A preparation method of AGM separator with small surface pores and its product

Abstract

The present invention discloses a method for preparing an AGM separator with a small surface pore size and its product. The preparation method comprises the following steps: (1) mixing fine glass fibers, chopped fibers, organic fibers, and water, and beating the mixture to obtain a uniform slurry; (2) inputting the slurry into a molding machine to obtain an AGM separator single-layer structure blank; (3) vacuum drying the AGM separator single-layer structure blank to obtain a dried AGM single-layer separator blank; (4) subjecting the AGM single-layer separator blank to a surface heat treatment; and (5) cutting and packaging the finished AGM separator. The present invention optimizes the surface structure of the AGM separator through surface heat treatment to form a multi-level pore structure, wherein the pore size of the surface area is significantly smaller than the pore size of the middle area, thereby significantly improving the mechanical strength of the entire AGM separator, which is beneficial to improving various performances of the AGM separator in batteries and promoting the promotion and application of the AGM separator. The overall structure is stable and the preparation steps are simple.

Description

Technical Field

[0001] The invention belongs to the technical field of AGM batteries, and particularly relates to a preparation method of an AGM separator with small surface pores and a product thereof. Background Art

[0002] AGM batteries differ from conventional liquid, flooded, and gel lead-acid batteries in that they feature an AGM (Absorbed Glass Mat) separator between the plates. This AGM separator absorbs acid, preventing it from overflowing, and regulates the battery's chemical reactions. For example, the pores in the AGM separator serve as pathways for ion migration, which, to a certain extent, determines the battery's reaction efficiency. The AGM separator ensures constant pressure within the battery, significantly extending the battery's cycle life. The AGM separator also provides oxygen recombination pathways, reducing electrolyte loss and eliminating the need for maintenance during battery operation. Therefore, balancing the pores in the AGM separator is crucial to ultimate battery performance. However, existing single-pore AGM structures either have excessive pores, facilitating acid injection but hindering acid retention, or excessive pores, hindering injection but facilitating pressure retention. Summary of the Invention

[0003] In order to solve the technical problems existing in the prior art, the purpose of the present invention is to provide a method for preparing an AGM separator with small surface pores and a product thereof.

[0004] In order to achieve the above-mentioned purpose and the above-mentioned technical effect, the technical solution adopted by the present invention is:

[0005] A method for preparing an AGM separator with small surface pores comprises the following steps:

[0006] (1) Slurry preparation:

[0007] The glass fibers are mixed with water and beaten to obtain a uniform slurry;

[0008] (2) Molding:

[0009] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0010] (3) Vacuum drying:

[0011] The AGM separator single-layer structure blank is vacuum dried to obtain a dry AGM single-layer separator blank:

[0012] (4) Surface heat treatment:

[0013] The AGM single-layer separator blank obtained in step (3) is subjected to surface heat treatment;

[0014] (5) Post-processing:

[0015] After cutting and packaging, the finished AGM separator is obtained.

[0016] Furthermore, in step (1), 60%-100% of glass fine fibers, 0%-20% of short fibers, 0%-20% of organic fibers, and water are mixed by weight, and a uniform slurry is obtained after beating, mixing, and removing slag.

[0017] Furthermore, by weight percentage, 80%-100% of glass fine fibers, 0%-12% of short fibers, 0%-8% of organic fibers, and water are mixed, and a uniform slurry is obtained after beating, mixing, and removing slag.

[0018] Furthermore, in step (4), the surface heat treatment temperature is 500-1400°C, the surface heat treatment time is 1-120s, and the surface heat treatment area is located in the 0-1mm thickness area of ​​the upper layer of the entire AGM separator.

[0019] Furthermore, the surface heat treatment temperature is 800-1100° C., the surface heat treatment time is 5-60 seconds, and the surface heat treatment area is located in the 0.1-0.5 mm thickness area of ​​the upper layer of the entire AGM separator.

[0020] Furthermore, in step (5), the thickness of the finished AGM separator is 0.3 mm to 4 mm, presenting a multi-level pore structure, and the pore size of the surface area is significantly smaller than that of the middle area.

[0021] The present invention also discloses an AGM separator with small surface pores prepared by the method for preparing the AGM separator with small surface pores as described above.

