High-performance AGM separator and preparation method thereof

Abstract

The invention discloses a high-performance AGM separator and a preparation method thereof, and belongs to the technical field of lead-acid battery manufacturing. The high-performance AGM separator comprises the following raw materials in percentage by weight: 95%-99% of modified glass fibers, 0.9%-4% of polytrimethylene terephthalate fibers and 0.1%-1% of a compatilizer, the modified glass fiber is epoxy group modified glass fiber, and the compatilizer is hyperbranched polysilane containing amino, sulfonic acid group and quaternary ammonium salt group. The preparation method of the separator comprises the following steps: mixing the modified glass fiber, the polytrimethylene terephthalate fiber and the compatilizer, pulping, proportioning, deslagging, papermaking, drying, rolling and slitting to obtain the AGM separator. The separator prepared by the method has excellent strength and liquid absorbency.

Description

Technical Field

[0001] The present invention belongs to the technical field of lead-acid battery manufacturing, and particularly relates to a high-performance AGM separator and a preparation method thereof. Background Art

[0002] The separator is an important component of the storage battery and does not belong to the active material. In some cases, it even plays a decisive role. Its material itself is an electronic insulator, and its porosity gives it ionic conductivity. The resistance of the separator is an important property of the separator, which is determined by the thickness, porosity, and tortuosity of the pores of the separator, and has an important impact on the capacity and terminal voltage level of the high-rate discharge of the storage battery; the stability of the separator in sulfuric acid directly affects the service life of the storage battery; the elasticity of the separator can delay the shedding of the positive active material; the pore size of the separator affects the degree of lead dendrite short circuit.

[0003] Currently, ultra-fine glass fiber separators (AGM) are commonly used in valve-regulated lead-acid batteries. The main function of this separator is to enable the flow of ions between the electrodes and has an extremely high porosity; large specific surface area and good wettability are the main characteristics of the separator that can adsorb the maximum amount of electrolyte. Patent CN107256937A records a lead-acid battery separator and a preparation method thereof. This patent discloses a lead-acid battery separator, which is composed of 95%-99% glass fiber and 1%-5% polytrimethylene terephthalate fiber by weight percentage. The lead-acid battery separator of this invention adds polytrimethylene terephthalate fiber on the basis of glass fiber. Utilizing the excellent elongation and compression recovery performance of this material, the prepared separator has good wet-state pressure retention performance. The lead-acid battery made of the separator of this invention and the conventional AGM separator have no significant difference in other performances, while the cycle service life of the battery is extended. However, the poor compatibility between glass fiber and polytrimethylene terephthalate fiber will lead to a decline in the comprehensive performance of the AGM separator. Summary of the Invention

[0004] In order to solve the problem of poor compatibility between glass fiber and polytrimethylene terephthalate fiber in the background art, the purpose of the present invention is to provide a high-performance AGM separator and a preparation method thereof.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] In the first aspect, the present invention provides a high-performance AGM separator, which includes the following raw materials by weight percentage: 95%-99% modified glass fiber, 0.9%-4% polytrimethylene terephthalate fiber, 0.1%-1% compatibilizer; the modified glass fiber is epoxy-group modified glass fiber, and the compatibilizer is a hyperbranched polysilane containing amino, sulfonic acid group, and quaternary ammonium salt groups.

[0007] The molecular chain of polytrimethylene terephthalate fiber (PTT) appears in a helical conformation. The greatest characteristic of this structure is its good stretchability. When subjected to external tensile or compressive stress, as long as the external force is removed, it will quickly recover its deformation. Once stretched, it is easy for the molecular chain to unfold and straighten. Generally, the tensile recovery rate of PTT fiber can reach over 95%. Its molecular arrangement is in a "Z" structure, with good elastic recovery, excellent elongation, compression recovery performance, and acid resistance. By adding PTT to the raw materials in the present invention, the AGM separator can have excellent elongation and compression recovery performance. Even under excessive compression deformation, the AGM separator still has the liquid absorption and moisturizing performance, improving the cycle life of the battery.

