AGM (absorptive glass mat) separator with high acid absorption capacity and preparation method of AGM separator

Abstract

The invention discloses an AGM (absorptive glass mat) separator with high acid absorption capacity and a preparation method thereof. The preparation method comprises the following steps: step 1, preparing a separator substrate from glass microfibers with the diameter of 0.5-3 microns through a wet forming process; step 2, dehydrating and drying the partition plate base material to obtain a first blank; step 3, dipping the first blank in a conductive treatment liquid, drying and curing, cleaning with deionized water, and dehydrating and drying to obtain a second blank; step 4, modifying the second blank to obtain the AGM separator, firstly, preparing a separator substrate into a three-layer fiber layer structure with a thin outer part and a thick center, and the three-layer fiber layer structure with the thin outer part and the thick center not only improves the liquid absorption amount, but also prevents lead dendrites from penetrating through the separator due to an overlarge pore diameter; the fumed silica can increase the acid absorption amount and capillary acid absorption height of the partition plate, and the silane coupling agent and polyacrylamide increase the crosslinking degree in the partition plate, so that the tensile strength and compressive strength of the partition plate are improved.

Description

Technical Field

[0001] The invention relates to the technical field of lead-acid batteries, and in particular to an AGM separator with high acid absorption capacity and a preparation method thereof. Background Art

[0002] Ultrafine glass fiber AGM separator is an important component in lead-acid batteries. The function of the AGM separator is to separate the positive and negative plates of the battery to prevent the battery from short-circuiting. At the same time, the porous separator can adsorb and fix sulfuric acid, allowing ions to migrate between the positive and negative plates through the pores of the separator to achieve current conduction and electrochemical reactions, so the AGM separator is required to have a very high porosity. However, too large a pore size can easily cause lead dendrites to penetrate, and a small-pore AGM separator has a small acid absorption capacity. Summary of the invention

[0003] The object of the present invention is to provide an AGM separator with high acid absorption capacity and a preparation method thereof in view of the deficiencies of the prior art.

[0004] The technical solution of the present invention to solve the above problem is: a method for preparing an AGM separator with high acid absorption capacity, which specifically comprises the following steps:

[0005] Step 1, preparing a separator substrate by a wet forming process using glass microfibers with a diameter of 0.5 to 3 μm;

[0006] Step 2, dehydrating and drying the separator substrate to obtain a first blank;

[0007] Step 3, dipping the first blank into a conductive treatment liquid, drying and curing it, then washing it with deionized water, and then dehydrating and drying it to obtain a second blank;

[0008] Step 4, modifying the second blank to obtain an AGM separator; specifically comprising the following steps:

[0009] 401) preparing a modified solution by uniformly mixing 2-4 parts of fumed silica, 0.5-1.5 parts of a silane coupling agent, 0.01-0.05 parts of polyacrylamide and 100 parts of deionized water by weight to obtain a modified solution;

[0010] 402) adding the modified solution into an ultrasonic dispersion water bath;

[0011] 403) the second blank is subjected to modification treatment in an ultrasonic dispersion water bath; the modification treatment is divided into two steps: the first step is to firstly perform conventional infiltration on the second blank and then control drying; the second step is to perform multiple extrusion infiltration;

[0012] 404) Dehydrate and dry the modified second blank to obtain an AGM separator.

[0013] Furthermore, the partition substrate prepared in step 1 has a medium-coarse fiber layer in the middle and medium-fine fiber layers on both sides. The medium-coarse fiber layer contains medium-coarse glass fiber cotton and coarse glass fiber cotton, and the medium-fine fiber layer contains fine glass fiber cotton and medium-coarse glass fiber cotton. The medium-coarse fiber layer and the medium-fine fiber layer use medium-coarse glass fiber cotton of the same diameter.

[0014] Furthermore, step 1 of preparing the separator substrate specifically comprises the following steps:

[0015] 101) Weigh 50-60 parts by weight of glass fiber wool with a diameter of 0.5-1.5 μm, 20-30 parts of glass fiber wool with a diameter of 1.5-2.5 μm, and 10-20 parts of glass fiber wool with a diameter of 2.5-3 μm;

[0016] 102) The three types of glass fiber wools are weighed and broken up into pulp to obtain fine glass fiber wool slurry, medium-coarse glass fiber wool slurry and coarse glass fiber wool slurry;

[0017] 103) mixing the fine glass fiber cotton slurry with half of the medium-coarse glass fiber cotton slurry and diluting with water to obtain a first slurry, and diluting the other half of the medium-coarse glass fiber cotton slurry and the coarse glass fiber cotton slurry with water to obtain a second slurry;

[0018] Half of the first slurry, the second slurry, and the other half of the first slurry are sequentially added into a molding machine to form a separator substrate.

