CN115832178A

CN115832178A - Composition containing metal-organic framework material, secondary battery, battery module, battery pack, and electric device

Info

Publication number: CN115832178A
Application number: CN202111395785.3A
Authority: CN
Inventors: 熊清云
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2021-11-23
Filing date: 2021-11-23
Publication date: 2023-03-21

Abstract

The present application relates to a composition containing a metal-organic framework material, a secondary battery, a battery module, a battery pack, and an electric device. The composition comprises a metal organic framework material and a binder; wherein the metal organic framework material comprises one or more combinations selected from HKUST-1, IRMOF, ZIF, MIL, uiO, PCP and PCN. In the present application, the composition can adsorb CO generated during the use of the secondary battery ₂ And CH ₄ And the like.

Description

Composition containing metal-organic framework material, secondary battery, battery module, battery pack, and electric device

Technical Field

The present application relates to a composition containing a metal-organic framework material, a secondary battery, a battery module, a battery pack, and an electric device.

Background

With the development of new energy automobiles and energy storage services, the market has higher and higher requirements on the service life of secondary batteries. Current methods for improving gassing and life of secondary batteries include the attachment of adsorbent materials inside the housing of the secondary battery. However, this method has a problem in that the process is complicated, and a groove needs to be added inside the secondary battery case, which reduces the energy density of the secondary battery. In addition, the pressing, rolling, or pressing of the adsorptive material and the case involves a risk of leakage, and is difficult to be practically applied to the industrial field, and the adhesion between the adsorptive material and the case of the secondary battery cannot be ensured, and the case may be likely to fall off in the practical case of the secondary battery. The prior art has the problems of complex process and high difficulty in industrial application, so the method for improving the service life of the secondary battery is still a problem to be solved urgently.

Disclosure of Invention

In order to solve the problems in the prior art, the composition containing the metal organic framework material is coated on the lug area of the current collector of the secondary battery, so that the internal short circuit of the secondary battery is reduced to the maximum extent, laser die cutting is facilitated, and CO generated in the using process of the secondary battery can be adsorbed ₂ And CH ₄ And the like.

According to a first aspect of the present application, there is provided a composition for coating a current collector tab region of a secondary battery, wherein the composition comprises a metal organic framework material and a binder; the metal organic framework material comprises one or more combination selected from HKUST-1, IRMOF, ZIF, MIL, uiO, PCP and PCN. In the application, the metal organic framework material has the advantages of light weight, high temperature resistance, good chemical stability, good insulating property, large specific surface area and super large adsorption capacity, and can adsorb CO generated in the using process of a secondary battery ₂ And CH ₄ And the like.

In an embodiment of the present application, the specific surface area of the metal-organic framework material layer is 600-6000m ² (ii) in terms of/g. In the application, the pore structure of the metal organic framework material is superior to that of the traditional microporous inorganic molecular sieve material in shape, specific surface area and adsorption performance, and the secondary battery current collector lug area (insulating layer) prepared from the metal organic framework material can adsorb gas (such as CO) with the weight percentage of up to 15 percent ₂ And CH ₄ Etc.), can better improve the gas generation problem in the use process of the secondary battery.

In embodiments of the present application, the binder comprises one or more of the following: polyvinylidene fluoride (PVDF), polyacrylic acid, polyimide, polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymers, tetrafluoroethylene-hexafluoropropylene copolymers, and fluoroacrylate resins. In an embodiment of the present application, the ratio of the metal-organic framework material to the binder is 9 to 7 by weight. In the present application, the adhesive bonding can conveniently apply the composition to the tab region of the secondary battery current collector, ensuring good adhesion of the insulating layer made of the composition containing the metal organic framework material, and reliable and practical industrialized manufacturing process.

In embodiments herein, the composition further comprises a solvent comprising one or more of the following: n-methylpyrrolidone (NMP), N-Dimethylformamides (DMF) and deionized water. In the present application, by using the above-mentioned suitable solvent, the industrial process of the composition of the present invention is reliable and practical.

According to a second aspect of the present application, there is provided the use of said composition for coating the current collector tab region of a secondary battery. By using the composition comprising the metal organic framework material, the secondary battery having the current collector tab region can have improved gas generation, thereby improving the service life of the secondary battery.

According to a third aspect of the present application, there is provided a method of coating a secondary battery current collector tab area, the method comprising:

(1) Mixing a metal-organic framework material, a binder, and optionally a solvent, providing a slurry comprising the metal-organic framework material, wherein the metal-organic framework material comprises a combination of one or more selected from the group consisting of HKUST-1, IRMOF, ZIF, MIL, uiO, PCP, and PCN;

(2) And coating the slurry on the lug area of the current collector of the secondary battery to form a metal organic framework material layer. In the application, the method has the advantages that the insulating layer which is not applied to the current collector electrode lug area is good in adhesion, reliable in industrial manufacturing process and high in practicability by adopting a proper adhesive and a proper coating technology.

In an embodiment of the present application, the method further comprises: (3) And coating a polymer layer which is air-tight and can be dissolved or dispersed in the electrolyte of the secondary battery on the metal organic framework material layer. In the present application, the polymer layer (also referred to as a barrier layer) that is gas-tight and soluble or dispersible in the electrolyte of the secondary battery can prevent the insulating layer of the current collector tab from adsorbing other gases during the manufacturing process of the secondary battery.

In an embodiment of the present application, the specific surface area of the metal-organic framework material layer is 600-6000m ² (ii)/g; the polymer layer is selected from the group consisting of Polystyrene (PS), polyamide, polyacrylonitrile, polyvinyl alcohol, polycarbonate, polyethylene vinyl acetate, and Oriented Polystyrene (OPS); the weight ratio of the metal-organic framework material to the binder is (9); and the solvent comprises one or more of: n-methylpyrrolidone (NMP), N-Dimethylformamides (DMF) and deionized water. In the application, the pore structure of the metal organic framework material is superior to that of the traditional microporous inorganic molecular sieve material in shape, specific surface area and adsorption performance, and the secondary battery current collector lug area (insulating layer) prepared from the metal organic framework material can adsorb gas (such as CO) with the weight percentage of up to 15 percent ₂ And CH ₄ Etc.), can better improve the gas generation problem in the use process of the secondary battery. Meanwhile, the adhesive bonding can be used for conveniently coating the composition on a tab area of a secondary battery current collector, and ensures that an insulating layer made of the composition containing the metal-organic framework material has good adhesion. Moreover, by using the appropriate solvent, the composition of the present invention can be reliably and practically used in an industrial process.