[0008] Further, the preparation method of the modified glass fiber is as follows:

[0009] A1: Add 30wt% hydrogen peroxide to the glass fiber, stir evenly, then heat and reflux at 105 - 110°C for 3 - 5h. After the reaction ends, filter, wash, and dry the reaction product to obtain hydroxylated glass fiber;

[0010] Among them, the mass ratio of 30wt% hydrogen peroxide to the glass fiber is (20 - 30):1.

[0011] A2: Add the hydroxylated glass fiber to a 90wt% ethanol aqueous solution, then add KH560, ultrasonicate for 2 - 3h, wash, and dry to obtain the modified glass fiber.

[0012] Among them, the dosage ratio of the hydroxylated glass fiber, ethanol aqueous solution, and KH560 is 10g:100mL:0.05 - 0.1g.

[0013] The glass fiber is treated with hydrogen peroxide so that its surface has hydroxyl (-OH) functional groups. When KH560 contacts the hydroxylated glass fiber, the silane oxy group will react with the hydroxyl groups on the glass fiber surface to form a silicon - oxygen bond (Si - O - Si), thereby connecting the KH560 molecules to the glass fiber surface and obtaining the modified glass fiber containing epoxy groups.

[0014] Further, in step A1, the single - filament diameter of the glass fiber is 11 - 17μm, and the particle aspect ratio is 13:1.

[0015] Further, the diameter of the polytrimethylene terephthalate fiber is 0.5 - 3.0μm, and the length is 4.0 - 8.0mm.

[0016] Further, the preparation method of the compatibilizer is as follows:

[0017] γ-aminopropyltriethoxysilane, 3-{(dimethyl(3-trimethoxysilyl)propyl)ammonio}propane-1-sulfonate, and deionized water were added to a three-necked flask, stirred at 20 °C for 30 min, then an acetic acid aqueous solution was added, and the temperature was raised to 60 °C for reaction for 6 h, and rotary evaporation was carried out to obtain a compatibilizer.

[0018] Among them, the dosage ratio of γ-aminopropyltriethoxysilane, 3-{(dimethyl(3-trimethoxysilyl)propyl)ammonio}propane-1-sulfonate, deionized water, and acetic acid aqueous solution was 4.4 g: 6.6 g: 1 mL: 0.5 - 2 mL; the mass fraction of the acetic acid aqueous solution was 50 - 67%.

[0019] In the above reaction steps, γ-aminopropyltriethoxysilane and 3-{(dimethyl(3-trimethoxysilyl)propyl)ammonio}propane-1-sulfonate were hydrolyzed under the action of water and acetic acid aqueous solution to generate silanol (Si-OH), and then the silanol condensed to form Si-O-Si bonds, and finally a hyperbranched structure was formed to obtain a compatibilizer. The compatibilizer in the present invention contains amino, sulfonic acid, and quaternary ammonium salt groups.

[0020] In a second aspect, the present invention provides a method for preparing a high-performance AGM separator, comprising the following steps:

[0021] The modified glass fiber, poly(trimethylene terephthalate) fiber, and compatibilizer were mixed, and after beating, sizing, slag removal, papermaking, drying, rolling, and slitting, an AGM separator was obtained.

[0022] The beneficial effects of the present invention:

[0023] 1. In the present invention, a compatibilizer is added to the raw materials for preparing the AGM separator. The compatibilizer is a hyperbranched polysilane containing amino, sulfonic acid, and quaternary ammonium salt groups. The amino group in the hyperbranched polysilane can react with the epoxy group on the surface of the modified glass fiber, and the amino group can form a hydrogen bond with the ester group in the poly(trimethylene terephthalate) fiber, thereby improving the compatibility between the glass fiber and the poly(trimethylene terephthalate) fiber. When the AGM separator undergoes excessive compression deformation, it still has the liquid absorption and moisture retention performance, improving the cycle life of the battery. Moreover, the high modulus of the glass fiber can inhibit the deformation of the separator, while the toughness of the PTT fiber can buffer the local stress concentration. Good compatibility between the two can synergistically improve the tensile and puncture resistance strengths of the separator. The hyperbranched polysilane has a three-dimensional network structure, which can form a cross-linked network between the glass fiber and the PTT fiber, thereby improving the toughness and strength of the separator.

