WO2023240600A1 - 粘结剂组合物及包括其的负极极片 - Google Patents

粘结剂组合物及包括其的负极极片 Download PDF

Info

Publication number
WO2023240600A1
WO2023240600A1 PCT/CN2022/099471 CN2022099471W WO2023240600A1 WO 2023240600 A1 WO2023240600 A1 WO 2023240600A1 CN 2022099471 W CN2022099471 W CN 2022099471W WO 2023240600 A1 WO2023240600 A1 WO 2023240600A1
Authority
WO
WIPO (PCT)
Prior art keywords
acid
negative electrode
weight
phenyl
optionally
Prior art date
Application number
PCT/CN2022/099471
Other languages
English (en)
French (fr)
Inventor
谌湘艳
石春美
唐代春
Original Assignee
宁德时代新能源科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2022/099471 priority Critical patent/WO2023240600A1/zh
Priority to CN202280059931.1A priority patent/CN117941105A/zh
Publication of WO2023240600A1 publication Critical patent/WO2023240600A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of lithium batteries, and in particular to a binder composition and a negative electrode sheet containing the binder composition.
  • the present application also relates to secondary batteries, battery modules, battery packs and electrical devices containing the above-mentioned binder composition and/or negative electrode sheet.
  • the present application was made in view of the above-mentioned problems, and its purpose is to provide a binder composition that can effectively maintain the electrode structure.
  • the purpose of this application is also to provide a negative electrode piece and a preparation method thereof.
  • this application provides a binder composition, a negative electrode sheet and a preparation method thereof.
  • the present application also provides secondary batteries, battery modules, battery packs and electrical devices including the binder composition and/or negative electrode sheet.
  • a first aspect of the application provides a binder composition, including a phenyl mono- or polycarboxylic acid and a polymer containing a hydroxyl group and a carboxyl group; based on the weight of the polymer containing a hydroxyl group and a carboxyl group, the benzene
  • the content of monobasic or polycarboxylic acid is 0.1% by weight to 3.0% by weight.
  • the binder composition of the present application can effectively reduce the rebound of the pole piece and alleviate the deterioration of the electrode structure; at the same time, it can also effectively inhibit the growth of lithium dendrites, reduce the resistance of the pole piece, and improve the normal and high temperature cycle performance of secondary batteries.
  • the phenyl mono- or polycarboxylic acid is present in an amount of 0.5 to 3.0 wt%, optionally 0.5 to 2.5 wt%, based on the weight of the hydroxyl and carboxyl-containing polymer. , further optionally 1.0% to 2.0% by weight. If the content relationship between the phenyl mono- or polycarboxylic acid and the polymer containing hydroxyl and carboxyl groups in the binder composition is within the above range, the pole piece performance can be further improved.
  • the phenyl mono- or polycarboxylic acid is selected from at least one of phenyl C 1-6 carboxylic acid or phenyl C 1-6 dicarboxylic acid, in each case, the phenyl C 1-6 dicarboxylic acid
  • One or more hydrogen atoms on the base are optionally substituted with the same or different groups selected from C 1-6 alkyl or hydroxyl
  • the phenyl monobasic or polycarboxylic acid is selected from at least the following One: benzoic acid, phenylacetic acid, phenylpropionic acid, terephthalic acid, phthalic acid, isophthalic acid, terephthalic acid, phthalic acid, isophthalic acid, terephthalic acid, ortho Phthalenedipropionic acid and isophthalic dipropionic acid; in each case, one or more hydrogen atoms on the phenyl group of the above compounds are optionally substituted with the same or different groups selected from: methyl, e
  • the polymer containing hydroxyl and carboxyl groups is selected from at least one of the following: carboxymethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, alginic acid, polyacrylic acid, or Its salt.
  • the above-mentioned polymer is beneficial to the in-situ cross-linking and polymerization of the binder composition of the present application and the active material, thereby achieving a series of improvements in pole piece and battery performance.
  • the above-mentioned polymer is conducive to the cross-linking polymerization of the binder composition of the present application and is conducive to the improvement of the performance of the pole piece.
  • a second aspect of the present application provides a negative electrode sheet.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode material layer disposed on at least one surface of the negative electrode current collector.
  • the negative electrode material layer includes a negative electrode active material and a binder.
  • Binder composition includes phenyl monobasic or polycarboxylic acid and a polymer containing hydroxyl and carboxyl groups, and based on the weight of the polymer containing hydroxyl and carboxyl groups, the phenyl monobasic or polycarboxylic acid The content of the polycarboxylic acid is 0.1 to 3.0% by weight; the negative active material, the phenyl mono- or polycarboxylic acid and the polymer containing hydroxyl and carboxyl groups undergo a cross-linking reaction to form bonds.
  • the negative pole piece of the present application has reduced pole piece rebound rate, reduced lithium dendrite growth, better cycle stability and first-cycle efficiency.
  • the phenyl mono- or polycarboxylic acid is present in an amount of 0.5 to 3.0 wt%, optionally 0.5 to 2.5 wt%, based on the weight of the polymer containing hydroxyl and carboxyl groups, further Optional 1.0 to 2.0 wt%. In this way, the negative electrode piece of the present application can have better overall performance.
  • the negative electrode material layer includes 1 to 5% by weight, optionally 1.5% to 4.0% by weight, more optionally 2.0% to 2.0% by weight. 3.5% by weight of the adhesive composition. Containing the binder composition with the above content, the performance of the negative electrode sheet of the present application is further improved.
  • the phenyl mono- or polycarboxylic acid is selected from at least one of phenyl C 1-6 carboxylic acid or phenyl C 1-6 dicarboxylic acid, in each case, the phenyl C 1-6 dicarboxylic acid
  • One or more hydrogen atoms on the base are optionally substituted with the same or different groups selected from C 1-6 alkyl or hydroxyl
  • the phenyl monobasic or polycarboxylic acid is selected from at least one of the following Species: benzoic acid, phenylacetic acid, phenylpropionic acid, terephthalic acid, phthalic acid, isophthalic acid, terephthalic acid, phthalic acid, isophthalic acid, terephthalic acid, phthalic acid dipropionic acid, isophthalic dipropionic acid, in each case one or more hydrogen atoms on the phenyl group of the above compounds are optionally substituted with the same or different groups selected from: methyl
  • the polymer containing hydroxyl and carboxyl groups is selected from at least one of the following materials: carboxymethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, alginic acid, polyacrylic acid or its Salt.
  • the above-mentioned polymer molecules are conducive to in-situ cross-linking and polymerization in the negative electrode sheet material layer, thereby achieving the improvement of the above-mentioned properties.
  • the negative active material is selected from carbon-based negative active materials, silicon-based negative active materials, or combinations thereof; optionally, the carbon-based negative active material is selected from natural graphite, artificial graphite, mesophase carbon fiber , at least one of mesophase carbon microspheres, soft carbon, and hard carbon; optionally, the silicon-based negative active material is selected from at least one of elemental silicon and silicon oxides.
  • the negative electrode sheet containing the above-mentioned negative electrode active material is more conducive to the binder composition of the present application, so that the electrode sheet can obtain good overall performance.
  • a third aspect of the present application provides a negative electrode piece, which is prepared by the following steps:
  • the negative electrode slurry includes a negative electrode active material and a binder composition.
  • the binder composition includes Phenyl mono- or polycarboxylic acid and a polymer containing a hydroxyl group and a carboxyl group, and the content of the phenyl mono- or polycarboxylic acid is 0.1% to 3.0% by weight based on the weight of the polymer containing a hydroxyl group and a carboxyl group. ;and
  • the negative pole piece of the present application has reduced pole piece rebound rate, reduced lithium dendrite growth, better cycle stability and first-cycle efficiency.
  • the phenyl mono- or polycarboxylic acid is present in an amount of 0.5 to 3.0 wt%, optionally 0.5 to 2.5 wt%, based on the weight of the hydroxyl and carboxyl-containing polymer. , further optionally 1.0% to 2.0% by weight.
  • the performance of the negative electrode sheet of the present application is further improved.
  • the heat treatment is performed by drying at a temperature of at least 60°C, optionally between 60°C and 120°C.
  • the temperature within such a range is conducive to the cross-linking polymerization of the binder composition and the negative active material.
  • a fourth aspect of the present application provides a secondary battery, including the binder composition of the first aspect of the present application or the negative electrode sheet of the second or third aspect of the present application.
  • a fifth aspect of the present application provides a battery module including the secondary battery of the fourth aspect of the present application.
  • a sixth aspect of the present application provides a battery pack, including the battery module of the fifth aspect of the present application.
  • a seventh aspect of the present application provides an electrical device, including at least one selected from the secondary battery of the fourth aspect of the present application, the battery module of the fifth aspect of the present application, or the battery pack of the sixth aspect of the present application. kind.
  • the binder composition of the present application can effectively alleviate the problem of unstable pole piece structure caused by the volume change of the pole piece material (such as pole piece rebound, bonding deterioration, etc.), inhibit the growth of lithium dendrites, and improve the pole piece structure. On-chip resistance, improving the normal and high temperature cycle performance of lithium-ion secondary batteries.
  • Figure 1 is a transmission electron microscope (TEM) image of lithium dendrites on the surface of the negative electrode sheet after 100 cycles of a secondary battery according to an embodiment of the present application.
  • TEM transmission electron microscope
  • Figure 2 is a TEM image of lithium dendrites on the surface of the negative electrode sheet of the secondary battery of Comparative Example 1 after 100 cycles.
  • Figure 3 is a TEM image of lithium dendrites on the surface of the negative electrode sheet of the secondary battery of Comparative Example 4 after 100 cycles.
  • FIG. 4 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 5 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 4 .
  • Figure 6 is a schematic diagram of a battery module according to an embodiment of the present application.
  • Figure 7 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 8 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 7 .
  • FIG. 9 is a schematic diagram of a power consumption device using a secondary battery as a power source according to an embodiment of the present application.
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, understand that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range “a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range “0-5" means that all real numbers between "0-5" have been listed in this article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • step (c) means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c). , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • the words “include” and “include” mentioned in this application represent open expressions, which may also be closed expressions.
  • the words “include” and “include” may mean that other components not listed may also be included or included, or only the listed components may be included or included.
  • condition "A or B” is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; Or both A and B are true (or exist).
  • Binder is the main component to maintain the electrode structure, and technicians have done a lot of work to improve its performance.
  • most of the currently commonly used binders cannot effectively alleviate the problems caused by volume changes in electrode materials.
  • polyvinylidene fluoride binders can only achieve ideal bonding effects in electrode materials with small volume changes; water-soluble polymers such as sodium carboxymethyl cellulose, sodium alginate, etc. are all linear chains Polymers cannot alleviate the stress caused by material volume changes in multiple directions. After long-term cycling, the active material particles and the binder will undergo irreversible slippage, resulting in a decrease in capacity.
  • this field has also put forward higher requirements for binders - this field needs a binder that can effectively maintain the electrode structure and alleviate problems caused by volume changes in electrode materials. .
  • this application provides a binder, a negative electrode sheet containing the binder, and a preparation method thereof.
  • the present application also provides secondary batteries, battery modules, battery packs and electrical devices containing the above-mentioned binder or negative electrode sheet.
  • the application proposes a binder composition including phenyl mono- or polycarboxylic acid and a polymer containing hydroxyl and carboxyl groups; and based on the weight of the polymer containing hydroxyl and carboxyl groups Calculated, the content of the phenyl monocarboxylic acid or polycarboxylic acid is 0.1% by weight to 3.0% by weight.
  • the binder composition of the present application can significantly improve the problems of pole piece rebound and bonding failure caused by the volume change of the negative electrode material, significantly inhibit the growth of negative electrode lithium dendrites, reduce the pole piece impedance, and significantly improve the normal and high temperature performance of secondary batteries. Cycle performance.
  • pole rebound refers to the phenomenon of an increase in the thickness of a fully charged battery pole compared to a fresh (not yet cycle tested) pole.
  • fully charged means that the secondary battery is charged to 4.25V at a constant current of 1/3C, and then charged to a constant voltage of 4.25V until the current is 0.05C.