According to a fourth aspect of the present application, there is provided a composite coating for a secondary battery current collector tab area, characterized in that the composite coating comprises: a metal-organic framework material layer formed from the composition; and a polymer layer which is gas-tight and soluble or dispersible in the electrolyte of the secondary battery.

According to a fifth aspect of the present application, there is provided a current collector tab of a secondary battery, characterized in that the current collector tab comprises a polymer layer that is gas-tight and soluble or dispersible in the electrolyte of the secondary battery, and a metal-organic framework material layer formed from the composition.

According to a sixth aspect of the present application, there is provided a secondary battery characterized by comprising a current collector tab.

According to a seventh aspect of the present application, there is provided a battery module including the secondary battery described herein.

According to an eighth aspect of the present application, there is provided a battery pack including the secondary battery or the battery module described herein.

According to a ninth aspect of the present application, there is provided an electric device including the secondary battery, the battery module, or the battery pack described herein, wherein the secondary battery or the battery module or the battery pack functions as a power source of the electric device or an energy storage unit of the electric device.

Compared with the prior art, the composition containing the metal organic framework material can improve the short circuit safety problem of the secondary battery, optimize the die cutting of the tab, and absorb the generated CO in the using process of the secondary battery ₂ And CH ₄ And the gas is mixed, the gas production of the secondary battery is improved, and the service life of the secondary battery is prolonged.

These and other features and advantages will become apparent upon reading the following detailed description and upon reference to the accompanying drawings. It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of aspects as claimed.

Drawings

Fig. 1 is a flow chart of the present application for coating the current collector tab area of a secondary battery.

Fig. 2 is a schematic view of a secondary battery tab after die cutting manufactured in example 1 of the present application.

Fig. 3 is a schematic view of a secondary battery tab after die cutting manufactured by comparative example 1 of the present application.

Fig. 4 is a schematic view of an embodiment of the secondary battery of the present application.

Fig. 5 is an exploded view of the secondary battery shown in fig. 4.

Fig. 6 is a schematic view of an embodiment of a battery module according to the present application.

Fig. 7 is a schematic diagram of an embodiment of a battery pack according to the present application.

Fig. 8 is an exploded view of the battery pack shown in fig. 7.

Fig. 9 is a schematic diagram of an embodiment of an apparatus using the secondary battery of the present application as a power source.

Description of reference numerals:

1. battery pack

2. Upper box body

3. Lower box body

4. Battery module

5. Secondary battery

51. Shell body

52. Electrode assembly

53. Cover plate

Detailed Description

The present application is described in detail below with reference to the attached drawing figures, and features of the present application will become further apparent from the detailed description below.

As disclosed herein, a "range" is defined in terms of lower and upper limits, with a given range being defined by the selection of one lower limit and one upper limit that define the boundaries of the particular range. Ranges defined in this manner may or may not include endpoints and may be arbitrarily combined, i.e., 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, it is understood that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if the

minimum range values

1 and 2 are listed, and if the

maximum range values

3,4, and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise stated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0 to 5" indicates that all real numbers between "0 to 5" have been listed herein, and "0 to 5" is only a shorthand representation of the combination of these numbers. In addition, when a parameter is an integer of 2 or more, it is equivalent to disclose that the parameter is, for example, an integer of 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, or the like.

In the present application, all embodiments and preferred embodiments mentioned herein may be combined with each other to form new solutions, if not specifically stated. In the present application, all technical features mentioned herein as well as preferred features may be combined with each other to form new solutions, if not specified otherwise.

In the present application, the terms "include" and "comprise" as used herein mean open or closed unless otherwise specified. For example, the terms "comprising" and "comprises" may mean that other components not listed may also be included or included, or that only listed components may be included or included.

In the description herein, the term "or" is inclusive, unless otherwise specified. For example, the phrase "a or B" means "a, B, or both a and B. More specifically, either of the following conditions satisfies the condition "a or B": a is true (or present) and B is false (or not present); a is false (or not present) and B is true (or present); or both a and B are true (or present).

As used herein, the term "gas-tight" refers to a material that is gas-tight and gas-impermeable. For the polymer layer, the polymer layer can insulate the insulating layer of the current collector tab from gas, and prevent the insulating layer from adsorbing other gas in the manufacturing process of the secondary battery. The polymer layer is thus gas-impermeable, also called barrier layer, for insulating gases.

In the prior art, the secondary battery tabs are coated by ceramic materials to improve the safety performance, reduce the internal short circuit of the secondary battery to the maximum extent and facilitate laser die cutting. However, the secondary battery generates CO during use ₂ And CH ₄ And the like, which affect the interface and service life of the secondary battery. At present, the prior art mentions MOF-74-Ni, mg-MOF-74 and MOF-74-Zn metal organic framework Materials (MOFs). However, these three materials can adsorb CO generated during the use of the secondary battery well ₂ But to CH ₄ The adsorption ability of (b) is insufficient. Furthermore, the prior art adheres adsorptivelyThe method of adding the substance into the battery shell is too complex, the energy density of the secondary battery can be reduced by adding the groove into the shell, the leakage risk exists in the mode of pressing, rolling or stamping the adsorptive substance and the shell, the difficulty is high in the practical application in the industrial field, the cohesiveness of the adsorptive substance and the battery shell cannot be ensured, and the falling risk exists in the practical battery shell.

In the present application, the inventors have discovered unique metal-organic framework materials, including combinations of one or more selected from HKUST-1, IRMOF, ZIF, MIL, uiO, PCP, and PCN. The metal organic framework materials have the advantages of light weight, high temperature resistance, good chemical stability, good insulating property, large specific surface area and super large adsorption capacity, and can adsorb CO generated in the using process of a secondary battery ₂ And CH ₄ And the like.

