7 μm-8 μm.

[0017] When the volume-average particle size Dv50 of the adhesive is 7 μm-8 μm, the performance of the resulting separator is excellent. Within the 7 μm-8 μm range, the values ​​include the minimum and maximum values ​​within this range, as well as the values ​​between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and values ​​such as 7 μm, 7.5 μm, and 8 μm.

[0018] Selectively, the constituent monomers of the polyacrylate polymer include a first polymerization flexibility monomer, a second polymerization polarity monomer, and a third polymerization molecular weight adjustment monomer.

[0019] The constituent monomers of the polyacrylate polymer in this application include a first polymerization flexibility monomer, a second polymerization polarity monomer, and a third polymerization molecular weight adjustment monomer. By subjecting the three types of monomers to a cross-linking reaction to obtain a polymer, the molecular weight and glass transition temperature of the polymer can be controlled, thereby improving the adhesion performance of the adhesive.

[0020] Optionally, the molar ratio of the first polymerization flexibility monomer, the second polymerization polarity monomer, and the third polymerization molecular weight adjustment monomer is 1:(0.01~0.8):(0.01~0.15), and optionally 1:(0.05~0.7):(0.05~0.12).

[0021] When the molar ratio of the first polymerization flexibility monomer, the second polymerization polarity monomer, and the third polymerization molecular weight adjustment monomer is 1:(0.01~0.8):(0.01~0.15), the adhesion effect of the adhesive is excellent. In the above 1:(0.01~0.8):(0.01~0.15), the value includes the minimum value and the maximum value of this range, and each value between such minimum value and maximum value. Specific examples include the point values in the examples and 1:0.01:0.01, 1:0.1:0.01, 1:0.4:0.01, 1:0.8:0.01, 1:0.01:0.05, 1:0.01:0.1, 1:0.01:0.15, 1:0.1:0.01, 1:0.1:0.05, 1:0.1:0.15, 1:0.4:0.01, 1:0.4:0.05, 1:0.4:0.15, 1:0.8:0.01, 1:0.8:0.05, 1:0.8:0.15, etc., but are not limited thereto.

[0022] Optionally, the molar ratio of the first polymerization flexibility monomer, the second polymerization polarity monomer, and the third polymerization molecular weight adjustment monomer is 1:(0.05~0.7):(0.05~0.12).

[0023] When the molar ratio of the first polymerizable flexible monomer, the second polymerizable polarity monomer, and the third polymerizable molecular weight adjusting monomer is 1:(0.05~0.7):(0.05~0.12), the adhesive effect of the adhesive is excellent. In the above 1:(0.05~0.7):(0.05~0.12), the value includes the minimum and maximum values ​​within this range, and each value between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and 1:0.05:0.05, 1:0.1:0.05, 1:0.4:0.05, 1:0.7:0.05, 1:0.1:0.05, 1:0.1:0.1, 1:0.1:0.12, etc.

[0024] Selectively, the structure of the first polymeric flexibility monomer contains an ester bond, the structure of the second polymeric polarity monomer contains a cyano group, and the third polymeric molecular weight adjustment monomer contains an amide bond.

[0025] Ester bonds can improve the flexibility of molecular chains, cyano groups can improve the polarity of monomers, and amide bonds are polar, readily form hydrogen bonds, and improve adhesion. By polymerizing the above three types of monomers, the polymer obtained by polymerizing the first polymeric flexibility monomer containing ester bonds, the second polymeric polarity monomer containing cyano groups, and the third polymeric molecular weight adjustment monomer containing amide bonds allows for control of the polymer's molecular weight and vitrification transition temperature, thereby improving the adhesive performance of the adhesive.

[0026] Selectively, the first polymerization flexibility monomer is an acrylate monomer, the second polymerization polarity monomer is an acrylonitrile monomer, and the third polymerization molecular weight adjustment monomer is an acrylamide monomer.

[0027] Acrylate monomers can improve the swelling resistance of polymers and, as flexible monomer segments in the molecular segment, adjust the vitrification transition temperature of the polymer, thereby improving the toughness during adhesive application and contributing to good adhesive properties. Acrylonitrile monomers have strongly polar cyano groups, which improve ionic conductivity and contribute to improved adhesion. Acrylamide monomers play a role in adjusting molecular weight and also possess relatively good adhesion. Polymers produced using these three types of monomers allow for control of the polymer's molecular weight and vitrification transition temperature, thereby improving the adhesive performance of the adhesive.

[0028] Selectively, the acrylate monomer comprises at least one of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate. and / or, the acrylonitrile monomer comprises at least one of acrylonitrile and methacrylonitrile, and / or, the acrylamide monomer comprises at least one of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide.

[0029] Based on acrylate monomers, the adhesive properties of the adhesive are improved. The acrylate monomers may include at least one of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate. In other words, the constituent monomers of the polyacrylate polymer may include one of the above acrylate monomers, or multiple of the above acrylate monomers, and are not specifically limited.

[0030] Based on acrylonitrile monomers, the adhesive properties of the adhesive are improved. The acrylonitrile monomer includes at least one of acrylonitrile and methacrylonitrile. That is, the constituent monomers of the polyacrylate polymer may include one of the above-mentioned acrylonitrile monomers, or may include multiple of the above-mentioned acrylonitrile monomers, and are not specifically limited.

[0031] Based on acrylamide monomers, the adhesive properties of the adhesive are improved. The acrylamide monomers include at least one of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide. That is, the constituent monomers of the polyacrylate polymer may include one of the above acrylamide monomers, or multiple of the above acrylamide monomers, and are not specifically limited.

[0032] Selectively, the polyvinylidene fluoride polymer includes at least one of the following: vinylidene fluoride polymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-pentafluoropropylene copolymer, vinylidene fluoride-tetrafluoropropylene copolymer, vinylidene fluoride-trifluoropropylene copolymer, vinylidene fluoride-perfluorobutene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trifluorochloroethylene copolymer, or vinylidene fluoride-vinyl copolymer.

[0033] Polyvinylidene fluoride polymers possess excellent chemical and corrosion resistance, as well as special properties such as high temperature resistance, oxidation resistance, weather resistance, and radiation resistance, and also exhibit piezoelectric, dielectric, and thermoelectric properties, making them commonly used in lithium-ion battery separators.

[0034] The polyvinylidene fluoride polymer used in this application comprises at least one of the following: vinylidene fluoride polymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-pentafluoropropylene copolymer, vinylidene fluoride-tetrafluoropropylene copolymer, vinylidene fluoride-trifluoropropylene copolymer, vinylidene fluoride-perfluorobutene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trifluorochloroethylene copolymer, or vinylidene fluoride-vinyl fluoride copolymer. In other words, the polyvinylidene fluoride polymer may comprise one of the above polyvinylidene fluoride polymers, or multiple of the above polyvinylidene fluoride polymers, and is not specifically limited.

[0035] This application further provides a method for manufacturing adhesives, The process involves adding water, an emulsifier, an initiator, and the constituent monomers of polyvinylidene fluoride polymer to a reaction vessel, stirring, heating under reaction pressure to carry out the polymerization reaction, obtaining a seed emulsion to be used as a reserve, and then... The steps include mixing and stirring water, an emulsifier, and the constituent monomers of a polyacrylate polymer to obtain a shell layer monomer pre-emulsion, which is used as a preliminary step. The process includes the steps of adding the shell layer monomer pre-emulsion, initiator, and water to the seed emulsion, stirring, heating, and reacting to obtain an adhesive with a core-shell structure.

[0036] This application describes a method for first obtaining a seed emulsion of polyvinylidene fluoride polymer for the core layer using emulsion polymerization, and then producing a polyacrylate-based polymer for the shell layer on the surface of the core layer structure using emulsion polymerization, ultimately forming an adhesive having a core-shell structure.

[0037] Selectively, the ratio of the constituent monomer mass of the polyvinylidene fluoride polymer to the constituent monomer mass of the polyacrylate polymer is (2-100):1, and selectively (10-80):1.

[0038] To obtain the raspberry-like core-shell structure mentioned above, the mass of the core layer structure is made greater than the mass of the shell layer structure, so that the surface of the core layer structure is not completely covered by the shell layer structure, thereby exposing part of the structure on the surface of the core layer structure, and thereby obtaining the raspberry-like core-shell structure. Here, the mass of the core layer structure is greater than the mass of the shell layer structure, and the mass ratio of the core layer structure to the shell layer structure may be (2~100):1, where (2~100):1 includes the minimum and maximum values ​​in this range, and the values ​​between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and 2:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, etc.

[0039] Selectively, the ratio of the constituent monomer mass of the polyvinylidene fluoride polymer to the constituent monomer mass of the polyacrylate polymer is (10-80):1.

[0040] To obtain the raspberry-like core-shell structure mentioned above, the mass of the core layer structure is made greater than the mass of the shell layer structure, so that the surface of the core layer structure is not completely covered by the shell layer structure, thereby exposing part of the structure on the surface of the core layer structure, and thereby obtaining the raspberry-like core-shell structure. Here, the mass of the core layer structure is greater than the mass of the shell layer structure, and the mass ratio of the core layer structure to the shell layer structure may be (10~80):1, where (10~80):1 includes the minimum and maximum values ​​within this range, and the values ​​between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, etc.

[0041] Selectively, the constituent monomers of the polyvinylidene fluoride polymer include vinylidene fluoride. Alternatively, the constituent monomers of the polyvinylidene fluoride polymer include at least one of vinylidene fluoride, hexafluoropropylene, pentafluoropropylene, tetrafluoropropylene, trifluoropropylene, perfluorobutene, tetrafluoroethylene, trifluoroethylene, trifluorochloroethylene, and vinyl fluoride.

[0042] A polyvinylidene fluoride polymer is a polymer in which vinylidene fluoride is the monomer, and the monomer of the polyvinylidene fluoride polymer further includes at least one of the following in addition to vinylidene fluoride: hexafluoropropylene, pentafluoropropylene, tetrafluoropropylene, trifluoropropylene, perfluorobutene, tetrafluoroethylene, trifluoroethylene, trifluorochloroethylene, and vinyl fluoride. In other words, the polyvinylidene fluoride polymer may be a homopolymer of vinylidene fluoride, or a copolymer of vinylidene fluoride and other fluorine-containing ethylenes, and is not specifically limited.

[0043] Embodiments of this application provide a separator, the separator comprising an adhesive as described above or an adhesive manufactured by the method for manufacturing the adhesive as described above.

[0044] The separator is coated with the aforementioned adhesive, which improves the bonding performance between the electrode plate and the adhesive, and can improve the opening problem in the conventional pre-cooled pressing process of battery cores.

