A thin bag-type puncture-resistant AGM separator and its preparation method

Abstract

The present invention relates to a thin, bag-type, puncture-resistant AGM separator and a method for preparing the same, belonging to the technical field of battery separators. The thin, bag-type, puncture-resistant AGM separator comprises the following raw materials in percentage by mass: 50% to 70% high-alkali glass fiber and 30% to 50% reinforcing fiber; the high-alkali glass fiber comprises high-alkali glass fiber with a beating degree of 29 to 44°SR and high-alkali glass fiber with a beating degree of 19 to 29°SR; and the reinforcing fiber is a sheath-core dual-melting-point fiber. The present invention prepares a thin, bag-type, puncture-resistant AGM separator suitable for starved lead-acid batteries. The separator has a bag-like structure that completely covers the plates, exhibits strong puncture resistance, is thin and uniform in thickness, has high air permeability, and exhibits low electrical resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of battery separators, and in particular to a thin bag-type puncture-resistant AGM separator and a preparation method thereof. Background Art

[0002] In lead-acid batteries, sulfuric acid, acting as an electrolyte, directly participates in the charge and discharge reactions. In traditional lead-acid batteries, except for components like the plates and separators, the entire battery is filled with sulfuric acid electrolyte. At this point, the battery is in a flooded state, hence the name "Enhanced Flooded Battery" (EFB). Flooded batteries use PE bag separators, and the plates are completely immersed in the electrolyte-filled bags, separating them from the other plates. However, flooded batteries require regular hydration and maintenance, are prone to generating gas and acid mist, and pose a risk of electrolyte leakage, posing safety risks during transportation and use. With the release of relevant national environmental protection policies, the development of lead-acid batteries has gradually shifted from EFB flooded batteries to AGM lean batteries.

[0003] AGM starved lead-acid batteries use ultra-fine glass fiber mat as a separator, separating the positive and negative electrodes, providing a path for oxygen recombination, and trapping the electrolyte within the separator. This eliminates the need for fluid electrolyte, resulting in maintenance-free operation and enhanced safety. However, compared to the bagged PE separators used in EFB batteries, conventional AGM battery glass fiber separators cover the front and back of the plates, while leaving both sides completely exposed. This reduces the battery's cycle life when active material on the plates detaches. Furthermore, the primary failure mode of AGM batteries is a short circuit, primarily caused by lead dendrites piercing the separator.

[0004] At present, valve-regulated maintenance-free barren liquid batteries are the mainstream development direction of lead-acid batteries at home and abroad. However, with the development of the industry, the current main technical development direction of lead-acid batteries is to improve energy density and life. Energy density is achieved by designing thinner plate thickness to increase the surface area of ​​active materials and utilization efficiency. The existing separator also limits the improvement of battery performance to a certain extent. There are the following problems: (1) Puncture resistance: In order to increase the number of plates assembled in the battery, the thickness of the separator needs to be designed to be thinner, but as the thickness of the separator becomes thinner, the risk of being punctured by lead dendrites increases. Therefore, the separator needs to have a higher puncture resistance to prevent the separator from being punctured by dendrites, resulting in a short circuit between the positive and negative electrodes; (2) Resistance: The resistance of the separator directly affects the charge and discharge characteristics of the lead-acid battery, such as charge and discharge efficiency, output power, battery life, etc.; (3) The plate is not covered: When the battery is charged and discharged, the positive and negative plates will expand or contract. The separator with a certain degree of elasticity can be better attached to the plate to prevent the active material from falling off, but the side is in an open state.

[0005] In summary, it is very necessary to research and develop a thin bag-type puncture-resistant AGM separator and a preparation method thereof. Summary of the Invention

[0006] In order to solve one or more technical problems of current starved lead-acid batteries, such as poor separator puncture ability, inconsistent thickness, and uncoated plates, the present invention provides a thin bag-type puncture-resistant AGM separator and a preparation method thereof.

[0007] In the first aspect, the present invention provides a thin bag-type puncture-resistant AGM separator, comprising the following raw materials in the following mass percentages: 50% to 70% high-alkali glass fiber and 30% to 50% reinforcing fiber; the high-alkali glass fiber includes high-alkali glass fiber with a beating degree of 29 to 44°SR and high-alkali glass fiber with a beating degree of 19 to 29°SR; the reinforcing fiber is a skin-core type double-melting point fiber.