In the present application, a composition for coating the current collector tab region of a secondary battery comprises a metal organic framework material and a binder; the metal organic framework material comprises one or more combination selected from HKUST-1, IRMOF, ZIF, MIL, uiO, PCP and PCN. In this context, HKUST-1 is also called metal organic framework compound-Cu-BTC, and generally has a particle size of 10-20 μm and a BET specific surface area of 1172m2/g or more. In some embodiments, the IRMOF includes IRMOF-6, MOF-5, MOF-200, MOF-177, and the like. In some embodiments, ZIFs include ZIF-67, ZIF-68, ZIF-69, ZIF-78, ZIF-8, ZIF-81, and the like). In some embodiments, MILs comprise MIL-101, MIL-53, and the like. In some embodiments, the UiO comprises UiO-66. In alternative embodiments, the metal organic framework material is HKUST-1, IRMOF-6, MOF-200, or PCN14. In the application, the metal organic framework material has the advantages of light weight, high temperature resistance, good chemical stability, good insulating property, large specific surface area and super large adsorption capacity, and can adsorb CO generated in the using process of a secondary battery ₂ And CH ₄ And the like.

In one embodiment of the present application, the specific surface area of the metal-organic framework material layer may be within a range of values inclusive of any two of the following: 600m ² /g、1000m ² /g、1500m ² /g、2000m ² /g、2500m ² /g、3000m ² /g、3500m ² /g、4000m ² /g、4500m ² /g、5000m ² /g、5500m ² /g、6000m ² (ii) in terms of/g. It is expressly intended that while the above values are listed in side by side, there is no intention that any two of the above-recited values be combined in any way as an end-point to achieve equivalent or similar performance. The same applies to the numerical ranges mentioned below. With respect to the preferred embodiments of the present application, the selection is made based only on the specific discussion below and the specific experimental data. In an alternative embodiment of the present application, the metal-organic framework material layer has a specific surface area of 600m ² /g-6000m ² (ii) in terms of/g. In the embodiments of the present application, the pore structure of the metal organic framework material is superior to that of the conventional microporous inorganic molecular sieve material in shape, specific surface area and adsorption performance, and the secondary battery current collector ear region (insulating layer) prepared from the material can adsorb up to 15wt% of gas (e.g., CO) ₂ And CH ₄ Etc.), can better improve the gas generation problem in the use process of the secondary battery.

In embodiments of the present application, the binder comprises one or more of the following: polyvinylidene fluoride (PVDF), polyacrylic acid, polyimide, polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymers, tetrafluoroethylene-hexafluoropropylene copolymers, and fluoroacrylate resins. In an alternative embodiment, the binder comprises polyvinylidene fluoride (PVDF).

In embodiments of the present application, the ratio of the metal-organic framework material to the binder may be within a range of values, by weight, inclusive of any two of the following: 1, 9. In the present application, the adhesive bonding can conveniently apply the composition to the tab region of the secondary battery current collector, ensuring good adhesion of the insulating layer made of the composition containing the metal organic framework material, and reliable and practical industrialized manufacturing process. In an alternative embodiment, the ratio of the metal-organic framework material to the binder is 83.

In embodiments herein, the composition further comprises a solvent comprising one or more of the following: n-methylpyrrolidone (NMP), N-Dimethylformamides (DMF) and deionized water. In the present application, by using the above-mentioned suitable solvent, the industrial process of the composition of the present invention is reliable and practical. In an alternative embodiment, the solvent is N-methylpyrrolidone.

In an embodiment of the present application, a method of coating a current collector tab area of a secondary battery includes: mixing a metal-organic framework material, a binder and optionally a solvent in a stirring device and dispersing using a high-speed disperser to provide a slurry comprising the metal-organic framework material, wherein the metal-organic framework material comprises a combination of one or more selected from the group consisting of HKUST-1, IRMOF, ZIF, MIL, uiO, PCP and PCN. In some embodiments, a slurry comprising a metal-organic framework material is vacuum filtered through a 150 mesh screen to provide a viscosity of the slurry in the range of 60 to 120 mPa-S ^-1 . In an alternative embodiment, the viscosity of the slurry is in the range of 80 to 110mPa · S ^-1 Or 90 to 100 mPas ^-1 。

In an embodiment of the present application, a method of coating a current collector tab area of a secondary battery includes: and coating the slurry on the lug area of the current collector of the secondary battery to form a metal organic framework material layer (also called an insulating layer). In some embodiments, the metal-organic framework material layer has a width of 2-10 millimeters (mm), 2-6 mm, 2-4mm, 4-10mm, 6-10mm, or 4-6mm. In some embodiments, the thickness of the layer of metal-organic framework material is 20-80 microns, 40-80 microns, 60-80 microns, 20-60 microns, 40-60 microns, or 20-40 microns.

In an embodiment of the present application, a method of coating a current collector tab area of a secondary battery includes: and coating a polymer layer which is air-tight and can be dissolved or dispersed in the electrolyte of the secondary battery on the metal organic framework material layer. In some embodiments, the polymer layer is selected from the group consisting of Polystyrene (PS), polyamide, polyacrylonitrile, polyvinyl alcohol, polycarbonate, polyethylene vinyl acetate, and Oriented Polystyrene (OPS). In some embodiments, the width of the polymer layer ensures complete or at least partial coverage of the metal-organic framework material layer, typically 2-10 mm, 2-6 mm, 2-4mm, 4-10mm, 6-10mm, or 4-6mm. In some embodiments, the polymer layer has a thickness of 50 to 150 microns, 50 to 120 microns, 50 to 80 microns, 80 to 150 microns, 80 to 120 microns, or 120 to 150 microns.