[0022] Furthermore, the thickness of the AGM separator is 0.3 mm to 4 mm, presenting a multi-level pore structure, with the pore size in the surface area being significantly smaller than that in the middle area.

[0023] Furthermore, the pore size of the surface region is 0.1-10 μm, and the pore size of the middle region is 1-30 μm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention discloses a preparation method and product of an AGM separator with small surface pores. The surface structure of the AGM separator is optimized by surface heat treatment to form a multi-level pore structure. The pore size of the surface area is significantly smaller than the pore size of the middle area, so that the mechanical strength of the entire AGM separator is greatly improved, which is beneficial to the improvement of its various performances in the battery and the promotion and application of the AGM separator. The overall structure is stable and the preparation steps are simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a SEM image of an AGM separator with small surface pores before surface heat treatment according to Example 1 of the present invention; wherein, Figure 1 a is a 100-fold SEM image before surface heat treatment. Figure 1 b is a 500x SEM image before surface heat treatment;

[0027] Figure 2 This is a SEM image of an AGM separator with small pores after surface heat treatment according to Example 1 of the present invention; wherein, Figure 2 a is a 100-fold SEM image after surface heat treatment. Figure 2 b is a 500x SEM image after surface heat treatment. DETAILED DESCRIPTION

[0028] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0029] The following is a brief summary of one or more aspects to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceivable aspects and is neither intended to identify key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that will be provided later.

[0030] The present invention discloses a method for preparing an AGM separator with small surface pores, comprising the following steps:

[0031] (1) Slurry preparation:

[0032] By weight percentage, 60%-100% of glass fine fiber, 0%-20% of short-cut fiber, 0%-20% of organic fiber and water are mixed, and a uniform slurry is obtained after beating, mixing and removing slag;

[0033] (2) Molding:

[0034] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0035] (3) Vacuum drying:

[0036] The AGM separator single-layer structure blank is vacuum dried to obtain a dry AGM single-layer separator blank:

[0037] (4) Surface heat treatment:

[0038] The AGM single-layer separator blank obtained in step (3) is subjected to surface heat treatment by surface flame baking, infrared heating, laser heating, contact resistance heating, or other surface heat treatment methods, with the surface heat treatment temperature being 500-1400°C, the surface heat treatment time being 1-120s, and the surface heat treatment area being located in the 0-1mm thickness area of ​​the upper layer of the entire AGM separator. Preferably, the surface heat treatment temperature is 800-1100°C, the surface heat treatment time is 5-60s, and the surface heat treatment area is located in the 0.1-0.5mm thickness area of ​​the upper layer of the entire AGM separator;

[0039] (5) Post-processing:

[0040] After cutting and packaging, the finished AGM separator is obtained, which has a thickness of 0.3mm-4mm and presents a multi-level pore structure. The pore size of the surface area is significantly smaller than the pore size of the middle area. Specifically, the pore size of the surface area is 0.1-10μm, and the pore size of the middle area is 1-30μm.

[0041] In step (1), 80%-100% of glass fiber, 0%-12% of short-cut fiber, 0%-8% of organic fiber and water are mixed by weight, and a uniform slurry is obtained after beating, mixing and removing slag.

[0042] The present invention also discloses a method for preparing an AGM separator with small surface pores as described above. The obtained AGM separator has a thickness of 0.3mm-4mm. The surface structure of the AGM separator is optimized by surface heat treatment to form a multi-level pore structure. The pore size of the surface area is significantly smaller than that of the middle area. The pore size of the surface area is 0.1-10μm, and the pore size of the middle area is 1-30μm. The mechanical strength and other properties of the overall AGM separator are greatly improved, which is beneficial to the improvement of its various performances in the battery and the promotion and application of the AGM separator. The overall structure is stable and the preparation steps are simple.

