A method for preparing a lithium battery separator

Abstract

The application relates to a preparation method of a lithium battery diaphragm and belongs to the technical field of lithium battery preparation. The method is as follows: epoxy resin, a diluent, a curing agent 1 and an oleophilic emulsifier are uniformly mixed to obtain dispersion liquid 1; an electrolyte solution is constantly dropped into the dispersion liquid 1, constant-temperature high-speed stirring is carried out, and a water-in-oil emulsion is obtained; under constant temperature, deionized water, a hydrophilic emulsifier and a curing agent 2 are uniformly mixed to obtain dispersion liquid 2; the water-in-oil emulsion is added into the dispersion liquid 2, high-speed emulsification is carried out, and a water-in-oil-in-water emulsion system is obtained; the water-in-oil-in-water emulsion system is subjected to temperature rising and curing; after curing, centrifugal separation, washing and drying are carried out, and a solid nanometer adhesive is obtained; the solid nanometer adhesive is ground, then is uniformly coated in a mold and is subjected to high-temperature treatment, and the lithium battery diaphragm is obtained. The electrolyte solution is selected as the inner water phase of the water-in-oil emulsion, the internal osmotic pressure of the emulsion can be increased, fusion between the emulsions can be prevented, and the particle size is increased.

Description

[0001] This application is a divisional application of the invention entitled "A method for preparing a dry electrode, separator and battery-structure integrated material for lithium batteries", filed on January 31, 2023, application number 2023100479284. Technical Field

[0002] This invention belongs to the field of lithium battery manufacturing technology, specifically relating to a method for preparing dry electrodes, separators, and battery-structure integrated materials for lithium batteries. Background Technology

[0003] The preparation of lithium-ion battery electrodes involves uniformly mixing electrode active materials, conductive agents, and binders, and then coating them onto a metal current collector. The electrode active materials determine the battery's energy density. Conductive agents improve electron transport efficiency within the electrode, thereby increasing the battery's specific capacity and rate charge / discharge capability. The main purpose of the binder is to adhere the electrode active materials and conductive agents to the metal current collector, ensuring a stable electrode structure. Although the binder, as one of the inactive components of the positive and negative electrode materials in lithium-ion batteries, accounts for only 1.5% to 3% of the total electrode material mass, it plays a crucial role in influencing the overall electrochemical performance of the battery. Therefore, it can be said that the binder is a decisive battery component in lithium-ion batteries, significantly impacting the battery's actual capacity, rate capability, and cycle life.

[0004] Currently, adhesives mainly fall into two categories: organic solvent-soluble adhesives, represented by polyvinylidene fluoride (PVDF), and water-soluble adhesives, represented by carboxymethyl cellulose / styrene-butadiene rubber (SBR). Both require the participation of a liquid solvent, and both are inactive components, potentially negatively impacting electron transport efficiency. Therefore, developing a conductive adhesive capable of completely dry bonding, thereby enabling the successful fabrication of dry electrodes for lithium-ion batteries, has significant practical implications.

[0005] The separator is a key component of liquid lithium-ion batteries. Current liquid lithium-ion batteries primarily use non-aqueous liquid electrolytes, employing porous separators between the positive and negative electrodes to isolate them and prevent short circuits. Simultaneously, lithium ions can be conducted through the pores within the separator within the electrolyte. As a lithium-ion battery separator, it must not only isolate the positive and negative electrodes but also meet other parameter requirements (liquid absorption rate, porosity, electrochemical stability, thermal stability, mechanical properties, etc.). Currently, separators are mainly classified into commercial polyolefin separators, polyolefin-modified separators, and non-woven fabric separators. However, several technical bottlenecks exist. For example, the inherent characteristics of polyolefins result in poor thermal stability, susceptibility to thermal shrinkage at high temperatures leading to short circuit risks, and poor liquid absorption and retention performance.

[0006] With the continuous advancement of aviation technology, air traffic growth has generally shown a significant upward trend. This growth leads to increased fuel combustion and exacerbated environmental pollution. The aviation industry (manufacturers and operators) is currently introducing new technologies and operational solutions to reduce aircraft fossil fuel consumption. However, it will be many years before all aircraft are replaced by a new generation of transportation. Electric aircraft are aircraft that use electric motors as their power source, with power sources including batteries, fuel cells, solar cells, and supercapacitors. Currently, the more successful manned electric aircraft primarily use batteries (mainly lithium-ion battery electric aircraft), solar cells (called solar-powered aircraft), or fuel cells as their power source. Electric propulsion systems have many important characteristics, such as their highly efficient energy conversion chain; some electric propulsion systems can even achieve zero emissions.

[0007] However, the application of electric propulsion systems in the aviation field is significantly more challenging than in ground transportation. Ground transportation can effectively address the additional weight issues arising from underdeveloped energy storage and propulsion technologies, while aircraft are highly sensitive to weight. Therefore, developing a battery-structure integrated composite material, by designing lithium batteries as self-adhesive composite materials, allows for a perfect integration of lithium batteries with composite materials such as wings, thereby reducing the aircraft's weight and achieving lightweight electric aircraft. Summary of the Invention

[0008] The purpose of this invention is to solve the problems of low bonding efficiency of lithium battery binders and their adverse effects on electron transport efficiency, poor thermal stability of polyolefin separators, poor liquid absorption and retention performance, and lightweighting of lithium batteries, and to provide a method for preparing dry electrode, separator and battery-structure integrated material for lithium batteries.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A method for preparing a dry electrode for a lithium battery, the method comprising the following steps:

[0011] Step 1: Mix and disperse the conductive nanoparticles, epoxy resin, diluent, curing agent 1 and lipophilic emulsifier evenly to obtain dispersion 1;

[0012] Step 2: Add the electrolyte solution dropwise to dispersion 1 at a constant rate, and stir at high speed under constant temperature to obtain a water-in-oil emulsion;

[0013] Step 3: Under constant temperature, uniformly mix and disperse deionized water, hydrophilic emulsifier and curing agent 2 to obtain dispersion 2;

[0014] Step 4: Add the water-in-oil emulsion to dispersion 2 and continue stirring at high speed to emulsify, thereby obtaining a water-in-oil emulsion system;

[0015] Step 5: Heat the water-in-oil-in-water emulsion system and stir continuously to solidify it;

[0016] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to obtain the nano-conductive adhesive;

[0017] Step 7: Mix the nano-conductive binder, active material, and conductive agent evenly and grind them thoroughly. Spread the mixed powder evenly on aluminum foil and press it into shape using a hot press at high temperature to obtain the lithium battery electrode.