  • the adhesive composition of the present application can alleviate or avoid pole piece rebound.
  • the adhesive composition of the present application can undergo in-situ cross-linking polymerization when used.
  • the polymer containing hydroxyl and carboxyl groups included in the adhesive composition has abundant hydroxyl and carboxyl groups, and therefore can provide good bonding effect by itself; at the same time, during use of the adhesive composition (for example , during the preparation of pole pieces), chemical bonds will occur between polymers containing hydroxyl and carboxyl groups, phenyl monovalent or polycarboxylic acids, and a large number of carboxyl groups and hydroxyl groups respectively carried on the active material under certain conditions (such as temperature increase)
  • a three-dimensional cross-linked network structure is formed in the final pole piece material layer.
  • such a network structure is spread throughout the pole piece material layer. Its structure not only has the flexibility brought by polymers containing hydroxyl and carboxyl groups, but also has the flexibility brought by phenyl monocarboxylic or polycarboxylic acids. Comes with rigidity. Moreover, it is worth noting that polymers containing hydroxyl and carboxyl groups and phenyl monocarboxylic or polycarboxylic acids exist in a certain content relationship, so that the rigidity and flexibility of the cross-linked network structure are properly matched - which can not only give the pole piece material layer The high flexibility can release the stress caused by the volume change of the pole piece material, improve the pole piece bonding, and effectively maintain the pole piece structure.
  • the benzene ring structure brought by phenylcarboxylic acid can also improve the heat resistance and chemical resistance and mechanical strength of the pole piece. The above-mentioned various benefits have improved the long-term performance of the pole piece.
  • the binder composition of the present application can also inhibit the growth of lithium dendrites.
  • the binder composition can help lithium ions be evenly distributed at the interface of the pole piece, so that they are less likely to be enriched and precipitated, thereby inhibiting the growth of lithium dendrites.
  • the inventor believes that the effect of the binder of the present application on inhibiting lithium dendrites may be due to its ability to contribute to the uniform distribution of lithium ions in the pole piece and avoid their local enrichment.
  • the large number of polar functional groups present in the three-dimensional cross-linked network formed by the binder composition and spread throughout the pole piece material layer can have an affinity for lithium ions and promote lithium ion. Ions are evenly distributed in the pole piece material layer; on the other hand, the benzene ring structure introduced by the binder composition promotes ion transmission due to its large electron cloud density and helps lithium ions quickly achieve uniform distribution.
  • the binder composition of the present application can also bring higher first-cycle efficiency to the battery. This may be because the binder composition of the present application can reduce the growth of lithium dendrites, reduce "dead lithium", and ensure the amount of active lithium ions participating in discharge, thus improving the first-cycle efficiency.
  • first-cycle efficiency also known as “first-cycle Coulomb efficiency” refers to the percentage of discharge capacity to charge capacity in the first charge-discharge cycle of a lithium-ion battery.
  • the adhesive composition of the present application can also reduce the resistance of the pole piece.
  • the phenyl mono- or polycarboxylic acid is present in an amount of 0.5 to 3.0 wt%, optionally 0.5 to 2.5 wt%, optionally based on the weight of the polymer containing hydroxyl and carboxyl groups. 1.0% to 2.0% by weight.
  • the content of the phenyl mono- or polycarboxylic acid is 0.1 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, based on the weight of the polymer containing hydroxyl and carboxyl groups. 2.5% by weight or 3.0% by weight, or a range consisting of any two thereof.
  • the polymer containing hydroxyl and carboxyl groups and the phenyl mono- or polycarboxylic acid exist in the above content relationship, which can more effectively alleviate the rebound of the pole piece, giving the pole piece and battery smaller internal resistance and good cycle performance. and higher first-week efficiency.
  • the phenyl mono- or polycarboxylic acid is selected from at least one of phenyl C 1-6 carboxylic acid or phenyl C 1-6 dicarboxylic acid, in each case, the phenyl C 1-6 dicarboxylic acid
  • One or more hydrogen atoms on the radical are optionally substituted with the same or different groups selected from C 1-6 alkyl or hydroxyl.
  • the phenyl mono- or polycarboxylic acid is selected from the group consisting of phenyl monocarboxylic acid, phenyl dicarboxylic acid and combinations thereof.
  • the phenyl mono- or polycarboxylic acid is selected from at least one of the following: benzoic acid, phenylacetic acid, phenylpropionic acid, terephthalic acid, phthalic acid, isophthalic acid Formic acid, terephthalic acid, phthalic acid, isophthalic acid, terephthalic acid, phthalic acid and isophthalic acid, in each case one or The plurality of hydrogen atoms are optionally substituted with the same or different groups selected from: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and hydroxyl.
  • phenyl dicarboxylic acids are preferred.
  • terephthalic acid is preferred.
  • the polymer containing hydroxyl and carboxyl groups is selected from at least one of the following materials: carboxymethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, alginic acid, polyacrylic acid, or Its salt.
  • the above-mentioned polymer molecules are rich in hydroxyl and carboxyl groups, which can provide good bonding properties, which is conducive to the in-situ cross-linking and polymerization of the binder composition of the present application and the active material, and brings appropriate strength to the pole piece material layer. Flexibility, thereby further improving the overall performance of the pole piece and battery.
  • the adhesive composition of the present application may also include suitable additives known in the art in appropriate amounts.
  • the total amount of the hydroxyl- and carboxyl-containing polymer and the phenyl mono- or polycarboxylic acid is 0.1% to 100% by weight, based on the total weight of the binder composition.
  • the adhesive composition consists of a polymer containing hydroxyl and carboxyl groups and a phenyl mono- or polycarboxylic acid. In some embodiments, the adhesive composition does not include a cross-linking agent.
  • the adhesive composition of the present application can achieve cross-linking and polymerization to form a three-dimensional network structure without including additional cross-linking agents or other additives.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode material layer disposed on at least one surface of the negative electrode current collector.
  • the negative electrode material layer includes a negative electrode active material and Binder composition;
  • the binder composition includes phenyl mono- or polycarboxylic acid and a polymer containing hydroxyl and carboxyl groups; based on the weight of the polymer containing hydroxyl and carboxyl groups, the phenyl mono- or polycarboxylic acid The acid content is 0.1% by weight to 3.0% by weight; the negative active material, the phenyl mono- or polycarboxylic acid and the polymer containing hydroxyl and carboxyl groups undergo a cross-linking reaction to form bonds.
  • the negative electrode sheet of the present application has good comprehensive performance: due to the in-situ cross-linking reaction between the negative active material and the binder composition, a rigid and flexible three-dimensional network structure is formed, which can release the energy generated by the volume change of the material. stress, has improved pole piece bonding, reduced pole piece rebound, and can maintain a good pole piece structure after long-term use; at the same time, the negative electrode piece of the present application also has reduced lithium dendrite growth and better cycle stability performance and better first-week efficiency.
  • the phenyl mono- or polycarboxylic acid is present in an amount of 0.5 to 3.0 wt%, optionally 0.5 to 2.5 wt%, based on the weight of the polymer containing hydroxyl and carboxyl groups, further Optional 1.0 to 2.0 wt%.
  • the negative electrode piece of the present application has better comprehensive performance: lower electrode piece rebound rate, smaller Internal resistance, good cycle performance and high first cycle efficiency.
  • the negative electrode material layer includes 1 to 5% by weight, optionally 1.5% to 4.0% by weight, more optionally 2.0% to 2.0% by weight. 3.5% by weight of the adhesive composition.
  • the negative electrode material layer contains a binder composition within the above content range, the negative electrode piece of the present application has further reduced plate rebound, inhibited lithium dendrite growth, better normal temperature/high temperature cycle stability and first-cycle efficiency.
  • the phenyl mono- or polycarboxylic acid is selected from at least one of phenyl C 1-6 carboxylic acid or phenyl C 1-6 dicarboxylic acid, in each case, the phenyl C 1-6 dicarboxylic acid
  • One or more hydrogen atoms on the radical are optionally substituted with the same or different groups selected from hydroxyl or C 1-6 alkyl.
  • the phenyl mono- or polycarboxylic acid is selected from at least one of the following: benzoic acid, phenylacetic acid, phenylpropionic acid, terephthalic acid, phthalic acid, isophthalic acid Formic acid, terephthalic acid, phthalic acid, isophthalic acid, terephthalic acid, phthalic acid, isophthalic acid, in each case, one or The plurality of hydrogen atoms are optionally substituted with the same or different groups selected from: methyl, ethyl, propyl, isopropyl, butyl, isobutyl and tert-butyl.
  • the polymer containing hydroxyl and carboxyl groups is selected from at least one of the following materials: carboxymethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, alginic acid, polyacrylic acid, or Its salt.
  • the above-mentioned polymer molecules are rich in hydroxyl and carboxyl groups, have good adhesion, and are conducive to in-situ cross-linking and polymerization in the negative electrode plate material layer, thereby further improving the overall performance of the electrode plate.
  • the negative active material is selected from carbon-based negative active materials, silicon-based negative active materials, or combinations thereof. In some embodiments, the negative active material is a silicon-based negative active material. In some embodiments, the negative active material is a combination of silicon-based negative active material and carbon-based negative active material. Optionally, the carbon-based negative active material is selected from at least one of natural graphite, artificial graphite, mesocarbon fiber, mesocarbon microspheres, soft carbon, and hard carbon. In some embodiments, optionally, the silicon-based negative active material is selected from at least one of elemental silicon and silicon oxides. In some embodiments, the negative active material is a combination of a carbon-based negative active material and a silicon-based negative active material.
  • binder composition of the present application in the negative electrode sheet with the above-mentioned negative electrode active material, because the binder composition of the present application can help alleviate the adverse effects caused by volume changes and improve the negative electrode electrode. Energy density and cycle performance of the chip.
  • the negative active material is surface hydroxylated.
  • Another embodiment of the present application provides a negative electrode piece, which is prepared by the following steps:
  • the negative electrode slurry includes a negative electrode active material and a binder composition.
  • the binder composition includes Phenyl mono- or polycarboxylic acid and a polymer containing a hydroxyl group and a carboxyl group; and the content of the phenyl mono- or polycarboxylic acid is 0.1% to 3.0% by weight based on the weight of the polymer containing a hydroxyl group and a carboxyl group. ;and
  • the negative electrode plate of the present application has reduced plate rebound rate, reduced lithium dendrite growth, better cycle stability and first-cycle efficiency.
  • the phenyl mono- or polycarboxylic acid is present in an amount of 0.5 to 3.0 wt%, optionally 0.5 to 2.5 wt%, based on the total weight of the polymer containing hydroxyl and carboxyl groups, Further optionally 1.0% to 2.0% by weight.
  • the negative electrode piece of the present application will have better overall performance: lower electrode piece rebound rate, Small internal resistance, good cycle performance and high first-cycle efficiency.
  • the negative electrode slurry includes 1 to 5% by weight, optionally 0.5 to 3.0% by weight of the binder composition based on the dry weight of the negative electrode slurry.
  • the comprehensive performance of the negative electrode piece of the present application is further improved: the rebound of the electrode piece is reduced, the growth of lithium dendrites is effectively suppressed, and the normal temperature/high temperature cycle stability is better and higher efficiency in the first week.
  • the negative electrode current collector is described in detail below.
  • the negative electrode current collector has two opposite surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • 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 material.
  • the composite current collector can be formed by forming metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode material layer optionally also includes other binders.
  • the further binder may be, for example, polytetrafluoroethylene (PTFE).
  • the negative electrode material layer optionally further 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.
  • the negative electrode material layer optionally also includes other auxiliaries, such as thickeners and the like.
  • a method for preparing a negative electrode sheet which includes the following steps:
  • the negative electrode slurry includes a negative electrode active material and a binder composition.
  • the binder composition includes Phenyl mono- or polycarboxylic acid and a polymer containing a hydroxyl group and a carboxyl group, and the content of the phenyl mono- or polycarboxylic acid is 0.1% to 3.0% by weight based on the weight of the polymer containing a hydroxyl group and a carboxyl group. ;and
