WO2023207319A1

WO2023207319A1 - Battery binder, preparation method therefor, and application thereof

Info

Publication number: WO2023207319A1
Application number: PCT/CN2023/079022
Authority: WO
Inventors: 岳敏; 周竹欣; 王路海; 刘林生; 钱超
Original assignee: 深圳市研一新材料有限责任公司
Priority date: 2022-04-25
Filing date: 2023-03-01
Publication date: 2023-11-02
Also published as: CN116995233A

Abstract

Disclosed are a battery binder, a preparation method therefor, and an application thereof. The battery binder comprises a block copolymer composed of a block A and a block B, wherein raw materials for preparation of the block A comprise an aromatic diisocyanate and an aromatic diamine, and raw materials for preparation of the block B comprise an aliphatic diisocyanate and an aliphatic diamine. The battery binder has excellent binding performance and flexibility, and can ensure that a prepared battery electrode sheet has excellent mechanical performance, so that a further prepared battery has excellent electrical performance; and the preparation method for the battery binder is simple and is mild in preparation conditions, and is thus suitable for large-scale industrialization.

Description

Binder for battery and preparation method and application thereof

Technical field

The embodiments of the present application relate to the technical field of adhesives, such as a battery adhesive and its preparation method and application.

Background technique

Lithium-ion battery binder is an inactive component in the battery. It accounts for a relatively small proportion in the lithium-ion battery. However, it connects active materials, conductive agents, current collectors and other materials into a whole, ensuring that the pole pieces have good mechanical properties. , processing performance and maintaining the integrity of the battery's conductive network during charging and discharging play a vital role.

Currently, the most widely used oil-soluble binder in lithium-ion batteries is polyvinylidene fluoride (PVDF). However, PVDF has a series of problems that are difficult to solve. For example, the monomers used to synthesize PVDF are fluorine-containing hydrocarbons, which can cause damage to the earth's ozone layer. Therefore, its production is strictly controlled, and PVDF has a large modulus. , will cause the electrode piece to be more brittle, and the active material will easily fall off or powder when used in large curvature bending applications. The bonding force of PVDF mainly comes from the interface effect of weak van der Waals forces, making it difficult to effectively maintain the electrode structure. If the electrode is intact, the PVDF will be prone to degradation or other side reactions during the charge and discharge cycle and high-temperature operation, causing the electrode to collapse. Therefore, PVDF has been unable to adapt to the binder needs of today's rapidly developing new energy technologies.

CN105514488A discloses a lithium ion battery binder and a lithium ion battery containing the binder, with a number average molecular weight of 500,000 to 1.2 million; the binder can greatly improve the flexibility of the positive electrode sheet and avoid Problems such as processing and battery performance caused by excessive brittleness of the pole pieces are beneficial to increasing the compaction density and battery energy density. Through copolymerization modification, acrylate and acrylic acid structures are introduced into the chain structure of PVDF, thereby improving the flexibility of the pole piece. However, the main structural unit of this binder is still polyvinylidene fluoride, which still cannot fundamentally solve the defects of PVDF itself.

CN112186189A discloses a binder for high-nickel ternary material positive electrode sheets. The binder is polyurethane fiber. The polyurethane fiber is composed of alternating soft segments and hard segments. Block copolymers. Compared with traditional PVDF, the binder provided by this application can be thinly and evenly coated on the surface of high-nickel ternary materials. On the one hand, it effectively avoids side reactions between high-nickel materials and electrolytes during charging and discharging. At the same time, the stability of the cathode-electrolyte interface (CEI) is improved, ensuring the circulation of the high-nickel ternary system. performance and safety; on the other hand, the binder also helps the conductive agent to be distributed more evenly in the electrode, thereby improving the overall conductivity of the battery to a greater extent, thereby improving the cycle performance of the battery and solving the problem of high nickel ternary Material batteries have problems with cycle performance and safety due to increased nickel content. However, the binder provided in this application is extremely water-absorbent, which requires high processing requirements for the cathode slurry. The preparation method is complex and the conditions are harsh. There are also problems of high raw material and production costs.

CN113773419A discloses a mussel bionic polymer and its preparation method, positive electrode binder and secondary battery. The mussel biomimetic polymer provided in this application has a dopamine structure and carboxyl groups, so it has strong adhesion to the metal current collector and the cathode active material. When used as a cathode binder, it can improve the resulting cathode material, cathode and Cycle performance, rate performance and conductive properties of secondary batteries. However, the hydroxyl group in the dopamine structure has poor electrochemical stability and is prone to electrochemical reactions to produce gas, making it difficult to adapt to high-voltage battery systems. Moreover, dopamine is expensive and difficult to apply industrially.

Therefore, developing a battery adhesive with both excellent bonding performance and flexibility is an urgent technical problem in this field.

Contents of the invention

The following is an overview of the topics described in detail in this article. This summary is not intended to limit the scope of the claims.

The embodiments of the present application provide a battery adhesive and its preparation method and application; the battery adhesive includes a block copolymer composed of block A and block B; the raw materials for preparing block A It includes aromatic diisocyanate and aromatic diamine; the raw materials for preparing block B include aliphatic diisocyanate and aliphatic diamine. The battery adhesive containing the block copolymer has both strong bonding strength and flexibility, so that the battery pole piece made by using the adhesive has excellent mechanical properties, thereby ensuring that the battery The pole pieces still have integrity after repeated charge and discharge, which increases the energy density of the battery pole pieces, thereby improving the battery life and safety.

In a first aspect, embodiments of the present application provide a battery adhesive, which battery adhesive includes a block copolymer composed of block A and block B;

The raw materials for preparing block A include aromatic diisocyanate and aromatic diamine;

The raw materials for preparing block B include aliphatic diisocyanate and aliphatic diamine.

The battery binder provided by this application includes a block copolymer composed of block A and block B; wherein, the block A is a rigid block, and the preparation raw materials include aromatic diisocyanate and aromatic diamine. , The block A can provide the toughness required by the binder, maintain the mechanical strength required by the binder, and also help improve the binder's tolerance to the electrolyte and ensure the integrity of the binder; The block B is a flexible block, and its preparation raw materials include aliphatic diisocyanate and aliphatic diamine. The block B can provide the flexibility required by the adhesive and improve the wetting ability of the adhesive to the substrate. , thereby improving the bonding force between the binder and the substrate, and at the same time giving the binder a certain swelling property of the electrolyte, increasing the rate of lithium ion transmission, and thus helping to reduce the impedance of the pole piece. Therefore, the battery adhesive provided by this application including block A and block B has both strong bonding strength and flexibility, while ensuring that the produced battery pole piece has high mechanical properties. , it can also maintain the structural integrity of the battery pole pieces after cyclic charging and discharging, thereby greatly increasing the energy density of the battery, improving the battery life and safety.

Preferably, the molar ratio of block A and block B is 1:(0.4~4), such as 1:0.8, 1:1.2, 1:1.6, 1:2, 1:2.4, 1:2.8, 1 :3.2 or 1:3.6, etc., more preferably 1:(1-2.5).

As a preferred technical solution of the present application, when the molar ratio of block A and block B is 1: (0.4-4), especially when the molar ratio is 1: (1-2.5), the obtained battery adhesive can be The flexibility of the binder and its bonding ability to the substrate are further improved, thereby further improving the electrical performance of the battery prepared from the battery binder.

Preferably, the molar percentage of aromatic diisocyanate in the raw materials for preparing block A is 30 to 49 mol%, such as 32 mol%, 34 mol%, 36 mol%, 38 mol%, 40 mol%, 42 mol%, 44 mol%, 46 mol%. % or 48mol%, etc.

Preferably, the molar percentage of aromatic diamines in the raw materials for preparing block A is 51 to 70 mol%, such as 52 mol%, 54 mol%, 56 mol%, 58 mol%, 60 mol%, 62 mol%, 64 mol%, 66mol% or 68mol%, etc.

Preferably, the molar percentage of aliphatic diisocyanate in the raw materials for preparing block B is 51 to 70 mol%, such as 52 mol%, 54 mol%, 56 mol%, 58 mol%, 60 mol%, 62 mol%, 64 mol%, 66 mol%. % or 68mol%, etc.

Preferably, the molar percentage of aliphatic diamine in the raw materials for preparing block B is 30 to 49 mol%, such as 32 mol%, 34 mol%, 36 mol%, 38 mol%, 40 mol%, 42 mol%, 44 mol%, 46mol% or 48mol%, etc.

