High-performance lead-acid battery separator and preparation method thereof

Abstract

The invention discloses a high-performance lead-acid battery separator and a preparation method thereof, and belongs to the technical field of battery separators. The partition plate comprises a three-layer structure from bottom to top, the bottom layer and the surface layer are both modified glass fiber mats, and the middle layer is a mixed fiber mat prepared from glass fibers and composite organic fibers; a middle-layer mixed fiber felt of the partition plate is impregnated with conductive liquid to load a conductive nano material; the modified glass fiber mat is prepared from modified glass fibers, the modified glass fibers are glass fiber grafted vinyl-containing siloxane, the composite organic fibers in the mixed fiber mat are skin-core structure fibers, a core layer material is polyphenylene sulfide, and a skin layer material is polyethylene. On the basis of the excellent performance of a traditional AGM separator, the puncture resistance of the separator is remarkably improved through the combination effect of fiber material modification, separator structure design and fiber compounding, and the service life of a battery can be prolonged when the separator is used for the lead-acid battery.

Description

Technical Field

[0001] This invention belongs to the field of battery separator technology, specifically relating to a high-performance lead-acid battery separator and its preparation method. Background Technology

[0002] The separator is a crucial component of a lead-acid battery, also known as the "third plate." Its quality directly affects the battery's function and efficiency. Separators are made of microporous rubber, plastic, or fiberglass materials and typically exist in the battery in sheet or pouch form. Their main functions are: preventing short circuits between the positive and negative plates and ensuring the shortest possible distance between them; ensuring the smooth passage of positive and negative ions in the electrolyte to participate in electrode reactions; acting as a carrier for the electrolyte; slowing the shedding of lead paste from the positive and negative plates and preventing damage from shock; and preventing the migration and diffusion of substances harmful to the electrodes through the separator.

[0003] The basic properties that lead-acid battery separators should generally possess include good corrosion resistance, wettability, aging resistance, and oxidation resistance. With the development of the chemical industry, various types of separators have gradually emerged. AGM separators are made of ultra-fine glass fiber cotton, possessing extremely high porosity (typically >90%) and strong liquid absorption capacity. It can adsorb all the electrolyte within its pores, resulting in no free-flowing electrolyte inside the battery. The AGM separator itself has very low resistance, and because the electrolyte is tightly adsorbed onto the electrode surface, the ion migration path is short, giving AGM batteries low internal resistance and excellent high-current discharge performance.

[0004] However, AGM separators have certain drawbacks, such as poor puncture resistance, which directly affects the battery's lifespan and safety. Summary of the Invention

[0005] This invention provides a high-performance lead-acid battery separator and its preparation method, which can solve the problem of poor puncture resistance of AGM separators in the prior art.

[0006] The objective of this invention can be achieved through the following technical solutions: A high-performance lead-acid battery separator, the separator comprising a three-layer structure from bottom to top, wherein the bottom and top layers are modified glass fiber felt, and the middle layer is a mixed fiber felt made of glass fiber and composite organic fiber; The middle layer of the partition, a mixed fiber felt, is loaded with conductive nanomaterials by being impregnated with a conductive liquid.

[0007] Furthermore, the modified glass fiber mat is prepared from modified glass fiber; the modified glass fiber is glass fiber grafted with vinyl siloxane.

[0008] Furthermore, the vinylsiloxane is at least one of vinyltrimethoxysilane and vinyltriethoxysilane.

[0009] Furthermore, the preparation steps of the modified glass fiber are as follows: Glass fibers were dispersed in anhydrous ethanol and stirred until homogeneous to obtain a glass fiber dispersion. Vinylsiloxane was dissolved in anhydrous ethanol to obtain a siloxane solution. The siloxane solution and the glass fiber dispersion were mixed, and an ammonia solution was added to adjust the pH to 9-10. The mixture was heated and stirred to react. After the reaction was completed, the mixture was filtered and dried to obtain modified glass fibers.

[0010] Vinylsiloxanes are hydrolyzed to form silanols, which then undergo a condensation reaction with hydroxyl groups on the surface of glass fibers to form stable siloxane bonds. Through this reaction, a large number of hydrophobic groups in the siloxanes are grafted onto the surface of the glass fibers, increasing the hydrophobicity of the glass fibers.

[0011] Because of its good wettability, pure glass fiber causes the gas channels in the separator to be almost completely blocked by the electrolyte, resulting in low oxygen recombination efficiency. The oxygen recombination efficiency of the separator directly affects the discharge performance and lifespan of the battery.

[0012] Furthermore, the mass ratio of the glass fiber to the vinyl siloxane is 1:2-5.

[0013] Furthermore, the concentration of the ammonia solution is 1wt%-10wt%.

[0014] Furthermore, the temperature of the heating and stirring reaction is 30-50℃, and the reaction time is 0.5-1.5h.

[0015] Furthermore, the composite organic fiber in the mixed fiber felt is a core-sheath structure fiber, the core material is polyphenylene sulfide, the sheath material is polyethylene, and the mass ratio of the core layer to the sheath layer is (5-6):(4-5).

