A method for preparing a high specific surface separator for a battery

Abstract

This invention discloses a method for preparing a high specific surface area separator for a storage battery, belonging to the field of storage battery technology. The preparation method includes: S1, adding glass fiber, modified glass fiber, and additives to water and pulping at 1000 rpm for 30-60 minutes to obtain a fiber slurry, and adjusting the pH of the fiber slurry to 1-2 with water; S2, filtering and dehydrating the fiber slurry obtained in S1 to obtain a primary wet separator; S3, coating the surface of the primary wet separator with a nano-silica solution and wetting it for 1-2 hours to obtain a treated wet separator; S4, filtering and dehydrating the treated wet separator to obtain a secondary wet separator; S5, drying the secondary wet separator at 120℃ for 8-10 minutes to obtain a high specific surface area separator for the storage battery. The specific surface area of ​​this battery separator is greater than 6 m². 2 / g, high specific surface area is beneficial to improving the acid absorption capacity of the partition.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to a method for preparing a high specific surface area separator for a battery. Background Technology

[0002] Battery separators are an important component of batteries. Their main function is to prevent short circuits between the positive and negative electrodes, while also promoting electrochemical reactions, improving battery performance, and extending battery life. Located between the positive and negative plates, the separator prevents direct contact while ensuring normal ion migration, thus facilitating the smooth conduction of ions within the battery's internal circuitry.

[0003] Currently, commonly used battery separators in China mainly include rubber separators, AGM separators, PVC separators, and PP separators. Among them, AGM separators (absorbent glass fiber separators) have become a new and widely used material due to their excellent mechanical and physical properties and high cost-effectiveness. With the continuous advancement of science and technology, as well as the development of the petroleum, chemical industry, and materials science, the application range of glass fiber separators (AGM separators) is becoming increasingly wide, gradually becoming a key material in the battery industry and developing into the mainstream separator in the battery field.

[0004] The specific surface area of ​​an AGM separator significantly impacts its overall performance. Currently, AGM separators are typically manufactured using a wet process, consisting of fine glass fibers with a diameter less than 1.2 μm, coarse glass fibers with a diameter of 2-11 μm, and a small amount of organic fibers. While increasing the amount of fine glass fibers can improve the specific surface area of ​​the AGM separator to some extent, the higher price of fine glass fibers increases costs. Therefore, in actual production, a balance must be struck between the amount of fine fibers used to optimize performance and cost. In existing technologies, the specific surface area of ​​AGM separators is generally low, typically between 0.8-1.4 m² / g. Increasing the specific surface area of ​​the separator is beneficial for improving its acid absorption capacity; higher acid absorption results in less acid stratification and more stable battery capacity. Therefore, it is necessary to develop separators with high specific surface areas. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a method for preparing a high specific gravity separator for a storage battery.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing a high specific surface area separator for a storage battery includes the following steps:

[0008] S1. Add glass fiber, modified glass fiber and additives to water, and beat at 1000 rpm for 30-60 minutes to obtain fiber pulp. Add water to adjust the pH of the fiber pulp to 1-2.

[0009] S2. The fiber slurry obtained in S1 is filtered and dewatered to obtain a primary wet partition.

[0010] S3. Coat the surface of the wet partition with nano-silica solution and immerse it for 1-2 hours to obtain the treated wet partition.

[0011] S4. The treated wet partition is filtered and dehydrated to obtain a secondary wet partition.

[0012] S5. Dry the secondary wet separator at 120℃ for 8-10 minutes to obtain a high specific surface area separator for the battery.

[0013] Furthermore, the modified glass fiber described in step S1 is prepared through the following steps:

[0014] S11. Dissolve polyacrylamide in ethylene glycol to obtain a polyacrylamide solution;

[0015] S12. Disperse the glass fiber in the polyacrylamide solution and impregnate for 60-90 minutes;

[0016] S13. After filtering and separating the glass fibers, the glass fibers are dried to obtain modified glass fibers.

[0017] Furthermore, the mass concentration of the polyacrylamide solution is 10-20%; the amount of glass fiber used is 0.3-0.5% of the mass of the polyacrylamide solution.

[0018] Furthermore, the additives mentioned in step S1 are dispersants, retention aids, and filter aids; the dispersant is one of sodium alginate, polyethylene glycol, and potassium pyrophosphate; the retention aid is one of alum, bentonite, and chitosan; and the filter aid is diatomaceous earth.

[0019] Furthermore, in step S2, the filtration pressure is 0.02-0.03 MPa, and the dehydration time is 2-5 seconds.

[0020] Furthermore, the moisture content of the primary wet partition in step S2 is 60-65%.