  • the negative electrode piece of the present application can be prepared.
  • the binder composition of the present application undergoes in-situ cross-linking and polymerization, forming a three-dimensional network structure in the obtained pole piece material layer, so that the negative electrode pole piece has good overall performance: lower Pole piece rebound rate, small internal resistance, good cycle performance and high first-cycle efficiency.
  • the phenyl mono- or polycarboxylic acid is selected from at least one of phenyl C 1-6 carboxylic acid or phenyl C 1-6 dicarboxylic acid, in each case, the phenyl C 1-6 dicarboxylic acid
  • One or more hydrogen atoms on the radical are optionally substituted with the same or different groups selected from hydroxyl or C 1-6 alkyl.
  • the phenyl mono- or polycarboxylic acid is selected from at least one of the following: benzoic acid, phenylacetic acid, phenylpropionic acid, terephthalic acid, phthalic acid, isophthalic acid
  • benzoic acid phenylacetic acid
  • phenylpropionic acid terephthalic acid, phthalic acid, isophthalic acid
  • isophthalic acid Formic acid, terephthalic acid, phthalic acid, isophthalic acid, terephthalic acid, phthalic acid, isophthalic acid, in each case, one or The plurality of hydrogen atoms are optionally substituted with the same or different groups selected from: hydroxyl, methyl, ethyl, propyl, isopropyl, butyl, isobutyl and tert-butyl.
  • the polymer containing hydroxyl and carboxyl groups is selected from at least one of the following materials: carboxymethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, alginic acid, polyacrylic acid, or Its salt.
  • the phenyl mono- or polycarboxylic acid is present in an amount of 0.5 to 3.0 wt%, optionally 0.5 to 2.5 wt%, based on the total weight of the polymer containing hydroxyl and carboxyl groups, Further optionally 1.0% to 2.0% by weight.
  • the negative electrode slurry based on the dry weight of the negative electrode slurry, includes 1 to 5% by weight, optionally 1.5% to 4.0% by weight, more optionally 2.0% to 2.0% by weight. 3.5% by weight of the adhesive composition.
  • the heat treatment is performed at a temperature of at least 60°C. In some embodiments, optionally, the heat treatment is performed at a temperature of 60°C to 120°C, optionally 80 to 120°C. The above temperature is beneficial to the in-situ cross-linking polymerization of the adhesive composition of the present application.
  • the heat treatment is performed by drying at a temperature of at least 60°C.
  • the binder composition and the negative active material can be cross-linked and polymerized without a special cross-linking polymerization step.
  • the negative electrode slurry is prepared by dispersing the negative active material, the conductive agent, the binder combination of the present application, and optionally other binders and optionally other components in a solvent.
  • the solvent is water, optionally deionized water.
  • the negative electrode slurry is applied on the negative electrode current collector by coating.
  • the method of the present application further includes a cold pressing step after the heat treatment step.
  • a secondary battery including the binder composition of the present application, the negative electrode sheet of the present application, or the negative electrode sheet prepared by the method of the present application.
  • a secondary battery typically includes a positive electrode plate, a negative electrode plate, an electrolyte and a separator.
  • active ions are inserted and detached back and forth between the positive and negative electrodes.
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the isolation film is placed between the positive electrode piece and the negative electrode piece. It mainly prevents the positive and negative electrodes from short-circuiting and allows ions to pass through.
  • the secondary battery is a lithium-ion secondary battery.
  • the negative electrode plate has been described in detail above, so the positive electrode plate, electrolyte and separator will be described in detail below.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.
  • the positive electrode film layer includes the positive electrode active material of the first aspect of the present application.
  • the positive electrode current collector has two surfaces facing each other in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • the metal foil aluminum foil can be used.
  • 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 can be formed by forming metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the cathode active material may be a cathode active material known in the art for batteries.
  • the cathode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials of batteries can also be used. Only one type of these positive electrode active materials may be used alone, or two or more types may be used in combination.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (can also be abbreviated to NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (can also be abbreviated to NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (can also be abbreviated to NCM 622 ), LiNi At least one of 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as Li Li
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon. At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • composites of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate and carbon.
  • At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.
  • the positive electrode film layer optionally further includes a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • the positive electrode film layer optionally further includes a conductive agent.
  • 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.
  • the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode piece can be obtained.
  • a solvent such as N -methylpyrrolidone
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the type of electrolyte in this application can be selected according to needs.
  • the electrolyte can be liquid, gel, or completely solid.
  • the electrolyte is an electrolyte solution.
  • the electrolyte solution includes electrolyte salts and solvents.
  • the electrolyte salt may be selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonimide, lithium bistrifluoromethanesulfonimide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluoroborate, lithium dioxaloborate, lithium difluorodioxalate phosphate and lithium tetrafluoroxalate phosphate.
  • the solvent may be selected from the group consisting of ethylene carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte optionally further includes additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.
  • the secondary battery further includes a separator film.
  • a separator film There is no particular restriction on the type of isolation membrane in this application. Any well-known porous structure isolation membrane with good chemical stability and mechanical stability can be used.
  • the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation film can be a single-layer film or a multi-layer composite film, with no special restrictions. When the isolation film is a multi-layer composite film, the materials of each layer can be the same or different, and there is no particular limitation.
  • the positive electrode piece, the negative electrode piece and the separator film can be made into an electrode assembly through a winding process or a lamination process.
  • the secondary battery may include an outer packaging.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 4 shows a square-structured secondary battery 5 as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity.
  • the housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 can cover the opening to close the accommodation cavity.
  • the positive electrode piece, the negative electrode piece and the isolation film can be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the containing cavity.
  • the electrolyte soaks into the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • secondary batteries can be assembled into battery modules, and the number of secondary batteries contained in the battery module can be one or more. The specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 6 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
  • the above-mentioned battery modules can also be assembled into a battery pack.
  • the number of battery modules contained in the battery pack can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box 2 and a lower box 3 .
  • the upper box 2 can be covered with the lower box 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided by the present application.
  • the secondary battery, battery module, or battery pack may be used as a power source for the electrical device, or may be used as an energy storage unit for the electrical device.
  • the electric device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, and electric golf carts). , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.
  • a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.
  • Figure 9 is an electrical device as an example.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc.
  • a battery pack or battery module can be used.
  • the device may be a mobile phone, a tablet, a laptop, etc.
  • the device is usually required to be thin and light, and a secondary battery can be used as a power source.
  • TPA Terephthalic acid
  • CMC carboxymethyl cellulose
  • TPA Terephthalic acid
  • CMC carboxymethyl cellulose
  • the content of terephthalic acid is 0.5% by weight based on the weight of CMC (as shown in Table 1).
  • the amount of water added is only necessary to allow TPA and CMC to dissolve.
  • the carbon black has a mass ratio of 23.84:71.51:2.2:2.45, and the solid content is adjusted to make a negative electrode slurry with a solid content of 95.35%.
  • the above negative electrode slurry is evenly coated on the copper foil (double-sided coating, one side weight is 0.131g/1540.25mm 2 ), dried at a temperature of 100°C, and then cold pressed and cut to obtain negative electrode pieces.
  • the content of the adhesive composition is 2.2% by weight based on the total weight of the pole piece material layer.
  • LiNi 0.8 Co 0.1 Mn 0.1 O 2 , carbon nanotube CNT, and binder PVDF were mixed at a mass ratio of 97:2:1 to prepare a cathode slurry (solid content: 97.44% ).
  • the positive electrode slurry is evenly coated on the aluminum foil (double-sided coating, one side weight is 0.131g/1540.25mm 2 ), and the positive electrode pieces are obtained after being fully dried, cold-pressed, and cut.
  • LiPF 6 was added to a mixed solution of ethylene carbonate (EC)/diethyl carbonate (DEC) (volume ratio 1:1 at room temperature) to obtain a solution with a concentration of 1M as the electrolyte.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • Use Celgard2300 as the separator area 53mm ⁇ 45mm
  • use the positive and negative electrode sheets prepared as above areas 51mm ⁇ 43mm and 50mm ⁇ 45mm respectively
  • They are stacked and wound in sequence, and then filled with 0.45g of electrolyte to assemble a lithium-ion secondary battery.
  • the battery capacity retention rate data corresponding to Example 1 in Table 1 is the data measured after 100 cycles under the above test conditions, that is, the value of P100.
  • the high temperature (45°C in this application) cycle retention test is performed at 45°C according to the above steps.
  • TEM Tecnai G2 Spirit transmission electron microscope
  • Table 1 shows the type and content of the phenyl mono- or polycarboxylic acid, as well as various performance data of the pole piece and the secondary battery.
  • Figure 1 shows a transmission electron microscope (TEM) image of the surface morphology of the negative electrode plate after 100 cycles of cycling.
  • TEM transmission electron microscope
  • phenyl mono- or polycarboxylic acids used in Examples 2-4 and Comparative Examples 1-3 are different from those in Example 1, and the remaining raw materials, preparation methods and testing methods are the same as in Example 1.
  • the types and contents of phenyl mono- or polycarboxylic acids are shown in Table 1.
  • the phenyl mono- or polybasic acid content is based on the weight percent of the polymer containing carboxyl and hydroxyl groups.
  • the adhesive compositions of the present application in Examples 1-4 all exhibit better inhibition of pole piece rebound and electrical properties. . This may be due to the fact that binder compositions containing phenyl mono- or polycarboxylic acids bring better heat resistance, chemical resistance and mechanical strength to the pole pieces, which is beneficial to improving capacity, compared to those containing aliphatic carboxylic acids. Maintain rate and control pole piece bounce.
  • Figure 2 shows a TEM image of the surface morphology of the negative electrode plate of Comparative Example 1 after 100 cycles.
  • Examples 5-14 and Comparative Example 4 use carboxymethylcellulose and terephthalic acid (TPA) to prepare negative electrode sheets and secondary batteries according to the method described in Example 1.
  • TPA carboxymethylcellulose and terephthalic acid
  • Table 2 The relationship between the contents of carboxymethylcellulose and terephthalic acid is specifically shown in Table 2.
  • the pole pieces and secondary batteries in the above examples and comparative examples were subjected to performance testing according to the test method described in Example 1, and the relevant data are shown in Table 2.
  • the negative electrode piece of the present application has better overall performance: lower rebound rate, good cycle capacity retention rate at 25°C/45°C, and higher first week efficiency. , the DCR value of the pole piece is small.
  • Figure 3 is a TEM image of the surface morphology of the negative electrode piece in Comparative Example 4 after being cycled for 100 cycles.
  • Examples 11-19 Use carboxymethyl cellulose and terephthalic acid (the content of terephthalic acid is 0.5% by weight based on the weight of carboxymethyl cellulose) to prepare negative electrode sheets according to the method described in Example 1 and secondary batteries. The difference from Example 1 is that when preparing the negative electrode sheet, the amount (dry weight) of the binder composition added is different.
  • the pole pieces and secondary batteries in the above examples and comparative examples were subjected to performance testing according to the test method described in Example 1. Relevant data are shown in Table 3.
  • the content of the binder composition is a weight percentage based on the total weight of the negative electrode material layer.
  • the adhesive composition of the present application has good comprehensive properties: reduced pole piece rebound, good normal/high temperature cycle performance, high first-week efficiency, and small internal resistance.