[0045] Embodiments of this application provide an electrode assembly, the electrode assembly including the separator described above.

[0046] The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator. This adhesive is applied to the separator, thereby bonding the electrode plate and the separator together, and improving the problem of openings between the electrode plate and the separator.

[0047] Embodiments of this application provide a battery cell, the battery cell including an electrode assembly as described above.

[0048] By applying the above electrode assembly to a battery cell, the cycle performance of the large jig for the battery cell can be improved.

[0049] Embodiments of this application provide a battery, the battery comprising the above-described battery cell.

[0050] Embodiments of this application provide a power consumption device, the power consumption device including the above-mentioned battery cell or battery. [Brief explanation of the drawing]

[0051] To more clearly illustrate the embodiments of this application or the technical concepts in the prior art, the following briefly introduces the drawings that may be used in the embodiments or prior art descriptions. It is obvious that the drawings in the following description are only a few embodiments of this application, and a person skilled in the art can obtain other drawings based on the structures shown in these drawings without expending any creative effort. [Figure 1]This is a flowchart of the method for manufacturing adhesive according to the embodiments of this application. [Figure 2] This is a flowchart of the method for manufacturing adhesive according to the embodiments of this application. [Figure 3] This is a schematic diagram of the core-shell structure of the adhesive according to an embodiment of this application. [Figure 4] This is a scanning electron microscope image of the adhesive according to the embodiment of this application. [Figure 5] This is a schematic diagram of an electrode assembly according to an embodiment of the present application. [Figure 6] Figure 5 is an exploded view of an electrode assembly according to an embodiment of this application. [Figure 7] This is a schematic diagram of a battery module according to an embodiment of the present application. [Figure 8] This is a schematic diagram of a battery pack according to an embodiment of the present application. [Figure 9] Figure 8 is an exploded view of a battery pack according to an embodiment of this application. [Figure 10] This is a schematic diagram of a power consumption device according to an embodiment of the present application. The realization of the objectives of the present application, its functional features and advantages will be further described with reference to the drawings, in conjunction with the embodiments. [Modes for carrying out the invention]

[0052] The following clearly and completely describes the technical concepts in the embodiments of this application, linking them to the drawings of the embodiments. Clearly, the embodiments described are only a subset of the embodiments of this application, not all of them. All other embodiments derived from the embodiments of this application without the creative effort of a person skilled in the art are all within the scope of protection of this application.

[0053] The following description will detail embodiments specifically disclosing the adhesive and its manufacturing method, as well as separators, electrode assemblies, battery cells, batteries, and power consumption devices containing the adhesive, with appropriate reference to the drawings. However, unnecessary details may be omitted. For example, detailed explanations of well-known matters and redundant explanations of structures that are actually the same may be omitted. This is to avoid making the following description unnecessarily long and to make it easily understandable to those skilled in the art. The drawings and the following description are provided to enable those skilled in the art to fully understand this application and do not limit the topics described in the claims.

[0054] The “range” disclosed in this application is limited in the form of a lower limit and an upper limit, and a given range is limited by selecting one lower limit and one upper limit, which define the boundary of a particular range. The range thus limited may or may not include the endpoints, and any combination is possible, that is, any lower limit can be combined with any upper limit to form a range. For example, if the ranges 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges 60-110 and 80-120 can also be assumed. Furthermore, if the minimum range values ​​are listed as 1 and 2, and the maximum range values ​​are listed as 3, 4 and 5, then the ranges 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5 can all be assumed. In this application, unless otherwise specified, the numerical range “ab” represents an abbreviation for any combination of real numbers a to b, where a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have already been listed in this specification, and "0-5" is simply an abbreviated representation of combinations of these numbers. Also, when a parameter is described as an integer ≥ 2, it is equivalent to disclosing that this parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0055] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical inventions.

[0056] Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical concepts.

[0057] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the fact that the method includes steps (a) and (b) means that the method may include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, the fact that the method referred to above may further include step (c) means that step (c) may be added to the method in any order, for example the method may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), and so on.

[0058] Unless otherwise specified, the terms “includes” and “inclusion” as used in this application may be open or closed. For example, “includes” and “inclusion” may mean that other components not listed may be included or inclusion, or that only the listed components may be included or inclusion.

[0059] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the conditions A is true (or exists) and B is false (or does not exist), the condition A is false (or does not exist) but B is true (or exists), and the condition both A and B are true (or exist) all satisfy "A or B."

[0060] The battery core has an opening problem; specifically, a gap easily forms between the electrode plate and the separator, which degrades the battery's cycle performance.

[0061] For example, polyvinylidene fluoride is widely used as a common adhesive in separators, but currently, the price of polyvinylidene fluoride is rising sharply, and market supply is tight. By coating the surface of lithium battery separators with polyvinylidene fluoride polymer, the problem of high-temperature shrinkage of the separator can be partially solved, and cold pressing is performed after winding the battery core. However, general polyvinylidene fluoride is a homopolymer with a crystallinity of about 50%, resulting in insufficient adhesion to the positive and negative electrode plates, which often leads to problems with openings in the battery core, and thus fails to meet the demand for coated separator performance in power lithium-ion batteries.

[0062] Specifically, by coating the surface of the battery separator with polyvinylidene fluoride polymer, the high-temperature shrinkage problem of the separator can be partially solved. Cold pressing is performed after winding the battery core, but general polyvinylidene fluoride is a homopolymer with a crystallinity of about 50%, resulting in insufficient adhesion to the positive and negative electrode plates, and the problem of openings in the battery core often occurs. When openings occur in the battery core, a gap is formed between the electrode plates and the separator, the overall structure of the battery core loosens, the hardness of the battery core decreases, and the cycle performance of the battery core deteriorates.

[0063] The battery core is formed by bonding positive and negative electrode plates and a separator. The battery core has a certain hardness; that is, the bonded positive and negative electrode plates and the separator are tightly supported by each other, forming a structure with a certain thickness. A structure of a certain thickness has a certain hardness. However, if the negative electrode expands during charging and discharging, and the adhesive force is weak, a gap is formed between the positive and negative electrode plates and the separator. The positive and negative electrode plates and the separator cannot be tightly supported by each other, the battery core loosens, and its hardness decreases. At this time, the power performance of the battery core deteriorates, for example, the rate performance decreases and the cycle performance deteriorates. For example, in electric vehicles, the battery core loosens, the battery charging speed slows down, the battery's cycle performance deteriorates, and this directly leads to a shorter battery life. As a result, electric vehicles need to replace batteries more frequently, increasing the cost for consumers of electric vehicles.

[0064] Based on this, the present application provides an adhesive comprising a core layer structure and a shell layer structure provided on the surface of the core layer structure, wherein the shell layer structure comprises a polyacrylate polymer and the core layer structure comprises a polyvinylidene fluoride polymer.

[0065] An adhesive is a material that possesses adhesive properties for bonding different substances together.

[0066] A core-shell structure consists of a central core and an outer shell that covers it.

[0067] In a core-shell structure, the core layer structure is defined as the structure located inside and covered by the outer shell layer.

[0068] In a core-shell structure, the shell layer structure is defined as a structure located on the outside and covering the surface of the core layer structure.

[0069] Polyacrylate polymers are polymers in which the acrylate monomer is used.

[0070] Polyvinylidene fluoride polymers use vinylidene fluoride as the monomer.

[0071] This application improves the crystallinity of the polyvinylidene fluoride polymer in the core-shell adhesive by coating the polyvinylidene fluoride polymer with a polyacrylate polymer, thereby improving the adhesive performance of the core-shell adhesive. This adhesive improves the adhesive strength between the separator and the electrode plate. The adhesive of this application provides good adhesive performance, prevents separation of the electrode plate and separator during electrode plate expansion, maintains good hardness of the battery core, and improves the dynamic performance and cycle performance of the battery core.

[0072] Theoretically, as crystallinity increases, the arrangement of molecular chains becomes tighter and more ordered, the porosity decreases, intermolecular interaction forces increase, and segment movement becomes more difficult. As a result, the yield stress, strength, modulus, and hardness of the polymer all improve. However, the elongation at break and impact toughness decrease, and crystallization clearly makes the polymer harder and more brittle, while also reducing its adhesive properties.

[0073] This application describes a method in which polyvinylidene fluoride polymer is coated with a polyacrylate polymer. Compared to uncoated polyvinylidene fluoride, the overall crystallinity of the core-shell structure adhesive of this application is reduced, improving adhesive performance. By using this core-shell structure adhesive, the adhesive strength between the separator and the electrode plate can be improved, and the problem of battery core openings can be avoided. At the same time, the reduced crystallinity increases the disorder of the molecular structure in the adhesive, increasing the porosity and further improving the permeability of the adhesive to liquids. By coating the separator with this adhesive, the permeability of the separator to the electrolyte is improved, which is advantageous in improving the battery's cycle performance.

[0074] In some embodiments, the shell layer structure includes multiple cases, which are spaced apart on the surface of the core layer structure.

[0075] As shown in Figures 3 and 4, the cases made of polyacrylate polymer are not continuously covering the surface of the core layer structure, but rather are attached to the surface of the core layer structure at intervals, resembling a raspberry-like structure. To understand this, the shell layer structure is equivalent to being made up of multiple cases, with gaps between adjacent cases, where the surface of the core layer structure can be exposed. Thus, the polyvinylidene fluoride polymer core layer structure is exposed, and because the core layer structure also has relatively good adhesion, the core layer structure exposed between the cases can also reinforce the adhesive performance. Furthermore, a shell layer structure that discontinuously covers the core layer structure has a larger specific surface area compared to a shell layer structure that completely covers the core layer structure, and thus, a surface structure with adhesive function can perform a greater degree of adhesion.

[0076] To make it easier to understand, crosslinking does not occur between the functional groups on the surface of the polyvinylidene fluoride polymer core layer and the polyacrylate polymer shell layer. Instead, the bond between the core layer and the shell layer is primarily ionic, and through the action of ionic bonds, van der Waals forces, etc., the constituent monomers of the polyvinylidene fluoride polymer are adsorbed onto the constituent monomers of the polyacrylate polymer.

[0077] In some embodiments, the mass ratio of polyvinylidene fluoride polymer to polyacrylate polymer is (2-100):1, and selectively (10-80):1.