[0016] Furthermore, the preparation steps of the composite organic fiber are as follows: Polyethylene and peroxide initiator are mixed evenly and fed into a screw extruder for melting and extrusion to form a skin melt. Polyphenylene sulfide chips are fed into a screw extruder for melting and extrusion to form a core melt. The skin melt and core melt are combined through a skin-core composite component and extruded through a skin-core composite spinneret. After cooling, oiling, stretching, and heat setting, composite organic fibers are obtained.

[0017] The core material of the composite organic fiber is high-strength polyphenylene sulfide, and the outer layer is polyethylene, both of which have good acid resistance. Using low-melting-point polyethylene as the outer layer allows for partial melting during the drying process of the fiber felt, achieving a bonded three-layer structure. The blending of composite organic fibers with glass fibers imparts excellent puncture resistance to the fiber felt.

[0018] Furthermore, the peroxide initiator is one of dimethylbenzoyl peroxide and dicumyl peroxide; The peroxide initiator is 0.1-0.4% of the mass of polyethylene.

[0019] Adding a peroxide initiator to the skin layer of the composite organic fiber causes the skin layer material to melt during the high-temperature drying process. Under the action of the peroxide initiator, free radicals are produced, which react with the vinyl groups containing vinyl siloxane grafted onto the modified glass fibers of the bottom and top layers, thereby enhancing the bonding strength between the intermediate layer, the top layer, and the bottom layer.

[0020] Furthermore, the preparation steps of the conductive liquid are as follows: KH550 silane coupling agent was added to anhydrous ethanol and stirred until homogeneous. Carboxylated multi-walled carbon nanotubes were then added and ultrasonically dispersed to obtain a conductive liquid.

[0021] Carboxylated multi-walled carbon nanotubes have good electrical conductivity. Due to hydrogen bonding and electrostatic interaction, the carbon nanotubes are uniformly coated on the surface of the glass fiber in the intermediate layer after impregnation. The physical overlap of the carbon nanotubes can enhance the conductivity, and the load on the intermediate layer can prevent them from falling off. The loading of carboxylated multi-walled carbon nanotubes on the intermediate layer fibers can also further improve the puncture resistance of the separator.

[0022] Furthermore, the mass ratio of the KH550 silane coupling agent to the carboxylated multi-walled carbon nanotubes is 1-2:1.

[0023] Furthermore, the concentration of carboxylated multi-walled carbon nanotubes in the conductive liquid is 0.5-1 g / L.

[0024] This invention also provides a method for preparing a high-performance lead-acid battery separator, comprising the following steps: S1. Modified glass fiber is pulped, mixed, and slag removed to obtain a uniform slurry A; S2. The uniform slurry A in S1 is fed into a molding machine for molding to form wet modified glass fiber mat. S3. After mixing glass fiber and composite organic fiber, a uniform slurry B is obtained through pulping, slurry preparation and slag removal. S4. The uniform slurry B in S4 is fed into a molding machine for molding to form a wet mixed fiber felt. S5. Immerse the wet mixed fiber felt in the conductive liquid for 6-10 hours; S6. Lay the wet modified glass fiber mat, the wet mixed fiber mat treated in S5, and the wet modified glass fiber mat together in order from bottom to top. After drying and curing at 130-150℃, roll them up and cut them to obtain the partition.

[0025] Furthermore, in S3, the mass ratio of the glass fiber to the composite organic fiber is (8-9):(1-2).

[0026] Furthermore, the thickness of the high-performance lead-acid battery separator is 1.0mm-3.0mm, and the thickness ratio of the bottom layer, the middle layer and the top layer is 1:1-2:1.

[0027] The beneficial effects of this invention are: (1) Based on the excellent performance of traditional AGM separators, this invention significantly improves the high-rate discharge performance and cycle life of lead-acid batteries through the combined effects of fiber material modification, separator structure design and fiber composite.

[0028] (2) The present invention loads conductive nanomaterials (carboxylated multi-walled carbon nanotubes) in the intermediate layer, providing an additional, low-resistance conduction path for electrons between the positive and negative electrodes. This greatly reduces the internal resistance of the battery, resulting in a smaller voltage drop and higher output power in high-rate discharge scenarios such as startup and acceleration.

[0029] (3) The present invention modifies glass fiber by containing vinyl siloxane to improve the hydrophobicity of glass fiber and enhance oxygen recombination efficiency. The resulting separator can extend battery life and improve cycle performance when used in lead-acid batteries.

[0030] (4) The present invention cleverly designs the middle layer structure of the separator, which is a mixture of composite organic fiber with glass fiber and core structure. The core layer of composite organic fiber is polyphenylene sulfide, which can provide extremely high temperature resistance and chemical corrosion resistance, improve the stability of the middle layer in the battery environment, and can serve as the skeleton support of composite organic fiber. The outer layer of composite organic fiber is polyethylene with a low melting point, which can be bonded to the surface layer and bottom layer through melting and chemical reaction during the drying process. Composite organic fiber gives the separator better mechanical properties.