[0018] A method for preparing a lithium battery separator, the method comprising the following steps:

[0019] Step 1: Mix and disperse epoxy resin, diluent, curing agent 1 and lipophilic emulsifier evenly to obtain dispersion 1;

[0020] Step 2: Add the electrolyte solution dropwise to dispersion 1 at a constant rate, and stir at high speed under constant temperature to obtain a water-in-oil emulsion;

[0021] Step 3: Under constant temperature, uniformly mix and disperse deionized water, hydrophilic emulsifier and curing agent 2 to obtain dispersion 2;

[0022] Step 4: Add the water-in-oil emulsion to dispersion 2 and continue stirring at high speed to emulsify, thereby obtaining a water-in-oil emulsion system;

[0023] Step 5: Heat the water-in-oil-in-water emulsion system and stir continuously to solidify it;

[0024] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to obtain a solid nano-adhesive;

[0025] Step 7: Grind the solid nano-adhesive and then spread it evenly in a stainless steel groove mold. After high-temperature treatment under certain pressure using a hot press, a lithium battery separator is obtained.

[0026] A method for preparing a battery-structure integrated composite material including the lithium battery separator prepared above, the method further comprising:

[0027] Step 8: Mix the nano-binder, positive electrode active material, and conductive agent evenly and grind them thoroughly. Spread the mixed powder evenly on aluminum foil and press it into shape using a hot press at high temperature to obtain the lithium battery positive electrode.

[0028] Step 9: Mix the nano-binder, negative electrode active material, and conductive agent evenly and grind them thoroughly. Spread the mixed powder evenly on copper foil and press it into shape using a hot press at high temperature to obtain the lithium battery negative electrode.

[0029] Step 10: Stack the negative electrode, separator, electrolyte, and positive electrode in the following order from bottom to top, and use a hot press to integrally hot press them at high temperature.

[0030] The advantages of this invention over the prior art are as follows:

[0031] (1) This invention realizes the synthesis of dry-process lithium battery electrodes. The nano-conductive adhesive prepared first, due to the retention of surface reactivity and the presence of a latent curing agent, can achieve self-adhesion through a post-curing reaction at a specific temperature. Then, the dry bonding of lithium battery electrodes is achieved using this adhesive. Unlike most electrode adhesives, the nano-conductive adhesive in this invention not only requires no solvent participation and has high bonding strength, but also retains a large number of pores after bonding to facilitate electron transport.

[0032] (2) By adding conductive nanoparticles, the present invention endows the adhesive with superior conductivity, which largely avoids the obstruction effect caused by traditional non-active insulating adhesives for electron transmission.

[0033] (3) The present invention uses two different curing agents at the same time. By taking advantage of the differences in the chemical properties and curing processes of different types of curing agents, curing agent 2 acts on epoxy particles to cure and form, thereby achieving the successful latent state of curing agent 1.

[0034] (4) The present invention selects an electrolyte solution as the inner aqueous phase of the water-in-oil emulsion. Firstly, it can increase the internal osmotic pressure of the emulsion, prevent the emulsions from fusing together, and increase the particle size. Secondly, some electrolytes have a catalytic effect on the ring-opening reaction of epoxy resin epoxy groups, which can accelerate the formation of epoxy resin spherical particles.

[0035] (5) In step three of this invention, the hydrophilic emulsifier is selected by the combined use of nonionic emulsifier and anionic emulsifier. With appropriate ratio, a better emulsification effect is achieved for water-in-oil emulsion.

[0036] (6) In the curing process of epoxy resin spherical particles in steps four and five of this invention, a gradual gradient of temperature is adopted instead of directly applying the optimal curing temperature of the curing agent. This avoids the damage to the water-in-oil-in-water emulsion caused by a sudden increase in temperature. The emulsification effect of emulsifiers is generally sensitive to temperature changes. When the temperature exceeds the critical point, the emulsification effect is destroyed, and the emulsion droplets break down or aggregate, resulting in a larger final particle size and uneven distribution.

[0037] (7) In this invention, the lithium battery electrode is prepared by hot pressing. First, it can make the electrode sheet thickness uniform and consistent. Second, it can increase the compaction density of the negative electrode material. Appropriate compaction density can increase the discharge capacity of the battery, reduce internal resistance, reduce polarization loss, extend the cycle life of the battery, and improve the utilization rate of lithium-ion battery.

[0038] (8) Epoxy resin has excellent mechanical properties and strong chemical resistance, and its temperature resistance is stronger than that of conventional separators. Because the adhesive is in the form of spherical particles, a large number of pores will be formed during the self-adhesive film formation process. The high porosity of the separator is the basic guarantee for the efficiency of lithium battery. In addition, the pore size of the separator can also be adjusted by the particle size of the solid adhesive.

[0039] (9) This invention innovatively achieves the synthesis of nano-adhesives with a particle size as small as 50 nm. Due to the retention of surface reactivity and the presence of latent curing agents, self-adhesion can be achieved through post-curing reaction at a specific temperature. Unlike most adhesives, the nano-adhesives in this invention not only have high bonding strength but also retain a large number of pores after bonding.

[0040] (10) This invention develops a battery-structure integrated composite material. By designing the lithium battery as a self-adhesive integrated composite material, the lithium battery can be directly used in various support structures, thereby reducing the load on the support structure itself and achieving structural lightweighting. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a lithium battery electrode prepared by a dry method.

[0042] Figure 2 This is a cyclic voltammetry curve of a dry electrode in a lithium battery.

[0043] Figure 3 SEM image of nano-adhesive.

[0044] Figure 4 This is a diagram of a lithium battery separator obtained by self-adhesion using a solid nano-binder.

[0045] Figure 5 SEM image of lithium battery separator obtained by self-adhesion with solid nano-binder.

[0046] Figure 6 This is a schematic diagram of a battery-structure integrated composite material structure. Detailed Implementation

[0047] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0048] Specific Implementation Method 1: This implementation method describes a method for preparing a dry electrode for lithium batteries. The method steps are as follows:

[0049] Step 1: The conductive nanoparticles, epoxy resin, diluent, curing agent 1 and lipophilic emulsifier are uniformly mixed and dispersed using a high-speed disperser to obtain dispersion 1.

[0050] Step 2: Add the electrolyte solution dropwise to dispersion 1 at a constant rate, and stir at high speed under constant temperature to obtain a water-in-oil emulsion;

[0051] Step 3: Under constant temperature, deionized water, hydrophilic emulsifier and curing agent 2 are uniformly mixed and dispersed using a high-speed disperser to obtain dispersion 2;

[0052] Step 4: Add the water-in-oil emulsion to dispersion 2 and continue stirring at high speed to emulsify, thereby obtaining a water-in-oil emulsion system;

[0053] Step 5: Heat the water-in-oil-in-water emulsion system, stir continuously, and adjust the curing temperature and time to control the formation of epoxy resin balls into nanoparticles and retain more reactive groups.