[0024] 2. The compatibilizer in the present invention also contains sulfonic acid and quaternary ammonium salt groups. The sulfonic acid and quaternary ammonium salt groups belong to hydrophilic groups, and the two can synergistically improve the liquid absorption performance of the AGM separator, thereby reducing the risk of electrolyte stratification during charge and discharge, and thus improving the cycle life of the battery.

[0025] 3. The present invention prepares an AGM separator with the best comprehensive performance by precisely controlling the addition amount of the compatibilizer. Specific Embodiments

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Example 1

[0028] A high-performance AGM separator, by weight percentage, comprises the following raw materials: 99% of modified glass fiber, 0.9% of polytrimethylene terephthalate fiber, and 0.1% of compatibilizer. The diameter of the polytrimethylene terephthalate fiber is 0.5 - 3.0 μm, and the length is 4.0 - 8.0 mm.

[0029] The preparation method of the modified glass fiber is as follows:

[0030] A1: Add 200 g of 30 wt% hydrogen peroxide to 10 g of glass fiber (the single filament diameter of the glass fiber is 11 - 17 μm, and the particle aspect ratio is 13:1), stir evenly, then heat and reflux at 105 °C for 3 h. After the reaction is completed, filter, wash, and dry the reaction product to obtain hydroxylated glass fiber;

[0031] A2: Add 10 g of hydroxylated glass fiber to 100 mL of 90 wt% ethanol aqueous solution, then add 0.05 g of KH560, ultrasonicate for 2 h, wash, and dry to obtain modified glass fiber.

[0032] The preparation method of the compatibilizer is as follows:

[0033] Add 4.4 g of γ-aminopropyltriethoxysilane, 6.6 g of 3-{(dimethyl(3-trimethoxysilyl)propyl)ammonio}propane-1-sulfonate, and 1 mL of deionized water to a three-necked flask, stir at 20 °C for 30 min, then add 0.5 mL of acetic acid aqueous solution with a mass fraction of 67%, heat to 60 °C and react for 6 h, rotary evaporate, and dry to obtain the compatibilizer.

[0034] A preparation method of a high-performance AGM separator comprises the following steps:

[0035] Mix the modified glass fiber, polytrimethylene terephthalate fiber, compatibilizer, and dilute sulfuric acid solution (specific gravity 1.28 g / cm 3 -1.32 g / cm3 ) Add them together to a beater for beating; after beating, the product is transferred to a pulp mixing tank by a pump. At the same time, purified water and white water are added for stirring and pulp mixing. After pulp mixing, it is transferred to a pulp storage tank by a pump, then stirred to remove impurities and transferred to a high-level tank, and then to a headbox, and then paper is made (using a fourdrinier to take the paper). After drying in a drying furnace, it is roll-pressed and shaped, and finally cut to the required size. Among them, the white water obtained in the papermaking section is returned to the beating and pulp mixing sections. When roll-pressing and shaping, the roll temperature is set and maintained at 70°C - 80°C.

[0036] Example 2

[0037] A high-performance AGM separator, by weight percentage, comprises the following raw materials: 97% of modified glass fiber, 2.5% of polytrimethylene terephthalate fiber, and 0.5% of compatibilizer. The polytrimethylene terephthalate fiber has a diameter of 0.5 - 3.0 μm and a length of 4.0 - 8.0 mm.

[0038] The preparation method of the modified glass fiber is as follows:

[0039] A1: Add 250 g of 30 wt% hydrogen peroxide to 10 g of glass fiber (the single filament diameter of the glass fiber is 11 - 17 μm, and the particle aspect ratio is 13:1), stir evenly, and then heat and reflux at 110°C for 4 h. After the reaction is completed, filter, wash, and dry the reaction product to obtain hydroxylated glass fiber;

[0040] A2: Add 10 g of hydroxylated glass fiber to 100 mL of 90 wt% ethanol aqueous solution, then add 0.1 g of KH560, ultrasonicate for 3 h, wash, and dry to obtain modified glass fiber.