[0078] To obtain the raspberry-like core-shell structure mentioned above, the mass of the polyvinylidene fluoride polymer is greater than the mass of the polyacrylate polymer, the mass of the core layer structure is greater than the mass of the shell layer structure, the surface of the core layer structure is not completely covered by the shell layer structure, and a portion of the structure is exposed on the surface of the core layer structure, thereby obtaining the raspberry-like core-shell structure. Here, the mass of the core layer structure is greater than the mass of the shell layer structure, and the mass ratio of the core layer structure to the shell layer structure may be (2~100):1, where (2~100):1 includes the minimum and maximum values ​​within this range, and the values ​​between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and 2:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, etc.

[0079] In some embodiments, the mass ratio of the core layer structure to the shell layer structure is (10-80):1.

[0080] To obtain the raspberry-like core-shell structure mentioned above, the mass of the polyvinylidene fluoride polymer is greater than the mass of the polyacrylate polymer, the mass of the core layer structure is greater than the mass of the shell layer structure, the surface of the core layer structure is not completely covered by the shell layer structure, and a portion of the structure is exposed on the surface of the core layer structure, thereby obtaining the raspberry-like core-shell structure. Here, the mass of the core layer structure is greater than the mass of the shell layer structure, and the mass ratio of the core layer structure to the shell layer structure may be (10~80):1, where (10~80):1 includes the minimum and maximum values ​​within this range, and the values ​​between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, etc.

[0081] The mass ratio test method involves recording the mass of monomers used to produce the core layer structure and the mass of monomers used to produce the shell layer structure during the reaction process of the adhesive manufacturing process, where m is the mass and n is the mass of monomers used to produce the shell layer structure. The mass ratio of the core layer structure to the shell layer structure is m:n.

[0082] In some embodiments, the volume-average particle size Dv50 of the adhesive is 0.5 μm-50 μm, and selectively 7 μm-8 μm.

[0083] Volume-average particle size of adhesive diameter Dv50 can be tested using methods known in the art. For example, characterization tests can be performed using a Malvern Mastersizer, as described in GB / T 19077-2016, using instruments such as the Malvern Mastersizer-3000.

[0084] Theoretically, the volume-average particle size Dv50 of the adhesive in this application may be less than 0.5 μm or greater than 50 μm. However, considering that the adhesive in this application is used in a separator, the volume-average particle size Dv50 of the adhesive cannot be too large or too small. If the adhesive is too small, it is likely to clog the holes in the separator, reducing the passability of lithium ions through the separator. If the adhesive is too large, a thick coating will be formed when the adhesive is applied to the separator. Therefore, to avoid affecting the energy density of batteries manufactured later, the volume-average particle size Dv50 of the adhesive is 0.5 μm-50 μm, and within the above 0.5 μm-50 μm range, the values ​​include the minimum and maximum values ​​within this range, and each value between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and 0.5 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc.

[0085] In some embodiments, the volume-average particle size Dv50 of the adhesive is 7 μm-8 μm.

[0086] When the volume-average particle size Dv50 of the adhesive is 7 μm-8 μm, the performance of the resulting separator is excellent. Within the 7 μm-8 μm range, the values ​​include the minimum and maximum values ​​within this range, as well as the values ​​between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and values ​​such as 7 μm, 7.5 μm, and 8 μm.

[0087] In some embodiments, the constituent monomers of the polyacrylate polymer include a first polymerization flexibility monomer, a second polymerization polarity monomer, and a third polymerization molecular weight adjustment monomer.

[0088] Regarding flexible monomers, the homopolymer vitrification temperature of flexible monomers is lower than that of rigid monomers. Flexible monomers have a certain degree of flexibility relative to rigid groups, allowing segments to move freely. Flexible monomers can adjust the vitrification transition temperature of segment polymers, improve toughness during adhesive application, and contribute to good adhesive properties.

[0089] Polar monomers are monomers that contain polar groups, and they contribute to improving the adhesion of polymers.

[0090] Molecular weight-adjusting monomers are monomers that participate in crosslinking reactions and are used to adjust the molecular weight of polymers. Having the molecular weight of an adhesive within a certain range contributes to improved adhesion.

[0091] The constituent monomers of the polyacrylate polymer in this application include a first polymerization flexibility monomer, a second polymerization polarity monomer, and a third polymerization molecular weight adjustment monomer. By crosslinking these three monomers to obtain a polymer, the molecular weight and vitrification transition temperature of the polymer can be controlled, thereby improving the adhesive performance of the adhesive.

[0092] The modified polymer has a lower softening point than pure polyvinylidene fluoride polymer, and when the battery core is pre-cooled and pressed, the adhesive can penetrate sufficiently into the gap between the positive and negative electrode plates and the separator, that is, there is a gap between the electrode plates and the separator, and the adhesive adheres. Agent The adhesive penetrates into the gap, effectively connecting the electrode plate and the separator, preventing the adhesive from easily detaching from the gap. During the expansion of the electrode plate, the adhesive maintains its toughness, allowing it to effectively connect both even during expansion. This enables the adhesive to fully demonstrate its bonding performance, further contributing to improvements in the battery's dynamic performance and the large jig's cycle performance.

[0093] Here, the softening point is the temperature at which a substance softens. It is related not only to the structure of the polymer but also to the size of its molecular weight. In this application, the softening point of the polymer is improved by adjusting the molecular weight of the polymer with a third polymerization molecular weight adjusting monomer.

[0094] Here, the cycle performance of the large fixture is a test performance of the battery core's cycle function. During the test, the fixture is attached to the battery core, and a constant force is applied to the fixture to press the battery core. When the battery core is fully charged, expansion occurs, and the battery core deforms due to the double pressure of the clamping force of the fixture and the expansion force. This test is used to test the shape retention performance and pressure resistance performance of the battery core. When the adhesive of this solution is used, the adhesive performance is good, so the expansion of the battery core is reduced, and the shape retention of the battery core is relatively good. The battery core using the adhesive of this application maintains its performance relatively well under the test conditions of the large fixture. The battery core obtained using the adhesive of this solution has excellent deformation retention. When the battery cores are assembled to form a battery, the battery core is less prone to deformation, so the space required to mount the battery core can be saved in the battery, thus making the volume of the battery smaller. Therefore, if the battery core is easily deformed, it will press against the surrounding structure. To avoid this phenomenon, a larger space is needed to accommodate the deformed battery core. In other words, space must be reserved within the battery to accommodate the deformed portion of the battery core, which occupies more space within the battery.

[0095] At the same time, good cycle performance of the battery core fixture also explains good cycle performance of the battery core itself. For example, if the battery core expands, the gap between the electrode plates and the separator increases, lengthening the path for lithium ions to pass through the positive and negative electrodes, resulting in poorer cycle performance.

[0096] In some embodiments, the molar ratio of the first polymerization-flexible monomer, the second polymerization-polarity monomer, and the third polymerization-molecular-weight-adjusting monomer is 1:(0.01~0.8):(0.01~0.15), and selectively 1:(0.05~0.7):(0.05~0.12).

[0097] The molar ratio test method involves recording the number of moles of each type of monomer used to produce the shell layer structure during the reaction process in the manufacturing of the adhesive. Here, the number of moles of each type of monomer is obtained by dividing the mass of each type of monomer by its molecular weight. If we define the number of moles of the first polymerization flexibility monomer as a, the number of moles of the second polymerization polarity monomer as b, and the number of moles of the third polymerization molecular weight adjustment monomer as c, then the molar ratio of the first polymerization flexibility monomer, the second polymerization polarity monomer, and the third polymerization molecular weight adjustment monomer is a:b:c.

[0098] When the molar ratio of the first polymerization flexibility monomer, the second polymerization polarity monomer, and the third polymerization molecular weight adjustment monomer is 1:(0.01~0.8):(0.01~0.15), the adhesive effect of the adhesive is excellent, and may be, for example, 1:0.01:0.01, 1:0.1:0.01, 1:0.4:0.01, 1:0.8:0.01, 1:0.01:0.05, 1:0.01:0.1, 1:0.01:0.15, 1:0.1:0.01, 1:0.1:0.05, 1:0.1:0.15, 1:0.4:0.01, 1:0.4:0.05, 1:0.4:0.15, 1:0.8:0.01, 1:0.8:0.05, 1:0.8:0.15, etc., and is not specifically limited.

[0099] In some embodiments, the molar ratio of the first polymerization-flexible monomer, the second polymerization-polarity monomer, and the third polymerization-molecular-weight-adjusting monomer is 1:(0.05~0.7):(0.05~0.12).

[0100] When the molar ratio of the first polymerizable flexible monomer, the second polymerizable polarity monomer, and the third polymerizable molecular weight adjusting monomer is 1:(0.05~0.7):(0.05~0.12), the adhesive effect of the adhesive is excellent. In the above 1:(0.05~0.7):(0.05~0.12), the value includes the minimum and maximum values ​​within this range, and each value between such minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the examples and 1:0.05:0.05, 1:0.1:0.05, 1:0.4:0.05, 1:0.7:0.05, 1:0.1:0.05, 1:0.1:0.1, 1:0.1:0.12, etc.

[0101] In some embodiments, the structure of the first polymerization flexibility monomer contains an ester bond (-COOR (where R is generally another non-H group such as an alkyl group)), the structure of the second polymerization polarity monomer contains a cyano group (-C3N), and the third polymerization molecular weight adjustment monomer contains an amide bond (-CO-NH-).

[0102] Ester bonds can improve the flexibility of molecular chains, cyano groups can improve the polarity of monomers, and amide bonds are polar, readily form hydrogen bonds, and improve adhesion. By polymerizing the above three types of monomers, the polymer obtained by polymerizing the first polymeric flexibility monomer containing ester bonds, the second polymeric polarity monomer containing cyano groups, and the third polymeric molecular weight adjustment monomer containing amide bonds allows for control of the polymer's molecular weight and vitrification transition temperature, thereby improving the adhesive performance of the adhesive.

[0103] In some embodiments, the first polymerization flexibility monomer is an acrylate monomer, the second polymerization polarity monomer is an acrylonitrile monomer, and the third polymerization molecular weight adjustment monomer is an acrylamide monomer.

[0104] Acrylate monomers can improve the swelling resistance of polymers and, as flexible monomer segments in molecular segments, can adjust the vitrification transition temperature of polymers, thereby improving toughness during adhesive application and contributing to good adhesive properties.

[0105] Acrylonitrile monomers have a highly polar cyano group, which improves ionic conductivity and contributes to improved adhesion.

[0106] Acrylamide monomers play a role in adjusting molecular weight and also possess relatively good adhesive properties.

[0107] The polymers produced using the three types of monomers mentioned above allow for control over the polymer's molecular weight and vitrification transition temperature, thereby improving the adhesive performance of the adhesive.