Preferably, the aromatic diisocyanate includes 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, xylylene diisocyanate, dimethyldiphenyl diisocyanate, terephthalene diisocyanate, 1,5 - Any one or at least two of naphthalene diisocyanate or 3,3-dichlorobiphenyl-4,4-diisocyanate combination.

Preferably, the aromatic diamine includes p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, Benzophenone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobiphenyl, 4,4'-diaminodiphenylmethane, 2, 2-Bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis(trifluoromethyl)diaminobiphenyl or 5-amino-2-(4-aminophenyl)benzo Any one or a combination of at least two imidazoles.

Preferably, the block A is prepared by the following method, which method includes reacting aromatic diisocyanate and aromatic diamine in a solvent to obtain the block A.

Preferably, the solvent includes N-methylpyrrolidone.

Preferably, the reaction time is 60 to 360 min, such as 80 min, 120 min, 160 min, 200 min, 240 min, 280 min, 320 min or 340 min, etc.

Preferably, the reaction temperature is 50-70°C, such as 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C or 68°C, etc.

Preferably, the method specifically includes the following steps:

(A1) Dissolve aromatic diisocyanate in a solvent to obtain an aromatic diisocyanate solution; dissolve aromatic diamine in a solvent to obtain an aromatic diamine solution;

(A2) Add the aromatic diisocyanate solution in step (A1) to the aromatic diamine solution in step (A1) and react to obtain the block A.

Preferably, the mass percentage of aromatic diisocyanate in the aromatic diisocyanate solution in step (A1) is 10 to 40%, such as 13%, 16%, 19%, 22%, 25%, 28%, 31%, 34% or 37% etc.

Preferably, the mass percentage of the aromatic diamine in the aromatic diamine solution described in step (A1) is 10 to 40%, such as 13%, 16%, 19%, 22%, 25%, 28% , 31%, 34% or 37%, etc.

Preferably, the adding time in step (A2) is 30 to 120 min, such as 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min or 110 min, etc.

Preferably, the aliphatic diisocyanate includes any one of hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate or lysine diisocyanate. or a combination of at least two.

Preferably, the aliphatic diamine includes any one or at least of aliphatic carbon chain diamine, ether diamine, double-terminated amino polyamide or double-terminated amino polybutadiene-acrylonitrile copolymer. A combination of both.

Preferably, the aliphatic carbon chain diamine includes 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine. Diamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine, 1,18-octadecane Diamine, 1,36-trihexadecanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 3,3- Dimethyl-1,6-hexanediamine, 2,2-dimethyl-1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4, 4-Trimethyl-1,6-hexanediamine, 2,4-diethyl-1,6-hexanediamine, 2,2-dimethyl-1,7-heptanediamine, 2,3- Dimethyl-1,7-heptanediamine, 2,4-dimethyl-1,7-heptanediamine, 2,5-dimethyl-1,7-heptanediamine, 2-methyl-1 ,8-octanediamine, 3-methyl-1,8-octanediamine, 4-methyl-1,8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1 ,4-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine, 3,4-dimethyl-1,8-octanediamine, 4,5 -Dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 3,3-dimethyl-1,8-octanediamine, 4,4-diamine Any one or a combination of at least two of methyl-1,8-octanediamine or 5-methyl-1,9-nonanediamine.

Preferably, the ether-based diamine includes bis(2-aminoethyl) ether, 3,6-dioxa-1,8-octanediamine, 4,7-dioxa-1,10-decane Diamine, 4,7-dioxa-2,9-decanediamine, 4,9-dioxa-1,12-dodecanediamine, 5,8-dioxa-3,10-decanediamine Any one or at least of dialkyldiamine, 4,7,10-trioxa-1,13-tridecanediamine, bis(3-aminopropyl)polytetrahydrofuran or polyoxyalkylenediamine A combination of both.

In this application, there is no particular limitation on the specific type of polyoxyalkylene diamine. Generally, the commercialized polyoxyalkylene diamine from Huntsman Company can be selected. D230、 D400、 D2000、 D4000、 XTJ511, XTJ523, XTJ536, XTJ542, XTJ559, XTJ568, XTJ569, ED600、 ED900、 ED2003, BASF’s Polyetheramine D230, Polyetheramine D400, Polyetheramine D2000, Nitroil’s PC DA250, PC DA400,PC DA650 or PC Any one of DA2000 or a combination of at least two.

Preferably, the double-terminated amino polyamide includes double-terminated amino polyamide 6, double-terminated amino polyamide 11, double-terminated amino polyamide 12, double-terminated amino polyamide 66, double-terminated amino polyamide 610, double-terminated amino polyamide Amide 612, double-terminated amino polyamide 1010, double-terminated amino polyamide 1011, double-terminated amino polyamide 1012, double-terminated amino polyamide 1013, double-terminated amino polyamide 1111, double-terminated amino polyamide 1112, double-terminated amino polyamide 1113. Any one or a combination of at least two of double-terminated amino polyamide 1212, double-terminated amino polyamide 1213, double-terminated amino polyamide 1313 or double-terminated amino polyamide 1414.

Preferably, the number of carbon atoms in the main chain of the aliphatic diamine is greater than 10, such as 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, etc.

As a preferred technical solution in this application, an aliphatic diamine containing more than 10 carbon atoms in the main chain is preferred in this application, so that block B can have better flexibility.

Preferably, the block B is prepared by the following method, which method includes reacting an aliphatic diisocyanate and an aliphatic diamine in a solvent to obtain the block B.

Preferably, the solvent includes N-methylpyrrolidone.

Preferably, the method specifically includes the following steps:

(B1) Dissolve aliphatic diisocyanate in a solvent to obtain an aliphatic diisocyanate solution; dissolve aliphatic diamine in a solvent to obtain an aliphatic diamine solution;

(B2) Add the aliphatic diisocyanate solution in step (B1) to the aliphatic diamine solution in step (B1) to react to obtain the block B.

Preferably, the mass percentage of aliphatic diisocyanate in the aliphatic diisocyanate solution described in step (B1) is 10 to 40%, such as 13%, 16%, 19%, 22%, 25%, 28%, 31%, 34% or 37% etc.

Preferably, the mass percentage of the aliphatic diamine in the aliphatic diamine solution in step (B1) is 10 to 40%, such as 13%, 16%, 19%, 22%, 25%, 28%. %, 31%, 34% or 37%, etc.

Preferably, the adding time in step (B2) is 30 to 60 min, such as 33 min, 36 min, 39 min, 42 min, 45 min, 48 min, 51 min, 54 min, 57 min or 60 min, etc.

Preferably, the viscosity of the block copolymer is 100 to 100000mPa·s, such as 500mPa·s, 1000mPa·s, 3000mPa·s, 6000mPa·s, 9000mPa·s, 10000mPa·s, 30000mPa·s, 60000mPa·s Or 90000mPa·s, etc., and more preferably 1000 to 10000mPa·s.

As the preferred technical solution of this application, a battery binder containing a block copolymer with a viscosity of 1,000 to 100,000 mPa·s can effectively improve the processing performance and coating appearance of the slurry. On the one hand, if the viscosity of the block copolymer is low, it will lead to insufficient suspension performance, which will cause the slurry to settle, reduce the peeling strength of the pole piece, and cause the active material layer in the pole piece to collapse due to insufficient cohesion. Powder loss; on the other hand, if the viscosity of the block copolymer is high, it will cause difficulty in processing and coating of the slurry, resulting in separation of the slurry. It is difficult to disperse, causing pitting, scratches or particles to appear on the surface of the active material layer of the pole piece.

Preferably, the glass transition temperature of the block copolymer is -20 to 160°C, such as 0°C, 20°C, 40°C, 60°C, 80°C, 100°C, 120°C or 140°C, and more preferably 40～120℃.

It should be noted that the “viscosity” of the above-mentioned block copolymer refers to the viscosity of the block copolymer with a mass concentration of 10% measured in N-methylpyrrolidone at 25±0.01°C.