[0031] (5) The present invention uses a three-layer composite fiber felt to form a partition. The multi-layer structure maintains the high porosity and excellent liquid absorption and retention capacity of the partition, and further improves the puncture resistance of the partition. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] Preparation of modified glass fibers: Glass fibers were dispersed in anhydrous ethanol and stirred until homogeneous to obtain a glass fiber dispersion with a concentration of 1 wt%. Vinyltrimethoxysilane was dissolved in anhydrous ethanol to obtain a siloxane solution with a concentration of 5 wt%. The siloxane solution and the glass fiber dispersion were mixed, with a mass ratio of glass fiber to vinyltrimethoxysilane of 1:3. Ammonia solution (concentration of 5 wt%) was added to adjust the pH to 10. The mixture was heated to 40°C and stirred for 1 hour. After the reaction was completed, the mixture was filtered and dried to obtain modified glass fibers.

[0035] Preparation of composite organic fibers: Polyethylene and dicumyl peroxide are uniformly mixed and fed into a screw extruder for melt extrusion to form a skin melt. The dicumyl peroxide content is 0.3% of the polyethylene mass. The temperatures of zones one to five of the screw extruder are 170℃, 190℃, 210℃, 220℃, and 225℃. Polyphenylene sulfide chips are fed into the screw extruder for melt extrusion to form a core melt. The temperatures of zones one to five of the screw extruder are 270℃, 300℃, 290℃, 295℃, and 300℃. The skin melt and core melt are combined through a skin-core composite assembly, with a core-to-skin mass ratio of 5.5:4.5. The mixture is then extruded through a skin-core composite spinneret, and after cooling, oiling, stretching, and heat setting, composite organic fibers are obtained.

[0036] Preparation of conductive liquid: KH550 silane coupling agent was added to anhydrous ethanol at a concentration of 1.6 g / L and stirred for 20 min to mix evenly. Carboxylated multi-walled carbon nanotubes were then added and ultrasonically dispersed for 40 min to obtain a conductive liquid with a concentration of 0.8 g / L of carboxylated multi-walled carbon nanotubes in the conductive liquid.

[0037] Preparation of partitions: S1. Modified glass fiber is pulped, mixed, and slag removed to obtain a uniform slurry A; S2. The uniform slurry A in S1 is fed into a molding machine for molding to form wet modified glass fiber mat. S3. Glass fiber and composite organic fiber are mixed at a mass ratio of 8.5:1.5. After pulping, mixing and deslagging, a uniform pulp B is obtained. S4. The uniform slurry B in S4 is fed into a molding machine for molding to form a wet mixed fiber felt. S5. Immerse the wet mixed fiber felt in the conductive liquid for 8 hours; S6. The wet modified glass fiber mat, the wet mixed fiber mat treated in S5, and the wet modified glass fiber mat are laid flat and stacked together in order from bottom to top. After drying and curing at 140℃, they are rolled up and cut to obtain a partition. The top and bottom layers of the partition are both modified glass fiber mat, and the middle layer is mixed fiber mat. The thickness of the partition is 2.0mm, and the thickness ratio of the bottom layer, the middle layer and the top layer is 1:1:1.

[0038] Example 2

[0039] The only difference from Example 1 is that the mass ratio of glass fiber to vinyltrimethoxysilane in the preparation of the modified glass fiber is 1:2. The steps for preparing the composite organic fiber, formulating the conductive liquid, and preparing the separator are the same as in Example 1. The specific steps for preparing the modified glass fiber are as follows: Glass fibers were dispersed in anhydrous ethanol and stirred until homogeneous to obtain a glass fiber dispersion with a concentration of 1 wt%. Vinyltrimethoxysilane was dissolved in anhydrous ethanol to obtain a siloxane solution with a concentration of 5 wt%. The siloxane solution and the glass fiber dispersion were mixed, with a mass ratio of glass fiber to vinyltrimethoxysilane of 1:2. Ammonia solution (concentration of 5 wt%) was added to adjust the pH to 10. The mixture was heated to 40°C and stirred for 1 hour. After the reaction was completed, the mixture was filtered and dried to obtain modified glass fibers.

[0040] Example 3

[0041] The only difference from Example 1 is that the mass ratio of glass fiber to vinyltrimethoxysilane in the preparation of the modified glass fiber is 1:5. The steps for preparing the composite organic fiber, preparing the conductive liquid, and preparing the separator are the same as in Example 1. The specific steps for preparing the modified glass fiber are as follows: Glass fibers were dispersed in anhydrous ethanol and stirred until homogeneous to obtain a glass fiber dispersion with a concentration of 1 wt%. Vinyltrimethoxysilane was dissolved in anhydrous ethanol to obtain a siloxane solution with a concentration of 5 wt%. The siloxane solution and the glass fiber dispersion were mixed, with a mass ratio of glass fiber to vinyltrimethoxysilane of 1:5. Ammonia solution (concentration of 5 wt%) was added to adjust the pH to 10. The mixture was heated to 40°C and stirred for 1 hour. After the reaction was completed, the mixture was filtered and dried to obtain modified glass fibers.