[0021] Furthermore, the nano-silica solution described in step S3 is prepared through the following steps:

[0022] Nano-silica is added to water and stirred at 1000 rpm for 30-60 minutes to obtain a nano-silica solution; the nano-silica has a particle size of 1-1.5 nm and a specific surface area of ​​500-600 m². 2 / g.

[0023] Furthermore, in step S4, the filtration pressure is 0.03-0.06 MPa, and the dehydration time is 6-10 s.

[0024] Furthermore, the moisture content of the secondary wet partition in step S4 is 55-60%.

[0025] Furthermore, the high specific surface area separator of the battery includes 80% glass fiber, 5-10% modified glass fiber, 0.5-1% additives and 5-10% nano-silica.

[0026] The beneficial effects of this invention are:

[0027] (1) In the preparation of the battery separator of the present invention, polyacrylamide modified glass fiber is used, which can enhance the internal cross-linking of the separator and form a network structure with the glass fiber, which is beneficial to increase the specific surface area of ​​the separator and improve the acid absorption capacity of the separator.

[0028] (2) Nano silica is used in the preparation of battery separators in this invention. Nano silica has a high specific surface area, which is beneficial to maintaining the stability and uniformity of the separator network structure and improving the acid absorption capacity of the separator. Under acidic conditions, nano silica can form a rich and porous network structure in glass fiber, which is beneficial to preparing separators with high specific surface area. Detailed Implementation

[0029] 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.

[0030] Example 1

[0031] This embodiment provides a method for preparing a high specific surface area separator for a storage battery, including the following steps:

[0032] S1. Add glass fiber, modified glass fiber, dispersant sodium alginate, retention aid alum and filter aid diatomaceous earth to water, and beat at 1000 rpm for 40 minutes to obtain fiber slurry. Add water to adjust the pH of the fiber slurry to 1-2.

[0033] S2. The fiber slurry obtained in S1 is filtered and dewatered. The filtration pressure is 0.03 MPa and the dewatering time is 5 s to obtain a primary wet partition with a moisture content of 60%.

[0034] S3. Coat the surface of the wet partition with nano-silica solution and wet it for 2 hours to obtain the treated wet partition.

[0035] S4. The treated wet partition is filtered and dehydrated. The filtration pressure is 0.05MPa and the dehydration time is 8s to obtain a secondary wet partition with a water content of 55%.

[0036] S5. Dry the secondary wet separator at 120℃ for 10 minutes to obtain a high specific surface area separator for the battery.

[0037] The modified glass fiber described in step S1 is prepared through the following steps:

[0038] S11. Dissolve polyacrylamide in ethylene glycol to obtain a polyacrylamide solution with a mass concentration of 15%.

[0039] S12. Disperse the glass fiber in the polyacrylamide solution and impregnate for 90 min; the amount of glass fiber is 0.4% of the mass of the polyacrylamide solution.

[0040] S13. After filtering and separating the glass fibers, the glass fibers are dried to obtain modified glass fibers.

[0041] The nano-silica solution described in step S3 is prepared through the following steps:

[0042] Nano-silica was added to water and stirred at 1000 rpm for 60 minutes to obtain a nano-silica solution; the nano-silica had a particle size of 1-1.5 nm and a specific surface area of ​​500-600 m². 2 / g.

[0043] The high specific gravity separator of the battery contains 80% glass fiber, 5% modified glass fiber, 1% additives and 5% nano silica.

[0044] Example 2

[0045] This embodiment provides a method for preparing a high specific surface area separator for a storage battery, including the following steps:

[0046] S1. Add glass fiber, modified glass fiber, dispersant polyethylene glycol, retention aid bentonite and filter aid diatomaceous earth to water, and beat at 1000 rpm for 40 minutes to obtain fiber slurry. Add water to adjust the pH of the fiber slurry to 1-2.

[0047] S2. The fiber slurry obtained in S1 is filtered and dewatered. The filtration pressure is 0.03 MPa and the dewatering time is 5 s to obtain a primary wet partition with a moisture content of 60%.

[0048] S3. Coat the surface of the wet partition with nano-silica solution and wet it for 2 hours to obtain the treated wet partition.

[0049] S4. The treated wet partition is filtered and dehydrated. The filtration pressure is 0.05MPa and the dehydration time is 8s to obtain a secondary wet partition with a water content of 55%.

[0050] S5. Dry the secondary wet separator at 120℃ for 10 minutes to obtain a high specific surface area separator for the battery.