[0041] The preparation method of the compatibilizer is as follows:

[0042] Add 4.4 g of γ-aminopropyltriethoxysilane, 6.6 g of 3-{(dimethyl(3-trimethoxysilyl)propyl)ammonio}propane-1-sulfonate, and 1 mL of deionized water to a three-necked flask, stir at 20°C for 30 min, then add 1.5 mL of acetic acid aqueous solution with a mass fraction of 67%, heat to 60°C and react for 6 h, rotary evaporate, and dry to obtain the compatibilizer.

[0043] A preparation method of a high-performance AGM separator, comprising the following steps:

[0044] Add the modified glass fiber, polytrimethylene terephthalate fiber, compatibilizer and dilute sulfuric acid solution (specific gravity 1.28 g / cm 3 - 1.32 g / cm 3)Add them together to a beater for beating; after beating, the product is transferred to a pulp mixing tank by a pump, and at the same time, purified water and white water are added for stirring and pulp mixing. After pulp mixing, it is transferred to a pulp storage tank by a pump, then the slag is removed by stirring and transferred to a high-level tank, and then to a headbox, and then paper is made (using a long wire to pick up). After drying on a drying furnace, it is roll-pressed and shaped, and finally cut into the required size. Among them, the white water obtained in the papermaking section is returned to the beating and pulp mixing sections. When roll-pressing and shaping, the roller temperature is set and maintained at 70°C - 80°C.

[0045] Example 3

[0046] A high-performance AGM separator, by weight percentage, comprises the following raw materials: 95% of modified glass fiber, 4% of polytrimethylene terephthalate fiber, and 1% of compatibilizer. The diameter of the polytrimethylene terephthalate fiber is 0.5 - 3.0 μm, and the length is 4.0 - 8.0 mm.

[0047] The preparation method of the modified glass fiber is as follows:

[0048] A1: Add 300 g of 30 wt% hydrogen peroxide to 10 g of glass fiber (the single filament diameter of the glass fiber is 11 - 17 μm, and the particle aspect ratio is 13:1), stir evenly, then heat and reflux at 110°C for 5 h. After the reaction ends, filter, wash, and dry the reaction product to obtain hydroxylated glass fiber;

[0049] A2: Add 10 g of hydroxylated glass fiber to 100 mL of 90 wt% ethanol aqueous solution, then add 0.1 g of KH560, ultrasonic for 2 - 3 h, wash, and dry to obtain modified glass fiber.

[0050] The preparation method of the compatibilizer is as follows:

[0051] Add 4.4 g of γ-aminopropyltriethoxysilane, 6.6 g of 3-{(dimethyl(3-trimethoxysilyl)propyl)ammonio}propane-1-sulfonate, and 1 mL of deionized water to a three-necked flask, stir at 20°C for 30 min, then add 2 mL of acetic acid aqueous solution with a mass fraction of 67%, heat up to 60°C and react for 6 h, rotary evaporate, and dry to obtain the compatibilizer.

[0052] A preparation method of a high-performance AGM separator comprises the following steps:

[0053] Add the modified glass fiber, polytrimethylene terephthalate fiber, compatibilizer, and dilute sulfuric acid solution (specific gravity 1.28 g / cm 3 - 1.32 g / cm 3) Add them together to a beating machine for beating; the product after beating is transferred to a pulp mixing tank by a pump, and at the same time, purified water and white water are added for stirring and pulp mixing. After pulp mixing, it is transferred to a pulp storage tank by a pump, then the slag is removed by stirring and transferred to a high-level tank, and then to a headbox, and then paper is made (using a long wire to take the paper). After drying in a drying furnace, it is roll-pressed and shaped, and finally cut to the required size. Among them, the white water obtained in the papermaking section is returned to the beating and pulp mixing sections. When roll-pressing and shaping, the roll temperature is set and maintained at 70°C - 80°C.