[0042] Example 4

[0043] The only difference from Example 1 is that the mass ratio of the core layer to the sheath layer in the composite organic fiber is 5:5. The steps for preparing the modified glass fiber, formulating the conductive liquid, and preparing the separator are the same as in Example 1. The specific steps for preparing the composite organic fiber are as follows: Polyethylene and dicumyl peroxide are uniformly mixed and fed into a screw extruder for melt extrusion to form a skin melt. The dicumyl peroxide content is 0.3% of the polyethylene mass. The temperatures of zones one to five of the screw extruder are 170℃, 190℃, 210℃, 220℃, and 225℃. Polyphenylene sulfide chips are fed into the screw extruder for melt extrusion to form a core melt. The temperatures of zones one to five of the screw extruder are 270℃, 300℃, 290℃, 295℃, and 300℃. The skin melt and core melt are combined through a skin-core composite assembly with a core-to-skin mass ratio of 5:5. The mixture is then extruded through a skin-core composite spinneret, cooled, oiled, drawn, and heat-set to obtain composite organic fibers.

[0044] Example 5

[0045] The only difference from Example 1 is that the mass ratio of the core layer to the sheath layer in the composite organic fiber is 6:4. The steps for preparing the modified glass fiber, formulating the conductive liquid, and preparing the separator are the same as in Example 1. The specific steps for preparing the composite organic fiber are as follows: Polyethylene and dicumyl peroxide are uniformly mixed and fed into a screw extruder for melt extrusion to form a skin melt. The dicumyl peroxide content is 0.3% of the polyethylene mass. The temperatures of zones one to five of the screw extruder are 170℃, 190℃, 210℃, 220℃, and 225℃. Polyphenylene sulfide chips are fed into the screw extruder for melt extrusion to form a core melt. The temperatures of zones one to five of the screw extruder are 270℃, 300℃, 290℃, 295℃, and 300℃. The skin melt and core melt are combined through a skin-core composite assembly, with a core-to-skin mass ratio of 6:4. The mixture is then extruded through a skin-core composite spinneret, and after cooling, oiling, stretching, and heat setting, composite organic fibers are obtained.

[0046] Example 6

[0047] The only difference from Example 1 is that the glass fiber and composite organic fiber in the intermediate layer of the separator are in a mass ratio of 8:2. The steps for preparing the modified glass fiber, the composite organic fiber, and the conductive liquid are the same as in Example 1. The specific steps for preparing the separator are as follows: S1. Modified glass fiber is pulped, mixed, and slag removed to obtain a uniform slurry A; S2. The uniform slurry A in S1 is fed into a molding machine for molding to form wet modified glass fiber mat. S3. Glass fiber and composite organic fiber are mixed at a mass ratio of 8:2. After pulping, mixing and slag removal, a uniform pulp B is obtained. S4. The uniform slurry B in S4 is fed into a molding machine for molding to form a wet mixed fiber felt. S5. Immerse the wet mixed fiber felt in the conductive liquid for 8 hours; S6. The wet modified glass fiber mat, the wet mixed fiber mat treated in S5, and the wet modified glass fiber mat are laid flat and stacked together in order from bottom to top. After drying and curing at 140℃, they are rolled up and cut to obtain a partition. The top and bottom layers of the partition are both modified glass fiber mat, and the middle layer is mixed fiber mat. The thickness of the partition is 2.0mm, and the thickness ratio of the bottom layer, the middle layer and the top layer is 1:1:1.

[0048] Example 7

[0049] The only difference from Example 1 is that the glass fiber and composite organic fiber in the intermediate layer of the separator are in a mass ratio of 9:1. The steps for preparing the modified glass fiber, the composite organic fiber, and the conductive liquid are the same as in Example 1. The specific steps for preparing the separator are as follows: S1. Modified glass fiber is pulped, mixed, and slag removed to obtain a uniform slurry A; S2. The uniform slurry A in S1 is fed into a molding machine for molding to form wet modified glass fiber mat. S3. Glass fiber and composite organic fiber are mixed at a mass ratio of 9:1. After pulping, mixing and slag removal, a uniform pulp B is obtained. S4. The uniform slurry B in S4 is fed into a molding machine for molding to form a wet mixed fiber felt. S5. Immerse the wet mixed fiber felt in the conductive liquid for 8 hours; S6. The wet modified glass fiber mat, the wet mixed fiber mat treated in S5, and the wet modified glass fiber mat are laid flat and stacked together in order from bottom to top. After drying and curing at 140℃, they are rolled up and cut to obtain a partition. The top and bottom layers of the partition are both modified glass fiber mat, and the middle layer is mixed fiber mat. The thickness of the partition is 2.0mm, and the thickness ratio of the bottom layer, the middle layer and the top layer is 1:1:1.