[0019] Further, step 403 is performed using a processing device, which includes a loading roller, a first wetting roller group, a drying roller group, a second wetting roller group and a unloading roller in sequence along the blank transmission method, the first wetting roller group includes two first transmission roller bodies, the lowermost ends of the two first transmission roller bodies are located below the liquid level line of the ultrasonic dispersion water bath, the drying roller group includes two second transmission roller bodies, the two second transmission roller bodies are located above the liquid level line, the second wetting roller group includes two third transmission roller bodies, the lowermost ends of the two third transmission roller bodies are located below the liquid level line of the ultrasonic dispersion water bath, and multiple groups of extrusion mechanisms are arranged between the two third transmission roller bodies, each group of extrusion mechanisms includes an upper pressing roller and a lower pressing roller, and an extrusion gap is formed between the upper pressing roller and the lower pressing roller.

[0020] Furthermore, the extrusion gap between the upper pressing roller and the lower pressing roller is adjustable.

[0021] The present invention has the beneficial effects:

[0022] The invention provides an AGM separator with high acid absorption and a preparation method thereof. Firstly, a separator substrate is prepared into a three-layer fiber layer structure with thin outer part and thick center. Since the medium-coarse fiber layer and the medium-fine fiber layer use glass fiber wool of the same diameter, they are more easily connected tightly during the molding process, thereby avoiding the formation of stratification between the medium-coarse fiber layer and the medium-fine fiber layer. The three-layer fiber layer structure with thin outer part and thick center not only improves the liquid absorption, but also avoids the lead dendrites penetrating the separator due to excessive pore size. Then, the separator substrate is modified, and the gas phase silica can increase the acid absorption and capillary acid absorption height of the separator, and the silane coupling agent and polyacrylamide increase the cross-linking degree inside the separator, thereby improving the tensile and compressive strengths of the separator. In the modification process, the first impregnation adopts conventional impregnation and then controls drying, and the compressive performance of both sides of the separator substrate is enhanced after the first modification. Then, the second modification is completed by multiple extrusion impregnations to ensure that the middle part of the separator substrate is fully impregnated. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the structure of the processing device;

[0024] In the figure: 1-ultrasonic dispersion water bath, 2-loading roller, 3-first transmission roller body, 4-second transmission roller body, 5-third transmission roller body, 6-unloading roller, 7-extrusion mechanism. DETAILED DESCRIPTION

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0026] A method for preparing an AGM separator with high acid absorption capacity comprises the following steps:

[0027] Step 1, using glass microfibers with a diameter of 0.5 to 3 μm to prepare a separator substrate through a wet molding process; comprising the following steps:

[0028] 104) Weigh 50-60 parts by weight of glass fiber wool with a diameter of 0.5-1.5 μm, 20-30 parts of glass fiber wool with a diameter of 1.5-2.5 μm, and 10-20 parts of glass fiber wool with a diameter of 2.5-3 μm;

[0029] 105) The three types of glass fiber wools are weighed and pulped to obtain fine glass fiber wool slurry, medium-coarse glass fiber wool slurry and coarse glass fiber wool slurry;

[0030] 106) mixing the fine glass fiber cotton slurry with half of the medium-coarse glass fiber cotton slurry and diluting with water to obtain a first slurry, and diluting the other half of the medium-coarse glass fiber cotton slurry and the coarse glass fiber cotton slurry with water to obtain a second slurry;

[0031] 107) Add half of the first slurry, the second slurry, and the other half of the first slurry into a molding machine in sequence to obtain a separator substrate, wherein the middle of the separator substrate is a medium-coarse fiber layer, and both sides are medium-fine fiber layers.

[0032] The separator substrate is formed into a three-layer fiber layer structure with thin outer part and thick center through the above preparation process. Since the medium-coarse fiber layer and the medium-fine fiber layer use the same diameter of glass fiber wool, the glass fiber wool of the same diameter is easier to be tightly connected during the molding process, avoiding the formation of stratification between the medium-coarse fiber layer and the medium-fine fiber layer. The three-layer fiber layer structure with thin outer part and thick center not only increases the liquid absorption, but also avoids the lead dendrites penetrating the separator due to excessive pore size.

[0033] Step 2, dehydrating and drying the separator substrate to obtain a first blank;

[0034] Step 3, dipping the first blank into a conductive treatment liquid, drying and curing it, then washing it with deionized water, and then dehydrating and drying it to obtain a second blank;

[0035] Step 4, modifying the second blank to obtain an AGM separator; specifically comprising the following steps:

[0036] 404) preparing a modified solution by uniformly mixing 2-4 parts of fumed silica, 0.5-1.5 parts of a silane coupling agent, 0.01-0.05 parts of polyacrylamide and 100 parts of deionized water by weight to obtain a modified solution;

[0037] 405) adding the modified solution into an ultrasonic dispersion water bath;

[0038] 406) subjecting the second blank to modification treatment in an ultrasonic dispersion water bath through a treatment device;

[0039] 407) Dehydrate and dry the modified second blank to obtain an AGM separator.