[0054] Example 4

[0055] The difference between this example and Example 1 is that:

[0056] A high-performance AGM separator, by weight percentage, comprises the following raw materials: 99% of modified glass fiber, 0.95% of polytrimethylene terephthalate fiber, 0.05% of compatibilizer.

[0057] The remaining raw materials and steps are the same as those in Example 1.

[0058] Example 5

[0059] The difference between this example and Example 3 is that:

[0060] A high-performance AGM separator, by weight percentage, comprises the following raw materials: 95% of modified glass fiber, 3.5% of polytrimethylene terephthalate fiber, 1.5% of compatibilizer.

[0061] The remaining raw materials and steps are the same as those in Example 3.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that:

[0064] The compatibilizer is γ-aminopropyltriethoxysilane, and the remaining raw materials and steps are the same as those in Example 1.

[0065] Comparative Example 2

[0066] The difference between this comparative example and Example 1 is that:

[0067] A high-performance AGM separator, by weight percentage, comprises the following raw materials: 99% of modified glass fiber, 1% of polytrimethylene terephthalate fiber, and the remaining raw materials and steps are the same as those in Example 1.

[0068] Comparative Example 3

[0069] The difference between this comparative example and Example 1 is that:

[0070] Replace the modified glass fiber with glass fiber, and the remaining raw materials and steps are the same as those in Example 1.

[0071] 1. Performance tests were carried out on the AGM separators prepared in Examples 1 - 5 and Comparative Examples 1 - 3. The test standards for strength and liquid absorption capacity were JB / T7630.1 - 2008, and the test results are shown in Table 1:

[0072] 2. The AGM separators prepared in Examples 1 - 5 and Comparative Examples 1 - 3 were respectively made into 6 - DZM - 20Ah lead - acid batteries, and then 2hr capacity detection, high - current discharge performance, charge acceptance performance, and cycle life performance tests were carried out respectively.

[0073] 2hr capacity detection: The detection method is as follows: After the battery is fully charged, it is left to stand in an environment with a temperature of 25℃ ± 2℃ for 1h - 24h. When the battery surface temperature is 25℃ ± 2℃, it is continuously discharged at a current of 10A until the battery terminal voltage reaches 10.50V and then terminated. Record the discharge time T(h), and the battery capacity is: Ca = 10T (Ah).

[0074] High - current discharge performance: The detection method is as follows: After the battery that has undergone the 2hr capacity test is fully charged, it is left to stand in an environment with a temperature of 25℃ ± 2℃ for 1h - 4h, and then discharged at a current of 36A until the battery terminal voltage reaches 10.50V and then terminated. Record the discharge duration t.

[0075] Cycle life test: The detection method is as follows: After the battery that has undergone the 2hr capacity test is fully charged, in an environment of 25℃ ± 5℃, it is discharged at a current of 10A for 1.60h, and then charged at a constant voltage of 15.00V and a current limit of 4A for 6.40h. The above is one cycle life count. When the battery is discharged for 1.60h and the battery terminal voltage is continuously lower than 10.50V three times, it is considered that the battery life has ended, and these three cycles are not included in the cycle count.

[0076] The test results are shown in Table 2.

[0077] Table 1

[0078] Project Strength (N / m) Liquid absorption amount (g / g) Example 1 2013 10.4 Example 2 2028 10.8 Example 3 2045 11.1 Example 4 1992 10.1 Example 5 2031 10.9 Comparative Example 1 1982 8.3 Comparative Example 2 1935 7.5 Comparative Example 3 1978 8.9