[0108] In some embodiments, the acrylate monomer comprises at least one of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate, and / or the acrylonitrile monomer comprises at least one of acrylonitrile and methacrylonitrile, and / or the acrylamide monomer comprises at least one of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide.

[0109] Based on acrylate monomers, the adhesive properties of the adhesive are improved. The acrylate monomers may include at least one of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate. In other words, the constituent monomers of the polyacrylate polymer may include one of the above acrylate monomers, or multiple of the above acrylate monomers, and are not specifically limited.

[0110] Based on acrylonitrile monomers, the adhesive properties of the adhesive are improved. The acrylonitrile monomer includes at least one of acrylonitrile and methacrylonitrile. That is, the constituent monomers of the polyacrylate polymer may include one of the above-mentioned acrylonitrile monomers, or may include multiple of the above-mentioned acrylonitrile monomers, and are not specifically limited.

[0111] Based on acrylamide monomers, the adhesive properties of the adhesive are improved. The acrylamide monomers include at least one of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide. That is, the constituent monomers of the polyacrylate polymer may include one of the above acrylamide monomers, or multiple of the above acrylamide monomers, and are not specifically limited.

[0112] In some embodiments, the polyvinylidene fluoride polymer includes at least one of the following: vinylidene fluoride polymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-pentafluoropropylene copolymer, vinylidene fluoride-tetrafluoropropylene copolymer, vinylidene fluoride-trifluoropropylene copolymer, vinylidene fluoride-perfluorobutene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trifluorochloroethylene copolymer, or vinylidene fluoride-vinyl copolymer.

[0113] Polyvinylidene fluoride polymers possess excellent chemical and corrosion resistance, as well as special properties such as high temperature resistance, oxidation resistance, weather resistance, and radiation resistance, and also exhibit piezoelectric, dielectric, and thermoelectric properties, making them commonly used in lithium-ion battery separators.

[0114] The polyvinylidene fluoride polymer used in this application comprises at least one of the following: vinylidene fluoride polymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-pentafluoropropylene copolymer, vinylidene fluoride-tetrafluoropropylene copolymer, vinylidene fluoride-trifluoropropylene copolymer, vinylidene fluoride-perfluorobutene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trifluorochloroethylene copolymer, or vinylidene fluoride-vinyl fluoride copolymer. In other words, the polyvinylidene fluoride polymer may comprise one of the above polyvinylidene fluoride polymers, or multiple of the above polyvinylidene fluoride polymers, and is not specifically limited.

[0115] As shown in Figure 1, this application further provides a method for manufacturing an adhesive. The process involves adding water, an emulsifier, an initiator, and the constituent monomers of polyvinylidene fluoride polymer to a reaction vessel, stirring, heating under reaction pressure to carry out the polymerization reaction, obtaining a seed emulsion to be used as a reserve, and then... The steps include mixing and stirring water, an emulsifier, and the constituent monomers of a polyacrylate polymer to obtain a shell layer monomer pre-emulsion, which is used as a preliminary step. The process includes the steps of adding a shell layer monomer pre-emulsion, an initiator, and water to a seed emulsion, stirring, heating, and reacting to obtain a core-shell adhesive.

[0116] This application describes a method for first obtaining a seed emulsion of polyvinylidene fluoride polymer for the core layer using emulsion polymerization, and then producing a polyacrylate-based polymer for the shell layer on the surface of the core layer structure using emulsion polymerization, ultimately forming an adhesive having a core-shell structure.

[0117] Emulsion polymerization is a process in which monomers are dispersed in water by mechanical stirring with an emulsifier to form an emulsion, and then an initiator is added to initiate monomer polymerization.

[0118] A core-shell structure consists of a central core and an outer shell that covers it.

[0119] In seed emulsions, a small amount of monomer is first used to produce seed latex using a general emulsion polymerization method. Then, a small amount of seed latex is added to a formal emulsion polymerization formula, and the polymerization reaction is carried out using the seed emulsion latex particles as a core, continuously growing the latex particles.

[0120] A pre-emulsification is a solution obtained by pre-emulsifying monomers. Emulsification is the process of uniformly dispersing a liquid in extremely small droplets in another immiscible liquid, mixing and stirring water, an emulsifier, and the constituent monomers of a polyacrylate polymer, thereby dispersing the constituent monomers of the polyacrylate polymer in water through the action of the emulsifier.

[0121] Regarding emulsifiers, they are substances that can convert immiscible oil and water into an emulsion that is less likely to form layers. Emulsifiers are generally surfactants that combine the properties of both hydrophilic polar groups and hydrophobic (lipophilic) nonpolar groups.

[0122] Regarding initiators, an initiator is a substance that can initiate the polymerization reaction of a monomer. For example, a radical initiator is a compound that is easily decomposed into radicals (i.e., primary radicals) by heat, and may be used to initiate radical polymerization and copolymerization reactions of ene-based and diene-based monomers.

[0123] For the sake of convenience of description, in the above method for manufacturing adhesives, the process of the manufacturing method is defined as Step 1, Step 2, and Step 3, in accordance with the order of the paragraphs described, and as can be understood by those skilled in the art, in the above method of the specific embodiment, the order in which each step is described does not mean a strict order of execution and does not constitute any limitation on the execution process, and the specific order of execution of each step should be determined by its function and possible inherent logic.

[0124] In step 1, water, emulsifier, initiator, and constituent monomers of polyvinylidene fluoride polymer are mixed and stirred. After stirring and dispersing the water and emulsifier, an emulsion is formed. That is, the emulsifier forms micelles in the aqueous phase, solubilizing the monomers in most of the micelles. Under constant pressure, the monomers enter the reaction system of the micelles, and under conditions where the temperature rises, the initiator starts polymerization of the monomers inside the micelles, obtaining a core layer seed emulsion. In step 2, water, emulsifier, and constituent monomers of the polyacrylate polymer are mixed and stirred. The emulsifier and water are similarly dispersed to form an emulsion. The constituent monomers of the polyacrylate polymer enter the micelles, obtaining a shell layer monomer preemulsification. Furthermore, in step 3, the initiator, water, and the shell layer monomer pre-emulsion obtained in step 2 are added to the seed emulsion obtained in step 1, and the mixture is stirred and heated to react, so that the constituent monomers of the polyacrylate polymer form a polymer on the surface of the core layer, and the polyacrylate polymer adheres to the surface of the core layer structure of the polyvinylidene fluoride polymer, obtaining an adhesive for the core-shell structure. In step 1, the dispersion polymerization and core formation mechanism of polyvinylidene fluoride belongs to the oligomeric core formation mechanism, and by increasing the content of the initiator or emulsifier at the same conversion rate, a smaller particle size of polyvinylidene fluoride latex particles can be obtained.

[0125] In Step 1, the constituent monomers of the polyvinylidene fluoride polymer are in a gaseous state and do not easily enter micelles at normal pressure. Therefore, the reaction is efficiently carried out by introducing the gaseous monomers into micelles using a pressurized method.

[0126] Steps 1 and 3 are both performed under heating conditions because a certain temperature is required to convert the initiators in Step 1 and Step 3 into having the function of initiating monomer polymerization.

[0127] At the same time, the fact that the mass of water in step 3 is 0 or greater means that in step 3, water may or may not be added, and as can be understood, if sufficient water is added in steps 1 and 2, that is, if the water added in steps 1 and 2 makes it possible for the solid content after the reactions in steps 1, 2 and 3 to be within a predetermined range, then water may not be added in step 3. If sufficient water is not added in steps 1 and 2, then in step 3, a certain amount of water needs to be added to adjust the solid content of the system so as not to increase the viscosity after the reaction and slow down the reaction rate.

[0128] To ensure clarity, the stirring rates in steps 1, 2, and 3 are 1000 r / min to 5000 r / min, and may be, for example, 1000 r / min, 2000 r / min, 3000 r / min, 4000 r / min, 5000 r / min, etc., and are not specifically limited. The stirring time may also be 60 min ± 20 min. Under these stirring conditions, a uniformly emulsified prepolymer is obtained and set aside.

[0129] In some embodiments, the ratio of the constituent monomer mass of the polyvinylidene fluoride polymer to the constituent monomer mass of the polyacrylate-based polymer is (2-100):1, and selectively (10-80):1.

[0130] To obtain the raspberry-like core-shell structure mentioned above, the mass of the core layer structure is made greater than the mass of the shell layer structure, so that the surface of the core layer structure is not completely covered by the shell layer structure, thereby exposing part of the structure on the surface of the core layer structure, and thus obtaining the raspberry-like core-shell structure. Here, the mass of the core layer structure is greater than the mass of the shell layer structure, and the mass ratio of the core layer structure to the shell layer structure may be (2 to 100):1, for example, 2:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, etc., and is not specifically limited.

[0131] In some embodiments, the process includes the steps of adding water, an emulsifier, an initiator, and constituent monomers of polyvinylidene fluoride polymer to a reaction vessel, stirring, heating at reaction pressure to carry out a polymerization reaction, obtaining a seed emulsion to be used as a reserve, removing oxygen gas from the reaction vessel, adding water, an emulsifier, an initiator, and constituent monomers of polyvinylidene fluoride polymer to the reaction vessel, stirring, raising the temperature to 75±10°C at reaction pressure to carry out a polymerization reaction, obtaining a seed emulsion to be used as a reserve.

[0132] Considering that oxygen gas acts as a polymerization inhibitor during polymerization and affects the polymerization reaction, it is necessary to remove the oxygen gas from the reaction vessel. For example, the oxygen gas may be removed from the reaction vessel before performing step 1, for example by replacing the oxygen gas by introducing nitrogen gas into the reaction vessel. After removing the oxygen gas, water, emulsifier, initiator, and constituent monomers of polyvinylidene fluoride polymer are added to the reaction vessel, stirred, and the temperature is raised to 75±10°C at the reaction pressure to carry out the polymerization reaction to obtain a seed emulsion, which may be used as a reserve.

[0133] In some embodiments, the oxygen gas in the reaction vessel is removed, water, an emulsifier, an initiator, and constituent monomers of polyvinylidene fluoride polymer are added to the reaction vessel, stirred, the temperature is raised to 75±10°C under reaction pressure to carry out the polymerization reaction, and a seed emulsion is obtained and set aside.

[0134] Considering that monomer emulsification can be more sufficiently achieved by first adding water, an emulsifier, and an initiator to a reaction vessel, stirring, and then adding the constituent monomers of polyvinylidene fluoride polymer, the step of producing a seed emulsion may be to first add water, an emulsifier, and an initiator to a reaction vessel, stir, remove oxygen gas from the reaction vessel, then add the constituent monomers of polyvinylidene fluoride polymer to the reaction vessel, raise the temperature to 75±10℃ at the reaction pressure, carry out the polymerization reaction, obtain a seed emulsion, and set it aside as a reserve.