As the preferred technical solution of this application, choosing a block copolymer with a glass transition temperature of -20 to 160°C is beneficial to making the battery binder have better bonding performance and better electrolyte resistance; on the one hand, if The glass transition temperature of the block copolymer is too low, which will lead to insufficient mechanical properties of the battery binder, making it difficult to maintain the integrity of the overall structure of the pole piece. At the same time, it will also cause the pole piece's electrolyte resistance to decrease, which will be harmful to the battery. The long cycle performance is unfavorable; on the other hand, if the glass transition temperature of the block copolymer is too high, the battery binder will be too hard and brittle, further causing the pole piece to easily break during processing. Failure will also cause the peeling strength of the pole piece to drop significantly, causing the active material layer of the pole piece to fall off due to insufficient cohesion.

Preferably, the elastic modulus of the block copolymer is 500-4000MPa, such as 1000MPa, 1500MPa, 2000MPa, 2500MPa, 3000MPa or 3500MPa, etc., more preferably 800-3000MPa, even more preferably 1200-2500MPa.

As the preferred technical solution of this application, selecting a block copolymer with an elastic modulus of 500 to 4000 MPa is beneficial to obtaining a battery binder with better flexibility. On the one hand, if the elastic modulus of the block copolymer is too low, the mechanical properties of the battery binder will be insufficient, making it difficult to maintain the integrity of the overall structure of the pole piece; on the other hand, if the block copolymer has If the elastic modulus is too high, the battery adhesive will be too hard and brittle, and the pole pieces will easily break and fail during the processing of the pole pieces.

Preferably, the battery adhesive further includes a binding substance and/or a conductive substance.

Preferably, based on the total weight of the battery adhesive being 100 parts, the content of the adhesive material is 1 to 49 parts by weight, such as 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight or 45 parts by weight, etc.

Preferably, the bonding substance includes polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride copolymer, polytetrafluoroethylene copolymer, polyimide, polyetherimide, polyamideimide. amine, polyesterimide, polycarbonateimide, polyureaimide, styrene-butadiene rubber, polyacrylonitrile, polyacrylic acid, polyacrylate, polyacrylic acid-polyacrylonitrile copolymer or polyacrylate-polymer Any one or a combination of at least two acrylonitrile copolymers.

Preferably, the bonding substance includes any one or a combination of at least two of polyvinylidene fluoride, polyimide, polyamideimide, polyacrylic acid or styrene-butadiene rubber.

Preferably, based on the total weight of the battery binder being 100 parts, the content of the conductive substance is 1 to 49 parts by weight, such as 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight. parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight or 45 parts by weight, etc.

Preferably, the conductive substance includes any one or a combination of at least two of conductive carbon black, conductive graphite, modified conductive graphite, metal particles, Ketjen black, carbon nanotubes, carbon fibers, graphene or conductive polymers. .

In a second aspect, embodiments of the present application provide a method for preparing a battery adhesive as described in the first aspect. The preparation method includes the following steps:

(1) Mix block A and block B and react to obtain an intermediate product;

(2) Add a chain extender to the intermediate product obtained in step (1) for reaction, and then add an end-capping agent for reaction to obtain the battery binder.

The preparation method of battery binder provided by this application is obtained through step-by-step polymerization reaction. The overall preparation method is simple, the conditions are mild, and it is suitable for large-scale industrial production.

Preferably, the mixing described in step (1) is performed by adding block A to block B.

Preferably, the adding time is 60 to 360 min, such as 100 min, 140 min, 180 min, 220 min, 260 min, 300 min or 340 min, etc.

Specifically, in step (1) of the preparation method provided by this application, the solution containing block A (N-methylpyrrolidone solution of block A) can be added to the solution containing block B (N-methylpyrrolidone solution of block A) within 60 to 360 minutes. N-methylpyrrolidone solution of block B) to obtain a mixed solution; controlling the adding time within 60 to 360 minutes will make the final battery binder have the best comprehensive performance; on the one hand, if the adding time If the addition time is too short, the reaction will be too violent and the final binder will deteriorate; on the other hand, if the addition time is too long, the reaction process will be slow and the production efficiency will decrease.

Preferably, the reaction time in step (1) is 60 to 360 min, such as 100 min, 140 min, 180 min, 220 min, 260 min, 300 min or 340 min, etc.

As the preferred technical solution of this application, the reaction time in step (1) is 60 to 360 minutes. If the reaction time is too short, it will easily lead to insufficient conversion rate of the reaction unit, resulting in a decrease in the performance of the final battery binder.

Preferably, the reaction temperature in step (1) is 60-90°C, such as 63°C, 66°C, 69°C, 72℃, 75℃, 78℃, 81℃, 84℃ or 87℃, etc.

As a preferred technical solution of the present application, if the reaction temperature in step (1) is 60-90°C, the final battery binder will have the best overall performance. On the one hand, when the reaction temperature is lower than 60°C, the reaction process will be slow and the production efficiency will decrease; on the other hand, when the reaction temperature is higher than 90°C, the reaction will be too violent and the battery binder will deteriorate. ; When the reaction time of the stage is shorter than the range described in this application, it is easy to cause insufficient conversion rate of the reaction unit and decrease in binder performance.

Preferably, the added amount of the chain extender in step (2) is 0.2-2% of the total mass of block A and block B, such as 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4% , 1.6% or 1.8%, etc.

Preferably, the chain extender in step (2) is an aliphatic diamine.

Preferably, the temperature at which the chain extender is added for reaction in step (2) is 60-90°C, such as 63°C, 66°C, 69°C, 72°C, 75°C, 78°C, 81°C, 84°C or 87°C wait.

Preferably, the reaction time for adding the chain extender in step (2) is 30 to 120 min, such as 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min, etc.

Preferably, the amount of the end-capping agent added in step (2) is 0.1 to 1% of the total mass of block A and block B, such as 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7% , 0.8% or 0.9%, etc.

Preferably, the capping agent in step (2) includes any one or a combination of at least two of methylamine, ethylamine, propylamine, dimethylamine, diethylamine, aniline, diphenylamine or p-aminobenzoic acid.

Preferably, the time for adding the end-capping agent to carry out the reaction in step (2) is 30 to 120 min, such as 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min or 110 min, etc.

Preferably, the temperature at which the end-capping agent is added for reaction in step (2) is 20-40°C, such as 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C or 38°C wait.

Preferably, before adding the capping agent in step (2), there is also a step of adding N-methylpyrrolidone for dilution.

As a preferred technical solution, the preparation method includes the following steps:

(1) Add the solution containing block A to the solution containing block B within 60 to 360 minutes, and react at 60 to 90°C for 60 to 360 minutes to obtain an intermediate product;

(2) Add a chain extender to the intermediate product obtained in step (1) and react at 60 to 90°C for 30 to 120 minutes. Add N-methylpyrrolidone to dilute, cool to 25 to 35°C, and then add an end-capping agent. React for 30 to 120 minutes to obtain the battery binder;

In a third aspect, embodiments of the present application provide a battery pole piece, which includes the battery adhesive as described in the first aspect.

Preferably, the battery electrode piece is a positive electrode piece or a negative electrode piece.

It should be noted that in actual applications, the battery adhesive provided in this application can also be applied to the battery positive electrode material, the edge of the positive electrode, the bottom of the positive electrode, the material of the negative electrode, the edge of the negative electrode, the bottom of the negative electrode, and the separator.

Moreover, when the battery binder provided in this application is applied to the positive electrode sheet and the negative electrode sheet of the battery, there is no particular limitation on the type of active material selected in the positive electrode sheet or the negative electrode sheet, and there is no particular limitation on the particle size of the active material. limited. The cathode active material used may include, but is not limited to, lithium iron phosphorus oxide, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium iron oxide, lithium nickel manganese oxide, and lithium cobalt nickel oxide. , lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide and their composites, any one or more combinations thereof; as for the negative active material used, but not limited to carbon/silicon materials, metals and One or more metal oxides; the carbon/silicon material, for example, natural graphite, artificial graphite, amorphous carbon, diamond-like carbon, carbon nanotubes, carbon/silicon hybrid materials, silicon oxide, silicon Any one or a combination of more; the metal can be, but is not limited to, one or two of lithium, aluminum, tin, silver, zinc, calcium, barium, mercury, platinum, technetium, bismuth, and indium. More than one metal alloy; the metal oxide can be, but is not limited to, one or more of aluminum oxide, tin oxide, indium oxide, zinc oxide, and lithium oxide.

In a fourth aspect, embodiments of the present application provide a lithium-ion battery, which includes the battery pole piece as described in the third aspect.