[0051] The modified glass fiber described in step S1 is prepared through the following steps:

[0052] S11. Dissolve polyacrylamide in ethylene glycol to obtain a polyacrylamide solution with a mass concentration of 15%.

[0053] S12. Disperse the glass fiber in the polyacrylamide solution and impregnate for 90 min; the amount of glass fiber is 0.4% of the mass of the polyacrylamide solution.

[0054] S13. After filtering and separating the glass fibers, the glass fibers are dried to obtain modified glass fibers.

[0055] The nano-silica solution described in step S3 is prepared through the following steps:

[0056] Nano-silica was added to water and stirred at 1000 rpm for 60 minutes to obtain a nano-silica solution; the nano-silica had a particle size of 1-1.5 nm and a specific surface area of ​​500-600 m². 2 / g.

[0057] The high specific surface area separator of the battery contains 80% glass fiber, 7% modified glass fiber, 1% additives and 5% nano silica.

[0058] Example 3

[0059] This embodiment provides a method for preparing a high specific surface area separator for a storage battery, including the following steps:

[0060] S1. Add glass fiber, modified glass fiber, dispersant potassium pyrophosphate, retention aid chitosan and filter aid diatomaceous earth to water, and beat at 1000 rpm for 40 minutes to obtain fiber slurry. Add water to adjust the pH of the fiber slurry to 1-2.

[0061] S2. The fiber slurry obtained in S1 is filtered and dewatered. The filtration pressure is 0.03 MPa and the dewatering time is 5 s to obtain a primary wet partition with a moisture content of 60%.

[0062] S3. Coat the surface of the wet partition with nano-silica solution and wet it for 2 hours to obtain the treated wet partition.

[0063] S4. The treated wet partition is filtered and dehydrated. The filtration pressure is 0.05MPa and the dehydration time is 8s to obtain a secondary wet partition with a water content of 55%.

[0064] S5. Dry the secondary wet separator at 120℃ for 10 minutes to obtain a high specific surface area separator for the battery.

[0065] The modified glass fiber described in step S1 is prepared through the following steps:

[0066] S11. Dissolve polyacrylamide in ethylene glycol to obtain a polyacrylamide solution with a mass concentration of 15%.

[0067] S12. Disperse the glass fiber in the polyacrylamide solution and impregnate for 90 min; the amount of glass fiber is 0.4% of the mass of the polyacrylamide solution.

[0068] S13. After filtering and separating the glass fibers, the glass fibers are dried to obtain modified glass fibers.

[0069] The nano-silica solution described in step S3 is prepared through the following steps:

[0070] Nano-silica was added to water and stirred at 1000 rpm for 60 minutes to obtain a nano-silica solution; the nano-silica had a particle size of 1-1.5 nm and a specific surface area of ​​500-600 m². 2 / g.

[0071] The high specific surface area separator of the battery contains 80% glass fiber, 10% modified glass fiber, 1% additives and 5% nano silica.

[0072] Example 4

[0073] This embodiment provides a method for preparing a high specific surface area separator for a storage battery, including the following steps:

[0074] S1. Add glass fiber, modified glass fiber, dispersant potassium pyrophosphate, retention aid chitosan and filter aid diatomaceous earth to water, and beat at 1000 rpm for 40 minutes to obtain fiber slurry. Add water to adjust the pH of the fiber slurry to 1-2.

[0075] S2. The fiber slurry obtained in S1 is filtered and dewatered. The filtration pressure is 0.03 MPa and the dewatering time is 5 s to obtain a primary wet partition with a moisture content of 60%.

[0076] S3. Coat the surface of the wet partition with nano-silica solution and wet it for 2 hours to obtain the treated wet partition.

[0077] S4. The treated wet partition is filtered and dehydrated. The filtration pressure is 0.05MPa and the dehydration time is 8s to obtain a secondary wet partition with a water content of 55%.

[0078] S5. Dry the secondary wet separator at 120℃ for 10 minutes to obtain a high specific surface area separator for the battery.

[0079] The modified glass fiber described in step S1 is prepared through the following steps:

[0080] S11. Dissolve polyacrylamide in ethylene glycol to obtain a polyacrylamide solution with a mass concentration of 15%.

[0081] S12. Disperse the glass fiber in the polyacrylamide solution and impregnate for 90 min; the amount of glass fiber is 0.4% of the mass of the polyacrylamide solution.

[0082] S13. After filtering and separating the glass fibers, the glass fibers are dried to obtain modified glass fibers.

[0083] The nano-silica solution described in step S3 is prepared through the following steps:

[0084] Nano-silica was added to water and stirred at 1000 rpm for 60 minutes to obtain a nano-silica solution; the nano-silica had a particle size of 1-1.5 nm and a specific surface area of ​​500-600 m². 2 / g.