[0135] In some embodiments, the oxygen gas in the reaction vessel is removed, water, an emulsifier, an initiator, and constituent monomers of polyvinylidene fluoride polymer are added to the reaction vessel, stirred, the temperature is raised to 75±10°C at the reaction pressure, and the polymerization reaction is carried out to obtain a seed emulsion, which is set aside as a reserve.

[0136] Considering that the constituent monomers of polyvinylidene fluoride polymer are gases, during the polymerization reaction, the monomers in the reaction vessel are constantly consumed, causing the pressure in the reaction vessel to constantly decrease. Once the pressure drops to a certain value, it becomes difficult for the monomers to enter the solution system, reach the micelles, and react. Therefore, it is necessary to control the pressure in the reaction vessel to a certain range to ensure that the monomers are effectively involved in the reaction. For this reason, the step of producing a seed emulsion may involve removing the oxygen gas from the reaction vessel, adding water, an emulsifier, an initiator, and the constituent monomers of polyvinylidene fluoride polymer to the reaction vessel, controlling the reaction pressure in the reaction vessel to 3.0 MPa to 4 MPa, stirring, raising the temperature to 75 ± 10°C, carrying out the polymerization reaction, and when the pressure in the reaction vessel drops to 3.0 MPa, continuing to add the constituent monomers of polyvinylidene fluoride polymer, controlling the pressure in the reaction vessel to 3.0 MPa to 4 MPa, and obtaining a seed emulsion to use as a reserve until the reaction is complete.

[0137] Considering that the reaction rate slows down if the pressure is too low, and energy consumption increases and the reaction becomes more vigorous if the pressure is too high, the control range for the reaction pressure is 3.0 MPa to 4 MPa, and may be, for example, 3.0 MPa, 3.5 MPa, or 4 MPa, without being specifically limited.

[0138] In some embodiments, the step of adding a shell layer monomer preemulsion, an initiator, and water to a seed emulsion, stirring, and heating to react, to obtain an adhesive, includes the step of adding water to the seed emulsion, stirring, adding the shell layer monomer preemulsion and initiator to the seed emulsion at a rate of 10 ml / min to 500 ml / min, heating to 90°C ± 10°C, stirring for 30 min ± 20 min to react, and obtaining an adhesive.

[0139] To avoid explosive polymerization caused by adding the shell layer monomer preemulsion and initiator together to the reaction vessel, the shell layer monomer preemulsion and initiator are added to the reaction vessel at a constant dropping rate. The dropping rate may be 10 ml / min, 50 ml / min, 100 ml / min, 150 ml / min, 200 ml / min, 250 ml / min, 300 ml / min, 350 ml / min, 400 ml / min, 450 ml / min, 500 ml / min, etc., and is not specifically limited. Simultaneously, to ensure the reaction proceeds effectively, the mixture is heated to 90°C ± 10°C during the reaction to initiate polymerization of the initiator, and the mixture is stirred for 30 min ± 20 min to obtain the adhesive.

[0140] In some embodiments, the step of obtaining an adhesive involves adding water to a seed emulsion, stirring, adding a shell layer monomer preemulsifier and initiator to the seed emulsion at a rate of 10 ml / min to 500 ml / min, heating to 90°C ± 10°C, stirring for 30 min ± 20 min to allow the reaction to occur, and then, after cooling, adjusting the pH to 6 to 8 to obtain the adhesive.

[0141] The core-shell structured adhesive obtained by manufacturing is prone to particle aggregation and deposition, which is unfavorable for use and storage. Therefore, to avoid aggregation and sedimentation of the core-shell structured adhesive, a pH adjusting reagent is added to the manufactured adhesive, which uniformly disperses the core-shell structured particles and stabilizes the system. The pH range of the adhesive is pH 6-8, and may be, for example, pH 6, pH 7, pH 8, etc., and is not specifically limited. This application does not limit the specific pH adjusting reagent used for clarity, and for example, aqueous ammonia may be used to adjust the pH.

[0142] In some embodiments, in step 1, the mass of the emulsifier is 0.1% to 5% of the mass of the constituent monomers of the polyvinylidene fluoride polymer, and the mass of the initiator is 0.15% to 1% of the mass of the constituent monomers of the polyvinylidene fluoride polymer.

[0143] The amount of emulsifier used must be appropriate. Emulsifiers are an important component of emulsion polymerization and can convert immiscible oil (monomer)-water into a fairly stable emulsion that is less prone to layering. In emulsion polymerization systems, emulsifiers primarily have three functions: firstly, they reduce surface tension and disperse monomers as fine droplets; secondly, they form a protective layer on the surface of droplets or colloidal particles to prevent aggregation and maintain the stability of the emulsion; and thirdly, they form micelles and solubilize monomers. The size and number of micelles depend on the amount of emulsifier used, so the amount of emulsifier used directly affects the performance of the product. In step 1, the mass of the emulsifier is 0.1% to 5% of the mass of the constituent monomers of the polyvinylidene fluoride polymer, and may be, for example, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 5%, etc., and is not specifically limited. The amount of initiator used greatly affects the polymerization rate and the performance of the product. If the amount of initiator used increases, the polymerization rate becomes faster, the polymerization reaction becomes unstable, the molecular weight and yield decrease, and the performance of the polymer deteriorates. Conversely, if the amount of initiator is insufficient, the polymerization reaction becomes difficult. Therefore, in step 1, the mass of the initiator is 0.15% to 1% of the mass of the constituent monomers of the polyvinylidene fluoride polymer, and may be, for example, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1%, etc., and is not specifically limited.

[0144] In some embodiments, in step 1, the emulsifier includes a polyfluoro compound, and the initiator includes an organic peroxide initiator and an inorganic peroxide initiator.

[0145] An emulsifier is a substance that can form water into an emulsion state. This application does not limit the specific type and structure of the emulsifier, and any substance that can perform the above function and does not affect the reaction system can be applied to this application. For example, in step 1, the emulsifier used includes a polyfluoro compound. An initiator is a substance that can initiate the polymerization reaction of a monomer. This application does not limit the specific type and structure of the initiator, and any substance that can perform the above function and does not affect the reaction system can be applied to this application. For example, in step 1, the initiator includes an organic peroxide initiator and an inorganic peroxide initiator, and the initiator used is preferably an organic peroxide initiator, which provides high stability to the polyvinylidene fluoride produced.

[0146] In some embodiments, in step 1, the emulsifier comprises at least one of ammonium perfluoropolyethercarboxylate, sodium perfluoropolyethercarboxylate, and potassium perfluoropolyethercarboxylate, and the initiator comprises at least one of benzoyl peroxide, di-tert-butyl peroxide, diisopropyl peroxydicarbonate, dinormalpropyl peroxydicarbonate, diethyl peroxydicarbonate, and persulfate.

[0147] An emulsifier is a substance that can form water into an emulsion. For example, the emulsifier used in step 1 includes at least one of ammonium perfluoropolyethercarboxylate, sodium perfluoropolyethercarboxylate, and potassium perfluoropolyethercarboxylate. That is, the emulsifier used may be one of the above, for example, sodium perfluoropolyethercarboxylate. The emulsifier can reduce the surface tension between droplets and prevent aggregation of monomer liquid or latex particles. At the same time, the emulsifier may be a mixture of several of the above substances. An initiator is a substance that can initiate the polymerization reaction of monomers. For example, the initiator used in step 1 includes at least one of benzoyl peroxide, di-tert-butyl peroxide, diisopropyl peroxydicarbonate, dinormalpropyl peroxydicarbonate, diethyl peroxydicarbonate, and persulfate. That is, the initiator used may be one of the above, for example, preferably diisopropyl peroxydicarbonate, and may be a mixture of several of the above substances.

[0148] In some embodiments, the constituent monomers of the polyvinylidene fluoride polymer include vinylidene fluoride, or the constituent monomers of the polyvinylidene fluoride polymer include at least one of vinylidene fluoride, vinylidene fluoride, hexafluoropropylene, pentafluoropropylene, tetrafluoropropylene, trifluoropropylene, perfluorobutene, tetrafluoroethylene, trifluoroethylene, trifluorochloroethylene, and vinyl fluoride.

[0149] A polyvinylidene fluoride polymer is a polymer in which vinylidene fluoride is the monomer, and the monomer of the polyvinylidene fluoride polymer further includes at least one of the following in addition to vinylidene fluoride: hexafluoropropylene, pentafluoropropylene, tetrafluoropropylene, trifluoropropylene, perfluorobutene, tetrafluoroethylene, trifluoroethylene, trifluorochloroethylene, and vinyl fluoride. In other words, the polyvinylidene fluoride polymer may be a homopolymer of vinylidene fluoride, or a copolymer of vinylidene fluoride and other fluorine-containing ethylenes, and is not specifically limited.

[0150] In some embodiments, step 1 includes adding water, an emulsifier, an initiator, and constituent monomers of polyvinylidene fluoride polymer to a reaction vessel, stirring, heating at reaction pressure to carry out a polymerization reaction, obtaining a seed emulsion to be used as a reserve, and adding water, a chain transfer agent, an emulsifier, an initiator, and constituent monomers of polyvinylidene fluoride polymer to a reaction vessel, stirring, heating at reaction pressure to carry out a polymerization reaction, obtaining a seed emulsion to be used as a reserve.

[0151] Chain transfer agents play a role in controlling the molecular weight distribution of products in polymerization reactions. Chain transfer is the process in which active centers move from one growing chain to another molecule in a chain polymerization reaction. The number of active centers remains unchanged, but the growing polymer chain loses its activity, forming a stable polymer and reducing the molecular weight of the product.

[0152] To effectively control the molecular weight of the reaction product, in step 1, water, a chain transfer agent, an emulsifier, an initiator, and the constituent monomers of the polyvinylidene fluoride polymer are added to the reaction vessel, stirred, and heated at reaction pressure to carry out the polymerization reaction and obtain a seed emulsion, which is to be used as a reserve. A seed emulsion is produced to obtain a polyvinylidene fluoride polymer of an appropriate molecular weight by adding a chain transfer agent during the polymerization reaction.

[0153] In some embodiments, the mass of the chain transfer agent is 1% to 3% of the mass of the constituent monomers of the polyvinylidene fluoride polymer, and the chain transfer agent includes alcohol compounds, ester compounds, ketone compounds, and halogenated alkanes.