[0040] The processing device includes a feeding roller, a first wetting roller group, a drying roller group, a second wetting roller group and a feeding roller in sequence along the blank transmission method. The first wetting roller group includes two first transmission roller bodies, and the lower ends of the two first transmission roller bodies are located below the liquid level line of the ultrasonic dispersion water bath. The drying roller group includes two second transmission roller bodies, and the two second transmission roller bodies are located above the liquid level line. The second wetting roller group includes two third transmission roller bodies, and the lower ends of the two third transmission roller bodies are located below the liquid level line of the ultrasonic dispersion water bath. Multiple groups of extrusion mechanisms are arranged between the two third transmission roller bodies, and each group of extrusion mechanisms includes an upper pressing roller and a lower pressing roller. An extrusion gap is formed between the upper pressing roller and the lower pressing roller. The infiltrated blank can squeeze out the internal liquid and air through the extrusion gap, and the blank is fully infiltrated through multiple extrusions and infiltrations.

[0041] In one embodiment, the extrusion gap between the upper pressing roller and the lower pressing roller is adjustable.

[0042] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing an AGM separator with high acid absorption, characterized in that: The specific steps include: Step 1, preparing a separator substrate by a wet forming process using glass microfibers with a diameter of 0.5 to 3 μm; Step 2, dehydrating and drying the separator substrate to obtain a first blank; Step 3, dipping the first blank into a conductive treatment liquid, drying and curing it, then washing it with deionized water, and then dehydrating and drying it to obtain a second blank; Step 4, modifying the second blank to obtain an AGM separator; specifically comprising the following steps: 401) preparing a modified solution by uniformly mixing 2-4 parts of fumed silica, 0.5-1.5 parts of a silane coupling agent, 0.01-0.05 parts of polyacrylamide and 100 parts of deionized water by weight to obtain a modified solution; 402) adding the modified solution into an ultrasonic dispersion water bath; 403) the second blank is subjected to modification treatment in an ultrasonic dispersion water bath; the modification treatment is divided into two steps: the first step is to firstly perform conventional infiltration on the second blank and then control drying; the second step is to perform multiple extrusion infiltration; 404) Dehydrating and drying the modified second blank to obtain an AGM separator.

2. The method for preparing a high acid absorption AGM separator according to claim 1, characterized in that: The partition substrate prepared in step 1 has a medium-coarse fiber layer in the middle and medium-fine fiber layers on both sides. The medium-coarse fiber layer contains medium-coarse glass fiber cotton and coarse glass fiber cotton, and the medium-fine fiber layer contains fine glass fiber cotton and medium-coarse glass fiber cotton. The medium-coarse fiber layer and the medium-fine fiber layer use medium-coarse glass fiber cotton of the same diameter.

3. A method for preparing a high acid absorption AGM separator according to claim 1 or 2, characterized in that: Step 1: Preparation of the separator substrate specifically includes the following steps: 101) Weigh 50-60 parts by weight of glass fiber wool with a diameter of 0.5-1.5 μm, 20-30 parts of glass fiber wool with a diameter of 1.5-2.5 μm, and 10-20 parts of glass fiber wool with a diameter of 2.5-3 μm; 102) The three types of glass fiber wools are weighed and broken up into pulp to obtain fine glass fiber wool slurry, medium-coarse glass fiber wool slurry and coarse glass fiber wool slurry; 103) mixing the fine glass fiber cotton slurry with half of the medium-coarse glass fiber cotton slurry and diluting with water to obtain a first slurry, and diluting the other half of the medium-coarse glass fiber cotton slurry and the coarse glass fiber cotton slurry with water to obtain a second slurry; Half of the first slurry, the second slurry, and the other half of the first slurry are sequentially added into a molding machine to form a separator substrate.

4. The method for preparing a high acid absorption AGM separator according to claim 1, characterized in that: Step 403 is performed using a processing device, which includes a loading roller, a first wetting roller group, a drying roller group, a second wetting roller group and a unloading roller in sequence along the blank transmission method. The first wetting roller group includes two first transmission roller bodies, and the lower ends of the two first transmission roller bodies are located below the liquid level line of the ultrasonic dispersion water bath. The drying roller group includes two second transmission roller bodies, and the two second transmission roller bodies are located above the liquid level line. The second wetting roller group includes two third transmission roller bodies, and the lower ends of the two third transmission roller bodies are located below the liquid level line of the ultrasonic dispersion water bath. A plurality of extrusion mechanisms are arranged between the two third transmission roller bodies, and each extrusion mechanism includes an upper pressing roller and a lower pressing roller, and an extrusion gap is formed between the upper pressing roller and the lower pressing roller.

5. The method for preparing a high acid absorption AGM separator according to claim 4, characterized in that: The extrusion gap between the upper pressing roller and the lower pressing roller is adjustable.

6. A high acid absorption AGM separator, characterized by: The preparation is carried out by the preparation method according to any one of claims 1 to 5.

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