Compared with related technologies, the embodiments of the present application have the following beneficial effects:

(1) The battery binder provided by the embodiments of the present application includes a block copolymer composed of block A and block B. The raw materials for preparing block A include aromatic diisocyanate and aromatic diamine. , the raw materials for preparing block B include aliphatic diisocyanate and aliphatic diamine. The block A is a rigid block containing a strong polar group, and the block B is a flexible block B. The battery binder provided by this application includes a block composed of block A and block B. The copolymer, therefore, combines the advantages of the above-mentioned block A and block B, and has excellent flexibility and bonding properties. When applied to the battery pole piece, the battery pole piece can have excellent mechanical properties, thereby making it contain The battery with the battery pole piece has excellent electrical properties. Specifically, the peeling strength of the positive electrode sheet obtained by using the battery adhesive provided by this application is 9-36N/m, and the internal resistance of the further prepared soft-pack battery is 294-870mΩ after 100 cycles. The final capacity retention rate is 94.8~99.4%.

(2) The block copolymer contained in the battery binder provided in the embodiments of the present application can be obtained through step-by-step polymerization. The overall preparation method is simple, the conditions are mild, and it is suitable for large-scale industrialization; and the prepared adhesive The binder can also improve the dispersion of the electrode slurry, which improves the processing problems that easily occur during the coating process with small particle size materials. It can also improve the relationship between the binder and the polymer, and between the polymer and the active material. , the bonding force between polymer and conductive agent and between polymer and current collector has important research value.

Other aspects will become apparent after reading and understanding the detailed description.

Detailed ways

The technical solutions of the present application will be further described below through specific implementations. Those skilled in the art should understand that the embodiments are only to help understand the present application and should not be regarded as specific limitations of the present application.

Example 1

A binder for batteries, which is a block copolymer formed by block A and block B with a molar ratio of 5:5;

The preparation method of the block copolymer includes the following steps:

(1) Synthesis of block A: Dissolve 105g (42mol%) 4,4'-diphenylmethane diisocyanate in 245g N-methylpyrrolidone to form an A1 solution with a mass content of 30%; dissolve 62.7g (58mol%) m-phenylenediamine was dissolved in 146g N-methylpyrrolidone to form an A2 solution with a mass content of 30%; then the A1 solution was added to the A2 solution at a constant speed within 60 minutes, and under stirring conditions, the mixture was Maintain the temperature of the reaction solution at 60°C and continue the reaction for 300 minutes to form a block A solution;

(2) Synthesis of block B: Dissolve 97.6g (58mol%) hexamethylene diisocyanate in 228g N-methylpyrrolidone to form a B1 solution with a mass content of 30%; dissolve 72.4g (42mol%) 1,10-decanediamine was dissolved in 169g N-methylpyrrolidone to form a B2 solution with a mass content of 30%; then the B1 solution was added to the B2 solution at a uniform speed within 40 minutes to stir and mix the reaction. The temperature of the mixed reaction solution Maintain the reaction at 60°C for 180 minutes to form a block B solution;

(3) Synthesis of block copolymer: Add the block A solution obtained in step (1) to the block B solution obtained in step (2) at a constant speed within 180 minutes, stir and mix, and maintain the temperature of the mixed reaction solution at 70°C. Continue the reaction for 240 minutes to form an intermediate with a molar ratio of block A to block B of 5:5; then add 3.38g (accounting for 1% of the total mass of block A and block B) to the intermediate. 1,6-hexanediamine is included Chain reaction for 60 minutes, then add 2291g N-methylpyrrolidone for dilution, lower the temperature of the mixed reaction solution to 30°C, add 1.02g (mass content: 0.3%) propylamine end-capping agent, react for 60 minutes, and obtain a solid content of 10 % block copolymer.

Example 2

The preparation method of the block copolymer includes the following steps:

(1) Synthesis of block A: Dissolve 105g (42mol%) 4,4'-diphenylmethane diisocyanate in 245g N-methylpyrrolidone to form an A1 solution with a mass content of 30%; dissolve 115g ( 58mol%) of 4,4'-diaminodiphenylmethane was dissolved in 268g N-methylpyrrolidone to form an A2 solution with a mass content of 30%; then the A1 solution was added to the A2 solution at a constant speed within 60 minutes, stirring Under the conditions, maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 300 minutes to form a block A solution;

(2) Synthesis of block B: Dissolve 97.6g (58mol%) hexamethylene diisocyanate in 228g N-methylpyrrolidone to form a B1 solution with a mass content of 30%; dissolve 168g (42mol%) Ether diamine D400 was dissolved in 392g N-methylpyrrolidone to form a B2 solution with a mass content of 30%; then the B1 solution was added to the B2 solution at a constant speed within 60 minutes to stir and mix the reaction. The temperature of the mixed reaction solution was maintained at 50°C and the reaction continued for 270 minutes. , forming block B solution;

(3) Synthesis of block copolymer: Add the block A solution obtained in step (1) to the block B solution obtained in step (2) at a constant speed within 180 minutes, stir and mix, and maintain the temperature of the mixed reaction solution at 70°C. Continue the reaction for 240 minutes to form an intermediate with a molar ratio of block A to block B of 5:5, and then add 9.71g (accounting for 2% of the total mass of block A and block B) to the intermediate. 1,12-Dodecanediamine was subjected to a bracketing chain reaction for 60 minutes, and 3352g of N-methylpyrrolidone was added for dilution; after the temperature of the mixed reaction solution was lowered to 30°C, 2.97g (mass content: 0.6%) of aniline was added. terminal agent and reacted for 60 minutes to obtain a block copolymer with a solid content of 10%.

Example 3

The preparation method of the block copolymer includes the following steps:

(1) Synthesis of block A: Dissolve 85.3g (49mol%) of toluene diisocyanate in 128g N-methylpyrrolidone to form an A1 solution with a mass content of 40%; dissolve 126.6g (51mol%) of 4,4'-diaminodiphenyl sulfone was dissolved in 1139.7g N-methylpyrrolidone to form an A2 solution with a mass content of 10%; then the A1 solution was added to the A2 solution at a constant speed within 60 minutes, and under stirring conditions, Maintain the temperature of the mixed reaction solution at 50°C and continue the reaction for 360 minutes to form a block A solution;

(2) Synthesis of block B: Dissolve 117.8g (53mol%) isophorone diisocyanate in 176.7g N-methylpyrrolidone to form a B1 solution with a mass content of 40%; dissolve 752g (47mol%) The double-terminated amino polybutadiene-acrylonitrile copolymer (from Noveon, USA, model 1300×16) was dissolved in 1128g N-methylpyrrolidone to form a B2 solution with a mass content of 40%. Then add the B1 solution to the B2 solution at a constant speed within 60 minutes, stir and mix the reaction, maintain the temperature of the mixed reaction solution at 70°C and continue the reaction for 60 minutes to form a block B solution;

(3) Synthesis of block copolymer: Add the block A solution obtained in step (1) to the block B solution obtained in step (2) at a uniform speed within 270 minutes, stir and mix the reaction; maintain the temperature of the mixed reaction solution at 80 Continue the reaction for 360 minutes at ℃ to form an intermediate with a molar ratio of block A to block B of 5:5, and then add 2.16g (accounting for 0.2% of the total mass of block A and block B) to the intermediate. The bis(2-aminoethyl) ether was subjected to a bracketing chain reaction for 30 minutes, and 7293g of N-methylpyrrolidone was added for dilution; after the temperature of the mixed reaction solution was lowered to 30°C, 10.8g (mass content: 1%) of N-methylpyrrolidone was added. Aminobenzoic acid end-capping agent, react for 120 minutes to obtain a block copolymer with a solid content of 10%.