[0154] The mass of the chain transfer agent is 1% to 3% of the mass of the constituent monomers of the polyvinylidene fluoride polymer, and may be, for example, 1%, 1.5%, 2%, 2.5%, 3%, etc., and is not specifically limited. The chain transfer agent includes alcohol compounds, ester compounds, ketone compounds, and halogenated alkanes, and is not limited to any specific type of chain transfer agent.

[0155] In some embodiments, in step 2, the mass of the emulsifier is 0.15% to 5% of the mass of the constituent monomers of the polyacrylate polymer, and in step 3, the mass of the initiator is 0.15% to 1% of the mass of the constituent monomers of the polyacrylate polymer.

[0156] The amount of emulsifier used must be appropriate. Emulsifiers are an important component of emulsion polymerization and can convert immiscible oil (monomer)-water into a fairly stable emulsion that is less prone to forming layers. In emulsion polymerization systems, emulsifiers primarily have three functions: firstly, they reduce surface tension and disperse monomers as fine droplets; secondly, they form a protective layer on the surface of droplets or colloidal particles to prevent aggregation and maintain the stability of the emulsion; and thirdly, they form micelles and solubilize monomers. The size and number of micelles depend on the amount of emulsifier used, so the amount of emulsifier used directly affects the performance of the product. In step 2, the mass of the emulsifier is 0.15% to 5% of the mass of the constituent monomers of the polyacrylate polymer, and may be, for example, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 5%, etc., and is not specifically limited. The amount of initiator used greatly affects the polymerization rate and the performance of the product. An increase in the amount of initiator leads to a faster polymerization rate, an unstable polymerization reaction, a decrease in molecular weight and yield, and a deterioration in polymer performance. Conversely, insufficient initiator makes the polymerization reaction difficult. Therefore, in step 3, the mass of the initiator is 0.15% to 1% of the mass of the constituent monomers of the polyacrylate polymer. For example, it may be 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1%, etc., and is not specifically limited.

[0157] In some embodiments, in step 2, the emulsifier includes an anionic emulsifier, and in step 3, the initiator includes an azo initiator, an organic peroxide initiator, and an inorganic peroxide initiator.

[0158] Anionic emulsifiers are surface active materials that, when dissolved in water, tend to dissociate their active portion into a negative ion. They are characterized by having one large organic anion and being able to react with a base to form a salt. They are classified into three types based on the structure of the negatively charged portion: carboxylate type, sulfonate type, and sulfate type.

[0159] Regarding azo initiators, azo initiators are radical initiators whose molecular structure contains two nitrogen double bonds.

[0160] Peroxide initiators are compounds containing a peroxy group (-OO-). When heated, the -OO- bond is broken, splitting into two corresponding radicals, thereby initiating monomer polymerization. They are called peroxide initiators. They are divided into two types: inorganic peroxides and organic peroxides. Inorganic peroxide initiators include hydrogen peroxide, ammonium persulfate, or potassium persulfate, while organic peroxide initiators include benzoyl peroxide, benzoyl t-butyl peroxide, and methyl ethyl ketone peroxide.

[0161] An emulsifier is a substance that can form water into an emulsion. This application does not limit the specific type and structure of the emulsifier, and any substance that can perform the above function and does not affect the reaction system can be applied to this application. For example, in step 2, the emulsifier used includes an anionic emulsifier. An initiator is a substance that can initiate the polymerization reaction of monomers. This application does not limit the specific type and structure of the initiator, and any substance that can perform the above function and does not affect the reaction system can be applied to this application. For example, in step 3, the initiator includes an azo initiator, an organic peroxide initiator, and an inorganic peroxide initiator.

[0162] In some embodiments, in step 2, the emulsifier comprises at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzenesulfonate, sodium styrenesulfonate, and sodium vinylsulfonate, and in step 3, the initiator comprises at least one of ammonium persulfate, potassium persulfate, sodium persulfate, and hydrogen peroxide, such as azobisisobutyronitrile, azobisisoheptanonitrile, cumene hydroperoxide, tert-butyl hydroperoxide, and benzoyl peroxide.

[0163] An emulsifier is a substance that can form water into an emulsion. For example, the emulsifier used in step 2 includes at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzenesulfonate, sodium styrenesulfonate, and sodium vinylsulfonate. That is, the emulsifier used may be just one of the above, and preferably, the emulsifier is sodium dodecylbenzenesulfonate, and may be a mixture of several of the above substances. An initiator is a substance that can initiate the polymerization reaction of monomers. For example, the initiator used in step 3 includes at least one of azobisisobutyronitrile, azobisisoheptanonitrile, cumene hydroperoxide, tert-butyl hydroperoxide, benzoyl peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, and hydrogen peroxide. That is, the initiator used may be just one of the above, and preferably, the initiator is potassium persulfate, and may be a mixture of several of the above substances.

[0164] In some embodiments, the sum of the masses of water in step 1, step 2, and step 3 accounts for 45%-60% of the total mass of all materials in step 1, step 2, and step 3, and the water in step 1, step 2, and step 3 is deionized water.

[0165] Water, as a dispersion medium, plays a role in mass transfer and temperature control. If too little or too much water is used, it becomes difficult to control the viscosity of the reaction system within a reasonable range. The total mass of water in Step 1, Step 2, and Step 3 accounts for 45%-60% of the total mass of all materials in Steps 1, 2, and 3, and may be, for example, 45%, 50%, 55%, 60%, etc., and is not specifically limited. At the same time, the water in Steps 1, 2, and 3 is deionized water to avoid impurities in the water affecting the polymerization reaction.

[0166] Embodiments of this application further provide a separator comprising an adhesive manufactured by the above-described adhesive or by a method for manufacturing such an adhesive. Since the adhesive employs all the technical solutions of all the embodiments described above, it has at least all the beneficial effects of the technical solutions of the embodiments described above, which will not be described further here.

[0167] The separator is coated with the aforementioned adhesive, which improves the bonding performance between the electrode plate and the adhesive, and can improve the opening problem in the conventional pre-cooled pressing process of battery cores.

[0168] Embodiments of this application further provide an electrode assembly, the electrode assembly including the separator described above. Since the separator employs all the technical solutions of all the embodiments described above, it has at least all the beneficial effects of the technical solutions of the embodiments described above, which will not be described further here.

[0169] The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator. This adhesive is applied to the separator, thereby bonding the electrode plate and the separator together, and improving the problem of openings between the electrode plate and the separator.

[0170] Embodiments of this application further provide a battery cell comprising an electrode assembly as described above. Since the electrode assembly employs all the technical solutions of all the embodiments described above, it has at least all the beneficial effects of the technical solutions of the embodiments described above, which will not be described further here.

[0171] By applying the above electrode assembly to a battery cell, the cycle performance of the large jig for the battery cell can be improved.

[0172] Embodiments of this application further provide a battery, the battery comprising the battery cell described above. Since the battery cell employs all the technical proposals of all the embodiments described above, it has at least all the beneficial effects of the technical proposals of the embodiments described above, which will not be described further here.

[0173] The battery includes a battery module and a battery pack.

[0174] Embodiments of this application further provide a power consumption device, the power consumption device including the above-described battery cell or battery. Since the battery cell or battery employs all the technical proposals of all the embodiments described above, it has at least all the beneficial effects of the technical proposals of the embodiments described above, which will not be described further here.

[0175] Furthermore, the electrode assembly, battery cell, battery, and power consumption device of this application will be described below with appropriate reference to the drawings.

[0176] One embodiment of this application provides an electrode assembly.

[0177] Generally, an electrode assembly includes a positive electrode plate, a negative electrode plate, an electrolyte, and a separator. During charging and discharging of the battery, active ions intermittently

[0178] The positive electrode plate includes a positive electrode current collector and a positive electrode film layer installed on at least one surface of the positive electrode current collector.

[0179] For example, a positive electrode current collector has two opposing surfaces in the thickness direction of itself, and the positive electrode film layer is installed on one or both of the two opposing surfaces of the positive electrode current collector.

[0180] In some embodiments, the positive electrode current collector may employ a metal foil sheet or a composite current collector. For example, as the metal foil sheet, an aluminum foil may be employed. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material 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, and silver alloy) on a polymer material substrate (such as substrates of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0181] In some embodiments, when the electrode assembly is a lithium-ion battery, the positive electrode active material may employ a positive electrode active material used in lithium-ion batteries known in the art. As an example, the positive electrode active material may include at least one material of a lithium-containing phosphate having an olivine structure, a lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and conventional materials that can be used as other battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Here, examples of the lithium transition metal oxide are lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 211 , 0.6 Co 1 / 3 Mn 1 / 3 O2 (which may be abbreviated as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which may be abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 ​​​​​​​0.2 Mn 0.2 O2(NCM 622 (It may also be abbreviated as LiNi) 0.8 Co 0.1 Mn 0.1 O2(NCM 811 (May be abbreviated as LiNi)), Lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05 It may include, but is not limited to, at least one of O2) and its modified compounds. Examples of lithium-containing phosphates with an olivine structure include, but is not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which may be abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), composite materials of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.

[0182] In some embodiments, the positive electrode film layer further selectively includes an adhesive. For example, the adhesive 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 fluorine-containing acrylate resin.

[0183] In some embodiments, the positive electrode film layer further selectively includes a conductive agent. For example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0184] In some embodiments, a positive electrode plate can 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 component, are dispersed in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry. The positive electrode slurry is then coated onto a positive electrode current collector, and after processes such as drying and cold pressing, a positive electrode plate is obtained.

[0185] The negative electrode plate includes a negative electrode current collector and a negative electrode film layer placed on at least one surface of the negative electrode current collector, the negative electrode film layer including a negative electrode active material.

[0186] For example, the negative electrode current collector has two opposing surfaces in its thickness direction, and the negative electrode film layer is placed on one or both of the two opposing surfaces of the negative electrode current collector.

[0187] In some embodiments, the negative electrode current collector may be a metal foil sheet or a composite current collector. For example, copper foil may be used as the metal foil sheet. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (such as copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys) on a polymer material substrate (for example, a substrate such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0188] In some embodiments, the negative electrode active material may be a negative electrode active material for batteries known in the art. For example, the negative electrode active material may include at least one material from among artificial graphite, natural graphite, soft carbon, hard carbon, silicone-based materials, tin-based materials, and lithium titanate. The silicone-based material may be selected from at least one of elemental silicon, silicone oxide, silicone carbon composite, silicone nitrogen composite, and silicone alloy. The tin-based material may be selected from at least one of elemental tin, tin oxide, and tin alloy. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used individually or in combination of two or more.

[0189] In some embodiments, the negative electrode film layer further selectively includes an adhesive. The adhesive may be selected from at least one of 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).