[0054] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to obtain the nano-conductive adhesive;

[0055] Step 7: Uniformly mix and thoroughly grind the nano-conductive adhesive, active material, and conductive agent. Spread the mixed powder evenly onto aluminum foil and press it into shape using a hot press at high temperature to obtain the lithium battery electrode. This method uses a double emulsion method, conductive particle filling, and successful latent curing agent to obtain a nanoscale solid conductive adhesive, and then achieves dry bonding of the lithium battery electrode without any solvent involved.

[0056] Specific Implementation Method Two: In the preparation method of a dry electrode for a lithium battery as described in Specific Implementation Method One, in step one, the conductive nanoparticles are at least one of silver nanoparticles, gold nanoparticles, copper nanoparticles, graphene, carbon nanotubes, conductive graphite, conductive carbon black, and carbon fiber; the epoxy resin is at least one of bisphenol A type epoxy resin, glycidyl ester epoxy resin, and alicyclic epoxy resin; the bisphenol A type epoxy resin is at least one of E55, E51, and E44; the glycidyl ester epoxy resin is at least one of 711#, TDE-85#, and 731#; the alicyclic epoxy resin is at least one of W-95#, 6221#, and 6206#; the diluent is at least one of ethylene glycol diglycidyl ether, phenyl glycidyl ether, polypropylene glycol diglycidyl ether, and butyl glycidyl ether; the curing... Agent 1 is at least one of maleic anhydride, phthalic anhydride, m-phenylenediamine, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenylmethane. This invention primarily utilizes the fact that the above-mentioned high-temperature curing agents do not react under low-temperature treatment during the nano-adhesive processing, thus achieving successful latency. The lipophilic emulsifier is at least one of Span 20, Span 40, Span 60, and Span 80. The mass ratio of epoxy resin to conductive nanoparticles is 100:1-5. The mass ratio of epoxy resin to diluent is 3-6:1. The mass ratio of epoxy resin to curing agent 1 is 10:2-3, based on the theoretical amount of curing agent 1 used to cure epoxy resin. The mass ratio of epoxy resin to lipophilic emulsifier is 5:2-5. In step two, the mass ratio of epoxy resin to electrolyte solution is 5:2-5.

[0057] Specific Implementation Method 3: In the preparation method of the dry electrode for lithium battery described in Specific Implementation Method 1, in step 2, the electrolyte solution is at least one of 0.1 mol / L sodium chloride solution, 0.1 mol / L potassium chloride solution, NH3·H2O-NH4Cl buffer solution with pH=10, and 0.1 mol / L sodium hydroxide solution; the constant reaction temperature is 40-60℃, the time is 10-15 min, and the stirring speed is 2500-3000 rpm.

[0058] Specific Implementation Method Four: In the preparation method of a dry electrode for a lithium battery described in Specific Implementation Method One, in step three, the hydrophilic emulsifier is one or a mixture of nonionic and anionic emulsifiers; either a single nonionic or anionic emulsifier can achieve emulsification, but using them in combination may yield better results; the nonionic emulsifier is at least one of polyoxyethylene ether, OP-10, and polyvinyl alcohol; the anionic emulsifier is at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and phosphate; the curing agent 2 is ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenediamine, or tetraethylenetriamine. One or a mixture of pentamines; curing agent 2 needs to be a fatty amine curing agent with a low curing temperature, because this type of curing agent must achieve partial curing of the epoxy nano-adhesive at a low temperature where curing agent 1 will not react; the mass ratio of deionized water to hydrophilic emulsifier is 15-20:1; the mass ratio of nonionic emulsifier to anionic emulsifier is 20:0-3; the mass ratio of deionized water to curing agent 2 is 30-40:1; this amount is based on the theoretical amount of curing agent 2 used to cure epoxy resin; in step four, the mass ratio of deionized water to water-in-oil emulsion is 15-20:1.

[0059] Specific Implementation Method 5: The method for preparing a dry electrode for a lithium battery as described in Specific Implementation Method 1, wherein the constant temperature in step 3 is 40-50℃; in steps 4 and 5, the stirring speed is 1000-1500 rpm; in step 5, the temperature is raised to 60-80℃, and the heating process plus heat preservation reaction takes 25-30 minutes; in step 7, the high temperature is the curing temperature of curing agent 1, and the hot press pressure is 2-4 MPa; in step 7, the active material is at least one of graphite, lithium titanate, and silicon-carbon alloy; the conductive agent is at least one of acetylene black, conductive carbon black, and Super P; the mass ratio of the nano-conductive binder to the active material is 1-3:17, and the mass ratio of the nano-conductive binder to the conductive agent is 1-2:1.

[0060] Specific Implementation Method Six: This implementation method describes a method for preparing a lithium battery separator, the steps of which are as follows:

[0061] Step 1: Mix and disperse epoxy resin, diluent, curing agent 1 and lipophilic emulsifier evenly using a high-speed disperser to obtain dispersion 1;

[0062] Step 2: Add the electrolyte solution dropwise to dispersion 1 at a constant rate, and stir at high speed under constant temperature to obtain a water-in-oil emulsion;

[0063] Step 3: Under constant temperature, deionized water, hydrophilic emulsifier and curing agent 2 are uniformly mixed and dispersed using a high-speed disperser to obtain dispersion 2;

[0064] Step 4: Add the water-in-oil emulsion to dispersion 2 and continue stirring at high speed to emulsify, thereby obtaining a water-in-oil emulsion system;

[0065] Step 5: Heat the water-in-oil-in-water emulsion system, stir continuously, and adjust the curing temperature and time to control the formation of epoxy resin balls into nanoparticles and retain more reactive groups.

[0066] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to obtain a solid nano-adhesive;

[0067] Step 7: The solid nano-adhesive is ground and then evenly spread into a stainless steel groove mold. After high-temperature treatment under certain pressure using a hot press, a lithium battery separator is obtained. A nanoscale self-adhesive epoxy resin adhesive is obtained through the successful latency of a dual emulsion method and curing agent. High-temperature treatment allows the adhesive to self-adhere and form a film. Because this solid adhesive is a cured epoxy resin, it exhibits excellent thermal stability, chemical corrosion resistance, and mechanical properties. Furthermore, the spherical adhesive exhibits high porosity during the self-adhesive film formation process.