Abstract

本申请提供了一种粘结剂组合物，包括苯基一元或多元羧酸和含有羟基和羧基的聚合物，并且基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重量％。本申请的粘结剂组合物能够原位交联形成三维网络结构，从而显著改善了负极材料的体积变化导致的极片反弹、粘结失效问题，显著抑制了负极锂枝晶生长，显著改善二次电池的高温循环性能。此外，本申请还提供一种包括所述粘结剂组合物的负极极片、其制备方法以及二次电池、电池模块、电池包和用电装置。

Description

粘结剂组合物及包括其的负极极片 技术领域
本申请涉及锂电池技术领域，尤其涉及一种粘结剂组合物和包含该粘结剂组合物的负极极片。本申请还涉及包含上述粘结剂组合物和/或负极极片的二次电池、电池模块、电池包和用电装置。
背景技术
随着锂离子电池已经成为电动汽车、便携电子设备的重要电源设备，人们对锂离子电池能量密度的要求也不断提高。但通常，高比容量的电极材料在嵌-脱锂的过程中，往往体积变化较大，从而在长期循环过程中可能导致粘结失效，破坏电极结构，加速电极容量衰减，缩短电池的循环寿命。作为维持电极结构的主要成分，目前常用的粘结剂大多不能有效缓解由电极材料体积变化带来的问题。因此，这成为限制电池能量密度改善的因素之一。
本领域需要一种能够有效维持电极结构、缓解电极材料体积变化带来的问题的粘结剂。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，提供一种能够有效维持电极结构的粘结剂组合物。本申请的目的还在于，提供一种负极极片及其制备方法。
为了达到上述目的，本申请提供了一种粘结剂组合物、一种负极极片及其制备方法。本申请还提供了包括所述粘结剂组合物和/或负极极片的二次电池、电池模块、电池包和用电装置。
本申请的第一方面提供了一种粘结剂组合物，包括苯基一元或多元羧酸和含有羟基和羧基的聚合物；基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重 量％。
本申请的粘结剂组合物能够有效减轻极片反弹，缓解电极结构劣化；同时，还能够有效抑制锂枝晶生长，降低极片阻抗，改善二次电池常温和高温循环性能等。
在任意实施方式中，基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.5重量％至3.0重量％，可选地0.5重量％至2.5重量％，进一步可选地1.0重量％至2.0重量％。粘结剂组合物中的苯基一元或多元羧酸与含有羟基和羧基的聚合物的含量关系在上述范围内，能够进一步改善极片性能。
在任意实施方式中，所述苯基一元或多元羧酸选自苯基C 1-6羧酸或苯基C 1-6二羧酸中的至少一种，在每种情况下，所述苯基上的一个或多个氢原子任选地被选自C 1-6烷基或羟基的相同或不同的基团取代；可选地，所述苯基一元或多元羧酸选自以下的至少一种：苯甲酸、苯乙酸、苯丙酸、对苯二甲酸、邻苯二甲酸、间苯二甲酸、对苯二乙酸、邻苯二乙酸、间苯二乙酸、对苯二丙酸、邻苯二丙酸和间苯二丙酸；在每种情况下，上述化合物的苯基上的一个或多个氢原子任选地被选自以下的相同或不同基团取代：甲基、乙基、丙基、异丙基、丁基、异丁基、叔丁基和羟基。通过包含上述苯基一元或多元羧酸，本申请的粘结剂组合物能够降低极片反弹率，降低内阻，改善首周效率，改善循环性能。
在任意实施方式中，所述含有羟基和羧基的聚合物选自以下物质中的至少一种：羧甲基纤维素、羧乙基纤维素、羧丙基纤维素、海藻酸、聚丙烯酸，或其盐。上述聚合物有利于本申请的粘结剂组合物与活性材料发生原位交联聚合，从而实现极片和电池性能的一系列改善。
上述聚合物有利于本申请的粘结剂组合物发生交联聚合，并有利于极片性能的改善。
本申请的第二方面提供一种负极极片，所述负极极片包括负极集流体和设置在所述负极集流体至少一个表面上的负极材料层，所述负极材料层包括负极活性材料和粘结剂组合物；所述粘结剂组合物包括苯基一元或多元羧酸和含有羟基和羧基的聚合物，并且基于所述含有 羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重量％；；所述负极活性材料、所述苯基一元或多元羧酸和所述含有羟基和羧基的聚合物发生交联反应成键。本申请的负极极片具有降低的极片反弹率，减轻的锂枝晶生长，较好的循环稳定性和首周效率。
在任意实施方式中，基于含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.5重量％至3.0重量％，可选地0.5重量％至2.5重量％，进一步可选地1.0重量％至2.0重量％。如此，本申请的负极极片可具有更好的综合性能。
在任意实施方式中，基于所述负极材料层的总重量计，所述负极材料层包括1重量％至5重量％，可选地1.5重量％至4.0重量％，更可选地2.0重量％至3.5重量％的所述粘结剂组合物。包含上述含量的粘结剂组合物，本申请负极极片的性能进一步改善。
在任意实施方式中，所述苯基一元或多元羧酸选自苯基C 1-6羧酸或苯基C 1-6二羧酸中的至少一种，在每种情况下，所述苯基上的一个或多个氢原子任选地被选自C 1-6烷基或羟基的相同或不同基团取代；可选地，所述苯基一元或多元羧酸选自以下的至少一种：苯甲酸、苯乙酸、苯丙酸、对苯二甲酸、邻苯二甲酸、间苯二甲酸、对苯二乙酸、邻苯二乙酸、间苯二乙酸、对苯二丙酸、邻苯二丙酸、间苯二丙酸，在每种情况下，上述化合物的苯基上的一个或多个氢原子任选地被选自以下的相同或不同基团取代：甲基、乙基、丙基、异丙基、丁基、异丁基和叔丁基。通过选择苯基一元或多元羧酸，能够进一步改善负极极片的性能。
在任意实施方式中，所述含有羟基和羧基的聚合物选自以下物质中的至少一种：羧甲基纤维素、羧乙基纤维素、羧丙基纤维素、海藻酸、聚丙烯酸或其盐。上述聚合物分子有利于在负极极片材料层中发生原位交联聚合，从而实现上述性能的改善。
在任意实施方式中，所述负极活性材料选自碳基负极活性材料、硅基负极活性材料或其组合；可选地，所述碳基负极活性材料选自天然石墨、人造石墨、中间相碳纤维、中间相碳微球、软碳、硬碳中的 至少一种；可选地，所述硅基负极活性材料选自单质硅、硅的氧化物中的至少一种。负极极片中包含上述负极活性材料，更利于本申请的粘结剂组合物发挥作用，从而使极片获得良好的综合性能。
本申请的第三方面提供一种负极极片，所述负极极片通过以下步骤制备：
(1)提供负极浆料并将其施加于负极集流体的至少一个表面上，得到极片坯料，所述负极浆料包括负极活性材料和粘结剂组合物，所述粘结剂组合物包括苯基一元或多元羧酸和含有羟基和羧基的聚合物，并且基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重量％；和
(2)热处理所述极片坯料，使所述负极活性材料、苯基一元或多元羧酸和含有羟基和羧基的聚合物发生交联反应成键。
本申请的负极极片具有降低的极片反弹率，减轻的锂枝晶生长，较好的循环稳定性和首周效率。
在任意实施方式中，基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.5重量％至3.0重量％，可选地0.5重量％至2.5重量％，进一步可选地1.0重量％至2.0重量％。进一步使粘结剂组合物中含有羟基和羧基的聚合物与苯基一元或多元羧酸存在上述含量关系时，本申请的负极极片的性能进一步改善。
在任意实施方式中，所述热处理在至少60℃，可选地在60℃-120℃的温度下通过干燥进行。这样范围内的温度有利于粘结剂组合物与负极活性材料发生交联聚合。
本申请的第四方面提供一种二次电池，包括本申请第一方面的粘结剂组合物或本申请第二方面或第三方面的负极极片。
本申请的第五方面提供一种电池模块，包括本申请的第四方面的二次电池。
本申请的第六方面提供一种电池包，包括本申请的第五方面的电池模块。
本申请的第七方面提供一种用电装置，包括选自本申请的第四方面的二次电池、本申请的第五方面的电池模块或本申请的第六方面的 电池包中的至少一种。
本申请的粘结剂组合物能够有效缓解由于极片材料的体积变化所带来的极片结构不稳定的问题(如，极片反弹、粘结恶化等)、抑制锂枝晶生长、改善极片内阻、改善锂离子二次电池的常温和高温循环性能。
附图说明
图1为本申请一实施方式的二次电池经循环100圈后负极极片表面锂枝晶的透射电子显微镜(TEM)图。
图2为对比例1的二次电池经循环100圈后负极极片表面锂枝晶的TEM图。
图3为对比例4的二次电池经循环100圈后负极极片表面锂枝晶的TEM图。
图4是本申请一实施方式的二次电池的示意图。
图5是图4所示的本申请一实施方式的二次电池的分解图。
图6是本申请一实施方式的电池模块的示意图。
图7是本申请一实施方式的电池包的示意图。
图8是图7所示的本申请一实施方式的电池包的分解图。
图9是本申请一实施方式的二次电池用作电源的用电装置的示意图。
附图标记说明：
1电池包；2上箱体；3下箱体；4电池模块；5二次电池；51壳体；52电极组件；53顶盖组件
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的粘结剂组合物、负极极片、二次电池、电池模块、电池包和电学装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外， 附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的 组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
随着锂离子电池已经成为电动汽车、便携电子设备的重要电源设备，人们对锂离子电池的要求也不断提高，特别是电池的能量密度。为了提高电池的能量密度，本领域采取了多种方式，其中之一就是采用高比容量的电极材料。但是，这样的电极材料在嵌-脱锂的过程中，往往存在较大的体积变化，从而在长期循环过程中可能导致粘结失效，破坏电极结构，加速电极容量衰减，缩短电池的循环寿命。这成为限制电池能量密度改善的重要因素之一。
粘结剂作为维持电极结构的主要成分，技术人员做了很多工作以期改善其性能。但是，目前常用的粘结剂大多不能有效缓解由电极材料体积变化带来的问题。例如，聚偏二氟乙烯粘结剂，只能在体积变化较小的电极材料中才能获得理想的粘结效果；水溶性聚合物如羧甲基纤维素钠、海藻酸钠等均为直链高分子，无法在多方向上缓解材料体积变化产生的应力作用，长期循环后活性材料颗粒与粘结剂会发生不可逆滑移，从而导致容量下降。
因此，为了寻求具有高比容量的电池，本领域对粘结剂也提出了更高的要求——本领域需要一种能够有效维持电极结构，缓解电极材料体积变化带来的问题的粘结剂。
鉴于上述问题，本申请提供一种粘结剂，并且提供包含该粘结剂的负极极片及其制备方法。此外，本申请还提供包含上述粘结剂或负极极片的二次电池、电池模块、电池包和用电装置。
粘结剂组合物
本申请的一个实施方式中，本申请提出了一种粘结剂组合物，包括苯基一元或多元羧酸以及含有羟基和羧基的聚合物；并且基于所述 含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重量％。
本申请的粘结剂组合物能够显著改善负极材料的体积变化导致的极片反弹、粘结失效问题，显著抑制了负极锂枝晶生长，降低极片阻抗，显著改善二次电池的常温和高温循环性能。
本文中，术语“极片反弹”意指相比于新鲜(尚未经过循环测试的)的极片，满充的电池极片的厚度增大的现象。本文中，术语“满充”意指二次电池以1/3C恒流充电至4.25V，再以4.25V恒压充电至电流为0.05C时的状态。
首先，本申请的粘结剂组合物能缓解或避免极片反弹。不希望囿于任何理论，本申请的粘结剂组合物在使用时可发生原位交联聚合。具体而言，粘结剂组合物中所包括的含有羟基和羧基的聚合物具有丰富的羟基和羧基，因此本身可提供良好的粘结作用；同时，在使用该粘结剂组合物期间(例如，极片制备期间)，含有羟基和羧基的聚合物、苯基一元或多元羧酸和活性材料上分别带有的大量羧基和羟基之间在一定条件下(如，温度升高)会发生化学键合、交联而在最终得到的极片材料层中形成三维交联网络结构。