[0050] Example 8

[0051] The only difference from Example 1 is that the concentration of carboxylated multi-walled carbon nanotubes in the conductive liquid is 0.5 g / L, while maintaining the same mass ratio of KH550 silane coupling agent to carboxylated multi-walled carbon nanotubes as in Example 1. The steps for preparing the modified glass fiber, the composite organic fiber, and the separator are the same as in Example 1. The specific steps for preparing the conductive liquid are as follows: KH550 silane coupling agent was added to anhydrous ethanol at a concentration of 1 g / L and stirred for 20 min to mix evenly. Carboxylated multi-walled carbon nanotubes were then added and ultrasonically dispersed for 40 min to obtain a conductive liquid with a concentration of 0.5 g / L of carboxylated multi-walled carbon nanotubes in the conductive liquid.

[0052] Example 9

[0053] The only difference from Example 1 is that the concentration of carboxylated multi-walled carbon nanotubes in the conductive liquid is 1 g / L, while the mass ratio of KH550 silane coupling agent to carboxylated multi-walled carbon nanotubes remains the same as in Example 1. The steps for preparing the modified glass fiber, the composite organic fiber, and the separator are the same as in Example 1. The specific steps for preparing the conductive liquid are as follows: KH550 silane coupling agent was added to anhydrous ethanol at a concentration of 2 g / L and stirred for 20 min to mix evenly. Carboxylated multi-walled carbon nanotubes were then added and ultrasonically dispersed for 40 min to obtain a conductive liquid with a concentration of 1 g / L of carboxylated multi-walled carbon nanotubes in the conductive liquid.

[0054] Comparative Example 1

[0055] The only difference from Example 1 is that the glass fiber in this comparative example is not modified, and the surface and bottom layers of the partition are made of glass fiber directly.

[0056] Preparation of composite organic fibers: Polyethylene and dicumyl peroxide are uniformly mixed and fed into a screw extruder for melt extrusion to form a skin melt. The dicumyl peroxide content is 0.3% of the polyethylene mass. The temperatures of zones one to five of the screw extruder are 170℃, 190℃, 210℃, 220℃, and 225℃. Polyphenylene sulfide chips are fed into the screw extruder for melt extrusion to form a core melt. The temperatures of zones one to five of the screw extruder are 270℃, 300℃, 290℃, 295℃, and 300℃. The skin melt and core melt are combined through a skin-core composite assembly, with a core-to-skin mass ratio of 5.5:4.5. The mixture is then extruded through a skin-core composite spinneret, and after cooling, oiling, stretching, and heat setting, composite organic fibers are obtained.

[0057] Preparation of conductive liquid: KH550 silane coupling agent was added to anhydrous ethanol at a concentration of 1.6 g / L and stirred for 20 min to mix evenly. Carboxylated multi-walled carbon nanotubes were then added and ultrasonically dispersed for 40 min to obtain a conductive liquid with a concentration of 0.8 g / L of carboxylated multi-walled carbon nanotubes in the conductive liquid.

[0058] Preparation of partitions: S1. Glass fiber is pulped, mixed, and slag removed to obtain a uniform slurry A; S2. The uniform slurry A from S1 is fed into a molding machine for molding to form a wet glass fiber mat. S3. Glass fiber and composite organic fiber are mixed at a mass ratio of 8.5:1.5. After pulping, mixing and deslagging, a uniform pulp B is obtained. S4. The uniform slurry B in S4 is fed into a molding machine for molding to form a wet mixed fiber felt. S5. Immerse the wet mixed fiber felt in the conductive liquid for 8 hours; S6. Lay the wet glass fiber mat, the wet mixed fiber mat treated in S5, and the wet glass fiber mat together in order from bottom to top. After drying and curing at 140℃, roll them up and cut them to obtain a partition. The top and bottom layers of the partition are glass fiber mats, and the middle layer is mixed fiber mat. The thickness of the partition is 2.0mm, and the thickness ratio of the bottom layer, the middle layer, and the top layer is 1:1:1.

[0059] Comparative Example 2

[0060] The only difference from Example 1 is that in this comparative example, the middle layer of the partition is directly replaced with polyethylene fiber with added dicumyl peroxide to replace the composite organic fiber.

[0061] Preparation of modified glass fibers: Glass fibers were dispersed in anhydrous ethanol and stirred until homogeneous to obtain a glass fiber dispersion with a concentration of 1 wt%. Vinyltrimethoxysilane was dissolved in anhydrous ethanol to obtain a siloxane solution with a concentration of 5 wt%. The siloxane solution and the glass fiber dispersion were mixed, with a mass ratio of glass fiber to vinyltrimethoxysilane of 1:3. Ammonia solution (concentration of 5 wt%) was added to adjust the pH to 10. The mixture was heated to 40°C and stirred for 1 hour. After the reaction was completed, the mixture was filtered and dried to obtain modified glass fibers.