Example 4

The preparation method of the block copolymer includes the following steps:

(1) Synthesis of block A: 56.5g (30mol%) xylylene diisocyanate was dissolved in 508.1g N-methylpyrrolidone to form an A1 solution with a mass content of 10%; 140.2g (70mol %) of 4,4'-diaminodiphenyl ether was dissolved in 210.3g N-methylpyrrolidone to form an A2 solution with a mass content of 40%; then the A1 solution was added to the A2 solution at a uniform speed within 30 minutes, stirring Under the conditions, maintain the temperature of the mixed reaction solution at 70°C and continue the reaction for 60 minutes to form a block A solution;

(2) Synthesis of block B: Dissolve 183.6g (70mol%) dicyclohexylmethane diisocyanate in 734.6g N-methylpyrrolidone to form a B1 solution with a mass content of 20%; dissolve 480g (30mol%) The double-terminated amino polybutadiene-acrylonitrile copolymer (Noveon, USA, model 1300×16) was dissolved in 720g N-methylpyrrolidone to form a B2 solution with a mass content of 40%. Then add the B1 solution to the B2 solution at a constant speed within 60 minutes, stir and mix the reaction, and maintain the temperature of the mixed reaction solution at Continue the reaction at 60°C for 240 minutes to form a block B solution;

(3) Synthesis of block copolymer: Add the block A solution obtained in step (1) to the block B solution obtained in step (2) at a constant speed within 120 minutes, stir and mix the reaction; maintain the temperature of the mixed reaction solution at 70 Continue the reaction for 300 minutes at ℃ to form an intermediate with a molar ratio of block A to block B of 5:5, and then add 1.72g (accounting for 0.2% of the total mass of block A and block B) bis(2-amino) Ethyl) ether was subjected to a chain reaction for 120 minutes, and 5593g N-methylpyrrolidone was added for dilution; after the temperature of the mixed reaction solution was lowered to 30°C, 0.86g (mass content: 0.1%) of diethylamine end-capping agent was added. After reacting for 120 minutes, a block copolymer with a solid content of 10% was obtained.

Example 5

A binder for batteries, which is a block copolymer formed by block A and block B with a molar ratio of 2:8;

The preparation method of the block copolymer includes the following steps:

(1) Synthesis of block A: Dissolve 49g (49mol%) 4,4'-diphenylmethane diisocyanate in 114g N-methylpyrrolidone to form an A1 solution with a mass content of 30%; dissolve 22.1g (51mol%) m-phenylenediamine was dissolved in 51.5g N-methylpyrrolidone to form an A2 solution with a mass content of 30%; then the A1 solution was added to the A2 solution at a constant speed within 60 minutes, and under stirring conditions, Maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 300 minutes to form a block A solution;

(2) Synthesis of block B: Dissolve 137.2g (51mol%) hexamethylene diisocyanate in 320.2g N-methylpyrrolidone to form a B1 solution with a mass content of 30%; dissolve 135.1g (49mol% ) of 1,10-decanediamine was dissolved in 315.2g N-methylpyrrolidone to form a B2 solution with a mass content of 30%. Then add the B1 solution to the B2 solution at a constant speed within 40 minutes, stir and mix the reaction, maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 180 minutes to form a block B solution;

(3) Synthesis of block copolymer: Add the block A solution obtained in step (1) to the block B solution obtained in step (2) at a uniform speed within 180 minutes, stir and mix the reaction; maintain the temperature of the mixed reaction solution at 70 Continue the reaction for 240 minutes at ℃ to form an intermediate with a molar ratio of block A to block B of 2:8, and then add 3.43g (accounting for 1% of the total mass of block A and block B) of 1,6-hexane The diamine was subjected to a bracketing chain reaction for 60 minutes, and 2330g N-methylpyrrolidone was added for dilution; after the temperature of the mixed reaction solution was lowered to 30°C, 1.04g (mass content: 0.3%) of propylamine end-capping agent was added, and the reaction was carried out for 60 minutes to obtain Block copolymer with 10% solids content.

Example 6

A binder for batteries, which is a block copolymer formed by block A and block B with a molar ratio of 7:3;

The preparation method of the block copolymer includes the following steps:

(1) Synthesis of block A: Dissolve 171.7g (49mol%) of 4,4'-diphenylmethane diisocyanate in 401g of N-methylpyrrolidone to form an A1 solution with a mass content of 30%; dissolve 77.2 g (51mol%) of m-phenylenediamine was dissolved in 180g N-methylpyrrolidone to form an A2 solution with a mass content of 30%; then the A1 solution was added to the A2 solution at a constant speed within 60 minutes, and under stirring conditions, Maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 300 minutes to form a block A solution;

(2) Synthesis of block B: Dissolve 51.5g (51mol%) hexamethylene diisocyanate in 120g N-methylpyrrolidone to form a B1 solution with a mass content of 30%; dissolve 50.7g (49mol%) 1,10-decanediamine was dissolved in 118.2g N-methylpyrrolidone to form a B2 solution with a mass content of 30%. Then add the B1 solution to the B2 solution at a constant speed within 40 minutes, stir and mix the reaction, maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 180 minutes to form a block B solution;

(3) Synthesis of block copolymer: Add the block A solution obtained in step (1) to the block B solution obtained in step (2) at a uniform speed within 180 minutes, stir and mix the reaction; maintain the temperature of the mixed reaction solution at 70 Continue the reaction for 240 minutes at ℃ to form an intermediate with a molar ratio of block A to block B of 7:3, and then add 3.51g (accounting for 1% of the total mass of block A and block B) of 1,6-hexane The diamine was subjected to a bracketing chain reaction for 60 minutes, and 2381g N-methylpyrrolidone was added for dilution; after the temperature of the mixed reaction solution was lowered to 30°C, 1.06g (mass content: 0.3%) of propylamine end-capping agent was added, and the reaction was carried out for 60 minutes to obtain Block copolymer with 10% solids content.

Example 7

A binder for batteries, which is composed of 90 parts by weight of block copolymer and 10 parts by weight of polyamide-imide;

Wherein, the block copolymer is the block copolymer obtained in Example 1;

The preparation method of polyamideimide is prepared with reference to patent CN113571704A.

Example 8

A binder for batteries, which is a block copolymer formed by block A and block B with a molar ratio of 9:1;

The preparation method of the block copolymer includes the following steps:

(1) Synthesis of block A: 189g (42mol%) of 4,4'-diphenylmethane diisocyanate Dissolve in 441g N-methylpyrrolidone to form an A1 solution with a mass content of 30%; dissolve 113g (58mol%) m-phenylenediamine in 263g N-methylpyrrolidone to form an A2 solution with a mass content of 30% ; Then add the A1 solution to the A2 solution at a constant speed within 60 minutes. Under stirring conditions, maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 300 minutes to form a block A solution;

(2) Synthesis of block B: Dissolve 19.5g (58mol%) hexamethylene diisocyanate in 45.5g N-methylpyrrolidone to form a B1 solution with a mass content of 30%; dissolve 14.5g (42mol% ) of 1,10-decanediamine was dissolved in 33.8g N-methylpyrrolidone to form a B2 solution with a mass content of 30%. Then add the B1 solution to the B2 solution at a constant speed within 40 minutes, stir and mix the reaction, maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 180 minutes to form a block B solution;

(3) Synthesis of block copolymer: Add the block A solution obtained in step (1) to the block B solution obtained in step (2) at a uniform speed within 180 minutes, stir and mix the reaction; maintain the temperature of the mixed reaction solution at 70 Continue the reaction for 240 minutes at ℃ to form an intermediate with a molar ratio of block A to block B of 9:1, and then add 3.36g (accounting for 1% of the total mass of block A and block B) of 1,6-hexane The diamine was subjected to a bracketing chain reaction for 60 minutes, and 2280g N-methylpyrrolidone was added for dilution; after the temperature of the mixed reaction solution was lowered to 30°C, 1.02g (mass content: 0.3%) of propylamine end-capping agent was added, and the reaction was carried out for 60 minutes to obtain Block copolymer with 10% solids content.