[0043] Example 1

[0044] A method for preparing an AGM separator with small surface pores comprises the following steps:

[0045] (1) Slurry preparation:

[0046] By weight percentage, 90% of 1.5 μm diameter glass fiber, 10% of chopped glass fiber, and an appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0047] (2) Molding:

[0048] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0049] (3) Vacuum drying:

[0050] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0051] (4) Surface heat treatment:

[0052] The surface of the AGM single-layer separator blank obtained in step (3) is heat-treated using an infrared heating device. The process parameters are: treatment temperature 900°C, treatment time 40s, and the surface heat treatment area is located in the 0.3mm thickness area of ​​the upper layer of the entire AGM separator;

[0053] (5) Post-processing:

[0054] After cutting and packaging, the finished AGM separator is obtained. The obtained AGM separator has a double-layer structure with a thickness of 1.5mm. Under dry conditions, the tensile strength of the overall AGM separator in the machine direction is 0.8KN / m, the elongation at break is 4%, the maximum pore size in the surface area is 5μm, the maximum pore size in the middle area is 20μm, and the acid absorption height of the overall AGM separator in 24 hours is 750mm.

[0055] Example 2

[0056] A method for preparing an AGM separator with small surface pores comprises the following steps:

[0057] (1) Slurry preparation:

[0058] By weight percentage, 88% of 1.5 μm diameter glass fiber, 6% of chopped glass fiber, 6% of organic fiber and appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0059] (2) Molding:

[0060] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0061] (3) Vacuum drying:

[0062] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0063] (4) Surface heat treatment:

[0064] The surface of the AGM single-layer separator blank obtained in step (3) is heat-treated using an infrared heating device. The process parameters are: treatment temperature 900°C, treatment time 5s, and the surface heat treatment area is located in the 0.3mm thickness area of ​​the upper layer of the entire AGM separator;

[0065] (5) Post-processing:

[0066] After cutting and packaging, the finished AGM separator is obtained. The obtained AGM separator has a double-layer structure with a thickness of 1.5mm. Under dry conditions, the tensile strength of the overall AGM separator in the machine direction is 1.2KN / m, the elongation at break is 4%, the maximum pore size in the surface area is 5μm, the maximum pore size in the middle area is 20μm, and the acid absorption height of the overall AGM separator in 24 hours is 700mm.

[0067] The rest is the same as in Example 1.

[0068] Example 3

[0069] A method for preparing an AGM separator with small surface pores comprises the following steps:

[0070] (1) Slurry preparation:

[0071] By weight percentage, 88% of 1.5 μm diameter glass fiber, 6% of chopped glass fiber, 6% of organic fiber and appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0072] (2) Molding:

[0073] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0074] (3) Vacuum drying:

[0075] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0076] (4) Surface heat treatment:

[0077] The surface of the AGM single-layer separator blank obtained in step (3) is heat-treated using an infrared heating device. The process parameters are: treatment temperature 900°C, treatment time 5s, and the surface heat treatment area is located in the 0.3mm thickness area of ​​the upper layer of the entire AGM separator;

[0078] (5) Post-processing:

[0079] After cutting and packaging, the finished AGM separator is obtained. The obtained AGM separator has a three-layer structure with a thickness of 1.5mm. Under dry conditions, the tensile strength of the overall AGM separator in the machine direction is 1.3KN / m, the elongation at break is 4%, the maximum pore size in the surface area is 5μm, the maximum pore size in the middle area is 20μm, and the acid absorption height of the overall AGM separator in 24 hours is 750mm.

[0080] The rest is the same as in Example 1.

[0081] Comparative Example 1

[0082] The difference between this comparative example and Example 1 is that this comparative example does not have a surface heat treatment step, that is, step (4) of Example 1 is omitted.

[0083] The preparation method of the AGM separator of this comparative example comprises the following steps:

[0084] (1) Slurry preparation:

[0085] By weight percentage, 90% of 1.5 μm diameter glass fiber, 10% of chopped glass fiber, and an appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0086] (2) Molding:

[0087] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0088] (3) Vacuum drying:

[0089] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0090] (4) Post-processing:

[0091] After cutting and packaging, the finished AGM separator is obtained. The obtained AGM separator is a single-layer structure with a thickness of 1.5mm. Under dry conditions, the tensile strength of the overall AGM separator in the machine direction is 0.5KN / m, the elongation at break is 4%, the maximum pore size is 20μm, and the acid absorption height of the overall AGM separator in 24h is 700mm.

[0092] The rest is the same as in Example 1.