[0062] Preparation of polyethylene fibers: Polyethylene and dicumyl peroxide are uniformly mixed and fed into a screw extruder for melting and extrusion to form a melt. The dicumyl peroxide content is 0.3% of the polyethylene mass. The temperatures of zones one to five of the screw extruder are 170℃, 190℃, 210℃, 220℃, and 225℃, respectively. After being extruded through a spinneret, the melt is cooled, oiled, drawn, and heat-set to obtain polyethylene fibers.

[0063] Preparation of conductive liquid: KH550 silane coupling agent was added to anhydrous ethanol at a concentration of 1.6 g / L and stirred for 20 min to mix evenly. Carboxylated multi-walled carbon nanotubes were then added and ultrasonically dispersed for 40 min to obtain a conductive liquid with a concentration of 0.8 g / L of carboxylated multi-walled carbon nanotubes in the conductive liquid.

[0064] Preparation of partitions: S1. Modified glass fiber is pulped, mixed, and slag removed to obtain a uniform slurry A; S2. The uniform slurry A in S1 is fed into a molding machine for molding to form wet modified glass fiber mat. S3. Glass fiber and polyethylene fiber are mixed at a mass ratio of 8.5:1.5. After pulping, mixing and deslagging, a uniform slurry B is obtained. S4. The uniform slurry B in S4 is fed into a molding machine for molding to form a wet mixed fiber felt. S5. Immerse the wet mixed fiber felt in the conductive liquid for 8 hours; S6. The wet modified glass fiber mat, the wet mixed fiber mat treated in S5, and the wet modified glass fiber mat are laid flat and stacked together in order from bottom to top. After drying and curing at 140℃, they are rolled up and cut to obtain a partition. The top and bottom layers of the partition are both modified glass fiber mat, and the middle layer is mixed fiber mat. The thickness of the partition is 2.0mm, and the thickness ratio of the bottom layer, the middle layer and the top layer is 1:1:1.

[0065] Comparative Example 3

[0066] The only difference from Example 1 is that the composite organic fiber skin layer in this comparative example does not contain dicumyl peroxide.

[0067] Preparation of modified glass fibers: Glass fibers were dispersed in anhydrous ethanol and stirred until homogeneous to obtain a glass fiber dispersion with a concentration of 1 wt%. Vinyltrimethoxysilane was dissolved in anhydrous ethanol to obtain a siloxane solution with a concentration of 5 wt%. The siloxane solution and the glass fiber dispersion were mixed, with a mass ratio of glass fiber to vinyltrimethoxysilane of 1:3. Ammonia solution (concentration of 5 wt%) was added to adjust the pH to 10. The mixture was heated to 40°C and stirred for 1 hour. After the reaction was completed, the mixture was filtered and dried to obtain modified glass fibers.

[0068] Preparation of composite organic fibers: Polyethylene is fed into a screw extruder for melting and extrusion to form a skin melt. The temperatures in zones one through five of the screw extruder are 170℃, 190℃, 210℃, 220℃, and 225℃, respectively. Polyphenylene sulfide (PPS) chips are fed into the screw extruder for melting and extrusion to form a core melt. The temperatures in zones one through five of the screw extruder are 270℃, 300℃, 290℃, 295℃, and 300℃, respectively. The skin melt and core melt are combined through a skin-core composite assembly, with a core-to-skin mass ratio of 5.5:4.5. The resulting fibers are extruded through a skin-core composite spinneret and then cooled, oiled, drawn, and heat-set to obtain composite organic fibers.

[0069] Preparation of conductive liquid: KH550 silane coupling agent was added to anhydrous ethanol at a concentration of 1.6 g / L and stirred for 20 min to mix evenly. Carboxylated multi-walled carbon nanotubes were then added and ultrasonically dispersed for 40 min to obtain a conductive liquid with a concentration of 0.8 g / L of carboxylated multi-walled carbon nanotubes in the conductive liquid.

[0070] Preparation of partitions: S1. Modified glass fiber is pulped, mixed, and slag removed to obtain a uniform slurry A; S2. The uniform slurry A in S1 is fed into a molding machine for molding to form wet modified glass fiber mat. S3. Glass fiber and composite organic fiber are mixed at a mass ratio of 8.5:1.5. After pulping, mixing and deslagging, a uniform pulp B is obtained. S4. The uniform slurry B in S4 is fed into a molding machine for molding to form a wet mixed fiber felt. S5. Immerse the wet mixed fiber felt in the conductive liquid for 8 hours; S6. The wet modified glass fiber mat, the wet mixed fiber mat treated in S5, and the wet modified glass fiber mat are laid flat and stacked together in order from bottom to top. After drying and curing at 140℃, they are rolled up and cut to obtain a partition. The top and bottom layers of the partition are both modified glass fiber mat, and the middle layer is mixed fiber mat. The thickness of the partition is 2.0mm, and the thickness ratio of the bottom layer, the middle layer and the top layer is 1:1:1.