Example 9

A binder for batteries, which is a block copolymer formed by block A and block B with a molar ratio of 1:5;

The preparation method of the block copolymer includes the following steps:

(1) Synthesis of block A: Dissolve 24.5g (49mol%) of 4,4'-diphenylmethane diisocyanate in 57.2g of N-methylpyrrolidone to form an A1 solution with a mass content of 30%; 11.0g (51mol%) m-phenylenediamine was dissolved in 25.7g N-methylpyrrolidone to form an A2 solution with a mass content of 30%; then the A1 solution was added to the A2 solution at a constant speed within 60 minutes, under stirring conditions , maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 300 minutes to form a block A solution;

(2) Synthesis of block B: Dissolve 85.8g (51mol%) hexamethylene diisocyanate in 200g N-methylpyrrolidone to form a B1 solution with a mass content of 30%; dissolve 84.4g (49mol%) 1,10-decanediamine was dissolved in 197g N-methylpyrrolidone to form a B2 solution with a mass content of 30%. Then add the B1 solution to the B2 solution at a constant speed within 40 minutes, stir and mix the reaction, maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 180 minutes to form a block B solution;

(3) Synthesis of block copolymer: Add the block A solution obtained in step (1) to the block B solution obtained in step (2) at a uniform speed within 180 minutes, stir and mix the reaction; maintain the temperature of the mixed reaction solution at 70 Continue the reaction for 240 minutes at ℃ to form an intermediate with a molar ratio of block A to block B of 1:5, and then add 2.06g (accounting for 1% of the total mass of block A and block B) of 1,6-hexane The diamine was subjected to a bracketing chain reaction for 60 minutes, and 1396g N-methylpyrrolidone was added for dilution; after the temperature of the mixed reaction solution was lowered to 30°C, 0.62g (mass content: 0.3%) of propylamine end-capping agent was added, and the reaction was carried out for 60 minutes to obtain Block copolymer with 10% solids content.

Example 10

The preparation method of the block copolymer includes the following steps:

(1) Synthesis of block A: Dissolve 49.0g (49mol%) of 4,4'-diphenylmethane diisocyanate in 114g of N-methylpyrrolidone to form an A1 solution with a mass content of 30%; dissolve 83.7 g (51mol%) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was dissolved in 195g N-methylpyrrolidone to form an A2 solution with a mass content of 30%; then the A1 solution was dissolved in Add it to the A2 solution at a constant speed within 60 minutes. Under stirring conditions, maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 300 minutes to form a block A solution;

(2) Synthesis of block B: Dissolve 137g (51mol%) hexamethylene diisocyanate in 320g N-methylpyrrolidone to form a B1 solution with a mass content of 30%; dissolve 1254g (49mol%) diisocyanate Amino-terminated polybutadiene-acrylonitrile copolymer (Noveon, USA, model 1300×16) was dissolved in 2927g N-methylpyrrolidone to form a B2 solution with a mass content of 30%. Then add the B1 solution to the B2 solution at a constant speed within 40 minutes, stir and mix the reaction, maintain the temperature of the mixed reaction solution at 60°C and continue the reaction for 180 minutes to form a block B solution;

(3) Synthesis of block copolymer: Add the block A solution obtained in step (1) to the block B solution obtained in step (2) at a uniform speed within 180 minutes, stir and mix the reaction; maintain the temperature of the mixed reaction solution at 70 Continue the reaction for 240 minutes at ℃ to form an intermediate with a molar ratio of block A to block B of 2:8, and then add 15.2g (accounting for 1% of the total mass of block A and block B) of 1,6-hexane The diamine was subjected to a bracketing chain reaction for 60 minutes, and 10342g N-methylpyrrolidone was added for dilution; after the temperature of the mixed reaction solution was lowered to 30°C, 4.62g (mass content: 0.3%) of propylamine end-capping agent was added, and the reaction was carried out for 60 minutes to obtain Block copolymer with 10% solids content.

Comparative example 1

An adhesive for batteries, which is a random copolymer;

The preparation method of the random copolymer includes: dissolving 105g of 4,4'-diphenylmethane diisocyanate in 245g of N-methylpyrrolidone to form an A1 solution with a mass content of 30%, and dissolving 97.6g of hexane. Methylene diisocyanate was dissolved in 228g N-methylpyrrolidone to form a B1 solution with a mass content of 30%, and then the A1 solution and B1 solution were mixed evenly; 62.7g m-phenylenediamine was dissolved in 146g N-methyl In pyrrolidone, an A2 solution with a mass content of 30% is formed; 72.4g of 1,10-decanediamine is dissolved in 169g N-methylpyrrolidone to form a B2 solution with a mass content of 30%, and then the A2 solution and B2 Mix the solution evenly, then add the mixed solution of A1 solution and B1 solution to the mixed solution of A2 solution and B2 solution at a uniform speed within 180 minutes, stir and mix the reaction, and maintain the temperature of the mixed reaction solution at 70°C to continue the reaction for 240 minutes. Then 3.38g of 1,6-hexanediamine was added for bracketing reaction for 60 minutes, and 2291g of N-methylpyrrolidone was added for dilution. After the temperature of the mixed reaction solution was lowered to 30°C, 1.02g of propylamine end-capping agent was added and the reaction was carried out for 60 minutes to obtain a random copolymer solution with a solid content of 10%.

Comparative example 2

A binder for batteries, which is a polymer containing only block B;

The preparation method of the polymer containing only block B includes: dissolving 85.8g (51mol%) hexamethylene diisocyanate in 200g N-methylpyrrolidone to form a B1 solution with a mass content of 30%; 196g (49mol%) ether-based diamine D400 was dissolved in 457g N-methylpyrrolidone to form a B2 solution with a mass content of 30%. Then add the B1 solution to the B2 solution at a constant speed within 40 minutes, stir and mix the reaction, and maintain the temperature of the mixed reaction solution at 60°C to continue the reaction for 180 minutes. Then add 2.82g of 1,6-hexanediamine for bracketing reaction for 60 minutes, and add 1912g of N-methylpyrrolidone for dilution; after lowering the temperature of the mixed reaction solution to 30°C, add 0.85g of propylamine end-capping agent, and the reaction After 60 minutes, a polymer containing only block B with a solid content of 10% was obtained.

Comparative example 3

A binder for batteries, which is a polymer containing only block A;

The preparation method of the polymer containing only block A includes: dissolving 128g (51mol%) of 4,4'-diphenylmethane diisocyanate in 298g of N-methylpyrrolidone to form a polymer with a mass content of 30% A1 solution: Dissolve 53g (49mol%) m-phenylenediamine in 124g N-methylpyrrolidone to form an A2 solution with a mass content of 30%. Then add the A1 solution to the A2 solution at a constant speed within 40 minutes, stir and mix the reaction, and maintain the temperature of the mixed reaction solution at 60°C to continue the reaction for 180 minutes. Then add 1.81 g of 1,6-hexanediamine was subjected to a bracketing reaction for 60 minutes, and 1225g of N-methylpyrrolidone was added for dilution; after the temperature of the mixed reaction solution was lowered to 30°C, 0.55g of propylamine end-capping agent was added, and the reaction was carried out for 60 minutes to obtain The battery adhesive.

Application example 1

A soft pack battery, the preparation method of which includes the following steps:

(1) Preparation of positive electrode sheet: In terms of solid parts by weight, mix 95 parts of lithium iron phosphate (Betteri, P198-S13), 2.5 parts of Super P conductive carbon black, and 2.5 parts of battery binder (Example 1) , add an appropriate amount of NMP according to the proportion of the total solid content of 63%, mix and stir in a vacuum mixing tank, disperse evenly, and prepare a battery slurry; filter the obtained battery slurry through a 100-mesh screen and use extrusion Press the coater to evenly coat the battery slurry on the front and back surfaces of the aluminum foil used as the current collector. The surface density of the coating is 350g/m ² , and perform blast drying at 105°C to remove the solvent. It is then rolled at room temperature to form a positive electrode piece;

(2) Preparation of negative electrode sheet: In terms of solid parts by weight, mix 96 parts of artificial graphite (Betteri, S360), 1 part of carbon nanotubes (Cabot, GCNTs5), 1 part of CMC (Dow, CRT30000PA), 2 parts of styrene-butadiene rubber emulsion (Japanese JSR, TRD104A), using water as the solvent, mix and disperse evenly to make a negative electrode slurry, then apply it on the front and back surfaces of the copper foil, air dry at 95°C, and remove Solvent. It is then rolled at room temperature to form a negative electrode piece;

(3) Weld the conductive tabs to the obtained positive electrode piece and negative electrode piece, place the polyethylene separator between the positive electrode piece and the negative electrode piece, roll it into a bare cell and wrap it in aluminum plastic film, and Inject the electrolyte composed of EC:EMC:DEC volume ratio = 1:1:1 (containing 1.0M LiPF ₆ ), encapsulate the battery, and then form the battery to obtain the soft pack battery.

Application examples 2 to 10

A soft pack battery, the only difference from Application Example 1 is that the battery adhesive obtained in Examples 2 to 10 is used instead of the battery adhesive obtained in Example 1, and other substances, contents and preparation methods are the same. Same as application example 1.