[0079] As can be seen from Table 1, the strength and liquid absorption capacity of the separators prepared in Examples 1 - 5 are superior to those of the separators prepared in Comparative Examples 1 - 3. The strength and liquid absorption capacity of Examples 4 and 5 are lower than those of Examples 1 and 3, indicating that the addition amount of the compatibilizer in the present invention is the optimal amount. Comparative Example 1 does not contain hyperbranched structures, sulfonic acid groups, and quaternary ammonium salt groups, and its strength and liquid absorption capacity both decrease compared with Example 1, indicating that hyperbranched polysilane has a three-dimensional network structure and can form a crosslinked network between glass fibers and PTT fibers, thereby improving the toughness and strength of the separator. The sulfonic acid group and the quaternary ammonium salt group belong to hydrophilic groups, and the two can synergistically improve the liquid absorption performance of the AGM separator; compared with Example 1, in Comparative Example 2, no compatibilizer is added, and both its strength and liquid absorption capacity decrease; in Comparative Example 3, the glass fiber surface does not contain epoxy groups, resulting in poor compatibility and a decrease in both its strength and liquid absorption capacity.

[0080] Table 2

[0081]

[0082]

[0083] As can be seen from Table 1, the electrochemical performance of the batteries prepared in Examples 1 - 5 is superior to that of the batteries prepared in Comparative Examples 1 - 3.

[0084] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0085] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-performance AGM separator, characterized in that, By weight percentage, it includes the following raw materials: 95%-99% of modified glass fiber, 0.9%-4% of polytrimethylene terephthalate fiber, and 0.1%-1% of compatibilizer; the modified glass fiber is epoxy-group modified glass fiber, and the compatibilizer is a hyperbranched polysilane containing amino group, sulfonic acid group and quaternary ammonium salt group.

2. The high-performance AGM separator according to claim 1, wherein, The preparation method of the modified glass fiber is as follows: A1: Add 30wt% hydrogen peroxide to the glass fiber, stir evenly, then heat and reflux at 105-110°C for 3-5h. After the reaction, filter, wash and dry the reaction product to obtain hydroxylated glass fiber. A2: Add the hydroxylated glass fiber to 90wt% ethanol aqueous solution, then add KH560, ultrasonicate for 2-3h, wash and dry to obtain the modified glass fiber.

3. The high-performance AGM separator according to claim 2, wherein In step A1, the mass ratio of 30wt% hydrogen peroxide to the glass fiber is (20-30):

1.

4. A high-performance AGM separator according to claim 2, characterized in that In step A2, the dosage ratio of hydroxylated glass fiber, ethanol aqueous solution and KH560 is 10g:100mL:0.05-0.1g.

5. The high-performance AGM separator according to claim 2, characterized in that, In step A1, the single filament diameter of the glass fiber is 11-17μm, and the particle aspect ratio is 13:

1.

6. The high-performance AGM separator according to claim 1, wherein The diameter of the polytrimethylene terephthalate fiber is 0.5-3.0μm, and the length is 4.0-8.0mm.

7. A high-performance AGM separator according to claim 1, characterized in that, The preparation method of the compatibilizer is as follows: Add γ-aminopropyltriethoxysilane, 3-{(dimethyl(3-trimethoxysilyl)propyl)ammonio}propane-1-sulfonate and deionized water into a three-necked flask, stir at 20°C for 30min, then add acetic acid aqueous solution, heat up to 60°C and react for 6h, and rotary evaporate to obtain the compatibilizer.

8. A high-performance AGM separator according to claim 7, characterized in that, The dosage ratio of γ-aminopropyltriethoxysilane, 3-{(dimethyl(3-trimethoxysilyl)propyl)ammonio}propane-1-sulfonate, deionized water and acetic acid aqueous solution is 4.4g:6.6g:1mL:0.5-2mL.

9. A high-performance AGM separator according to claim 7, characterized in that, The mass fraction of the acetic acid aqueous solution is 50-67%.

10. A method for preparing a high-performance AGM separator according to any one of claims 1-9, characterized in that, It includes the following steps: Mix the modified glass fiber, polytrimethylene terephthalate fiber and the compatibilizer, and obtain the AGM separator through beating, pulp preparation, slag removal, papermaking, drying, rolling and slitting.

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