[0085] The high specific surface area separator of the battery contains 80% glass fiber, 10% modified glass fiber, 1% additives and 7% nano silica.

[0086] Example 5

[0087] This embodiment provides a method for preparing a high specific surface area separator for a storage battery, including the following steps:

[0088] S1. Add glass fiber, modified glass fiber, dispersant potassium pyrophosphate, retention aid chitosan and filter aid diatomaceous earth to water, and beat at 1000 rpm for 40 minutes to obtain fiber slurry. Add water to adjust the pH of the fiber slurry to 1-2.

[0089] S2. The fiber slurry obtained in S1 is filtered and dewatered. The filtration pressure is 0.03 MPa and the dewatering time is 5 s to obtain a primary wet partition with a moisture content of 60%.

[0090] S3. Coat the surface of the wet partition with nano-silica solution and wet it for 2 hours to obtain the treated wet partition.

[0091] S4. The treated wet partition is filtered and dehydrated. The filtration pressure is 0.05MPa and the dehydration time is 8s to obtain a secondary wet partition with a water content of 55%.

[0092] S5. Dry the secondary wet separator at 120℃ for 10 minutes to obtain a high specific surface area separator for the battery.

[0093] The modified glass fiber described in step S1 is prepared through the following steps:

[0094] S11. Dissolve polyacrylamide in ethylene glycol to obtain a polyacrylamide solution with a mass concentration of 15%.

[0095] S12. Disperse the glass fiber in the polyacrylamide solution and impregnate for 90 min; the amount of glass fiber is 0.4% of the mass of the polyacrylamide solution.

[0096] S13. After filtering and separating the glass fibers, the glass fibers are dried to obtain modified glass fibers.

[0097] The nano-silica solution described in step S3 is prepared through the following steps:

[0098] Nano-silica was added to water and stirred at 1000 rpm for 60 minutes to obtain a nano-silica solution; the nano-silica had a particle size of 1-1.5 nm and a specific surface area of ​​500-600 m². 2 / g.

[0099] The high specific surface area separator of the battery contains 80% glass fiber, 10% modified glass fiber, 1% additives and 10% nano silica.

[0100] Comparative Example 1

[0101] This comparative example provides a method for preparing a battery separator, including the following steps:

[0102] S1. Add glass fiber, dispersant sodium alginate, retention aid alum and filter aid diatomaceous earth to water, and beat at 1000 rpm for 40 minutes to obtain fiber slurry. Add water to adjust the pH of the fiber slurry to 1-2.

[0103] S2. The fiber slurry obtained in S1 is filtered and dewatered. The filtration pressure is 0.03 MPa and the dewatering time is 5 s to obtain a primary wet partition with a moisture content of 60%.

[0104] S3. Coat the surface of the wet partition with nano-silica solution and wet it for 2 hours to obtain the treated wet partition.

[0105] S4. The treated wet partition is filtered and dehydrated. The filtration pressure is 0.05MPa and the dehydration time is 8s to obtain a secondary wet partition with a water content of 55%.

[0106] S5. Dry the secondary wet separator at 120℃ for 10 minutes to obtain the battery separator.

[0107] The nano-silica solution described in step S3 is prepared through the following steps:

[0108] Nano-silica was added to water and stirred at 1000 rpm for 60 minutes to obtain a nano-silica solution; the nano-silica had a particle size of 1-1.5 nm and a specific surface area of ​​500-600 m². 2 / g.

[0109] The high specific gravity separator of the battery contains 85% glass fiber, 1% additives and 5% nano silica.

[0110] Comparative Example 2

[0111] This comparative example provides a method for preparing a battery separator, including the following steps:

[0112] S1. Add glass fiber, modified glass fiber, dispersant sodium alginate, retention aid alum and filter aid diatomaceous earth to water, and beat at 1000 rpm for 40 minutes to obtain fiber slurry. Add water to adjust the pH of the fiber slurry to 1-2.

[0113] S2. The fiber slurry obtained in S1 is filtered and dewatered. The filtration pressure is 0.03 MPa and the dewatering time is 5 s to obtain a primary wet partition with a moisture content of 60%.

[0114] S3. Dry the wet separator at 120°C for 10 minutes to obtain the battery separator.

[0115] The modified glass fiber described in step S1 is prepared through the following steps:

[0116] S11. Dissolve polyacrylamide in ethylene glycol to obtain a polyacrylamide solution with a mass concentration of 15%.