[0068] Specific Embodiment Seven: In the preparation method of a lithium battery separator described in Specific Embodiment Six, in step one, the epoxy resin is at least one of bisphenol A type epoxy resin, glycidyl ester epoxy resin, and alicyclic epoxy resin; the bisphenol A type epoxy resin is at least one of E55, E51, and E44; the glycidyl ester epoxy resin is at least one of 711#, TDE-85#, and 731#; the alicyclic epoxy resin is at least one of W-95#, 6221#, and 6206#; the diluent is at least one of ethylene glycol diglycidyl ether, phenyl glycidyl ether, polypropylene glycol diglycidyl ether, and butyl glycidyl ether; the curing agent 1 is maleic anhydride, phthalic anhydride, ... The invention utilizes one or a mixture of m-phenylenediamine, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenylmethane. The high-temperature curing agent does not react under low-temperature treatment during the nano-adhesive processing, thus achieving successful latency. The lipophilic emulsifier is at least one of Span 20, Span 40, Span 60, and Span 80. The mass ratio of epoxy resin to diluent is 3-6:1. The mass ratio of epoxy resin to curing agent 1 is 10:2-3, based on the theoretical amount of curing agent 1 used to cure epoxy resin. The mass ratio of epoxy resin to lipophilic emulsifier is 5:2-5. In step two, the mass ratio of epoxy resin to electrolyte solution is 5:2-5.

[0069] Specific Embodiment Eight: A method for preparing a lithium battery separator as described in Specific Embodiment Six or Seven, wherein in step two, the electrolyte solution is at least one of 0.1 mol / L sodium chloride solution, 0.1 mol / L potassium chloride solution, pH=10 NH3·H2O-NH4Cl buffer solution, and 0.1 mol / L sodium hydroxide solution; the constant reaction temperature is 40-60℃, the time is 10-15 min, and the stirring speed is 2500-3000 rpm. In step three, the initial temperature is 40-50℃; in step five, the temperature is raised to 60-80℃, and the heating process plus heat preservation reaction takes 25-30 minutes; the stirring speed is 1000-1500 rpm; in step seven, the amount of solid nano-adhesive is 0.02-0.05 g; the high temperature is the curing temperature of curing agent 1; at this temperature, curing agent 1 will react with the epoxy groups of epoxy resin, thereby causing cross-linking reaction between epoxy nanoparticles; the stainless steel mold groove size is 40*40*10 mm. 3 When uniformly spreading the nano-adhesive, use a coating knife to initially control its thickness to 0.05-0.1mm; the pressure of the hot press is 1-2MPa.

[0070] Specific Embodiment Nine: In the preparation method of a lithium battery separator described in Specific Embodiment Six, in step three, the hydrophilic emulsifier is one or a mixture of nonionic and anionic emulsifiers; either a single nonionic or anionic emulsifier can achieve emulsification, but using them in combination may yield better results; the nonionic emulsifier is at least one of polyoxyethylene ether, OP-10, and polyvinyl alcohol; the anionic emulsifier is at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and phosphate; the curing agent 2 is ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. One or a mixture; Curing agent 2 needs to be a fatty amine curing agent with a low curing temperature, because this type of curing agent must achieve partial curing of the epoxy nano-adhesive at a low temperature where curing agent 1 will not react; the mass ratio of deionized water to hydrophilic emulsifier is 15-20:1; the mass ratio of nonionic emulsifier to anionic emulsifier is 20:0-3 (if used in combination); the mass ratio of deionized water to curing agent 2 is 30-40:1; this amount is based on the theoretical amount of curing agent 2 used to cure epoxy resin; in step four, the mass ratio of deionized water to water-in-oil emulsion is 15-20:1.

[0071] Specific Embodiment Ten: A method for preparing a battery-structure integrated composite material including a lithium battery separator prepared according to any one of Specific Embodiments Six to Nine, the method further comprising:

[0072] Step 8: Mix the nano-binder, positive electrode active material, and conductive agent evenly and grind thoroughly. Spread the mixed powder evenly on aluminum foil and press it into shape using a hot press at high temperature to obtain the lithium battery positive electrode. The positive electrode active material is at least one of lithium manganese oxide, lithium cobalt oxide, and nickel-cobalt-manganese ternary materials. The conductive agent is at least one of acetylene black, conductive carbon black, and Super P. The mass ratio of the nano-binder to the positive electrode active material is 1-3:17, and the mass ratio of the nano-binder to the conductive agent is 1-2:1.

[0073] Step 9: Mix the nano-binder, negative electrode active material, and conductive agent evenly and grind thoroughly. Spread the mixed powder evenly on copper foil and press it into shape using a hot press at high temperature to obtain the lithium battery negative electrode. The negative electrode active material is at least one of graphite, lithium titanate, and silicon-carbon alloy. The conductive agent is at least one of acetylene black, conductive carbon black, and Super P. The mass ratio of the nano-binder to the negative electrode active material is 1-3:17, and the mass ratio of the nano-binder to the conductive agent is 1-2:1.

[0074] Step 10: Stack the negative electrode, separator, electrolyte, and positive electrode in the following order from bottom to top, and use a hot press to integrally hot press them at high temperature. This method obtains nanoscale solid epoxy resin binder particles by using a double emulsion method and successful latent curing agent. The positive and negative active materials are then bonded to the current collector along with a conductive agent using this nano-binder to form the positive and negative electrode sheets. High-temperature treatment causes the solid spherical binder to self-bond and form a film, thereby obtaining an epoxy resin-based lithium battery separator. The positive and negative electrode sheets and the battery separator are then hot-pressed in the lithium battery assembly sequence to form an integrated lithium battery composite material.

[0075] Example 1:

[0076] Step 1: Mix and disperse 0.1g of nano Ag particles, 10g of bisphenol A epoxy resin E44, 3.3g of ethylene glycol diglycidyl ether, 2g of maleic anhydride and 4g of Span 80 uniformly using a high-speed disperser at a speed of 2500rpm to obtain dispersion 1.

[0077] Step 2: Add 4g of sodium chloride solution dropwise to dispersion 1 at a constant rate, and stir at 2500rpm at 40℃ to obtain a water-in-oil emulsion. Since the electrolyte solution acts as the internal aqueous phase of the emulsion, it will increase the osmotic pressure inside the emulsion, preventing droplet aggregation.

[0078] Step 3: At 40℃, 200g of deionized water, 13.3g of polyoxyethylene ether and 6.6g of diethylenetriamine are uniformly mixed and dispersed using a high-speed disperser at 1000rpm to obtain dispersion 2.

[0079] Step 4: Add 13.3g of water-in-oil emulsion to dispersion 2 and emulsify at 1000rpm to obtain a water-in-oil emulsion system;

[0080] Step 5: Heat the water-in-oil-in-water emulsion system to 60℃ and stir continuously for a total of 25 minutes. A gradual, gradient heating method is used to cure the epoxy spherical particles, rather than directly applying the optimal curing temperature of curing agent 2. This avoids the damage to the water-in-oil-in-water emulsion caused by sudden temperature increases. Emulsifiers are generally sensitive to temperature changes; when the temperature exceeds the critical point, the emulsification process is disrupted, and the emulsion droplets break down or coalesce, resulting in larger and less uniform particle sizes. Furthermore, gradual heating and curing also facilitates control of the reaction rate and makes it easier to retain surface reactive groups.