[0093] Comparative Example 2

[0094] A method for preparing an AGM separator comprises the following steps:

[0095] (1) Slurry preparation:

[0096] By weight percentage, 90% of 1.5 μm diameter glass fiber, 10% of chopped glass fiber, and an appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0097] (2) Molding:

[0098] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0099] (3) Vacuum drying:

[0100] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0101] (4) Surface heat treatment:

[0102] The surface of the AGM single-layer separator blank obtained in step (3) is heat-treated using an infrared heating device. The process parameters are: treatment temperature 1500°C, treatment time 100s, and the surface treatment area is located in the 0.3mm thickness area of ​​the upper layer of the entire AGM separator;

[0103] (5) Post-processing:

[0104] After cutting and packaging, the finished AGM separator is obtained. The obtained AGM separator is a single-layer structure with a thickness of 1.3mm. Under dry conditions, the tensile strength of the overall AGM separator in the machine direction is 0.7KN / m, the elongation at break is 0.2%, the maximum pore size is 1μm, and the acid absorption height of the overall AGM separator in 24h is 500mm.

[0105] The rest is the same as in Example 1.

[0106] Comparative Example 3

[0107] A method for preparing an AGM separator comprises the following steps:

[0108] (1) Slurry preparation:

[0109] By weight percentage, 90% of 1.5 μm diameter glass fiber, 10% of chopped glass fiber, and an appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0110] (2) Molding:

[0111] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0112] (3) Vacuum drying:

[0113] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0114] (4) Surface heat treatment:

[0115] The surface of the AGM single-layer separator blank obtained in step (3) is heat-treated using an infrared heating device. The process parameters are: treatment temperature 400°C, treatment time 100s, and the surface treatment area is located in the 0.3mm thickness area of ​​the upper layer of the entire AGM separator;

[0116] (5) Post-processing:

[0117] After cutting and packaging, the finished AGM separator is obtained. The obtained AGM separator is a single-layer structure with a thickness of 1.5mm. Under dry conditions, the tensile strength of the overall AGM separator in the machine direction is 0.5KN / m, the elongation at break is 4%, the maximum pore size is 20μm, and the acid absorption height of the overall AGM separator in 24h is 700mm.

[0118] The rest is the same as in Example 1.

[0119] Comparative Example 4

[0120] A method for preparing an AGM separator comprises the following steps:

[0121] (1) Slurry preparation:

[0122] By weight percentage, 90% of 1.5 μm diameter glass fiber, 10% of chopped glass fiber, and an appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0123] (2) Molding:

[0124] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0125] (3) Vacuum drying:

[0126] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0127] (4) Surface heat treatment:

[0128] The surface of the AGM single-layer separator blank obtained in step (3) is heat-treated using an infrared heating device. The process parameters are: treatment temperature 1000°C, treatment time 150s, and the surface treatment area is located in the 0.3mm thickness area of ​​the upper layer of the entire AGM separator;

[0129] (5) Post-processing:

[0130] After cutting and packaging, the finished AGM separator is obtained. The obtained AGM separator is a single-layer structure with a thickness of 1.4mm. Under dry conditions, the tensile strength of the overall AGM separator in the machine direction is 0.75KN / m, the elongation at break is 0.5%, the maximum pore size is 2μm, and the acid absorption height of the overall AGM separator in 24h is 600mm.

[0131] The rest is the same as in Example 1.

[0132] Comparative Example 5

[0133] A method for preparing an AGM separator comprises the following steps:

[0134] (1) Slurry preparation:

[0135] By weight percentage, 90% of 1.5 μm diameter glass fiber, 10% of chopped glass fiber, and an appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0136] (2) Molding:

[0137] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0138] (3) Vacuum drying:

[0139] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0140] (4) Surface heat treatment:

[0141] The surface of the AGM single-layer separator blank obtained in step (3) is heat-treated using an infrared heating device, with the following process parameters: treatment temperature 1000°C, treatment time 100s, and surface treatment area deep into the entire AGM separator;

[0142] (5) Post-processing:

[0143] After cutting and packaging, the finished AGM separator is obtained. The obtained AGM separator is a single-layer structure with a thickness of 1.4mm. Under dry conditions, the tensile strength of the overall AGM separator in the machine direction is 0.75KN / m, the elongation at break is 0.5%, the maximum pore size is 2μm, and the acid absorption height of the overall AGM separator in 24h is 600mm.

[0144] The rest is the same as in Example 1.

[0145] Comparative Example 6

[0146] The difference between this comparative example and Example 2 is that this comparative example does not have a surface heat treatment step, that is, step (4) of Example 2 is omitted.