Comparative application examples 1 to 3

A soft pack battery, the only difference from Application Example 1 is that the battery adhesive obtained in Comparative Examples 1 to 3 is used to replace the battery adhesive obtained in Example 1, and other substances, contents and preparation methods are the same. Same as application example 1.

Performance Testing:

(1) Glass transition temperature: Measured using differential scanning calorimetry (DSC) according to the test method provided by "ASTM D3418"; specifically, the sample is coated on a glass plate and dried in a vacuum at 120°C form a solid film. NETZSCH DSC 204F1Phoenix is used, the test temperature range is -20~200℃, the heating rate is 10℃/min, the temperature is raised from -20℃ to 200℃, and then the sample is cooled to -20℃ at 10℃/min, and After 3 minutes, perform the second heating process, analyze the record of the second heating process, and obtain the glass transition temperature (Tg) of the sample;

(2) Elastic modulus: Coat the prepared sample on a glass plate, dry it in a vacuum oven at 120°C, and then peel it off from the glass plate to obtain a polymer film with uniform thickness. According to the test standards provided by "ASTM D882", the elastic modulus of the film is measured; specifically, a universal electronic testing machine is used, the width of the film to be tested is 15mm, the length is 200mm, and the tensile speed is 25mm/min. Record the average of the three recorded values as the final result.

The adhesives obtained in Examples 1 to 10 and Comparative Examples 1 to 3 were tested according to the above test methods (1) and (2). The test results are shown in Table 1:

Table 1

(3) Peeling strength: Cut the positive electrode sheet prepared in step (1) of the application example and comparative application example into 10×2cm strips, and fix it to a 1mm thick steel plate with double-sided tape on the current collector side. coating layer Attach 3M tape to the side. At 25°C, use a universal electronic testing machine to perform a pulling peeling experiment in the 180° direction at a peeling speed of 100mm/min, and record the average peeling stress;

(4) Internal resistance: Use Solartron electrochemical workstation to test the internal resistance of soft-pack batteries;

(5) Cycle performance: Use a battery test cabinet to formulate and divide the soft-pack battery prepared above; the formation step is to charge with a constant current of 0.05C for 2.0h, and then charge with a constant current of 0.15C for 2.5h; the step of dividing the capacity is In order to charge to 4.2V at a constant current of 0.33C, then charge at a constant voltage of 4.2V to a cut-off current of 0.02C, and discharge to 2.5V at a rate of 0.33C; at 25°C, the battery after being reduced to a constant capacity is charged at a constant voltage of 0.33C. Charge to 4.2V with current, then charge with constant voltage to cut-off current of 0.02C, leave it for 5 minutes, discharge to 2.5V at 0.33C, leave it for 5 minutes, record the discharge capacity after the first cycle; again, charge with constant current of 0.5C to 4.2V , then charge at a constant voltage to the cut-off current of 0.02C, leave it for 5 minutes, discharge to 2.5V at 0.5C, leave it for 5 minutes, and cycle in this manner. After 100 charge/discharge cycles, record the discharge capacity after the 100th cycle; use the following The formula to calculate the capacity retention rate of the battery after 100 cycles: Capacity retention rate after 100 cycles (%) = discharge capacity after the 100th cycle/discharge capacity after the first cycle.

The positive electrode pieces obtained in Application Examples 1 to 10 and Comparative Application Examples 1 to 3 were tested according to the above test method (3); ~3 The soft pack battery obtained was tested, and the test results are shown in Table 2:

Table 2

It can be seen from Table 1 and Table 2 that the peel strength of the positive electrode sheet obtained by using the binder provided by this application is 9 to 36 N/m (Application Examples 1 to 10), and the soft package prepared by using the above positive electrode sheet The internal resistance of the battery is 294~870mΩ, and the capacity retention rate after 100 cycles is 94.8~99.4%.

Comparing Application Examples 1 to 10 and Comparative Application Example 1, it can be found that Comparative Application Example 1 uses the random polymer provided in Comparative Example 1 as a battery binder, while Application Examples 1 to 10 respectively use Example 1 The block copolymers provided in Application Examples 1 to 10 are used as battery binders. In comparison, the pole pieces provided in Application Examples 1 to 10 have higher peel strength, so that the soft pack batteries prepared therefrom have lower inner strength. resistance, and the cycle performance is also better.

Comparing Application Examples 1 to 7 and Comparative Application Examples 2 to 3, it can be found that Comparative Application Example 2 uses the binder containing only block B provided in Comparative Example 2, so that although the bonding strength of the prepared pole piece is relatively high, However, the internal resistance of the further prepared soft pack battery increased and the cycle performance decreased; in Comparative Application Example 3, the adhesive containing only block A provided in Comparative Example 3 was used, and the bonding strength of the pole piece prepared was is lower, and further causes the prepared soft pack battery to have higher internal resistance and poor cycle performance.

Further comparison between Application Example 1 and Application Examples 8 to 9 shows that the battery binder provided in Example 8 used in Application Example 8 is because the molar ratio of block A to block B in its block copolymer is too high. The glass transition temperature of the prepared binder is too high and the modulus is too large, which makes the peeling strength of the electrode piece prepared by using it too low, and the internal resistance of the further prepared soft pack battery is too high, and the cycle The battery adhesive provided in Example 9 is used in Application Example 9 because the molar ratio of block A to block B in its block copolymer is too low. Although the vitrification of the prepared adhesive is The transition temperature and modulus are both within the obvious limits of this method, but the internal resistance of the further prepared pouch battery is too high and the cycle performance is poor.

Further comparison of Application Example 1 and Application Example 10 shows that although the molar ratio of block A to block B in the binder provided in Comparative Example 10 is within the preferred range described in this application, its glass transition temperature is too low. , the modulus is too small, so the bonding strength of the prepared pole pieces is also slightly reduced, the internal resistance of the prepared soft pack battery is slightly increased, and the cycle performance is reduced.

In summary, the battery adhesive provided by this application contains a block copolymer composed of block A and block B obtained by step polymerization, which can effectively improve the use of the block copolymer as a battery adhesive. The peeling strength of the pole piece when the agent is used, reduces the internal resistance of the battery, and improves the battery cycle capacity retention rate.

The applicant declares that this application uses the above embodiments to illustrate a battery binder and its preparation method and application. However, this application is not limited to the above embodiments, which does not mean that this application must rely on the above embodiments to implement it. . Those skilled in the art should understand that any improvements to the present application, equivalent replacement of raw materials of the product of the present application, addition of auxiliary ingredients, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present application.

Claims

A battery adhesive, wherein the battery adhesive includes a block copolymer composed of block A and block B;

The raw materials for preparing block A include aromatic diisocyanate and aromatic diamine;

The raw materials for preparing block B include aliphatic diisocyanate and aliphatic diamine.
The battery binder according to claim 1, wherein the molar ratio of block A and block B is 1: (0.4-4), preferably 1: (1-2.5).
The battery binder according to claim 1 or 2, wherein the molar percentage of aromatic diisocyanate in the raw materials for preparing block A is 30 to 49 mol%;

Preferably, the molar percentage of aromatic diamine in the raw materials for preparing block A is 51 to 70 mol%;

Preferably, the molar percentage of aliphatic diisocyanate in the raw materials for preparing block B is 51 to 70 mol%;

Preferably, the molar percentage of aliphatic diamine in the raw materials for preparing block B is 30 to 49 mol%.
The battery binder according to any one of claims 1 to 3, wherein the aromatic diisocyanate includes 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, and xylylene diisocyanate. , any one or a combination of at least two of dimethylbiphenyl diisocyanate, p-phenylene diisocyanate, 1,5-naphthalene diisocyanate or 3,3-dichlorobiphenyl-4,4-diisocyanate.
The battery binder according to any one of claims 1 to 4, wherein the aromatic diamine includes p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3 ,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-di Aminobiphenyl, 4,4'-diaminodiphenylmethane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis(trifluoromethyl)diaminobiphenyl Any one or a combination of at least two of benzene or 5-amino-2-(4-aminophenyl)benzimidazole.
The battery binder according to any one of claims 1 to 3, wherein the block A is prepared by the following method, which method includes: adding aromatic diisocyanate and aromatic diamine in a solvent. Carry out the reaction to obtain the block A;

Preferably, the solvent includes N-methylpyrrolidone;