[0081] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to remove residual emulsifier on the surface, and obtain the nano-conductive adhesive;

[0082] Step 7: Mix 0.02g of nano-conductive binder, 0.34g of graphite, and 0.02g of acetylene black evenly and grind thoroughly. Spread the mixed powder evenly on aluminum foil and press it at 160℃ under 2MPa pressure for 3 hours to obtain the dry-processed lithium battery electrode. Hot pressing can make the electrode sheet thickness uniform and increase the compaction density of the negative electrode material. Appropriate compaction density can increase the battery's discharge capacity, reduce internal resistance, reduce polarization loss, extend the battery's cycle life, and improve the utilization rate of lithium-ion batteries.

[0083] Example 2:

[0084] Step 1: Mix and disperse 0.5g of nano Au particles, 10g of bisphenol A epoxy resin E51, 1.7g of polyethylene glycol diglycidyl ether, 3g of 4,4'-diaminodiphenylmethane and 10g of Span 60 uniformly using a high-speed disperser at 3000rpm to obtain dispersion 1.

[0085] Step 2: Add 10g of sodium hydroxide solution dropwise to dispersion 1 at a constant rate, and stir at 3000rpm at 60℃ to obtain a water-in-oil emulsion. On the one hand, since the electrolyte solution acts as the inner aqueous phase of the emulsion, it will increase the osmotic pressure inside the emulsion, preventing droplet aggregation. On the other hand, sodium hydroxide has a catalytic effect on the ring-opening reaction of epoxy resin epoxy groups, which can accelerate the formation of epoxy resin spherical particles.

[0086] Step 3: At 50℃, 200g of deionized water, 10g of OP-10 and 5g of triethylenetetramine are uniformly mixed and dispersed using a high-speed disperser at 1500rpm to obtain dispersion 2.

[0087] Step 4: Add 10g of water-in-oil emulsion to dispersion 2 and emulsify at high speed of 1500rpm to obtain a water-in-oil emulsion system;

[0088] Step 5: Heat the water-in-oil-in-water emulsion system to 80°C and stir continuously. The total heating and holding time is 30 minutes to control the formation of nanoscale particles of epoxy resin balls and to retain more reactive groups.

[0089] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to remove residual emulsifier on the surface, and obtain the nano-conductive adhesive;

[0090] Step 7: Mix 0.06g of nano-conductive binder, 0.34g of lithium titanate, and 0.03g of conductive carbon black evenly and grind thoroughly. Spread the mixed powder evenly onto aluminum foil and press it at 80℃ and 2MPa for 2 hours using a hot press. Then, press it again at 160℃ and 2MPa for 2 hours to obtain the lithium battery electrode prepared by the dry method. Hot pressing can make the electrode sheet thickness uniform and increase the compaction density of the negative electrode material. Appropriate compaction density can increase the discharge capacity of the battery, reduce internal resistance, reduce polarization loss, extend the cycle life of the battery, and improve the utilization rate of lithium-ion batteries.

[0091] Example 3:

[0092] Step 1: Mix and disperse 0.08g graphene, 0.08g carbon fiber, 10g epoxy resin 711#, 1.25g butyl glycidyl ether, 1.25g polyethylene glycol diglycidyl ether, 2.5g m-phenylenediamine and 6g Span 40 evenly using a high-speed disperser at 2700 rpm to obtain dispersion 1.

[0093] Step 2: Add 4g of NH3·H2O-NH4Cl buffer solution and 4g of potassium chloride solution dropwise to dispersion 1 at a constant rate, and stir at 2700 rpm at 50°C to obtain a water-in-oil emulsion. Since the electrolyte solution acts as the inner aqueous phase of the emulsion, it will increase the osmotic pressure inside the emulsion, preventing droplet aggregation.

[0094] Step 3: At 45℃, 200g of deionized water, 6g of polyvinyl alcohol, 6g of OP-10, 3g of triethylenetetramine, and 3g of tetraethylenepentamine are uniformly mixed and dispersed using a high-speed disperser at 1300rpm to obtain dispersion 2.

[0095] Step 4: Add 12g of water-in-oil emulsion to dispersion 2 and emulsify at 1300rpm to obtain a water-in-oil emulsion system.

[0096] Step 5: Heat the water-in-oil-in-water emulsion system to 70°C and stir continuously. The total heating and holding time is 27 minutes to control the formation of nanoscale particles of epoxy resin balls and to retain more reactive groups.

[0097] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to remove residual emulsifier on the surface, and obtain the nano-conductive adhesive;

[0098] Step 7: Mix 0.04g of nano-conductive binder, 0.34g of silicon-carbon alloy, and 0.026g of Super P evenly and grind thoroughly. Spread the mixed powder evenly onto aluminum foil and press it at 80℃ and 2MPa for 2 hours using a hot press. Then, continue pressing at 150℃ and 2MPa for 2 hours to obtain the dry-processed lithium battery electrode. Hot pressing can ensure uniform electrode thickness and increase the compaction density of the negative electrode material. Appropriate compaction density can increase the battery's discharge capacity, reduce internal resistance, reduce polarization loss, extend the battery's cycle life, and improve the utilization rate of lithium-ion batteries.

[0099] Figure 1 This invention relates to the dry fabrication of lithium battery electrodes. As shown in the figure, the lithium battery electrodes in this invention are uniformly distributed and firmly bonded on the aluminum foil.

[0100] Figure 2 The figure shows the cyclic voltammetry curves of a dry electrode for a lithium battery. As shown, the battery cycle is relatively stable after three activation cycles.

[0101] Example 4:

[0102] Step 1: Mix and disperse 10g of bisphenol A epoxy resin E44, 3.3g of ethylene glycol diglycidyl ether, 2g of maleic anhydride and 4g of Span 80 evenly using a high-speed disperser at a speed of 2500rpm to obtain dispersion 1.

[0103] Step 2: Add 4g of sodium chloride solution dropwise to dispersion 1 at a constant rate, and stir at 2500rpm at 40℃ to obtain a water-in-oil emulsion. Since the electrolyte solution acts as the internal aqueous phase of the emulsion, it will increase the osmotic pressure inside the emulsion, preventing droplet aggregation.

[0104] Step 3: At 40℃, 200g of deionized water, 13.3g of polyoxyethylene ether and 6.6g of diethylenetriamine are uniformly mixed and dispersed using a high-speed disperser at 1000rpm to obtain dispersion 2.

[0105] Step 4: Add 13.3g of water-in-oil emulsion to dispersion 2 and emulsify at 1000rpm to obtain a water-in-oil emulsion system;

[0106] Step 5: Heat the water-in-oil-in-water emulsion system to 60℃ and stir continuously for a total of 25 minutes. A gradual, gradient heating method is used to cure the epoxy spherical particles, rather than directly applying the optimal curing temperature of curing agent 2. This avoids the damage to the water-in-oil-in-water emulsion caused by sudden temperature increases. Emulsifiers are generally sensitive to temperature changes; when the temperature exceeds the critical point, the emulsification process is disrupted, and the emulsion droplets break down or coalesce, resulting in larger and less uniform particle sizes. Furthermore, gradual heating and curing also facilitates control of the reaction rate and makes it easier to retain surface reactive groups.