如本领域技术人员所能够领会的，这样的网络结构遍布于极片材料层中，其结构既具有含有羟基和羧基的聚合物所带来的柔性，又具有苯基一元或多元羧酸所带来的刚性。并且，值得注意的是，含有羟基和羧基的聚合物和苯基一元或多元羧酸以一定的含量关系存在，使交联网络结构的刚性和柔性配合适当——既能赋予极片材料层以较高的柔韧性以释放由极片材料体积变化而产生的应力、改善极片粘结、有效维持极片结构，同时又可以有足够的刚性来效抑制极片反弹。此外，苯基羧酸所带来的苯环结构还能改善极片的耐热性和耐化学性机械强度。上述种种益处，实现了极片的长期使用性能的改善。
其次，本申请的粘结剂组合物还能抑制锂枝晶生长。不希望囿于任何理论，所述粘结剂组合物能够帮助锂离子在极片界面处均匀分布，从而不易富集、析出，从而抑制锂枝晶生长。并且，发明人认为，本申请的粘结剂抑制锂枝晶的效果可能是由于其能够有助于锂离子在 极片中的均匀分布，避免其局部富集。这样的效果可能是通过以下两方面实现的：一方面，粘结剂组合物所形成的遍布于极片材料层的三维交联网络中存在的大量极性官能团可对锂离子有亲和力，促进锂离子在极片材料层中均匀分布；另一方面，粘结剂组合物所引入的苯环结构由于其电子云密度较大，促进离子传输，帮助锂离子快速实现均匀分布。
进一步地，本申请的粘结剂组合物还能够为电池带来较高的首周效率。这可能是因为本申请的粘结剂组合物可减轻锂枝晶生长，减少“死锂”，保证了参与放电的活性锂离子的量，从而提高了首周效率。
本文中，术语“首周效率”，又称“首次库伦效率”，是指在锂离子电池在首次充放电循环中，放电容量与充电容量的百分比。
最后，本申请的粘结剂组合物还可降低极片阻抗。
在一些实施方式中，基于含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.5重量％至3.0重量％，可选0.5重量％至2.5重量％，可选地1.0重量％至2.0重量％。在一些实施方式中，基于含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％、0.5重量％、1.0重量％、1.5重量％、2.0重量％、2.5重量％或3.0重量％，或其任意两者组成的范围。粘结剂组合物中，含有羟基和羧基的聚合物与苯基一元或多元羧酸以上述含量关系存在，能够更有效缓解极片反弹，赋予极片和电池较小内阻、良好的循环性能和较高的首周效率。
在一些实施方式中，所述苯基一元或多元羧酸选自苯基C 1-6羧酸或苯基C 1-6二羧酸中的至少一种，在每种情况下，所述苯基上一个或多个氢原子任选地被选自C 1-6烷基或羟基的相同或不同的基团取代。
在本文中，“任选地被取代”及其类似表述具有本领域技术人员通常理解的含义，意指可以是取代的，也可以是未取代的。例如，上文中所述“所述苯基上一个或多个氢原子任选地被选自C 1-6烷基或羟基的相同或不同的基团取代”，意为：所述苯基上的一个或多个氢原子是未被取代的，或者是被选自C 1-6烷基或羟基的相同或不同基团取代的。
在一些实施方式中，可选地，所述苯基一元或多元羧酸选自苯基一元羧酸、苯基二元羧酸及其组合。在一些实施方式中，可选地，所述苯基一元或多元羧酸选自以下的至少一种：苯甲酸、苯乙酸、苯丙酸、对苯二甲酸、邻苯二甲酸、间苯二甲酸、对苯二乙酸、邻苯二乙酸、间苯二乙酸、对苯二丙酸、邻苯二丙酸和间苯二丙酸，在每种情况下，上述化合物的苯基上的一个或多个氢原子任选地被选自以下的相同或不同基团取代：甲基、乙基、丙基、异丙基、丁基、异丁基、叔丁基和羟基。在一些实施方式中，苯基二元羧酸是优选的。在一些实施方式中，对苯二甲酸是优选的。通过包含上述苯基一元或多元羧酸，本申请的粘结剂组合物能够进一步降低极片反弹率，降低内阻，改善首周效率，改善循环性能。
在一些实施方式中，所述含有羟基和羧基的聚合物选自以下物质中的至少一种：羧甲基纤维素、羧乙基纤维素、羧丙基纤维素、海藻酸、聚丙烯酸，或其盐。上述聚合物分子中具有丰富的羟基和羧基，本身能够提供良好的粘结性能，有利于本申请的粘结剂组合物与活性材料发生原位交联聚合，为极片材料层带来适当的柔性，从而进一步改善极片和电池综合性能。
在一些实施方式中，本申请的粘结剂组合物还可以适量包括本领域已知的适合的添加剂。
在一些实施方式中，基于粘结剂组合物的总重量计，所述含有羟基和羧基的聚合物和所述苯基一元或多元羧酸的总量为0.1重量％至100重量％。
在一些实施方式中，粘结剂组合物由含有羟基和羧基的聚合物和苯基一元或多元羧酸组成。在一些实施方式中，粘结剂组合物不包括交联剂。本申请的粘结剂组合物可在不包括附加交联剂或其他添加剂的情况下，实现交联聚合，形成立体网络结构。
负极极片
本申请的一个实施方式中提供一种负极极片，所述负极极片包括负极集流体和设置在所述负极集流体至少一个表面上的负极材料层，所述负极材料层包括负极活性材料和粘结剂组合物；所述粘结剂组合 物包括苯基一元或多元羧酸和含有羟基和羧基的聚合物；基于含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重量％；所述负极活性材料、苯基一元或多元羧酸和含有羟基和羧基的聚合物发生交联反应成键。
本申请的负极极片具有良好的综合性能：由于其中的负极活性材料与粘结剂组合物发生原位交联反应成键而形成刚柔适当的三维网络结构，从而能释放材料体积变化所产生的应力，具有改善的极片粘结，减轻的极片反弹，长期使用也能维持良好的极片结构；同时，本申请的负极极片还具有减轻的锂枝晶生长、较好的循环稳定性和较好的首周效率。
在一些实施方式中，基于含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.5重量％至3.0重量％，可选地0.5重量％至2.5重量％，进一步可选地1.0重量％至2.0重量％。进一步粘结剂组合物中含有羟基和羧基的聚合物与苯基一元或多元羧酸的含量关系，本申请的负极极片具有更好的综合性能：较低的极片反弹率，较小的内阻，良好的循环性能和较高的首周效率。
在一些实施方式中，基于所述负极材料层的总重量计，所述负极材料层包括1重量％至5重量％，可选地1.5重量％至4.0重量％，更可选地2.0重量％至3.5重量％的所述粘结剂组合物。当负极材料层包含上述含量范围的粘结剂组合物时，本申请负极极片具有进一步减轻的极片反弹，抑制的锂枝晶生长，较好的常温/高温循环稳定性和首周效率。
在一些实施方式中，所述苯基一元或多元羧酸选自苯基C 1-6羧酸或苯基C 1-6二羧酸中的至少一种，在每种情况下，所述苯基上的一个或多个氢原子任选地被选自羟基或C 1-6烷基的相同或不同的基团取代。在一些实施方式中，可选地，所述苯基一元或多元羧酸选自以下的至少一种：苯甲酸、苯乙酸、苯丙酸、对苯二甲酸、邻苯二甲酸、间苯二甲酸、对苯二乙酸、邻苯二乙酸、间苯二乙酸、对苯二丙酸、邻苯二丙酸、间苯二丙酸，在每种情况下，上述化合物的苯基上的一个或多个氢原子任选地被选自以下的相同或不同基团取代：甲基、乙 基、丙基、异丙基、丁基、异丁基和叔丁基。通过选择苯基一元或多元羧酸，能够进一步改善负极极片的极片反弹、内阻、首周效率和循环性能。
在一些实施方式中，所述含有羟基和羧基的聚合物选自以下物质中的至少一种：羧甲基纤维素、羧乙基纤维素、羧丙基纤维素、海藻酸、聚丙烯酸，或其盐。上述聚合物分子中具有丰富的羟基和羧基，粘结力好，并有利于在负极极片材料层中发生原位交联聚合，从而进一步改善极片综合性能。
在一些实施方式中，所述负极活性材料选自碳基负极活性材料、硅基负极活性材料或其组合。在一些实施方式中，所述负极活性材料是硅基负极活性材料。在一些实施方式中，所述负极活性材料是硅基负极活性材料和碳基负极活性材料的组合。可选地，所述碳基负极活性材料选自天然石墨、人造石墨、中间相碳纤维、中间相碳微球、软碳、硬碳中的至少一种。在一些实施方式中，可选地，所述硅基负极活性材料选自单质硅、硅的氧化物中的至少一种。在一些实施方式中，所述负极活性材料是碳基负极活性材料与硅基负极活性材料的组合。在具有上述负极活性材料的负极极片中包含本申请的粘结剂组合物是特别有利的，因为本申请的粘结剂组合物能够有助于缓解体积变化带来的不利影响，改善负极极片的能量密度和循环性能等。
在一些实施方式中，所述负极活性材料是表面羟基化的。
本申请的另一个实施方式中提供一种负极极片，所述负极极片通过以下步骤制备：
(1)提供负极浆料并将其施加于负极集流体的至少一个表面上，得到极片坯料，所述负极浆料包括负极活性材料和粘结剂组合物，所述粘结剂组合物包括苯基一元或多元羧酸和含有羟基和羧基的聚合物；并且基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重量％；和
(2)热处理所述极片坯料，使所述负极活性材料、苯基一元或多元羧酸和含有羟基和羧基的聚合物发生交联反应成键。
本申请的负极极片具有降低的极片反弹率，减轻的锂枝晶生长， 较好的循环稳定性和首周效率。
在一些实施方式中，基于含有羟基和羧基的聚合物的总重量计，所述苯基一元或多元羧酸的含量是0.5重量％至3.0重量％，可选地0.5重量％至2.5重量％，进一步可选地1.0重量％至2.0重量％。进一步控制粘结剂组合物中的苯基一元或多元羧酸与含有羟基和羧基的聚合物的含量关系，本申请的负极极片会具有更好的综合性能：较低的极片反弹率，较小的内阻，良好的循环性能和较高的首周效率。
在一些实施方式中，基于所述负极浆料的干重计，所述负极浆料包括1重量％至5重量％，可选地0.5重量％至3.0重量％的所述粘结剂组合物。当负极浆料包含上述含量范围的粘结剂组合物时，得到的本申请负极极片综合性能进一步改善：极片反弹减轻，锂枝晶生长被有效抑制，的常温/高温循环稳定性较好和首周效率较高。
以下详细描述负极集流体。作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，所述负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极材料层还任选地包括其他粘结剂。所述其他粘结剂可以是例如聚四氟乙烯(PTFE)。
在一些实施方式中，负极材料层还可选地包括导电剂。导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，负极材料层还可选地包括其他助剂，例如增稠剂等。
本申请的又一实施方式中提供一种制备负极极片的方法，包括以 下步骤：
(1)提供负极浆料并将其施加于负极集流体的至少一个表面上，得到极片坯料，所述负极浆料包括负极活性材料和粘结剂组合物，所述粘结剂组合物包括苯基一元或多元羧酸和含有羟基和羧基的聚合物，并且基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重量％；和
(2)热处理所述极片坯料，使所述负极活性材料、苯基一元或多元羧酸和含有羟基和羧基的聚合物发生交联反应成键。
通过上述方法，能够制备得到本申请的负极极片。其中，在热处理步骤中，本申请的粘结剂组合物发生原位交联聚合，在所得到的极片材料层中形成三维网络结构，从而使负极极片具有良好的综合性能：较低的极片反弹率，较小的内阻，良好的循环性能和较高的首周效率。
在一些实施方式中，所述苯基一元或多元羧酸选自苯基C 1-6羧酸或苯基C 1-6二羧酸中的至少一种，在每种情况下，所述苯基上的一个或多个氢原子任选地被选自羟基或C 1-6烷基的相同或不同基团取代。在一些实施方式中，可选地，所述苯基一元或多元羧酸选自以下的至少一种：苯甲酸、苯乙酸、苯丙酸、对苯二甲酸、邻苯二甲酸、间苯二甲酸、对苯二乙酸、邻苯二乙酸、间苯二乙酸、对苯二丙酸、邻苯二丙酸、间苯二丙酸，在每种情况下，上述化合物的苯基上的一个或多个氢原子任选地被选自以下的相同或不同基团取代：羟基、甲基、乙基、丙基、异丙基、丁基、异丁基和叔丁基。
在一些实施方式中，所述含有羟基和羧基的聚合物选自以下物质中的至少一种：羧甲基纤维素、羧乙基纤维素、羧丙基纤维素、海藻酸、聚丙烯酸，或其盐。
在一些实施方式中，基于含有羟基和羧基的聚合物的总重量计，所述苯基一元或多元羧酸的含量是0.5重量％至3.0重量％，可选地0.5重量％至2.5重量％，进一步可选地1.0重量％至2.0重量％。
在一些实施方式中，基于所述负极浆料的干重计，所述负极浆料包括1重量％至5重量％，可选地1.5重量％至4.0重量％，更可选地2.0重量％至3.5重量％的所述粘结剂组合物。
在一些实施方式中，所述热处理在至少60℃的温度下进行。在一些实施方式中，可选地，所述热处理在60℃-120℃，可选地在80-120℃的温度下进行。上述温度有利于本申请的粘结剂组合物发生原位交联聚合。