[0117] S12. Disperse the glass fiber in the polyacrylamide solution and impregnate for 90 min; the amount of glass fiber is 0.4% of the mass of the polyacrylamide solution.

[0118] S13. After filtering and separating the glass fibers, the glass fibers are dried to obtain modified glass fibers.

[0119] The high specific gravity separator of the battery contains 85% glass fiber, 5% modified glass fiber and 1% additives.

[0120] The specific surface area of ​​the high specific surface area separators of the batteries obtained in Examples 1-5 and Comparative Examples 1-2 was measured, and the results are shown in Table 1:

[0121] Table 1

[0122]

[0123] As shown in Table 1, when polyacrylamide-modified glass fiber and nano-silica were added during the preparation of battery separators in Examples 1-5, the specific surface area of ​​the resulting separators was all over 6 m². 2 The specific surface area of ​​the separator is above / g because, on the one hand, polyacrylamide-modified glass fiber is used in the preparation of the battery separator, which can enhance the internal cross-linking of the separator and form a network structure with the glass, which is beneficial to increasing the specific surface area of ​​the separator and improving its acid absorption capacity; on the other hand, nano-silica is used in the preparation of the battery separator. Nano-silica has a high specific surface area, which is beneficial to maintaining the stability and uniformity of the separator network structure and improving the acid absorption capacity of the separator; under acidic conditions, nano-silica can form a rich and porous network structure in the glass fiber, which is beneficial to preparing a separator with a high specific surface area.

[0124] Compared with Example 1, no polyacrylamide-modified glass fiber was added when preparing the battery separator, resulting in a smaller specific surface area of ​​the battery separator. Compared with Example 1, no nano-silica was added when preparing the battery separator, resulting in a smaller specific surface area of ​​the battery separator.

[0125] 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.

[0126] 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 method for preparing a high specific surface area separator for a storage battery, characterized in that, Includes the following steps: S1. Add glass fiber, modified glass fiber and additives to water, and beat at 1000 rpm for 30-60 minutes to obtain fiber pulp. Add water to adjust the pH of the fiber pulp to 1-2. S2. The fiber slurry obtained in S1 is filtered and dewatered to obtain a primary wet partition. S3. Coat the surface of the wet partition with nano-silica solution and immerse it for 1-2 hours to obtain the treated wet partition. S4. The treated wet partition is filtered and dehydrated to obtain a secondary wet partition. S5. Dry the secondary wet separator at 120℃ for 8-10 minutes to obtain a high specific surface area separator for the battery. The modified glass fiber described in step S1 is prepared through the following steps: S11. Dissolve polyacrylamide in ethylene glycol to obtain a polyacrylamide solution; S12. Disperse the glass fiber in the polyacrylamide solution and impregnate for 60-90 minutes; S13. After filtering and separating the glass fibers, the glass fibers are dried to obtain modified glass fibers. The mass concentration of the polyacrylamide solution is 10-20%; the amount of glass fiber used is 0.3-0.5% of the mass of the polyacrylamide solution.

2. The method for preparing a high specific surface area separator for a storage battery according to claim 1, characterized in that, The additives mentioned in step S1 are dispersants, retention aids, and filter aids; the dispersant is one of sodium alginate, polyethylene glycol, and potassium pyrophosphate; the retention aid is one of alum, bentonite, and chitosan; and the filter aid is diatomaceous earth.

3. The method for preparing a high specific surface area separator for a storage battery according to claim 1, characterized in that, In step S2, the filtration pressure is 0.02-0.03 MPa and the dehydration time is 2-5 seconds.

4. The method for preparing a high specific surface area separator for a storage battery according to claim 1, characterized in that, The moisture content of the wet partition in step S2 is 60-65%.

5. The method for preparing a high specific surface area separator for a storage battery according to claim 1, characterized in that, The nano-silica solution described in step S3 is prepared through the following steps: Nano-silica is added to water and stirred at 1000 rpm for 30-60 minutes to obtain a nano-silica solution; the nano-silica has a particle size of 1-1.5 nm and a specific surface area of ​​500-600 m². 2 / g.

6. The method for preparing a high specific surface area separator for a storage battery according to claim 1, characterized in that, In step S4, the filtration pressure is 0.03-0.06 MPa and the dehydration time is 6-10 s.

7. The method for preparing a high specific surface area separator for a storage battery according to claim 1, characterized in that, The moisture content of the secondary wet partition in step S4 is 55-60%.

8. The method for preparing a high specific surface area separator for a storage battery according to claim 1, characterized in that, The high specific surface area separator of the battery contains 80% glass fiber, 5-10% modified glass fiber, 0.5-1% additives and 5-10% nano-silica.

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