[0107] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to remove residual emulsifier from the surface, and obtain a solid nano-adhesive;

[0108] Step 7: Grind 0.02g of solid nano-adhesive, then use a coating knife to control the film thickness to 0.05mm, and evenly spread the adhesive in a groove with dimensions of 40*40*10mm. 3 In a stainless steel mold, after being treated at 160°C for 3 hours under 1MPa using a hot press, the epoxy resin solid adhesive can self-bond to obtain a lithium battery separator.

[0109] Example 5:

[0110] Step 1: Mix and disperse 10g of bisphenol A epoxy resin E51, 1.7g of polyethylene glycol diglycidyl ether, 3g of 4,4'-diaminodiphenylmethane and 10g of Span 60 evenly using a high-speed disperser at a speed of 3000rpm to obtain dispersion 1.

[0111] Step 2: Add 10g of sodium hydroxide solution dropwise to dispersion 1 at a constant rate, and stir at 3000rpm at 60℃ to obtain a water-in-oil emulsion. On the one hand, since the electrolyte solution acts as the inner aqueous phase of the emulsion, it will increase the osmotic pressure inside the emulsion, preventing droplet aggregation. On the other hand, sodium hydroxide has a catalytic effect on the ring-opening reaction of epoxy resin epoxy groups, which can accelerate the formation of epoxy resin spherical particles.

[0112] Step 3: At 50℃, 200g of deionized water, 10g of OP-10 and 5g of triethylenetetramine are uniformly mixed and dispersed using a high-speed disperser at 1500rpm to obtain dispersion 2.

[0113] Step 4: Add 10g of water-in-oil emulsion to dispersion 2 and emulsify at high speed of 1500rpm to obtain a water-in-oil emulsion system;

[0114] Step 5: Heat the water-in-oil-in-water emulsion system to 80°C and stir continuously. The total heating and holding time is 30 minutes to control the formation of nanoscale particles of epoxy resin balls and to retain more reactive groups.

[0115] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to remove residual emulsifier from the surface, and obtain a solid nano-adhesive;

[0116] Step 7: Grind 0.05g of solid nano-adhesive, then use a coating knife to control the film thickness to 0.1mm, and evenly spread the adhesive in a groove with dimensions of 40*40*10mm. 3 In a stainless steel mold, after being subjected to high-temperature treatment at 2MPa and 80℃ for 2 hours followed by 160℃ for 2 hours using a hot press, the epoxy resin solid adhesive can self-bond to obtain a lithium battery separator.

[0117] Example 6:

[0118] Step 1: Mix and disperse 10g of epoxy resin 711#, 1.25g of butyl glycidyl ether, 1.25g of polyethylene glycol diglycidyl ether, 2.5g of m-phenylenediamine and 6g of Span 40 evenly using a high-speed disperser at a speed of 2700 rpm to obtain dispersion 1.

[0119] Step 2: Add 4g of NH3·H2O-NH4Cl buffer solution and 4g of potassium chloride solution dropwise to dispersion 1 at a constant rate, and stir at 2700 rpm at 50°C to obtain a water-in-oil emulsion. Since the electrolyte solution acts as the inner aqueous phase of the emulsion, it will increase the osmotic pressure inside the emulsion, preventing droplet aggregation.

[0120] Step 3: At 45℃, 200g of deionized water, 6g of polyvinyl alcohol, 6g of OP-10, 3g of triethylenetetramine, and 3g of tetraethylenepentamine are uniformly mixed and dispersed using a high-speed disperser at 1300rpm to obtain dispersion 2.

[0121] Step 4: Add 12g of water-in-oil emulsion to dispersion 2 and emulsify at 1300rpm to obtain a water-in-oil emulsion system.

[0122] Step 5: Heat the water-in-oil-in-water emulsion system to 70℃ and stir continuously for a total reaction time of 27 minutes. A gradual temperature gradient is used to cure the epoxy spherical particles, rather than directly applying the optimal curing temperature of curing agent 2. This avoids the damage to the water-in-oil-in-water emulsion caused by sudden temperature increases. Emulsifiers are generally sensitive to temperature changes; when the temperature exceeds the critical point, the emulsification is disrupted, and the emulsion droplets break down or coalesce, resulting in larger and less uniform particle size. Furthermore, gradual temperature curing also helps control the reaction rate and makes it easier to retain surface reactive groups.

[0123] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to remove residual emulsifier from the surface, and obtain a solid nano-adhesive;

[0124] Step 7: Grind 0.03g of solid nano-adhesive, then use a coating knife to control the film thickness to 0.07mm, and evenly spread the adhesive in a groove with dimensions of 40*40*10mm. 3 In a stainless steel mold, after being subjected to high-temperature treatment at 1.5 MPa and 80°C for 2 hours followed by 150°C for 2 hours using a hot press, the epoxy resin solid adhesive can self-bond to obtain a lithium battery separator.

[0125] Figure 3 The image shows a SEM image of the nano-adhesive. As shown, the solid nano-adhesive in this invention has a minimum particle size of approximately 50 nm and exhibits a regular spherical shape.

[0126] Figure 4 The lithium battery separator is obtained by self-adhesion using a solid nano-binder. As shown in the figure, the solid binder can successfully self-adhere to form a film with uniform thickness under high-temperature hot pressing.

[0127] Figure 5 SEM image of the lithium battery separator obtained by self-adhesion with solid nano-binder. As shown in the figure, the lithium battery separator has high porosity, which is beneficial for ion exchange during lithium battery operation.

[0128] Example 7:

[0129] Step 1: Mix and disperse 10g of bisphenol A epoxy resin E44, 3.3g of ethylene glycol diglycidyl ether, 2g of maleic anhydride and 4g of Span 80 evenly using a high-speed disperser at a speed of 2500rpm to obtain dispersion 1.

[0130] Step 2: Add 4g of sodium chloride solution dropwise to dispersion 1 at a constant rate, and stir at 2500rpm at 40℃ to obtain a water-in-oil emulsion. Since the electrolyte solution acts as the internal aqueous phase of the emulsion, it will increase the osmotic pressure inside the emulsion, preventing droplet aggregation.

[0131] Step 3: At 40℃, 200g of deionized water, 13.3g of polyoxyethylene ether and 6.6g of diethylenetriamine are uniformly mixed and dispersed using a high-speed disperser at 1000rpm to obtain dispersion 2.