在一些实施方式中，所述热处理在至少60℃的温度下通过干燥进行。在极片的干燥步骤中，粘结剂组合物和负极活性材料即可发生交联聚合，而无需专门的交联聚合步骤。
在一些实施方式中，负极浆料如下制备：将所述负极活性材料、导电剂、本申请的粘结剂组合，以及任选地其他粘结剂和任选地其他组分分散于溶剂中。在一些实施方式中，所述溶剂是水，可选地是去离子水。
在一些实施方式中，通过涂覆将负极浆料施加在负极集流体上。
在一些实施方式中，本申请的方法在热处理步骤后，还包括冷压步骤。
二次电池、电池模块、电池包和用电装置
另外，以下适当参照附图对本申请的二次电池、电池模块、电池包和用电装置进行说明。
本申请的一个实施方式中，提供一种二次电池，包括本申请的粘结剂组合物、本申请的负极极片或通过本申请的方法制备得到的负极极片。
通常情况下，二次电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使离子通过。
在一些实施方式中，二次电池是锂离子二次电池。
负极极片已经在上文中详细描述，因此以下将详细描述正极极片、电解液和隔离膜。
[正极极片]
正极极片包括正极集流体以及设置在正极集流体至少一个表面 的正极膜层，所述正极膜层包括本申请第一方面的正极活性材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在一些实施方式中，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，正极活性材料可采用本领域公知的用于电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi 1/3Co 1/3Mn 1/3O 2(也可以简称为NCM 333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM 523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM 211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM 622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM 811)、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例， 所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
[电解质]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。
在一些实施方式中，所述电解质采用电解液。所述电解液包括电解质盐和溶剂。
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。
在一些实施方式中，溶剂可选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
在一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善 电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
[隔离膜]
在一些实施方式中，二次电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
在一些实施方式中，二次电池可包括外包装。该外包装可用于封装上述电极组件及电解质。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图4是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图5，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，二次电池可以组装成电池模块，电池模块所 含二次电池的数量可以为一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图6是作为一个示例的电池模块4。参照图6，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图7和图8是作为一个示例的电池包1。参照图7和图8，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等，但不限于此。
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。
图9是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。 该装置通常要求轻薄化，可以采用二次电池作为电源。
实施例
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
实施例1
制备部分
1.粘结剂组合物的制备
将对苯二甲酸(TPA)与羧甲基纤维素(CMC)在适量水中溶解混合，得到粘结剂组合物溶液。其中，基于CMC的重量计，对苯二甲酸的含量为0.5重量％(如表1所示)。并且，加水的量只需要使TPA和CMC能够溶解即可。
2.负极极片的制备
将纳米硅材料、石墨材料和导电碳黑sp干混，再加入上述粘结剂组合物溶液和水继续混合，使其中的纳米硅材料、石墨材料、粘结剂组合物(干重)和导电碳黑以质量比23.84:71.51:2.2:2.45，调节固含量，制成固含量为95.35％的负极浆料。将上述负极浆料均匀涂在铜箔上(双面涂布，单面重量为0.131g/1540.25mm 2)，在100℃的温度下干燥后，再经冷压、分切得到负极极片。
也即，在实施例1的极片中，基于极片材料层的总重量计，粘结剂组合物的含量为2.2重量％。
3.正极极片的制备
以甲基吡咯烷酮(NMP)为溶剂，将LiNi 0.8Co 0.1Mn 0.1O 2、碳纳米管CNT、粘结剂PVDF以质量比97:2:1混合，制成正极浆料(固含量为97.44％)。将正极浆料均匀涂在铝箔上(双面涂布，单面重量为0.131g/1540.25mm 2)，经充分干燥、冷压、分切后得到正极极片。
4.锂离子二次电池的制备
在碳酸亚乙酯(EC)/碳酸二乙酯(DEC)(室温下体积比1:1)的混合溶液加入LiPF 6得到浓度为1M的溶液作为电解液。以Celgard2300为隔膜(面积为53mm×45mm)，在低湿恒温房内用如上制备的正、负极极片(面积分别为51mm×43mm和50mm×45mm)，以“正极片-隔离膜-负极片”的顺序叠置、卷绕，再充入0.45g电解液，组装成锂离子二次电池。
测试部分
1.负极极片反弹率测试
用千分尺测量新鲜负极极片(并未经过循环测试)的厚度h 0。然后用该极片制备锂离子二次电池。
将新制锂离子二次电池以1/3C恒流充电至4.25V，再以4.25V恒定电压充电至电流为0.1C，此时电池为满充(电压窗口为2.5-4.25V)，然后将其拆解，取出满充的负极极片，用千分尺测量此时负极极片的厚度(h 1)，则极片反弹率＝(h 1/h 0-1)×100％；
2循环容量保持率测试
在25℃下，将新制锂离子二次电池以1/3C恒流充电至4.25V，再以4.25V恒定电压充电至电流为0.05C，搁置5min，再以1/3C放电至2.5V，测得容量记为初始容量C0。对上述同一个电池重复以上步骤，并同时记录循环第n次后电池的放电容量Cn，则n次循环(即，n圈(cls))后电池容量保持率Pn＝Cn/C0*100％。
表1中实施例1对应的电池容量保持率数据是在上述测试条件下循环100次之后测得的数据，即P100的值。
高温(在本申请中为45℃)循环保持率测试是在45℃下按照上述步骤进行。
3.首周效率测试
在25℃下，将新制锂离子二次电池以1/3C恒流充电至4.25V，再以4.25V恒定电压充电至电流为0.05C，测得充电初始容量C0，搁置5min，再以1/3C放电至2.5V，测得容量记为放电初始容量C1。电池首周效率P1＝C1/C0*100％。
4. 50％荷电状态(SOC)下的放电直流阻抗(DCR)测试
在25℃下，将新制锂离子二次电池以1/3C恒流充电至4.25V，再以4.25V恒定电压充电至电流为0.05C，测得充电初始容量C0，搁置5min，再以1/3C放电至2.5V，测得容量记为放电初始容量C1。
在25℃下，将上述锂离子二次电池以1/3C恒流充电至4.25V，再以4.25V恒定电压充电至电流为0.05C，再以1/3C恒流放电至0.5C1，此时为50％SOC。将此状态的二次电池搁置5min，再以4C放电30s，测得放电前后电压变化为ΔU，电流前后变化为ΔI，得到50％SOC下的放电DCR值＝ΔU/ΔI。
5、抑制锂枝晶生长测试——极片表面观察
将循环100圈的二次电池以1/3C的倍率放电至2.5V，然后将其拆解，取出负极极片用Tecnai G2 Spirit透射电子显微镜(TEM)进行扫描测试，对负极极片的表面形貌进行观测，以确定枝晶生长情况。
表1示出了其中的苯基一元或多元羧酸的种类和含量，以及极片和二次电池的各项性能数据。
图1示出了负极极片经循环100圈的极片表面形貌的透射电子显微镜(TEM)图。
实施例2-4和对比例1-3
实施例2-4和对比例1-3所采用的苯基一元或多元羧酸不同于实施例1，其余原料、制备方法和测试方法均与实施例1中相同。其中苯基一元或多元羧酸的种类和含量均示于表1。
表1
Figure PCTCN2022099471-appb-000001
Figure PCTCN2022099471-appb-000002
*苯基一元或多元酸的含量是基于含有羧基和羟基的聚合物的重量百分含量。
由表1可见，相较于对比例1-3(包含非苯基羧酸)，实施例1-4中的本申请的粘结剂组合物都表现出更好的抑制极片反弹和电性能。这可能是由于相较于包含脂族羧酸，包含苯基一元或多元羧酸的粘结剂组合物为极片带来更好的耐热性、耐化学性和机械强度，有利于改善容量保持率并控制极片反弹。
图2示出了对比例1的负极极片经循环100圈的极片表面形貌的TEM图。
实施例5-10和对比例4-5
实施例5-14和对比例4采用羧甲基纤维素和对苯二甲酸(TPA)按照实施例1中所述方法制备负极极片和二次电池，其与实施例1的不同之处在于羧甲基纤维素和对苯二甲酸的含量关系，具体示于表2。上述实施例和对比例中的极片和二次电池按照实施例1中所述的测试方法进行性能测试，相关数据示于表2。
表2：
Figure PCTCN2022099471-appb-000003
Figure PCTCN2022099471-appb-000004
由表2可见，相较于对比例中的负极极片，本申请的负极极片的综合性能更佳：反弹率较低，25℃/45℃的循环容量保持率良好，首周效率较高，极片DCR值较小。
图3为对比例4中的负极极片经循环100圈后极片表面形貌的TEM图。
比较图1-3中负极极片表面的锂枝晶形貌可见，图1中所示的包含本申请的粘结剂组合物的负极极片在循环100圈后其极片表面锂枝晶较少，而图2-3中所示的对比例极片表面的锂枝晶显著较多，这证明了本申请的粘结剂组合物和负极极片能够有效抑制负极极片表面的锂枝晶生长。
实施例11-19
实施例11-19采用羧甲基纤维素和对苯二甲酸(基于羧甲基纤维素的重量计，对苯二甲酸的含量为0.5重量％)按照实施例1中所述方法制备负极极片和二次电池。其中，与实施例1不同之处在于制备负极极片时，粘结剂组合物的加入量(干重)不同。上述实施例和对比例中的极片和二次电池按照实施例1中所述的测试方法进行性能测试。相关数据示于表3。
表3中，粘结剂组合物的含量是基于负极材料层总重量计的重量百分比。
表3：
Figure PCTCN2022099471-appb-000005
Figure PCTCN2022099471-appb-000006
由表3可见，本申请的粘结剂组合物具备良好综合性能：减轻的极片反弹，常温/高温的循环性能良好，首周效率较高，内阻较小。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (17)