[0147] A method for preparing an AGM separator comprises the following steps:

[0148] (1) Slurry preparation:

[0149] By weight percentage, 88% of 1.5 μm diameter glass fiber, 6% of chopped glass fiber, 6% of organic fiber and appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0150] (2) Molding:

[0151] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0152] (3) Vacuum drying:

[0153] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0154] (4) Post-processing:

[0155] After cutting and packaging, the finished AGM separator is obtained. The obtained AGM separator is a single-layer structure with a thickness of 1.5mm. Under dry conditions, the tensile strength of the overall AGM separator in the machine direction is 0.8KN / m, the elongation at break is 4%, the maximum pore size is 20μm, and the acid absorption height of the overall AGM separator in 24h is 550mm.

[0156] The rest is the same as Example 2.

[0157] Comparative Example 7

[0158] A method for preparing an AGM separator comprises the following steps:

[0159] (1) Slurry preparation:

[0160] By weight percentage, 88% of 1.5 μm diameter glass fiber, 6% of chopped glass fiber, 6% of organic fiber and appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0161] (2) Molding:

[0162] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0163] (3) Vacuum drying:

[0164] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0165] (4) Surface heat treatment:

[0166] The surface of the AGM single-layer separator blank obtained in step (3) was heat-treated using an infrared heating device at a treatment temperature of 1500°C and a treatment time of 100s. The AGM separator turned yellow-black and could no longer be used for subsequent processing.

[0167] The rest is the same as Example 2.

[0168] Comparative Example 8

[0169] A method for preparing an AGM separator comprises the following steps:

[0170] (1) Slurry preparation:

[0171] By weight percentage, 88% of 1.5 μm diameter glass fiber, 6% of chopped glass fiber, 6% of organic fiber and appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0172] (2) Molding:

[0173] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0174] (3) Vacuum drying:

[0175] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0176] (4) Surface heat treatment:

[0177] The surface of the AGM single-layer separator blank obtained in step (3) is heat-treated using an infrared heating device. The process parameters are: treatment temperature 400°C, treatment time 100s, and the surface treatment area is located in the 0.3mm thickness area of ​​the upper layer of the entire AGM separator;

[0178] (5) Post-processing:

[0179] After cutting and packaging, the finished AGM separator is obtained. The obtained AGM separator is a single-layer structure with a thickness of 1.5mm. Under dry conditions, the tensile strength of the overall AGM separator in the machine direction is 0.6KN / m, the elongation at break is 4%, the maximum pore size is 20μm, and the acid absorption height of the overall AGM separator in 24h is 550mm.

[0180] The rest is the same as Example 2.

[0181] Comparative Example 9

[0182] A method for preparing an AGM separator comprises the following steps:

[0183] (1) Slurry preparation:

[0184] By weight percentage, 88% of 1.5 μm diameter glass fiber, 6% of chopped glass fiber, 6% of organic fiber and appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0185] (2) Molding:

[0186] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0187] (3) Vacuum drying:

[0188] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0189] (4) Surface heat treatment:

[0190] The surface of the AGM single-layer separator blank obtained in step (3) was heat-treated using an infrared heating device at a temperature of 1000°C and a treatment time of 150s. The AGM separator turned yellow-black and could no longer be used for subsequent processing.

[0191] The rest is the same as Example 2.

[0192] Comparative Example 10

[0193] A method for preparing an AGM separator comprises the following steps:

[0194] (1) Slurry preparation:

[0195] By weight percentage, 88% of 1.5 μm diameter glass fiber, 6% of chopped glass fiber, 6% of organic fiber and appropriate amount of water are mixed, beaten, and filtered to remove residue to obtain a uniform slurry;

[0196] (2) Molding:

[0197] The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator;

[0198] (3) Vacuum drying:

[0199] The AGM separator single-layer structure blank is vacuum dehydrated and dried, and the weight is controlled at 250gsm to obtain a dry AGM single-layer separator blank:

[0200] (4) Surface heat treatment:

[0201] The surface of the AGM single-layer separator blank obtained in step (3) was heat-treated using an infrared heating device at a treatment temperature of 1000°C and a treatment time of 100s. The surface treatment area penetrated deep into the entire AGM separator, and the AGM separator was yellow-black and could no longer be processed and used.