[0071] Comparative Example 4

[0072] The only difference from Example 1 is that no conductive liquid impregnation treatment was performed in this comparative example.

[0073] Preparation of modified glass fibers: Glass fibers were dispersed in anhydrous ethanol and stirred until homogeneous to obtain a glass fiber dispersion with a concentration of 1 wt%. Vinyltrimethoxysilane was dissolved in anhydrous ethanol to obtain a siloxane solution with a concentration of 5 wt%. The siloxane solution and the glass fiber dispersion were mixed, with a mass ratio of glass fiber to vinyltrimethoxysilane of 1:3. Ammonia solution (concentration of 5 wt%) was added to adjust the pH to 10. The mixture was heated to 40°C and stirred for 1 hour. After the reaction was completed, the mixture was filtered and dried to obtain modified glass fibers.

[0074] Preparation of composite organic fibers: Polyethylene and dicumyl peroxide are uniformly mixed and fed into a screw extruder for melt extrusion to form a skin melt. The dicumyl peroxide content is 0.3% of the polyethylene mass. The temperatures of zones one to five of the screw extruder are 170℃, 190℃, 210℃, 220℃, and 225℃. Polyphenylene sulfide chips are fed into the screw extruder for melt extrusion to form a core melt. The temperatures of zones one to five of the screw extruder are 270℃, 300℃, 290℃, 295℃, and 300℃. The skin melt and core melt are combined through a skin-core composite assembly, with a core-to-skin mass ratio of 5.5:4.5. The mixture is then extruded through a skin-core composite spinneret, and after cooling, oiling, stretching, and heat setting, composite organic fibers are obtained.

[0075] Preparation of partitions: S1. Modified glass fiber is pulped, mixed, and slag removed to obtain a uniform slurry A; S2. The uniform slurry A in S1 is fed into a molding machine for molding to form wet modified glass fiber mat. S3. Glass fiber and composite organic fiber are mixed at a mass ratio of 8.5:1.5. After pulping, mixing and deslagging, a uniform pulp B is obtained. S4. The uniform slurry B in S4 is fed into a molding machine for molding to form a wet mixed fiber felt. S5. The wet modified glass fiber mat, the wet mixed fiber mat treated in S5, and the wet modified glass fiber mat are laid flat and stacked together in order from bottom to top. After drying and curing at 140℃, they are rolled up and cut to obtain a partition. The top and bottom layers of the partition are both modified glass fiber mats, and the middle layer is a mixed fiber mat. The thickness of the partition is 2.0mm, and the thickness ratio of the bottom layer, the middle layer, and the top layer is 1:1:1.

[0076] Comparative Example 5

[0077] The only difference from Example 1 is that the partition in this comparative example has only one layer of structure, which is a modified glass fiber felt.

[0078] Preparation of modified glass fibers: Glass fibers were dispersed in anhydrous ethanol and stirred until homogeneous to obtain a glass fiber dispersion with a concentration of 1 wt%. Vinyltrimethoxysilane was dissolved in anhydrous ethanol to obtain a siloxane solution with a concentration of 5 wt%. The siloxane solution and the glass fiber dispersion were mixed, with a mass ratio of glass fiber to vinyltrimethoxysilane of 1:3. Ammonia solution (concentration of 5 wt%) was added to adjust the pH to 10. The mixture was heated to 40°C and stirred for 1 hour. After the reaction was completed, the mixture was filtered and dried to obtain modified glass fibers.

[0079] Preparation of partitions: S1. Modified glass fiber is pulped, mixed, and slag removed to obtain a uniform slurry A; S2. The uniform slurry A in S1 is fed into a molding machine for molding to form wet modified glass fiber mat. S3. After drying and curing the wet-modified glass fiber mat at 140℃, roll it up and cut it to obtain a partition with a thickness of 2.0mm.

[0080] The partitions prepared in Examples 1-9 and Comparative Examples 1-5 were subjected to performance tests, and the results are shown in Table 1.

[0081] Puncture resistance, pressurized acid absorption, and electrical resistance are tested according to standard GB / T 28535-2018.

[0082] Cycle life testing: The separators prepared in the examples and comparative examples were assembled into a 6-DZM-20Ah lead-acid battery. After the lead-acid battery was fully charged, it was discharged at 10A for 1.60 hours at 25°C, and then charged at a constant voltage of 15.00V and a current-limited of 4A for 6.40 hours. This constitutes one cycle life. When the battery terminal voltage drops below 10.50V three times consecutively after discharging for 1.60 hours, the battery life is considered to have ended, and these three cycles are not counted in the cycle life test.