  1. 一种粘结剂组合物，包括苯基一元或多元羧酸以及含有羟基和羧基的聚合物；基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重量％。
  2. 根据权利要求1所述的粘结剂组合物，其中基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.5重量％至3.0重量％，可选地0.5重量％至2.5重量％，进一步可选地1.0重量％至2.0重量％。
  3. 根据权利要求1或2所述的粘结剂组合物，其中所述苯基一元或多元羧酸选自苯基C 1-6羧酸或苯基C 1-6二羧酸中的至少一种，在每种情况下，所述苯基上的一个或多个氢原子任选地被选自C 1-6烷基或羟基的相同或不同的基团取代；
    可选地，所述苯基一元或多元羧酸选自以下的至少一种：苯甲酸、苯乙酸、苯丙酸、对苯二甲酸、邻苯二甲酸、间苯二甲酸、对苯二乙酸、邻苯二乙酸、间苯二乙酸、对苯二丙酸、邻苯二丙酸和间苯二丙酸；在每种情况下，上述化合物的苯基上的一个或多个氢原子任选地被选自以下的相同或不同基团取代：甲基、乙基、丙基、异丙基、丁基、异丁基、叔丁基和羟基。
  4. 根据权利要求1至3中任一项所述的粘结剂组合物，其中所述含有羟基和羧基的聚合物选自以下物质中的至少一种：羧甲基纤维素、羧乙基纤维素、羧丙基纤维素、海藻酸、聚丙烯酸，或其盐。
  5. 一种负极极片，所述负极极片包括负极集流体和设置在所述负极集流体至少一个表面上的负极材料层，所述负极材料层包括负极活性材料和粘结剂组合物；所述粘结剂组合物包括苯基一元或多元羧酸和含有羟基和羧基的聚合物，并且基于所述含有羟基和羧基的聚合 物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重量％；所述负极活性材料、所述苯基一元或多元羧酸和所述含有羟基和羧基的聚合物发生交联反应成键。
  6. 根据权利要求5所述的负极极片，其中基于含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.5重量％至3.0重量％，可选地1.0重量％至2.0重量％。
  7. 根据权利要求5或6中任一项所述的负极极片，其中基于所述负极材料层的总重量计，所述负极材料层包括1重量％至5重量％，可选地1.5重量％至4.0重量％，更可选地2.0重量％至3.5重量％的所述粘结剂组合物。
  8. 根据权利要求5至7中任一项所述的负极极片，其中所述苯基一元或多元羧酸选自苯基C 1-6羧酸或苯基C 1-6二羧酸中的至少一种，在每种情况下，所述苯基上的一个或多个氢原子任选地被选自C 1-6烷基或羟基的相同或不同的基团取代；
    可选地，所述苯基一元或多元羧酸选自以下的至少一种：苯甲酸、苯乙酸、苯丙酸、对苯二甲酸、邻苯二甲酸、间苯二甲酸、对苯二乙酸、邻苯二乙酸、间苯二乙酸、对苯二丙酸、邻苯二丙酸、间苯二丙酸，在每种情况下，上述化合物的苯基上的一个或多个氢原子任选地被选自以下的相同或不同基团取代：甲基、乙基、丙基、异丙基、丁基、异丁基和叔丁基。
  9. 根据权利要求5至8中任一项所述的负极极片，其中所述含有羟基和羧基的聚合物选自以下物质中的至少一种：羧甲基纤维素、羧乙基纤维素、羧丙基纤维素、海藻酸、聚丙烯酸，或其盐。
  10. 根据权利要求5至9中任一项所述的负极极片，其中所述负极活性材料选自碳基负极活性材料、硅基负极活性材料，或其组合；
    可选地，所述碳基负极活性材料选自天然石墨、人造石墨、中间相碳纤维、中间相碳微球、软碳、硬碳中的至少一种；
    可选地，所述硅基负极活性材料选自单质硅、硅的氧化物中的至少一种。
  11. 一种负极极片，所述负极极片通过以下步骤制备：
    (1)提供负极浆料并将其施加于负极集流体的至少一个表面上，得到极片坯料，所述负极浆料包括负极活性材料和粘结剂组合物，所述粘结剂组合物包括苯基一元或多元羧酸和含有羟基和羧基的聚合物，并且基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.1重量％至3.0重量％；和
    (2)热处理所述极片坯料，使所述负极活性材料、苯基一元或多元羧酸和含有羟基和羧基的聚合物发生交联反应成键。
  12. 根据权利要求11所述的负极极片，其中基于所述含有羟基和羧基的聚合物的重量计，所述苯基一元或多元羧酸的含量是0.5重量％至3.0重量％，可选地1.0重量％至2.0重量％。
  13. 根据权利要求11或12所述的负极极片，其中所述热处理在至少60℃，可选地在60℃-120℃的温度下通过干燥进行。
  14. 一种二次电池，包括权利要求1至4中任一项所述的粘结剂组合物或权利要求5至13中任一项所述的负极极片。
  15. 一种电池模块，包括权利要求14所述的二次电池。
  16. 一种电池包，包括权利要求15所述的电池模块。
  17. 一种用电装置，包括选自权利要求14所述的二次电池、权利要求15所述的电池模块或权利要求16所述的电池包中的至少一种。
PCT/CN2022/099471 2022-06-17 2022-06-17 粘结剂组合物及包括其的负极极片 WO2023240600A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/CN2022/099471 WO2023240600A1 (zh) 2022-06-17 2022-06-17 粘结剂组合物及包括其的负极极片
CN202280059931.1A CN117941105A (zh) 2022-06-17 2022-06-17 粘结剂组合物及包括其的负极极片