[0202] The rest is the same as Example 2.

[0203] Figure 1 This is a SEM image of an AGM separator with small surface pores before surface heat treatment according to Example 1 of the present invention; wherein, Figure 1 a is a 100-fold SEM image before surface heat treatment. Figure 1 b is a 500-fold SEM image before surface heat treatment.

[0204] Figure 2This is a SEM image of an AGM separator with small pores after surface heat treatment according to Example 1 of the present invention; wherein, Figure 2 a is a 100-fold SEM image after surface heat treatment. Figure 2 b is a 500x SEM image after surface heat treatment.

[0205] Depend on Figure 1-2 It can be seen that compared with the AGM separator that has not been subjected to surface heat treatment, the surface structure of the AGM separator is optimized after surface heat treatment, and the surface pores are shrunk, which is beneficial to improving the strength of the AGM and increasing the 24-hour acid absorption value.

[0206] The AGM separators obtained in Examples 1-3 and Comparative Examples 1-10 were respectively assembled and tested in batteries under a pressure of 50 kPa. The performance and final battery effects are summarized in Table 1-2 below.

[0207] Table 1

[0208] AGM separator Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 structure Single layer Single layer Single layer Single layer Single layer Double layer Tensile strength (KN / m) 0.5 0.7 0.5 0.75 0.75 0.8 Elongation at break (%) 4 0.2 4 0.5 0.5 4 Acid absorption height (mm) 700 500 700 600 600 750 Processing efficiency - -- - -- -- + Acid injection speed ++ - ++ - - ++ resistance ++ + ++ + + ++ Cycle performance + - + -- -- ++

[0209] As can be seen from the above, the AGM separator of Example 1 has excellent performance in all aspects (tensile strength, acid absorption strength, processing efficiency, cycle performance, etc.). Compared with Example 1, Comparative Example 1 has no surface heat treatment, the surface heat treatment temperature of Comparative Example 2 is too high, the surface heat treatment temperature of Comparative Example 3 is too low, the surface heat treatment time of Comparative Example 4 is too long, and the surface heat treatment area of ​​Comparative Example 5 is too large, resulting in the tensile strength, acid absorption strength and cycle performance of Comparative Examples 1-5 being lower than that of Example 1. This shows that the surface heat treatment step of the present invention has an important influence on the performance improvement of the AGM separator, which is beneficial to improving the AGM strength and improving the 24-hour acid absorption value, and the surface heat treatment process parameters, including treatment temperature, treatment time and treatment area, will affect the performance of the AGM separator. Exceeding the process parameter range recorded in the present invention will reduce the performance of the AGM separator. Only by adopting the process parameters recorded in the present invention can the performance of the AGM separator be improved. It was also found that since Comparative Example 1 had no surface heat treatment and the surface heat treatment of Comparative Example 3 was ineffective (the temperature was too low), the elongation at break of the two was basically the same (4%). After the surface heat treatment was optimized in Example 1, the elongation at break remained unchanged, but at the same time, the tensile strength, acid absorption strength, processing efficiency, cycle performance and other properties were significantly improved. However, since the surface heat treatment of Comparative Examples 2, 4 and 5 was excessive (the temperature was too high, the time was too long, and the area was too large), the elongation at break was reduced, and other properties were also reduced.

[0210] Table 2

[0211] AGM separator Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Example 2 Example 3 structure Single layer Single layer Single layer Single layer Single layer Double layer Three-layer Tensile strength (KN / m) 0.8 NA 0.6 NA NA 1.2 1.3 Elongation at break (%) 4 NA 4 NA NA 4 4 Acid absorption height (mm) 550 NA 550 NA NA 700 750 Processing efficiency + NA - NA NA ++ ++ Acid injection speed + NA + NA NA ++ ++ resistance - NA - NA NA + + Cycle performance + NA + NA NA ++ ++