Preferably, the reaction time is 60 to 360 minutes;

Preferably, the temperature of the reaction is 50-70°C;

Preferably, the method specifically includes the following steps:

(A1) Dissolve aromatic diisocyanate in a solvent to obtain an aromatic diisocyanate solution; dissolve aromatic diamine in a solvent to obtain an aromatic diamine solution;

(A2) Add the aromatic diisocyanate solution obtained in step (A1) to the aromatic diamine solution obtained in step (A1) and react to obtain the block A;

Preferably, the mass percentage of aromatic diisocyanate in the aromatic diisocyanate solution described in step (A1) is 10 to 40%;

Preferably, the mass percentage of the aromatic diamine in the aromatic diamine solution described in step (A1) is 10 to 40%;

Preferably, the adding time in step (A2) is 30 to 120 minutes.
The battery binder according to any one of claims 1 to 6, wherein the aliphatic diisocyanate includes hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone Any one or a combination of at least two of ketone diisocyanate, dicyclohexylmethane diisocyanate or lysine diisocyanate.
The battery binder according to any one of claims 1 to 7, wherein the aliphatic diamine includes an aliphatic carbon chain diamine, an ether diamine, a double-ended amino polyamide or a double-ended Any one or a combination of at least two of aminopolybutadiene-acrylonitrile copolymers.
The battery binder according to claim 8, wherein the aliphatic carbon chain diamine includes 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1 ,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-decanediamine Hexanediamine, 1,18-octadecanediamine, 1,36-trihexadecanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl- 1,6-hexanediamine, 3,3-dimethyl-1,6-hexanediamine, 2,2-dimethyl-1,6-hexanediamine, 2,2,4-trimethyl- 1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2,4-diethyl-1,6-hexanediamine, 2,2-dimethyl- 1,7-heptanediamine, 2,3-dimethyl-1,7-heptanediamine, 2,4-dimethyl-1,7-heptanediamine, 2,5-dimethyl-1, 7-Heptanediamine, 2-methyl-1,8-octanediamine, 3-methyl-1,8-octanediamine, 4-methyl-1,8-octanediamine, 1,3-diamine Methyl-1,8-octanediamine, 1,4-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine, 3,4-dimethyl -1,8-octanediamine, 4,5-dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 3,3-dimethyl-1 , any one or a combination of at least two of 8-octanediamine, 4,4-dimethyl-1,8-octanediamine or 5-methyl-1,9-nonanediamine;

Preferably, the ether-based diamine includes bis(2-aminoethyl) ether, 3,6-dioxa-1,8-octanediamine, 4,7-dioxa-1,10-decane Diamine, 4,7-dioxa-2,9-decanediamine, 4,9-dioxa-1,12-dodecanediamine, 5,8-dioxa-3,10-decanediamine Dialkanediamine, 4,7,10-trioxa-1,13-tridecanediamine, bis(3-aminopropyl) Any one or a combination of at least two of polytetrahydrofuran or polyoxyalkylenediamine;

Preferably, the double-terminated amino polyamide includes double-terminated amino polyamide 6, double-terminated amino polyamide 11, double-terminated amino polyamide 12, double-terminated amino polyamide 66, double-terminated amino polyamide 610, double-terminated amino polyamide Amide 612, double-terminated amino polyamide 1010, double-terminated amino polyamide 1011, double-terminated amino polyamide 1012, double-terminated amino polyamide 1013, double-terminated amino polyamide 1111, double-terminated amino polyamide 1112, double-terminated amino polyamide 1113. Any one or a combination of at least two of double-terminated amino polyamide 1212, double-terminated amino polyamide 1213, double-terminated amino polyamide 1313 or double-terminated amino polyamide 1414;

Preferably, the number of carbon atoms in the main chain of the aliphatic diamine is greater than 10.
The battery binder according to any one of claims 1 to 9, wherein the block B is prepared by the following method, which method includes: adding aliphatic diisocyanate and aliphatic diamine in a solvent Carry out the reaction to obtain the block B;

Preferably, the solvent includes N-methylpyrrolidone;

Preferably, the reaction time is 60 to 360 minutes;

Preferably, the temperature of the reaction is 50-70°C;

Preferably, the method specifically includes the following steps:

(B1) Dissolve aliphatic diisocyanate in a solvent to obtain an aliphatic diisocyanate solution; dissolve aliphatic diamine in a solvent to obtain an aliphatic diamine solution;

(B2) Add the aliphatic diisocyanate solution obtained in step (B1) to the aliphatic diamine solution obtained in step (B1) and react to obtain the block B;

Preferably, the mass percentage of aliphatic diisocyanate in the aliphatic diisocyanate solution described in step (B1) is 10 to 40%;

Preferably, the mass percentage of the aliphatic diamine in the aliphatic diamine solution described in step (B1) is 10 to 40%;

Preferably, the adding time in step (B2) is 30 to 60 minutes.
The battery binder according to any one of claims 1 to 10, wherein the viscosity of the block copolymer is 100 to 100000 mPa·s, preferably 1000 to 10000 mPa·s;

Preferably, the glass transition temperature of the block copolymer is -20 to 160°C, more preferably 40 to 120°C;

Preferably, the elastic modulus of the block copolymer is 500-4000MPa, more preferably 800-3000MPa, even more preferably 1200-2500MPa;

Preferably, the battery adhesive further includes a binding substance and/or a conductive substance;

Preferably, based on 100 parts of the total weight of the battery adhesive, the content of the adhesive material is 1 to 49 parts by weight;

Preferably, the bonding substance includes polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride copolymer, polytetrafluoroethylene copolymer, polyimide, polyetherimide, polyamideimide. amine, polyesterimide, polycarbonateimide, polyureaimide, styrene-butadiene rubber, polyacrylonitrile, polyacrylic acid, polyacrylate, polyacrylic acid-polyacrylonitrile copolymer or polyacrylate-polymer Any one or a combination of at least two of acrylonitrile copolymers;

Preferably, the bonding substance includes any one or a combination of at least two of polyvinylidene fluoride, polyimide, polyamideimide, polyacrylic acid or styrene-butadiene rubber;

Preferably, based on 100 parts of the total weight of the battery binder, the content of the conductive substance is 1 to 49 parts by weight;

Preferably, the conductive substance includes any one or a combination of at least two of conductive carbon black, conductive graphite, modified conductive graphite, metal particles, Ketjen black, carbon nanotubes, carbon fibers, graphene or conductive polymers. .
A method for preparing a battery adhesive according to any one of claims 1 to 11, which includes the following steps:

(1) Mix block A and block B and react to obtain an intermediate product;

(2) Add a chain extender to the intermediate product obtained in step (1) for reaction, and then add an end-capping agent for reaction to obtain the battery binder.
The method for preparing a battery binder according to claim 12, wherein the mixing in step (1) is performed by adding block A to block B;

Preferably, the adding time is 60 to 360 minutes;

Preferably, the reaction time in step (1) is 60 to 360 minutes;

Preferably, the reaction temperature in step (1) is 60 to 90°C;

Preferably, the added amount of the chain extender in step (2) is 0.2 to 2% of the total mass of block A and block B;

Preferably, the chain extender in step (2) is an aliphatic diamine;

Preferably, the temperature at which the chain extender is added to carry out the reaction in step (2) is 60 to 90°C;

Preferably, the reaction time for adding the chain extender in step (2) is 30 to 120 minutes;

Preferably, the amount of the end-capping agent added in step (2) is 0.1 to 1% of the total mass of block A and block B;

Preferably, the capping agent in step (2) includes any one or a combination of at least two of methylamine, ethylamine, propylamine, dimethylamine, diethylamine, aniline, diphenylamine or p-aminobenzoic acid;

Preferably, the time for adding the end-capping agent to carry out the reaction in step (2) is 30 to 120 minutes;

Preferably, the temperature at which the end-capping agent is added to carry out the reaction in step (2) is 20 to 40°C;

Preferably, before adding the capping agent in step (2), there is also a step of adding N-methylpyrrolidone for dilution.
A battery pole piece, wherein the battery pole piece includes the battery adhesive according to any one of claims 1 to 11;

Preferably, the battery electrode piece is a positive electrode piece or a negative electrode piece.
A lithium ion battery, wherein the lithium ion battery includes the battery pole piece as claimed in claim 14.