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2022/099471 WO2023240600A1 (zh) 2022-06-17 2022-06-17 粘结剂组合物及包括其的负极极片

Publications (1)

Publication Number Publication Date
WO2023240600A1 true WO2023240600A1 (zh) 2023-12-21

Family

ID=89192934

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/099471 WO2023240600A1 (zh) 2022-06-17 2022-06-17 粘结剂组合物及包括其的负极极片

Country Status (2)

Country Link
CN (1) CN117941105A (zh)
WO (1) WO2023240600A1 (zh)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005087202A1 (en) * 2004-02-10 2005-09-22 Ranbaxy Laboratories Limited Glucosamine polyacrylate inter-polymer complex and processes for their production
US20150303456A1 (en) * 2014-04-18 2015-10-22 Samsung Sdi Co., Ltd. Negative electrode composition, and negative electrode and lithium battery containing the same
JP2016058283A (ja) * 2014-09-10 2016-04-21 日産自動車株式会社 電気デバイス用負極およびその製造方法
CN106159271A (zh) * 2015-04-22 2016-11-23 北京有色金属研究总院 一种锂离子电池用原位交联聚合物粘结剂及其制备的电极
CN112563478A (zh) * 2020-12-10 2021-03-26 深圳中科瑞能实业有限公司 一种基于改性的合金型负极浆料及制备方法、二次电池

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005087202A1 (en) * 2004-02-10 2005-09-22 Ranbaxy Laboratories Limited Glucosamine polyacrylate inter-polymer complex and processes for their production
US20150303456A1 (en) * 2014-04-18 2015-10-22 Samsung Sdi Co., Ltd. Negative electrode composition, and negative electrode and lithium battery containing the same
JP2016058283A (ja) * 2014-09-10 2016-04-21 日産自動車株式会社 電気デバイス用負極およびその製造方法
CN106159271A (zh) * 2015-04-22 2016-11-23 北京有色金属研究总院 一种锂离子电池用原位交联聚合物粘结剂及其制备的电极
CN112563478A (zh) * 2020-12-10 2021-03-26 深圳中科瑞能实业有限公司 一种基于改性的合金型负极浆料及制备方法、二次电池

Also Published As

Publication number Publication date
CN117941105A (zh) 2024-04-26

Similar Documents

Publication Publication Date Title
WO2024011512A1 (zh) 负极极片、制备负极极片的方法、二次电池、电池模块、电池包和用电装置
WO2023082918A1 (zh) 锂离子电池、电池模块、电池包及用电装置
WO2024012166A1 (zh) 二次电池及用电装置
WO2023197807A1 (zh) 正极材料及其制备方法、复合正极材料、正极极片及二次电池
WO2023082924A1 (zh) 极片、锂离子电池、电池模块、电池包及用电装置
WO2023071807A1 (zh) 隔膜及其制备方法、二次电池、电池模块、电池包和用电装置
WO2023108352A1 (zh) 一种正极活性材料及其相关的极片、二次电池、电池模块、电池包和装置
WO2023137624A1 (zh) 二次电池、电池模块、电池包以及用电装置
WO2023141871A1 (zh) 碳纤维补锂膜、其制法、包含其的二次电池和用电装置
WO2023142024A1 (zh) 一种长寿命二次电池及电池模块、电池包和用电装置
WO2023087218A1 (zh) 负极极片及其制备方法、二次电池、电池模块、电池包和用电装置
WO2023060529A1 (zh) 锂离子电池
WO2023283960A1 (zh) 正极极片、二次电池及其制备方法与包含该二次电池的电池模块、电池包和用电装置
WO2023240600A1 (zh) 粘结剂组合物及包括其的负极极片
WO2024040504A1 (zh) 二次电池、其制备方法及包含其的用电装置
WO2023130210A1 (zh) 二次电池的补锂方法及充放电方法
WO2024011511A1 (zh) 正极浆料及其制备方法、正极极片、二次电池、电池模块、电池包及用电装置
WO2024040585A1 (zh) 补锂浆料、正极浆料、二次电池、二次电池的制备方法和用电装置
WO2023216241A1 (zh) 二次电池及其制备方法、电池模块、电池包和用电装置
WO2023130851A1 (zh) 一种硅负极材料以及包含其的二次电池、电池模块、电池包和用电装置
WO2024020841A1 (zh) 二次电池、电池模块、电池包和用电装置
WO2023240612A1 (zh) 负极极片、二次电池、电池模块、电池包和用电装置
WO2023061136A1 (zh) 一种极片及其制备方法
WO2024040472A1 (zh) 二次电池、电池模块、电池包和用电装置
WO2023202238A1 (zh) 负极极片、二次电池、电池模块、电池包及用电装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22946287

Country of ref document: EP

Kind code of ref document: A1