[0190] In some embodiments, the negative electrode film layer further selectively includes a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0191] In some embodiments, the negative electrode film layer further selectively includes other auxiliary agents, such as thickeners (e.g., sodium carboxymethylcellulose (CMC-Na)).

[0192] In some embodiments, the negative electrode plate can 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 component, are dispersed in a solvent (e.g., deionized water) to form a negative electrode slurry. The negative electrode slurry is then coated onto a negative electrode current collector, and after processes such as drying and cold pressing, the negative electrode plate is obtained.

[0193] The electrolyte plays a role in conducting ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and it can be selected according to the needs.

[0194] In some embodiments, an electrolyte solution is used as the electrolyte. The electrolyte solution contains an electrolyte salt and a solvent.

[0195] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluorobis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0196] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, ethyl methyl sulfone, and diethyl sulfone.

[0197] In some embodiments, the electrolyte further selectively includes additives. For example, the additives may include negative electrode film forming additives, positive electrode film forming additives, and further additives that can improve some of the battery's performance characteristics, such as additives that improve the battery's overcharge performance, or additives that improve the battery's high-temperature or low-temperature performance.

[0198] In some embodiments, the electrode assembly further includes a separator. This application is not particularly limited to the type of separator, and any known porous separator having good chemical and mechanical stability may be selected.

[0199] In some embodiments, the material of the separator may be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multilayer composite film, and is not particularly limited. When the separator is a multilayer composite film, the materials of each layer may be the same or different, and is not particularly limited.

[0200] In some embodiments, the positive electrode plate, negative electrode plate, and separator can be manufactured into an electrode assembly by a winding process or a lamination process.

[0201] In some embodiments, the electrode assembly may include an outer casing. This outer casing may be used to package the electrode assembly and the electrolyte.

[0202] In some embodiments, the outer casing of the electrode assembly may be a rigid case, such as a rigid plastic case, an aluminum case, or a steel case. The outer casing of the electrode assembly may also be a pouch, such as a bag-shaped pouch. The material of the pouch may be plastic, and examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0203] This application does not particularly limit the shape of the electrode assembly, which may be cylindrical, square, or any other shape. For example, Figure 5 shows a square structure as an example. battery cell The answer is 5.

[0204] In some embodiments, referring to Figure 6, the casing 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, the bottom plate and side plates enclosing and forming a housing cavity. The case 51 has an opening that communicates with the housing cavity, and the cover plate 53 can cover the opening to seal the housing cavity. The positive electrode plate, negative electrode plate and separator can form an electrode assembly 52 by a winding process or a lamination process. The electrode assembly 52 is packaged within the housing cavity. The electrolyte is impregnated into the electrode assembly 52. battery cell The number of electrode assemblies 52 included in 5 may be one or more, and a person skilled in the art can select them according to their specific needs.

[0205] In some embodiments, electrode assemblies can be assembled into a battery module, and the number of electrode assemblies included in the battery module 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 module.

[0206] Figure 7 shows an example of a battery module 4. Referring to Figure 7, the battery module 4 has multiple battery cell 5 may be installed in sequence along the longitudinal direction of the battery module 4. Of course, they may be arranged in any other manner. Furthermore, these multiple battery cell You can fix the value at 5.

[0207] Selectively, the battery module 4 may further include a housing having a dwelling space, and multiple battery cell Unit 5 will be housed in this containment space.

[0208] 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 may be one or more, and the specific number can be selected by those skilled in the art depending on the application and capacity of the battery pack.

[0209] Figures 8 and 9 show an example of a battery pack 1. Referring to Figures 8 and 9, 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, the upper housing 2 being able to cover the lower housing 3 and forming a sealed space for housing the battery modules 4. The plurality of battery modules 4 may be arranged in the battery box in any manner.

[0210] Furthermore, this application provides a power consumption device comprising at least one of an electrode assembly, battery module, or battery pack according to this application. The electrode assembly, battery module, or battery pack may be used as a power source for the power consumption device or as an energy storage unit for the power consumption device. The power consumption 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 and satellites, energy storage systems, etc.

[0211] As a power consumption device, an electrode assembly, battery module, or battery pack can be selected according to the usage requirements.

[0212] Figure 10 shows an example of a power consumption device. This power consumption device is 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 of the electrode assembly of this power consumption device, a battery pack or battery module can be employed.

[0213] Other examples of devices may include mobile phones, tablet computers, and laptop computers. These devices generally require a thin profile, and therefore utilize an electrode assembly as the power source.

[0214] Examples The following describes embodiments of this application. The embodiments described below are illustrative and are used solely for interpreting this application and should not be construed as limitations thereon. Unless specific technical or conditional descriptions are given in the embodiments, the embodiments shall be carried out in accordance with the technical or conditional descriptions in the literature in the art or in accordance with the product descriptions. Unless the manufacturer is specified, the reagents or equipment used are all common products available on the market.

[0215] Example 1 Manufacturing of adhesives Step 1: Add 800g of deionized water, 3g of sodium perfluoropolyethercarboxylate, and 1.5g of diisopropyl peroxydicarbonate to a 5L high-pressure reaction vessel A, start stirring, evacuate, replace the gas with nitrogen gas, introduce vinylidene fluoride and hexafluoropropylene gas into high-pressure reaction vessel A, raise the pressure inside the vessel to 3.5 MPa, raise the reaction temperature of the system to 75°C, and start the polymerization reaction. When the pressure inside high-pressure reaction vessel A drops to 3.0 MPa, continue introducing vinylidene fluoride and hexafluoropropylene gas, control the pressure inside high-pressure reaction vessel A to 3.0-3.5 MPa, the total amount of vinylidene fluoride and hexafluoropropylene added is 200g, stop the reaction when the pressure drops below 2 MPa to obtain a seed emulsion. Step 2: Add 75.24 g of methyl acrylate, 18.55 g of acrylonitrile, and 6.21 g of acrylamide to reaction vessel B, with a molar ratio of 1:0.4:0.1. Add 3.6 g of sodium dodecyl sulfonate and 100 g of deionized water, and stir thoroughly to disperse and emulsify, obtaining a shell layer monomer preemulsification. Step 3: 100 g of deionized water was added to high-pressure reaction vessel A, and with high-speed stirring, the shell layer monomer preemulsification and initiator solution (formed by dissolving 0.2 g of potassium persulfate in deionized water to form the initiator) from reaction vessel B were slowly added dropwise using a peristaltic pump. After the dropwise addition was complete, the temperature was raised to 90°C and the reaction was maintained for 0.5 hours, then cooled to 40°C, the pH was adjusted to 7-8 with ammonia water, and then filtered and discharged.

[0216] Manufacturing of separators A commercially available PP-PE copolymer micro-perforated film with a thickness of 20 μm and an average hole diameter of 80 nm was used as the substrate. The adhesive manufactured as described above was uniformly stirred and mixed in deionized water to obtain a slurry (solid content 20%). The slurry was uniformly applied to two surfaces of the substrate, dried to remove the solvent, and coated onto the substrate at a coating density of 1.0 g / m². 2 Thus, a separator was obtained.

[0217] Manufacturing of positive electrode plates A cathode slurry was prepared by thoroughly stirring and homogeneously mixing polyvinylidene fluoride (PVDF), lithium iron phosphate (LFP), the conductive agent carbon black, and N-methylpyrrolidone (NMP) in a mass ratio of 1.2:58.38:0.42:40. This cathode slurry was then applied at a rate of 200 g / m³. 2 The positive electrode plate was obtained by uniformly coating the aluminum foil of the positive electrode current collector with the specified amount of material, followed by drying, cold pressing, and slitting.

[0218] Manufacturing of negative electrode plates Artificial graphite, acetylene black (a conductive agent), styrene-butadiene rubber (SBR) (an adhesive), and sodium carboxymethylcellulose (CMC-Na) (a thickener) were added to deionized water in a mass ratio of 96.2:1.0:1.6:1.2. After thorough stirring to ensure uniform mixing, a negative electrode slurry (63% solid content) was prepared. This negative electrode slurry was prepared at a concentration of 98 g / m³. 2 The negative electrode plate was obtained by coating the copper foil of the negative electrode current collector with the specified amount of material, followed by drying, cold pressing, and slitting.

[0219] Manufacturing of electrolyte At 25°C, ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain a mixed solvent. LiPF6 is then dissolved in this mixed solvent to obtain an electrolyte, where the concentration of LiPF6 is 1 mol / L.

[0220] Battery cell manufacturing The positive electrode plate, separator, and negative electrode plate were stacked in order and wound up, then pre-press molded (during which the separator and electrode plates were bonded) to obtain an electrode assembly. The electrode assembly was placed in an outer casing, the manufactured electrolyte was added, and after going through processes such as packaging, standing, chemical conversion, and aging, a battery cell was obtained.

[0221] The parameters (shown in Table 1, for example) were changed in Example 1 to obtain experimental data for Examples 2 to 17.

[0222] Comparative Example 1: Manufacturing Steps for Polyvinylidene Fluoride Polymer 200 g of deionized water, 1 g of sodium perfluoropolyethercarboxylate, and 0.5 g of diisopropyl peroxydicarbonate were added to a high-pressure reaction vessel, stirring was started, the vessel was evacuated, and the gas was replaced with nitrogen gas. Vinylidene fluoride and hexafluoropropylene gas were introduced into the high-pressure reaction vessel, and the pressure inside the vessel was increased to 3.5 MPa. The reaction temperature of the system was raised to 75°C to start the polymerization reaction. When the pressure inside the high-pressure reaction vessel dropped to 3.0 MPa, the introduction of vinylidene fluoride and hexafluoropropylene gas was continued, and the pressure inside the high-pressure reaction vessel was controlled to 3.0-3.5 MPa. The total amount of vinylidene fluoride and hexafluoropropylene added was 200 g. The reaction was stopped when the pressure dropped to below 2 MPa, filtered, and discharged.

[0223] Comparative Example 2: Steps for producing a polymer obtained by polymerizing the first polymerization flexibility monomer. In a three-necked flask, 752.4 g of methyl acrylate, 36 g of sodium dodecyl sulfonate, and 1.2 kg of deionized water were added and thoroughly stirred to disperse and emulsify. The temperature was raised to 70°C, and the initiator solution (a solution formed by dissolving 0.6 g of potassium persulfate in deionized water) was added. The mixture was stirred for 30 minutes to allow the reaction to proceed. The temperature was then raised to 80°C, and the initiator solution (a solution formed by dissolving 1.2 g of potassium persulfate in 100 g of deionized water) was slowly added dropwise using a peristaltic pump. After the dropwise addition was complete, the temperature was raised to 90°C and the reaction was maintained for 0.5 hours. The mixture was then cooled to 40°C, the pH was adjusted to 7 with ammonia water, the reaction was stopped, filtered, and the mixture was drained.