[0083] Table 1

[0084] As shown in Table 1, compared to Example 1, in Examples 1-3, the amount of siloxane grafting on the modified glass fiber in Example 2 is reduced. This weakens the adhesion between the intermediate layer, surface layer, and bottom layer, resulting in a lower structural density and a significant decrease in the puncture resistance of the partition. In Example 3, the amount of siloxane grafting on the modified glass fiber is increased, but the hydrophobicity of the modified glass fiber is also enhanced. Furthermore, the reaction between the vinyl ester on the surface of the modified glass fiber and the molten polyethylene guides the polyethylene melt into the pores, leading to a decrease in porosity and hindering acid absorption. Examples 4 and 5 are based on Example 1, with adjustments made to the composite organic fiber. The skin and core materials of the composite organic fiber are different. When the proportion of polyethylene in the skin layer increases, the puncture strength slightly improves, but melting during the drying process causes pore blockage, reducing acid absorption. In Examples 6 and 7, the ratio of glass fiber to composite organic fiber in the intermediate layer mixed fiber felt differs from that in Example 1. The increase in composite organic fiber enhances the puncture resistance of the separator, but reduces its acid absorption and cycle performance. In Example 7, the proportion of composite organic fiber is lower than in Example 1, resulting in reduced separator resilience and decreased separator stability during cycling. Among Examples 1, 8, and 9, Example 1 exhibits the best cycle performance. Combining the structures of the comparative examples and the embodiments, the separator of this invention possesses excellent puncture resistance and low resistance, providing lead-acid batteries with better cycle performance.

[0085] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0086] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-performance lead-acid battery separator, characterized in that, The partition consists of three layers from bottom to top: the bottom and top layers are modified glass fiber felt, and the middle layer is a mixed fiber felt made of glass fiber and composite organic fiber. The middle layer of the partition is a mixed fiber felt that is impregnated with a conductive liquid and loaded with conductive nanomaterials. The modified glass fiber mat is prepared from modified glass fiber; the modified glass fiber is glass fiber grafted with vinyl siloxane. The composite organic fiber in the mixed fiber felt is a core-sheath structure fiber, with the core material being polyphenylene sulfide and the sheath material being polyethylene, and the mass ratio of the core layer to the sheath layer being (5-6):(4-5).

2. The high-performance lead-acid battery separator according to claim 1, characterized in that, The vinylsiloxane is at least one of vinyltrimethoxysilane and vinyltriethoxysilane.

3. The high-performance lead-acid battery separator according to claim 1, characterized in that, The preparation steps of the modified glass fiber are as follows: Glass fibers were dispersed in anhydrous ethanol and stirred until homogeneous to obtain a glass fiber dispersion. Vinylsiloxane was dissolved in anhydrous ethanol to obtain a siloxane solution. The siloxane solution and the glass fiber dispersion were mixed, and an ammonia solution was added to adjust the pH to 9-10. The mixture was heated and stirred to react. After the reaction was completed, the mixture was filtered and dried to obtain modified glass fibers.

4. A high-performance lead-acid battery separator according to claim 3, characterized in that, The mass ratio of the glass fiber to the vinyl siloxane is 1:2-5.

5. A high-performance lead-acid battery separator according to claim 1, characterized in that, The preparation steps of the composite organic fiber are as follows: Polyethylene and peroxide initiator are mixed evenly and fed into a screw extruder for melting and extrusion to form a skin melt. Polyphenylene sulfide chips are fed into a screw extruder for melting and extrusion to form a core melt. The skin melt and core melt are combined through a skin-core composite component and extruded through a skin-core composite spinneret. After cooling, oiling, stretching, and heat setting, composite organic fibers are obtained.

6. A high-performance lead-acid battery separator according to claim 1, characterized in that, The preparation steps of the conductive liquid are as follows: KH550 silane coupling agent was added to anhydrous ethanol and stirred until homogeneous. Carboxylated multi-walled carbon nanotubes were then added and ultrasonically dispersed to obtain a conductive liquid.

7. A high-performance lead-acid battery separator according to claim 6, characterized in that, The concentration of carboxylated multi-walled carbon nanotubes in the conductive liquid is 0.5-1 g / L.

8. A high-performance lead-acid battery separator according to claim 1, characterized in that, The thickness of the high-performance lead-acid battery separator is 1.0mm-3.0mm, and the thickness ratio of the bottom layer, the middle layer and the top layer is 1:1-2:

1.

9. A method for preparing a high-performance lead-acid battery separator as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Modified glass fiber is pulped, mixed, and slag removed to obtain a uniform slurry A; S2. The uniform slurry A in S1 is fed into a molding machine for molding to form wet modified glass fiber mat. S3. After mixing glass fiber and composite organic fiber, a uniform slurry B is obtained through pulping, slurry preparation and slag removal. S4. The uniform slurry B in S4 is fed into a molding machine for molding to form a wet mixed fiber felt. S5. Immerse the wet mixed fiber felt in the conductive liquid for 6-10 hours; S6. Lay the wet modified glass fiber mat, the wet mixed fiber mat treated in S5, and the wet modified glass fiber mat together in order from bottom to top. After drying and curing at 130-150℃, roll them up and cut them to obtain the partition.

10. The method for preparing a high-performance lead-acid battery separator according to claim 9, characterized in that, In S3, the mass ratio of glass fiber to composite organic fiber is (8-9):(1-2).

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