In the present application, the polymer layer (also referred to as a barrier layer) that is gas-tight and soluble or dispersible in the electrolyte of the secondary battery can prevent the insulating layer of the current collector tab from adsorbing other gases during the manufacturing process of the secondary battery. In the application, the pore structure of the metal organic framework material is superior to that of the traditional microporous inorganic molecular sieve material in shape, specific surface area and adsorption performance, and the secondary battery current collector lug area (insulating layer) prepared from the metal organic framework material can adsorb gas (such as CO) with the weight percentage of up to 15 percent ₂ And CH ₄ Etc.), can better improve the gas generation problem in the use process of the secondary battery. Meanwhile, the adhesive bonding can be conveniently applied to the tab area of the secondary battery current collector, and ensures good adhesion of the insulating layer made of the composition containing the metal organic framework material. Moreover, by using the above-mentioned suitable solvent, the composition of the present invention can be ensured to be industrially manufactured reliably and practically.

Hereinafter, the performance improvement of the present application due to the differential capacity design on two sides of the positive electrode plate is mainly characterized based on the secondary battery, especially based on the lithium ion secondary battery, but it needs to be particularly emphasized here that the present application can be used for any electric device comprising a carbon-based electrode, and the electric device can benefit from the design.

Coating method

In some embodiments of the present application, the method of coating the current collector tab area of a secondary battery is illustrated in fig. 1. Step P10 includes a method of preparing the metal-organic framework material, and the preparation method is not particularly limited. In the application, the metal organic framework material can be selected from one or more of HKUST-1, IRMOFs series, ZIFs series, MIL series, uiO series, PCP series, PCN series and the like. In alternative embodiments of the present application, the metal-organic framework material can be HKUST-1, IRMOF-6, MOF-200, and PCN14.

Taking the HKUST-1 metal-organic framework material as an example, in some specific embodiments, the preparation method of the metal-organic framework material comprises the following steps: under the action of ultrasonic waves, a copper salt (copper acetate monohydrate, 8.62 mmol) which provides metallic copper ions is dissolved in 24mL of a mixed solvent of deionized water, N-N Dimethylformamide (DMF) and ethanol (wherein the volume ratio of water, DMF and ethanol is 1. Mixing the two solutions, adding the mixture into a 100mL centrifuge tube, stirring for 10 minutes, adding triethanolamine (TEA, 1.0mL, 6.93mmol), uniformly stirring, and carrying out intermittent ultrasonic treatment for 30 minutes under 300W ultrasonic power (namely, stopping the ultrasonic treatment for 3 seconds after 2 seconds and circulating the ultrasonic treatment in sequence), wherein the reaction temperature is 20-50 ℃. After the obtained product is filtered, the product is replaced by water twice and DMF three times, and the product is soaked in a certain amount of DMF for 12 hours; suction filtration and three-time replacement with dichloromethane were carried out and the product was immersed in dichloromethane for 12 hours. And drying the sample obtained after suction filtration for 24 hours under vacuum to obtain the HKUST-1.

Step P10 comprises a method of preparing a composition (i.e. a slurry) comprising a metal-organic framework material, wherein the slurry comprises the metal-organic framework material, a binder and optionally a solvent. In some embodiments, the binder may be polyvinylidene fluoride, and the solvent may be N-methylpyrrolidone; and the ratio of metal-organic framework material to binder is 9 to 7, preferably 83.

In some embodiments, the slurry may be prepared by:

(1) Preparing glue solution:

weighing a binder, dissolving the binder in N-methyl pyrrolidone, wherein the weight of the binder is 7-30% of that of the solvent, and the binder is preferably 18%;

(2) Preparing slurry: adding metal organic framework material particles into the glue solution; the ratio of the metal-organic framework material particles to the binder is 9 to 7, preferably 83; and

(3) And (3) filtering: passing through a 150-mesh sieve, and performing vacuum filtration on the dispersed slurry to obtain final slurry; wherein the viscosity range of the slurry is 60-120 mPa.S ^-1 Preferably 80 to 110 mPas ^-1 More preferably 90 to 100 mPaS ^-1 。

Step P30 comprises the steps of coating the slurry containing the metal organic framework material on the ear area of the current collector of the lithium ion battery to form an insulating coating; the width of the insulating coating is 2-10 mm, and the thickness is 20-80 microns.

Step P40 comprises applying a barrier layer made of a polymer film that is impermeable to air (gas) and can be dissolved or dispersed by the electrolyte in the secondary battery, which may be selected from the group consisting of Polystyrene (PS), polyamide, polyacrylonitrile, polyvinyl alcohol, polycarbonate, polyethylene vinyl acetate and Oriented Polystyrene (OPS), on top of the insulating coating.

Tab of secondary battery

In the present application, the secondary battery current collector tab area is coated with the above slurry, and die-cut to form the tab area structure shown in fig. 2. As shown in fig. 2, a metal-organic framework material layer (also referred to as an insulating layer) 213a and a barrier layer 213b formed of a polymer film on the insulating layer 213a are coated between the current collector 212 and the pole piece active material 211. In fig. 3, a tab area configuration without the insulating and barrier layers of the present application is shown. The pole piece active 311 is in direct contact with the current collector 312. In the present application, the insulating layer 213a is coated on the tab region of the current collector, so that the powder falling or the internal short circuit possibly caused by the occurrence of burrs caused by the pole piece active material in the die cutting process can be prevented in the manufacturing process of the secondary battery. Moreover, the insulating layer 213a can play a role in isolation, so as to avoid physical short circuit between the positive electrode and the negative electrode caused by shrinkage of the secondary battery isolating membrane, and greatly improve the safety and reliability of the secondary battery cell.

Secondary battery

In one embodiment of the present application, there is provided a secondary battery which may be a lithium ion secondary battery, a potassium ion secondary battery, a sodium ion secondary battery, a lithium sulfur battery, or the like, and particularly preferably a lithium ion secondary battery. The secondary battery of the present application includes a positive electrode (pole piece), a negative electrode (pole piece), a separator, an electrolyte/liquid, and the like. In the process of charging and discharging the battery, active ions are embedded and separated back and forth between the positive pole piece and the negative pole piece. The electrolyte plays a role in conducting ions between the positive pole piece and the negative pole piece.