[0132] Step 4: Add 13.3g of water-in-oil emulsion to dispersion 2 and emulsify at 1000rpm to obtain a water-in-oil emulsion system;

[0133] Step 5: Heat the water-in-oil-in-water emulsion system to 60℃ and stir continuously for a total of 25 minutes. A gradual, gradient heating method is used to cure the epoxy spherical particles, rather than directly applying the optimal curing temperature of curing agent 2. This avoids the damage to the water-in-oil-in-water emulsion caused by sudden temperature increases. Emulsifiers are generally sensitive to temperature changes; when the temperature exceeds the critical point, the emulsification process is disrupted, and the emulsion droplets break down or coalesce, resulting in larger and less uniform particle sizes. Furthermore, gradual heating and curing also facilitates control of the reaction rate and makes it easier to retain surface reactive groups.

[0134] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to remove residual emulsifier from the surface, and obtain a solid nano-adhesive;

[0135] Step 7: Mix 0.02g of nano-binder, 0.34g of lithium manganese oxide, and 0.02g of acetylene black evenly and grind thoroughly. Spread the mixed powder evenly onto aluminum foil and press it at 160℃ under 2MPa pressure for 1.5h (half the time for complete curing of maleic anhydride, to maintain a certain reactivity for final battery assembly). This yields the dry-processed lithium battery positive electrode. Hot pressing can ensure uniform electrode thickness and increase the compaction density of the negative electrode material. Appropriate compaction density can increase the battery's discharge capacity, reduce internal resistance, reduce polarization loss, extend the battery's cycle life, and improve the utilization rate of lithium-ion batteries.

[0136] Step 8: Mix 0.02g of nano-binder, 0.34g of graphite, and 0.02g of acetylene black evenly and grind thoroughly. Spread the mixed powder evenly on copper foil and press it at 160°C under a pressure of 2MPa for 1.5 hours (half the time for maleic anhydride to completely cure, to maintain a certain reactivity for the final battery assembly). This will give you the dry-processed lithium battery negative electrode.

[0137] Step 9: Grind 0.02g of solid nano-adhesive, then use a coating knife to control the film thickness to 0.05mm, and evenly spread the adhesive in a groove with dimensions of 40*40*10mm. 3In a stainless steel mold, after being treated at 160°C for 1.5 hours at 1 MPa using a hot press (half the time for complete curing of maleic anhydride, to maintain a certain reactivity for final battery assembly), the epoxy resin solid adhesive can self-bond to obtain a lithium battery separator.

[0138] Step 10: Stack the negative electrode, separator, electrolyte, and positive electrode in the following order from bottom to top. Then, use a hot press to heat-press the electrode at 160°C for 1.5 hours under 2MPa.

[0139] Example 8:

[0140] Step 1: Mix and disperse 10g of bisphenol A epoxy resin E51, 1.7g of polyethylene glycol diglycidyl ether, 3g of 4,4'-diaminodiphenylmethane and 10g of Span 60 evenly using a high-speed disperser at a speed of 3000rpm to obtain dispersion 1.

[0141] Step 2: Add 10g of sodium hydroxide solution dropwise to dispersion 1 at a constant rate, and stir at 3000rpm at 60℃ to obtain a water-in-oil emulsion. On the one hand, since the electrolyte solution acts as the inner aqueous phase of the emulsion, it will increase the osmotic pressure inside the emulsion, preventing droplet aggregation. On the other hand, sodium hydroxide has a catalytic effect on the ring-opening reaction of epoxy resin epoxy groups, which can accelerate the formation of epoxy resin spherical particles.

[0142] Step 3: At 50℃, 200g of deionized water, 10g of OP-10 and 5g of triethylenetetramine are uniformly mixed and dispersed using a high-speed disperser at 1500rpm to obtain dispersion 2.

[0143] Step 4: Add 10g of water-in-oil emulsion to dispersion 2 and emulsify at high speed of 1500rpm to obtain a water-in-oil emulsion system;

[0144] Step 5: Heat the water-in-oil-in-water emulsion system to 80°C and stir continuously. The total heating and holding time is 30 minutes to control the formation of nanoscale particles of epoxy resin balls and to retain more reactive groups.

[0145] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to remove residual emulsifier from the surface, and obtain a solid nano-adhesive;

[0146] Step 7: Mix 0.06g of nano-binder, 0.34g of lithium cobalt oxide and 0.03g of conductive carbon black evenly and grind them thoroughly. Spread the mixed powder evenly on aluminum foil and press it at 80°C and 2MPa pressure for 2 hours to obtain the lithium battery positive electrode prepared by dry method.

[0147] Step 8: Mix 0.06g of nano-binder, 0.34g of lithium titanate, and 0.03g of conductive carbon black evenly and grind them thoroughly. Spread the mixed powder evenly on copper foil and press it at 80°C and 2MPa pressure for 2 hours to obtain the dry-processed lithium battery negative electrode.

[0148] Step 9: Grind 0.05g of solid nano-adhesive, then use a coating knife to control the film thickness to 0.1mm, and evenly spread the adhesive in a groove with dimensions of 40*40*10mm. 3 In a stainless steel mold, after being treated with a hot press at 2 MPa and 80°C for 2 hours, the epoxy resin solid adhesive can self-bond to obtain a lithium battery separator.

[0149] Step 10: Stack the negative electrode, separator, electrolyte, and positive electrode in the following order from bottom to top. Then, use a hot press to heat-press the entire assembly at 160°C for 2 hours at 2 MPa. (The complete curing process of 4,4'-diaminodiphenylmethane involves 2 hours at 80°C followed by 2 hours at 160°C. The preparation of the positive and negative electrodes and separator is only carried out at 80°C to maintain a certain level of reactivity for final battery assembly.)

[0150] Example 9:

[0151] Step 1: Mix and disperse 10g of epoxy resin 711#, 1.25g of butyl glycidyl ether, 1.25g of polyethylene glycol diglycidyl ether, 2.5g of m-phenylenediamine and 6g of Span 40 evenly using a high-speed disperser at a speed of 2700 rpm to obtain dispersion 1.

[0152] Step 2: Add 4g of NH3·H2O-NH4Cl buffer solution and 4g of potassium chloride solution dropwise to dispersion 1 at a constant rate, and stir at 2700 rpm at 50°C to obtain a water-in-oil emulsion. Since the electrolyte solution acts as the inner aqueous phase of the emulsion, it will increase the osmotic pressure inside the emulsion, preventing droplet aggregation.

[0153] Step 3: At 45℃, 200g of deionized water, 6g of polyvinyl alcohol, 6g of OP-10, 3g of triethylenetetramine, and 3g of tetraethylenepentamine are uniformly mixed and dispersed using a high-speed disperser at 1300rpm to obtain dispersion 2.

[0154] Step 4: Add 12g of water-in-oil emulsion to dispersion 2 and emulsify at 1300rpm to obtain a water-in-oil emulsion system.