[0212] It can be seen from the above that compared with Examples 2-3, Comparative Example 6 has no surface heat treatment, the surface heat treatment temperature of Comparative Example 7 is too high, the surface heat treatment temperature of Comparative Example 8 is too low, the surface heat treatment time of Comparative Example 9 is too long, and the surface heat treatment area of ​​Comparative Example 10 is too large, resulting in the tensile strength, acid absorption strength and cycle performance of Comparative Examples 6-10 being lower than those of Examples 2-3. This shows that the surface heat treatment step of the present invention has an important influence on the performance improvement of the AGM separator, and the surface heat treatment process parameters, including treatment temperature, treatment time and treatment area, will affect the performance of the AGM separator. Exceeding the process parameter range recorded in the present invention will reduce the performance of the AGM separator and may even cause the AGM separator to be yellow-black and unable to be used for subsequent processing. Only by adopting the process parameters recorded in the present invention can the performance of the AGM separator be improved. Comparing Comparative Examples 2 and 9, it can be seen that, under the same heat treatment conditions, reducing the amount of fine glass fiber and increasing the amount of chopped glass fiber and organic fiber results in the AGM separator being yellow-black and unusable for subsequent processing. This indicates that the compounding ratio of fine glass fiber, chopped glass fiber, and organic fiber has a significant impact on the preparation of the AGM separator required by the present invention. The amount of fine glass fiber, chopped glass fiber, and organic fiber, in conjunction with the surface heat treatment process parameters, is beneficial for obtaining the AGM separator required by the present invention. It was also found that the AGM separators of Comparative Examples 1-10 were single-layered, due to poor surface heat treatment results. However, the AGM separators of Examples 1-2 were double-layered, and the AGM separator of Example 3 was triple-layered. Both maintained a portion of their original macroporous structure and, after surface heat treatment, gained a surface structure with small pores, contributing to improved performance across various aspects of the AGM separators.

[0213] Parts or structures not specifically described in the present invention may adopt existing technologies or existing products and will not be described in detail here.

[0214] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing an AGM separator with small surface pores, characterized in that: The following steps are involved: (1) Slurry preparation: The glass fibers are mixed with water and beaten to obtain a uniform slurry; (2) Molding: The slurry is fed into a forming machine to obtain a single-layer structured blank of an AGM separator; (3) Vacuum drying: The AGM separator single-layer structure blank is vacuum dried to obtain a dry AGM single-layer separator blank: (4) Surface heat treatment: The AGM single-layer separator blank obtained in step (3) is subjected to surface heat treatment; (5) Post-processing: After cutting and packaging, the finished AGM separator is obtained; In step (1), 60%-100% of glass fine fibers, 0%-20% of short fibers, 0%-20% of organic fibers, and water are mixed by weight, and a uniform slurry is obtained after beating, mixing, and removing slag; In step (4), the surface heat treatment temperature is 500-1400°C, the surface heat treatment time is 1-120s, and the surface heat treatment area is located in the 0.1-1mm thickness area of ​​the upper layer of the entire AGM separator; The finished AGM separator presents a multi-level pore structure, and the pore size in the surface area is significantly smaller than the pore size in the middle area.

2. The method for preparing an AGM separator with small surface pores according to claim 1, characterized in that: In step (1), 80%-100% of glass fiber, 0%-12% of short-cut fiber, 0%-8% of organic fiber and water are mixed by weight, and a uniform slurry is obtained after beating, mixing and removing slag.

3. The method for preparing an AGM separator with small surface pores according to claim 1, characterized in that: In step (4), the surface heat treatment temperature is 800-1100°C, the surface heat treatment time is 5-60s, and the surface heat treatment area is located in the 0.1-0.5mm thickness area of ​​the upper layer of the entire AGM separator.

4. The method for preparing an AGM separator with small surface pores according to claim 1, characterized in that: In step (5), the thickness of the finished AGM separator is 0.3 mm to 4 mm.

5. The method for preparing an AGM separator with small surface pores according to claim 1, characterized in that: The pore size of the surface area is 0.1-10 μm, and the pore size of the middle area is 1-30 μm.

6. An AGM separator with small surface pores prepared according to the method for preparing an AGM separator with small surface pores according to any one of claims 1 to 5.

7. The AGM separator with small surface pores according to claim 6, characterized in that: The thickness of the AGM separator is 0.3 mm to 4 mm, and it presents a multi-level pore structure, with the pore size in the surface area being significantly smaller than that in the middle area.

8. The AGM separator with small surface pores according to claim 7, characterized in that: The pore size of the surface area is 0.1-10 μm, and the pore size of the middle area is 1-30 μm.

Images