[ Positive electrode sheet ]

In the secondary battery of the present application, the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer (or referred to as a positive electrode active material layer) disposed on at least one surface of the positive electrode current collector and including a positive electrode active material. For example, the positive electrode current collector has two surfaces opposite to each other in the thickness direction thereof, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive electrode current collector. In the secondary battery of the present application, the positive electrode current collector may be a metal foil or a composite current collector, for example, the metal foil may be an aluminum foil, and 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 (aluminum, aluminum alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene PP, polyethylene terephthalate PET, polybutylene terephthalate PBT, polystyrene PS, polyethylene PE, and copolymers thereof, etc.).

In the application, the compaction density of the first positive electrode active material layer and the second positive electrode active material layer of the secondary battery is controlled, so that the ion transmission path can be reduced, the cycle life of the secondary battery is prolonged, and the condition that the particle of the active material is broken due to overhigh compaction density, the specific surface area (BET) is increased, and the secondary battery is deteriorated to a certain extent due to outlet side reaction is avoided. Generally, the first positive electrode active materialThe compacted density of the layer and the second positive electrode active material layer may be 2.0 to 3.6g/cm ³ . In one embodiment of the present application, the compacted densities of the first and second positive electrode active material layers may be within a range of values inclusive of any two of the following: 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5. In an alternative embodiment of the present application, the first and second positive electrode active material layers may have a compacted density of 2.3 to 3.5g/cm ³ 。

In the secondary battery of the present application, the positive electrode active material (substance) may employ a positive electrode active material for a secondary battery known in the art. For example, the positive electrode active material may include one or more of the following: olivine structured lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as a positive electrode active material of a secondary battery may be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of the lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (e.g., liCoO) ₂ ) Lithium nickel oxide (e.g., liNiO) ₂ ) Lithium manganese oxide (e.g., liMnO) ₂ 、LiMn ₂ O ₄ ) Lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., liNi) _1/3 Co _1/3 Mn _1/3 O ₂ (NCM333)、LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (NCM523)、LiNi _0.5 Co _0.25 Mn _0.25 O ₂ (NCM211)、LiNi _0.6 Co _0.2 Mn _0.2 O ₂ (NCM622)、LiNi _0.8 Co _0.1 Mn _0.1 O ₂ (NCM 811)), lithium nickel cobalt aluminum oxides (e.g., liNi-Co-Al oxides) _0.85 Co _0.15 Al _0.05 O ₂ ) And modified compounds thereof, and the like. Examples of olivine structured lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (e.g., liFePO) ₄ (LFP)), a composite material of lithium iron phosphate and carbon, and manganese phosphateLithium (e.g. LiMnPO) ₄ ) One or more of a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. In an embodiment of the present application, the second positive electrode active material and the third positive electrode active material are the same or different and are selected from lithium iron phosphate (LFP), lithium Manganate (LMO), lithium Nickel Cobalt Manganate (NCM), lithium Cobaltate (LCO), lithium Nickel Cobalt Aluminate (NCA), and an oxide containing active sodium ions, a polyanionic material, or a prussian blue-based material.

In some embodiments, the positive electrode film layer further optionally includes a binder. Non-limiting examples of binders that may be used in the positive electrode film layer may include one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin. In an embodiment of the present application, the first positive electrode active material layer and/or the second positive electrode active material layer each independently contains a binder selected from the group consisting of polyvinylidene fluoride, polyacrylic acid, polytetrafluoroethylene, polyimide, and a combination thereof.

In some embodiments, the positive electrode film layer may also optionally include a conductive agent. Examples of the conductive agent for the positive electrode film layer may include one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In an embodiment of the present application, the first positive electrode active material layer and/or the second positive electrode active material layer each independently contains a conductive agent of graphite, carbon black, acetylene black, graphene, carbon nanotubes, and a combination thereof.

In one embodiment of the present application, the positive electrode may be prepared by: dispersing the above components for preparing the positive electrode, such as the positive electrode active material, the conductive agent, the binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a uniform positive electrode slurry; and coating the positive electrode slurry on a positive electrode current collector, and drying, cold pressing and the like to obtain the positive electrode piece.

[ negative electrode sheet ]

The secondary battery comprises a negative pole piece, wherein the negative pole piece comprises a negative pole current collector and a negative pole film layer (or called as a negative pole active material layer) arranged on at least one surface of the negative pole current collector, and in the embodiment of the application, the first negative pole active material and the second negative pole active material are the same or different and respectively and independently contain natural graphite, artificial graphite, graphene, carbon nano tubes, soft carbon, hard carbon and a combination of two or more of the natural graphite, the artificial graphite, the graphene, the carbon nano tubes, the soft carbon and the hard carbon.

In an embodiment of the present application, the first and second anode active material layers may have a compacted density of 0.5 to 2.0g/cm ³ . In one embodiment of the present application, the compacted densities of the first and second anode active material layers may be within a range of values inclusive of any two of the following: 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0. In an alternative embodiment of the present application, the first and second positive electrode active material layers may have a compacted density of 1.0 to 1.8g/cm ³ 。

In one embodiment of the present application, the negative electrode film layer may further include a certain amount of other common negative electrode active materials, for example, one or more of natural graphite, other artificial graphite, soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate, in addition to the negative electrode active materials described above in the present application. The silicon-based material can be one or more selected from simple substance silicon, silicon oxide and silicon-carbon composite. The tin-based material can be one or more selected from simple substance tin, tin oxide compound and tin alloy.

In the secondary battery of the present application, the negative electrode membrane contains a negative electrode active material, and optionally a binder, an optional conductive agent, and other optional auxiliaries, and is usually formed by coating and drying a negative electrode slurry. The negative electrode slurry coating is generally formed by dispersing a negative electrode active material and optionally a conductive agent and a binder, etc. in a solvent and uniformly stirring. The solvent may be N-methylpyrrolidone (NMP) or deionized water.

As an example, the conductive agent may include one or more of superconducting carbon, carbon black (e.g., acetylene black, ketjen black), carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

As an example, the binder may include one or more of Styrene Butadiene Rubber (SBR), water-soluble unsaturated resin SR-1B, polyacrylic acid (PAA), sodium Polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium Alginate (SA), and carboxymethyl chitosan (CMCS). As an example, the binder may include one or more of Styrene Butadiene Rubber (SBR), polyvinyl alcohol (PVA), sodium Alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). Other optional auxiliaries are, for example, thickeners (e.g.sodium carboxymethylcellulose, CMC-Na), PTC thermistor materials, etc.