[0155] Step 5: Heat the water-in-oil-in-water emulsion system to 70℃ and stir continuously for a total reaction time of 27 minutes. A gradual temperature gradient is used to cure the epoxy spherical particles, rather than directly applying the optimal curing temperature of curing agent 2. This avoids the damage to the water-in-oil-in-water emulsion caused by sudden temperature increases. Emulsifiers are generally sensitive to temperature changes; when the temperature exceeds the critical point, the emulsification is disrupted, and the emulsion droplets break down or coalesce, resulting in larger and less uniform particle size. Furthermore, gradual temperature curing also helps control the reaction rate and makes it easier to retain surface reactive groups.

[0156] Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to remove residual emulsifier from the surface, and obtain a solid nano-adhesive;

[0157] Step 7: Mix 0.04g of nano-binder, 0.34g of nickel-cobalt-manganese ternary material and 0.026g of Super P evenly and grind thoroughly. Spread the mixed powder evenly on aluminum foil and press it at 80℃ and 2MPa pressure for 2 hours to obtain the dry-processed lithium battery cathode.

[0158] Step 8: Mix 0.04g of nano-binder, 0.34g of silicon-carbon alloy, and 0.026g of Super P evenly and grind thoroughly. Spread the mixed powder evenly on copper foil and press it at 80°C and 2MPa pressure for 2 hours to obtain the dry-processed lithium battery negative electrode.

[0159] Step 9: Grind 0.03g of solid nano-adhesive, then use a coating knife to control the film thickness to 0.07mm, and evenly spread the adhesive in a groove with dimensions of 40*40*10mm. 3 In a stainless steel mold, after being treated at 80°C for 2 hours under 1.5 MPa using a hot press, the epoxy resin solid adhesive can self-bond to obtain a lithium battery separator.

[0160] Step 10: Stack the negative electrode, separator, electrolyte, and positive electrode in the following order from bottom to top. Use a hot press to heat-press the entire assembly at 2 MPa and 150°C for 2 hours. (The complete curing process of m-phenylenediamine involves 2 hours at 80°C followed by 2 hours at 150°C. The positive and negative electrode and separator are prepared at only 80°C to maintain a certain level of reactivity for final battery assembly.) Figure 6 This is a schematic diagram of a battery-structure integrated composite material structure.

Claims

1. A method for preparing a lithium battery separator, characterized in that: The method steps are as follows: Step 1: Mix and disperse epoxy resin, diluent, curing agent 1 and lipophilic emulsifier evenly to obtain dispersion 1; the curing agent 1 is one or a mixture of maleic anhydride, phthalic anhydride, m-phenylenediamine, 3,3'-diethyl-4,4'-diaminodiphenylmethane and 4,4'-diaminodiphenylmethane. Step 2: Add the electrolyte solution dropwise to dispersion 1 at a constant rate, and stir at a constant temperature of 40-60℃ to obtain a water-in-oil emulsion; Step 3: At a constant temperature of 40-50℃, deionized water, hydrophilic emulsifier and curing agent 2 are uniformly mixed and dispersed to obtain dispersion 2; the curing agent 2 is one or a mixture of ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine. Step 4: Add the water-in-oil emulsion to dispersion 2 and continue stirring at high speed to emulsify, thereby obtaining a water-in-oil emulsion system; Step 5: Heat the water-in-oil-in-water emulsion system to 60-80℃ and stir continuously to solidify it; The heating process, including the heat preservation reaction, takes 25-30 minutes in total. Step 6: Centrifuge, wash, and dry the cured water-in-oil-in-water emulsion system to obtain a solid nano-adhesive; Step 7: Grind the solid nano-adhesive and then spread it evenly in a stainless steel groove mold. After high-temperature treatment under certain pressure using a hot press, a lithium battery separator is obtained; the high temperature is the curing temperature of curing agent 1.

2. The method for preparing a lithium battery separator according to claim 1, characterized in that: In step one, the epoxy resin is at least one of bisphenol A type epoxy resin, glycidyl ester epoxy resin, and alicyclic epoxy resin; the diluent is at least one of ethylene glycol diglycidyl ether, phenyl glycidyl ether, polypropylene glycol diglycidyl ether, and butyl glycidyl ether; and the lipophilic emulsifier is at least one of Span 20, Span 40, Span 60, and Span 80.

3. The method for preparing a lithium battery separator according to claim 2, characterized in that: In step one, the bisphenol A type epoxy resin is at least one of E55, E51 and E44; the glycidyl ester epoxy resin is at least one of 711#, TDE-85# and 731#; and the alicyclic epoxy resin is at least one of W-95#, 6221# and 6206#.

4. The method for preparing a lithium battery separator according to claim 1, characterized in that: In step one, the mass ratio of epoxy resin to diluent is 3-6:1; the mass ratio of epoxy resin to curing agent 1 is 10:2-3; and the mass ratio of epoxy resin to oleophilic emulsifier is 5:2-5.

5. The method for preparing a lithium battery separator according to claim 1, characterized in that: In step two, the mass ratio of the electrolyte solution to the epoxy resin in step one is 2-5:

5.

6. A method for preparing a lithium battery separator according to claim 1 or 5, characterized in that: In step two, the electrolyte solution is at least one of the following: a 0.1 mol / L sodium chloride solution, a 0.1 mol / L potassium chloride solution, an NH3·H2O-NH4Cl buffer solution with pH=10, and a 0.1 mol / L sodium hydroxide solution.

7. A method for preparing a lithium battery separator according to claim 1 or 5, characterized in that: In step two, the temperature is maintained for 10-15 minutes, and the stirring speed is 2500-3000 rpm; in step five, the stirring speed is 1000-1500 rpm; in step seven, the amount of solid nano-binder is 0.02-0.05 g; the groove size of the stainless steel groove mold is 40×40×10mm. 3 When uniformly spreading the nano-adhesive, use a coating knife to initially control its thickness to 0.05-0.1 mm; the pressure of the hot press is 1-2 MPa.

8. The method for preparing a lithium battery separator according to claim 1, characterized in that: In step three, the hydrophilic emulsifier is one or a mixture of nonionic and anionic emulsifiers; the nonionic emulsifier is at least one of polyoxyethylene ether, OP-10 and polyvinyl alcohol; the anionic emulsifier is at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and phosphate.

9. The method for preparing a lithium battery separator according to claim 8, characterized in that: In step three, the mass ratio of deionized water to hydrophilic emulsifier is 15-20:1; the mass ratio of nonionic emulsifier to anionic emulsifier is 20:0-3; and the mass ratio of deionized water to curing agent 2 is 30-40:

1.

10. The method for preparing a lithium battery separator according to claim 1, characterized in that: In step four, the mass ratio of the water-in-oil emulsion to the deionized water in step three is 1:15-20.

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