[0224] Comparative Example 3: Steps for producing a polymer obtained by polymerizing a second polymerization polar monomer. Deionized water and a fixed proportion of initiator were added to a three-necked flask containing a reflux condenser, thermometer, and magnetic stirring bar. After uniform stirring at room temperature, the mixture was heated to a set temperature to promote the decomposition of the initiator. Approximately half an hour after the temperature stabilized, a peristaltic pump was used to control the concentration of acrylonitrile entering the polymerization system, and the monomer was added to the water in small droplets to initiate the polymerization reaction. After the monomer addition was complete, the reaction was continued at a constant temperature for a set period of time while stirring. After the reaction was complete, the three-necked flask was moved to air and cooled to room temperature to stop the reaction, then filtered and drained.

[0225] Comparative Example 4: Steps for producing a polymer obtained by polymerizing a third polymerization molecular weight-adjusted monomer. First, an acrylamide solution was prepared by adding 120 g of water to 30 g to 90 g of acrylamide monomer, and an initiator solution was obtained by dissolving 0.02 g to 1 g of persulfate in 30 g of water. 37.5 g of isopropyl alcohol solvent was added to a 250 mL four-necked reaction flask, and the mixture was opened and stirred at a stirring speed of 200 r / min. The temperature was raised until reflux was achieved, and the monomer solution and initiator solution were added dropwise continuously, controlling the dropping rate, and the dropping time was 120 min. The reflux reaction was maintained for 2 hours, the isopropyl alcohol was distilled to obtain the polyacrylamide solution, filtered, and drained.

[0226] Comparative Example 5: Step of mixing polyvinylidene fluoride and polyacrylate and polymerizing them. The polyvinylidene fluoride solution prepared in Comparative Example 1 and the polyacrylate solution prepared in Comparative Example 2 were mixed in a mass ratio of 1:1, and the mixture was uniformly stirred to obtain a blended solution of polyvinylidene fluoride and polyacrylate. This mixture was then filtered and drained.

[0227] As shown in Tables 1 and 2, in Examples 1-4, 16 and 17, the proportions of the three polymers in the core layer were changed while keeping other conditions the same, and in Examples 5-8 and 12-15, the masses of the core layer and shell layer were changed while keeping other conditions the same.

[0228] As shown in Table 3, Comparative Example 1 is an adhesive obtained by producing a polyvinylidene fluoride polymer, Comparative Example 2 is an adhesive obtained by producing an acrylate-based polymer, Comparative Example 3 is an adhesive obtained by producing an acrylonitrile-based polymer, Comparative Example 4 is an adhesive obtained by producing an acrylamide-based polymer, and Comparative Example 5 is an adhesive obtained by producing a polymer obtained by mixing and polymerizing polyvinylidene fluoride and polyacrylate.

[0229] [Table 1]

[0230] [Table 2]

[0231] [Table 3]

[0232] Performance testing: 1. Steps for testing the adhesive strength between the separator and the electrode plate. A battery electrode plate and separator were stacked and placed in a hot press machine. The hot press machine parameters were set to a temperature of 25°C, a pressure of 10t, and a time of 30s. A separator / positive electrode plate sample was manufactured by applying pressure and bonding the plates together. The separator / electrode plate sample was then cut into a 150 x 20 mm rectangular spline. One side of the electrode plate of the rectangular spline was attached to a steel plate using double-sided adhesive. A test sample was prepared by separating the separator and electrode plate by a length of 2 cm along the longitudinal direction at one end of the rectangular spline.

[0233] The steel plate was kept horizontal and fixed with the lower jig of a universal testing machine (Xieqiang Instrument Manufacturing (Shanghai) Co., Ltd., model number CTM2100). The peeled end of the separator was fixed with the upper jig of the universal testing machine, and a tensile machine was connected. The test conditions were set to a tensile rate of 20 mm / min and a horizontal tension of 10 cm. Once the tensile force stabilized, the tensile force value was recorded, and the adhesive strength between the separator and the electrode plate was obtained from the ratio of the tensile force value to the sample width.

[0234] 2. Cycle performance test step of the large fixture A jig force of 10,000 N is applied to the outside of the battery core, and a cycle test is performed in this state. The test steps are as follows: At 25°C, the battery manufactured in Example 1 is charged with a constant current of 1 / 3C to 3.8V, then charged further with a constant voltage of 3.8V until the current becomes 0.05C, left for 5 minutes, and then discharged at 1 / 3C to 2.0V. The obtained discharge capacity is taken as the initial capacity C0. The above steps are repeated for the same battery, and the discharge capacity Cn of the battery from the nth cycle onward is recorded simultaneously. The battery capacity retention rate Pn after each cycle is given by Pn = (Cn / C0) × 100%. In other words, the difference in cycle performance can be expressed by the battery capacity retention rate after 500 cycles.

[0235] [Table 4]

[0236] As shown in Table 4, the battery cores obtained using the adhesives in Examples 1 to 17 exhibited good adhesion between the separator and the electrode plate, while the battery cores obtained using the adhesives in Comparative Examples 1 to 5 exhibited inferior adhesion between the separator and the electrode plate compared to Examples 1 to 17. It was explained that the adhesive performance of the adhesives in Examples 1 to 17 was superior to that of the adhesives in Comparative Examples 1 to 5. Furthermore, the battery cycle performance in Examples 1 to 17 was superior to that of Comparative Examples 1 to 5. It was explained that by using this improved adhesive in the battery separator, the battery cycle performance can be effectively improved.

[0237] The foregoing is merely a preferred embodiment of the present application and does not limit the scope of the patent. Any equivalent structural transformations or direct / indirect applications in other related technical fields that utilize the content of the specification and drawings of this application, based on the concept of this application, are all included within the scope of patent protection. [Explanation of symbols]

[0238] Code Name Code Name 1 Battery Pack 51 Cases 2 Upper housing 52 Electrode assembly 3 Lower enclosure 53 Cover plate 4. Battery module with 6 core layer structure 5 battery cell 7. Shell layer structure

Claims

1. An adhesive comprising a core layer structure and a shell layer structure provided on the surface of the core layer structure, wherein the shell layer structure comprises a polyacrylate polymer and the core layer structure comprises a polyvinylidene fluoride polymer. The constituent monomers of the polyacrylate polymer include a first polymerization flexibility monomer, a second polymerization polarity monomer, and a third polymerization molecular weight adjustment monomer. The molar ratio of the first polymerization-flexible monomer, the second polymerization-polarity monomer, and the third polymerization-molecular-weight-adjusting monomer is 1:(0.01-0.8):(0.01-0.15). The first polymerization flexibility monomer is an acrylate monomer, the second polymerization polarity monomer is an acrylonitrile monomer, and the third polymerization molecular weight adjustment monomer is an acrylamide monomer. The acrylate monomer includes methyl acrylate, The acrylonitrile monomer comprises acrylonitrile, The acrylamide monomer is an adhesive containing acrylamide.

2. The adhesive according to claim 1, wherein the shell layer structure includes a plurality of cases, and the plurality of cases are installed at intervals on the surface of the core layer structure.

3. The adhesive according to claim 1 or 2, wherein the mass ratio of the polyvinylidene fluoride polymer to the polyacrylate polymer is (2 to 100):

1.

4. The adhesive according to claim 1 or 2, wherein the volume average particle size Dv50 of the adhesive is 0.5 μm to 50 μm.

5. The adhesive according to claim 1 or 2, wherein the polyvinylidene fluoride polymer comprises at least one of vinylidene fluoride polymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-pentafluoropropylene copolymer, vinylidene fluoride-tetrafluoropropylene copolymer, vinylidene fluoride-trifluoropropylene copolymer, vinylidene fluoride-perfluorobutene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trifluorochloroethylene copolymer, or vinylidene fluoride-vinyl fluoride copolymer.

6. A method for manufacturing adhesives, The process involves adding water, an emulsifier, an initiator, and the constituent monomers of polyvinylidene fluoride polymer to a reaction vessel, stirring, heating under reaction pressure to carry out the polymerization reaction, obtaining a seed emulsion to be used as a reserve, and then... The steps include mixing and stirring water, an emulsifier, and the constituent monomers of a polyacrylate polymer to obtain a shell layer monomer pre-emulsion, which is used as a preliminary step. The process includes the steps of adding the shell layer monomer preemulsion and initiator to the seed emulsion, stirring, heating, and reacting to obtain a core-shell structure adhesive. The adhesive comprises a core layer structure and a shell layer structure provided on the surface of the core layer structure, wherein the shell layer structure comprises a polyacrylate polymer, and the core layer structure comprises a polyvinylidene fluoride polymer. The constituent monomers of the polyacrylate polymer include a first polymerization flexibility monomer, a second polymerization polarity monomer, and a third polymerization molecular weight adjustment monomer. The molar ratio of the first polymerization-flexible monomer, the second polymerization-polarity monomer, and the third polymerization-molecular-weight-adjusting monomer is 1:(0.01-0.8):(0.01-0.15). The first polymerization flexibility monomer is an acrylate monomer, the second polymerization polarity monomer is an acrylonitrile monomer, and the third polymerization molecular weight adjustment monomer is an acrylamide monomer. The acrylate monomer includes methyl acrylate, The acrylonitrile monomer comprises acrylonitrile, The acrylamide monomer comprises acrylamide. A method for manufacturing adhesives.

7. The method for producing an adhesive according to claim 6, wherein the ratio of the mass of constituent monomers of the polyvinylidene fluoride polymer to the mass of constituent monomers of the polyacrylate polymer is (2 to 100):

1.

8. The constituent monomers of the polyvinylidene fluoride polymer include vinylidene fluoride. Alternatively, the method for producing an adhesive according to claim 6 or 7, wherein the constituent monomers of the polyvinylidene fluoride polymer include at least one of vinylidene fluoride, hexafluoropropylene, pentafluoropropylene, tetrafluoropropylene, trifluoropropylene, perfluorobutene, tetrafluoroethylene, trifluoroethylene, trifluorochloroethylene, and vinyl fluoride.

9. A separator comprising the adhesive described in claim 1.

10. An electrode assembly comprising the separator described in claim 9.

11. A battery cell comprising the electrode assembly described in claim 10.

12. A battery comprising the battery cell described in claim 11.

13. A power consumption device comprising a battery cell according to claim 11 or a battery according to claim 12.

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