In addition, in the secondary battery of the present application, the negative electrode sheet does not exclude other additional functional layers than the negative electrode film layer. For example, in certain embodiments, the negative electrode sheet of the present application may further include a conductive primer layer (e.g., composed of a conductive agent and a binder) interposed between the negative electrode current collector and the first negative electrode film layer, disposed on the surface of the negative electrode current collector. In some other embodiments, the negative electrode sheet of the present application may further include a protective cover layer covering the surface of the second negative electrode film layer.

In the secondary battery of the present application, the negative electrode current collector may be a metal foil or a composite current collector, for example, the metal foil may be a foil made of copper foil, silver foil, iron foil, or an alloy of the above metals. 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, and may be formed by forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, etc.) on the polymer material base layer (e.g., a base layer made of polypropylene PP, polyethylene terephthalate PET, polybutylene terephthalate PBT, polystyrene PS, polyethylene PE, and copolymers thereof).

[ electrolyte ]

The electrolyte plays a role in conducting ions between the positive pole piece and the negative pole piece. The electrolyte may be selected from solid electrolytes and liquid electrolytes (i.e., electrolytes)At least one of (1). In some embodiments, the electrolyte is an electrolytic solution. The electrolyte includes an electrolyte salt and a solvent. In some embodiments, the electrolyte salt may be selected from LiPF ₆ (lithium hexafluorophosphate) and LiBF ₄ Lithium tetrafluoroborate (LiClO), liClO ₄ (lithium perchlorate) LiAsF ₆ (lithium hexafluoroarsenate), liFSI (lithium bis (fluorosulfonylimide), liTFSI (lithium bis (trifluoromethanesulfonylimide)), liTFS (lithium trifluoromethanesulfonate), liDFOB (lithium difluorooxalato borate), liBOB (lithium dioxaoxalato borate), liPO ₂ F ₂ One or more of (lithium difluorophosphate), liDFOP (lithium difluorooxalate phosphate) and LiTFOP (lithium tetrafluorooxalate phosphate). In one embodiment of the present application, the solvent may be selected from one or more of the following: ethylene Carbonate (EC), propylene Carbonate (PC), ethyl Methyl Carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl Propyl Carbonate (MPC), ethyl Propyl Carbonate (EPC), butylene Carbonate (BC), fluoroethylene carbonate (FEC), methyl Formate (MF), methyl Acetate (MA), ethyl Acetate (EA), propyl Acetate (PA), methyl Propionate (MP), ethyl Propionate (EP), propyl Propionate (PP), methyl Butyrate (MB), ethyl Butyrate (EB), 1, 4-butyrolactone (GBL), sulfolane (SF), dimethylsulfone (MSM), methylethylsulfone (EMS) and diethylsulfone (ESE). In one embodiment of the present application, the solvent is present in an amount of 60 to 99 wt.%, such as 65 to 95 wt.%, or 70 to 90 wt.%, or 75 to 89 wt.%, or 80 to 85 wt.%, based on the total weight of the electrolyte. In one embodiment herein, the electrolyte is present in an amount of 1 to 40 weight percent, such as 5 to 35 weight percent, or 10 to 30 weight percent, or 11 to 25 weight percent, or 15 to 20 weight percent, based on the total weight of the electrolyte.

In one embodiment of the present application, additives may be optionally included in the electrolyte. For example, the additives may include one or more of the following: the film forming additive for the negative electrode and the film forming additive for the positive electrode can also comprise additives capable of improving certain performances of the battery, such as additives for improving the overcharge performance of the battery, additives for improving the high-temperature performance of the battery, additives for improving the low-temperature performance of the battery and the like.

[ separator ]

In one embodiment of the present application, the secondary battery further includes a separation film, the separation film separates the anode side from the cathode side of the secondary battery, and provides selective permeation or blocking for different kinds, sizes and charges of materials in the system, for example, the separation film can insulate electrons, physically separate the anode and cathode active materials of the secondary battery, prevent internal short circuit and form an electric field in a certain direction, and enable ions in the battery to move between the anode and the cathode through the separation film. In one embodiment of the present application, the material used to prepare the separation film may include one or more 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. When the barrier film is a multilayer composite film, the materials of the layers may be the same or different. In an embodiment of the present application, the separator is selected from the group consisting of polyolefin-based separators, polyester separators, polyimide separators, polyamide separators, and cellulose separators.

In one embodiment of the present application, the positive electrode tab, the negative electrode tab and the separator may be manufactured into an electrode assembly/bare cell through a winding process or a lamination process.

In one embodiment of the present application, a secondary battery may include an exterior package, which may be used to enclose the electrode assembly and the electrolyte. In some embodiments, the outer package of the secondary battery may be a hard case, such as a hard plastic case, an aluminum case, a steel case, or the like. In other embodiments, the outer package of the secondary battery may be a pouch, for example, a pouch type pouch. The soft bag can be made of plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS) and the like.

The shape of the secondary battery of the present application may be cylindrical, square, or any other shape. Fig. 4 is a secondary battery 5 of a square structure as an example. Fig. 5 shows an exploded view of the secondary battery 5 of fig. 4, and the exterior package may include a case 51 and a cap plate 53, and the case 51 may include a bottom plate and side plates coupled to the bottom plate, which enclose a receiving cavity. The housing 51 has an opening communicating with the accommodating chamber, and a cover plate 53 can be provided to cover the opening to close the accommodating chamber. The positive electrode piece, the negative electrode piece and the isolating film can form an electrode assembly 52 through a winding process or a lamination process, the electrode assembly is packaged in the containing cavity, and the electrolyte is soaked in the electrode assembly 52. The secondary battery 5 may contain one or more electrode assemblies 52.

In one embodiment of the present application, several secondary batteries may be assembled together to constitute a battery module in which two or more secondary batteries are included, the specific number depending on the application of the battery module and the parameters of a single battery module.

Fig. 6 is a battery module 4 as an example. Referring to fig. 6, in the battery module 4, a plurality of secondary batteries 5 may be arranged in series along the longitudinal direction of the battery module 4. Of course, the arrangement may be in any other manner. The plurality of secondary batteries 5 may be further fixed by a fastener.

Alternatively, the battery module 4 may further include a case having an accommodation space in which the plurality of secondary batteries 5 are accommodated.

In one embodiment of the present application, two or more of the above-described battery modules may be assembled into a battery pack, and the number of battery modules included in the battery pack depends on the application of the battery pack and the parameters of the individual battery modules. The battery pack can include the battery box and set up a plurality of battery module in the battery box, and this battery box includes box and lower box, and the box can be covered and well match on the box down to the upper box, forms the enclosure space that is used for holding battery module. Two or more battery modules may be arranged in the battery case in a desired manner.

Fig. 7 and 8 are a battery pack 1 as an example. Referring to fig. 7 and 8, a battery pack 1 may include a battery case and a plurality of battery modules 4 disposed in the battery case. The battery box comprises an upper box body 2 and a lower box body 3, wherein the upper box body 2 is used for covering the lower box body 3 and forming a closed space for accommodating a battery module 4. A plurality of battery modules 4 may be arranged in any manner in the battery box.

Electric device

In one embodiment of the present application, the electric device of the present application includes at least one of the secondary battery, the battery module, or the battery pack of the present application, and the secondary battery, the battery module, or the battery pack may be used as a power source of the electric device and may also be used as an energy storage unit of the electric device. The electric devices include, but are not limited to, mobile digital devices (e.g., mobile phones, notebook computers, etc.), electric vehicles (e.g., 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, and the like.

Fig. 9 is an apparatus as an example. The device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the demand of the device for high power and high energy density, a battery pack or a battery module may be used.

As another example, the device may be a cell phone, tablet, laptop, etc. The device is generally required to be thin and light, and a secondary battery may be used as a power source.

Hereinafter, the effects of the secondary battery manufactured according to the embodiment of the present application on the performance of the electrochemical device are characterized based on specific examples, but it is particularly pointed out that the scope of protection of the present application is defined by the claims, not limited to the above specific embodiments.

Examples

Unless otherwise indicated, all starting materials used in the present invention are analytical grade and all water is deionized.

Example 1

In example 1, HKUST-1 was used as the metal-organic framework material. HKUST-1 is either commercially available or prepared in the laboratory. In this example, HKUST-1 was prepared as follows:

under the action of ultrasonic wave, 8.62mmol of copper acetate monohydrate is dissolved in 24mL of deionized water, and a mixed solution of N-N Dimethylformamide (DMF) and ethanolIn the preparation. Wherein the volume ratio of water, DMF and ethanol is 1. 1.00g of trimesic acid (4.76 mmol) was dissolved in 24mL of the above-mentioned mixed solvent in the same manner. The two solutions were mixed and added to a 100mL centrifuge tube, stirred for 10 minutes, and 1.0mL triethanolamine (TEA, 6.93 mmol) was added. After the mixture is uniformly stirred, intermittent ultrasound is carried out for 30 minutes under 300W ultrasound power (namely, the ultrasound is stopped for 3 seconds after 2 seconds and is circulated in sequence), and the reaction temperature is 20-50 ℃. After the reaction, the product was filtered with suction, replaced with water twice, replaced with DMF three times, and soaked in an amount of DMF for 12 hours. After that, suction filtration was performed, the mixture was replaced three times with dichloromethane, and it was immersed in dichloromethane for 12 hours. After suction filtration, the resulting product was dried under vacuum for 24 hours to obtain HKUST-1 used in the examples of the present application. The specific surface area of HKUST-1 was measured to be about 2400m ² /g。

18g of polyvinylidene fluoride was dissolved in 82g of N-methylpyrrolidone to give a dope. 82g of metal-organic framework material HKUST-1 was added to the above gum solution. After the stirring, the dispersion was carried out using a high-speed disperser. The dispersed mixture was vacuum filtered through a 150 mesh screen to obtain the final slurry. And (3) applying the slurry containing the metal organic framework material to the ear region of the current collector of the lithium ion battery to form an insulating coating. The insulating coating had a width of 8 mm and a thickness of 60 microns. Polystyrene (PS) was coated on the upper layer of the insulating coating layer to form a barrier layer having a thickness of 100 μm. After die cutting, a secondary battery current collector tab area structure as shown in fig. 2 is formed.

And (3) assembling the polar lug region structure shown in the figure 2 into a secondary lithium ion battery consisting of a shell, a positive pole piece, a negative pole piece, a separation film and electrolyte. Then, the secondary lithium ion battery was stored at 60 ℃ for 90 days.

The gas composition in the secondary battery cell was measured by GC-MS, and the internal pressure in the cell was measured by a pressure gauge. The results are shown in table 1 below.

Comparative example 1

Secondary lithium ion batteries (see fig. 3) were assembled and formed in the same manner as described in example 1, except that the insulating coating and barrier layer applied in example 1 were not included, and were also stored at 60 c for 90 days. Similarly, the gas composition in the secondary battery cell was measured by GC-MS, and the internal pressure in the cell was measured by a pressure gauge. The results are shown in table 1 below.

Table 1:

as can be seen from Table 1, after the secondary lithium ion battery of comparative example 1 was stored at 60 ℃ for 90 days, CO was added ₂ And CH ₄ The contents were 54.35% and 11.13%, respectively, which were mainly caused by the decomposition repair of the SEI film during storage.

Comparative example 2

In comparative example 2, MOF-74-Ni was used as the metal-organic framework material; the preparation method of the MOF-74-Ni comprises the following steps:

5mmol of nickel nitrate was dissolved in 150 mL of a mixed solvent of N, N-dimethylformamides, ethanol and water (50 mL each of N, N-Dimethylformamides (DMF), ethanol and water). 2.5mmol of 2, 5-dimethylterephthalic acid was dissolved therein and sonicated to form a homogeneous mixed solution. The mixed solution was transferred to a 200mL round bottom flask and connected to a condensing reflux apparatus to obtain a crude MOF-74-Ni sample after stirring and reaction. After standing for 4 hours, the supernatant was replaced with an absolute ethanol solution, and left to stand for 8 hours to remove DMF from the solution, filtered and dried at 100 ℃ for 6 hours or more, and degassed at 200 ℃ under vacuum for 300 minutes to obtain purified MOF-74-Ni in the form of powder.

18g of polyvinylidene fluoride was dissolved in 82g of N-methylpyrrolidone to give a dope. 82g of MOF-74-Ni, a metal-organic framework material, were added to the above-mentioned glue solution. After the stirring, the dispersion was carried out using a high-speed disperser. The dispersed mixture was vacuum filtered through a 150 mesh screen to obtain the final slurry. And (3) coating the slurry containing the metal organic framework material on the electrode lug area of the current collector of the lithium ion battery to form an insulating coating. The insulating coating had a width of 8 mm and a thickness of 60 microns. Polystyrene (PS) was coated on the upper layer of the insulating coating layer to form a barrier layer having a thickness of 100 μm. After die cutting, a secondary battery current collector tab area structure as shown in fig. 2 is formed.

The gas composition in the secondary battery cell was measured by GC-MS, and the internal pressure in the cell was measured by a pressure gauge. The results are shown in Table 2 below.

Table 2:

as can be seen from Table 2, the secondary battery having the insulating coating layer of HKUST-1, obtained in example 1 of the present application, had better CO ₂ And CH ₄ And (4) adsorption capacity.

Examples 2 to 7

Except that IRMOF-6 (IRMOF, specific surface area about 1700 m) was used separately ² /g), ZIF-67 (ZIF, specific surface area about 1500 m) ² Per g), MIL-101 (MIL, specific surface area about 3250m ² Per g), uiO-66 (UiO, specific surface area about 800m ² G), PCP (specific surface area about 1200 m) ² (PCN, specific surface area about 2600 m) and PCN14 (PCN) ² /g) as a metal-organic framework material, a secondary lithium ion battery (see FIG. 2) was assembled in the same manner as described in example 1 and stored at 60 ℃ for 90 days as well. Similarly, the gas composition in the secondary battery cell was measured by GC-MS, and the internal pressure in the cell was measured by a pressure gauge. The results are shown in Table 3 below.

Table 3:

the present application is not limited to the above embodiments. The above embodiments are merely examples, and embodiments having substantially the same configuration as the technical idea and exhibiting the same operation and effect within the technical scope of the present application are included in the technical scope of the present application. In addition, various modifications that can be conceived by those skilled in the art are applied to the embodiments and other embodiments are also included in the scope of the present application, in which some of the constituent elements in the embodiments are combined and constructed, without departing from the scope of the present application.

Claims

1. A composition for coating the tab region of a current collector of a secondary battery, characterized in that the composition comprises a metal organic framework material and a binder;

wherein the metal organic framework material comprises one or more combinations selected from HKUST-1, IRMOF, ZIF, MIL, uiO, PCP and PCN.

2. The composition as claimed in claim 1, wherein the metal-organic framework material layer has a specific surface area of 600-6000m ² /g。

3. The composition of claim 1 or 2, wherein the binder comprises one or more of: polyvinylidene fluoride (PVDF), polyacrylic acid, polyimide, polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymers, tetrafluoroethylene-hexafluoropropylene copolymers, and fluoroacrylate resins.

4. A composition according to any one of claims 1 to 3, characterized in that the ratio of the metal-organic framework material to the binder is from 9 to 7.

5. The composition of any one of claims 1 to 4, further comprising a solvent comprising one or more of: n-methylpyrrolidone (NMP), N-Dimethylformamides (DMF) and deionized water.

6. Use of the composition according to any one of claims 1 to 5 for coating the ear regions of current collectors of secondary batteries.

7. A method of coating a secondary battery current collector tab area, the method comprising:

(2) And coating the slurry on the lug area of the current collector of the secondary battery to form a metal organic framework material layer.

8. The method of claim 7, further comprising:

(3) And coating a polymer layer which is air-tight and can be dissolved or dispersed in the electrolyte of the secondary battery on the metal organic framework material layer.

9. The method according to claim 7 or 8, wherein the metal-organic framework material layer has a specific surface area of 600-6000m ² /g；

The polymer layer is selected from the group consisting of Polystyrene (PS), polyamide, polyacrylonitrile, polyvinyl alcohol, polycarbonate, polyethylene vinyl acetate, and Oriented Polystyrene (OPS);

the weight ratio of the metal-organic framework material to the binder is 9; and

the solvent includes one or more of: n-methylpyrrolidone (NMP), N-Dimethylformamides (DMF) and deionized water.

10. A composite coating for a secondary battery current collector tab area, the composite coating comprising:

a layer of a metal organic framework material formed from the composition of any one of claims 1-5; and

and the polymer layer is gas-tight and can be dissolved or dispersed in the electrolyte of the secondary battery, wherein the polymer layer covers the metal organic framework material layer to prevent the metal organic framework material layer from adsorbing gas in the manufacturing process of the secondary battery.

11. The method of claim 10, wherein the metal-organic framework material layer has a thickness of 20-80 microns.

12. The method of claim 10, wherein the polymer layer has a thickness of 50-150 microns.

13. A current collector tab for a secondary battery, comprising a gas-tight polymer layer soluble or dispersible in a secondary battery electrolyte, and a metal-organic framework material layer formed from the composition of any of claims 1-5.

14. A secondary battery, characterized in that the secondary battery comprises the current collector tab of claim 11.

15. A battery module characterized by comprising the secondary battery according to claim 12.

16. A battery pack characterized by comprising the secondary battery according to claim 12 or the battery module according to claim 13.

17. An electric device, characterized by comprising the secondary battery according to any one of claims 12, or the battery module according to claim 13, or the battery pack according to claim 14, the secondary battery or the battery module or the battery pack serving as a power source of the electric device or an energy storage unit of the electric device.