[0008] Preferably, the thin bag-type puncture-resistant AGM separator comprises the following raw materials in the following mass percentages: 30% to 40% high alkali glass fiber with a beating degree of 29 to 44°SR, 20% to 40% high alkali glass fiber with a beating degree of 19 to 29°SR, and 30% to 50% reinforcing fiber.

[0009] Preferably, the high alkali glass fiber with a beating degree of 29-44°SR is obtained by a flame process.

[0010] Preferably, the high alkali glass fiber with a beating degree of 19-29°SR is obtained by a centrifugal method.

[0011] Preferably, the raw material used for the core-sheath dual-melting-point fiber includes at least one of polyethylene terephthalate, polypropylene, and polyethylene.

[0012] Preferably, the sheath layer melting point of the sheath-core dual-melting-point fiber is 100-165°C, and the core layer melting point is not less than 180°C.

[0013] A method for preparing a thin bag-type puncture-resistant AGM separator, comprising:

[0014] (1) adding high alkali glass fiber with a beating degree of 29-44°SR, high alkali glass fiber with a beating degree of 19-29°SR, and reinforcing fiber to acidic decomposition water for decomposition to obtain a slurry;

[0015] (2) diluting the slurry and transferring it to a forming net, and vacuum dehydrating the slurry to obtain a wet fiber mat; transferring the wet fiber mat to an oven, heating it, and cooling it to obtain a separator;

[0016] (3) Folding the partition in half or stacking the partitions and performing heat pressing and edge sealing to obtain the thin bag-type puncture-resistant AGM partition.

[0017] Preferably, in step (1), the disintegration time is 10 to 20 minutes, and the fiber concentration in the slurry is 10 to 15 g / L.

[0018] Preferably, in step (1), the pH value of the acidic hydrolysis water is 2-3.

[0019] Preferably, in step (1): high alkali glass fiber with a beating degree of 29-44°SR and high alkali glass fiber with a beating degree of 19-29°SR are added to acidic decomposition water and dispersed for 5-10 minutes, and then the reinforcing fiber is added and dispersed for 5-10 minutes for decomposition.

[0020] Preferably, in step (2): the fiber concentration in the diluted slurry is 1.4 to 3.6 g / L.

[0021] Preferably, in step (2): the heating temperature is higher than the melting point of the sheath layer of the sheath-core dual-melting-point fiber and lower than the melting point of the core layer.

[0022] Preferably, in step (3): the temperature of the hot pressing edge sealing is higher than the melting point of the sheath layer of the sheath-core dual-melting-point fiber and lower than the melting point of the core layer.

[0023] Preferably, in step (3), the temperature of the hot pressing edge sealing is 100-200° C., and the pressure is 0.1-0.5 MPa.

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

[0025] (1) In the present invention, the low-beating glass fiber plays a skeleton role in the thin bag-type puncture-resistant AGM separator, ensuring the acid absorption capacity of the separator and increasing the ion and reaction material transfer channels in the separator; the puncture resistance of the prepared AGM separator is improved by adding reinforcing fibers, thereby avoiding the decrease in puncture strength caused by the thinning of the separator and the increase of low-beating glass fiber, and preventing lead dendrite puncture short circuit.

[0026] (2) The thin bag-type puncture-resistant AGM separator prepared by the present invention is used in starved lead-acid batteries. Therefore, the thin bag-type puncture-resistant AGM separator needs to have a certain electrolyte adsorption capacity. Glass fiber has a better adsorption capacity for acidic electrolyte than chemical fiber, so glass fiber is still used as the main component in the ratio. Experiments have confirmed that by limiting the above raw material components, it is possible to avoid the problem of poor electrolyte adsorption capacity of the separator when the amount of glass fiber is too small, and to avoid the problem of poor puncture resistance of the separator or even lead dendrite puncture short circuit when the amount of glass fiber is too large.

[0027] (3) In the present invention, the puncture resistance of the thin bag-type puncture-resistant AGM separator is improved by adding dual-melting-point reinforcing fibers. During the preparation process, the low-melting-point skin layer will melt first, and the melted part will bond with the high-alkali glass fiber to form a mesh structure. At this time, the core layer has a higher melting point and plays the role of a skeleton fiber together with the high-alkali glass fiber in the thin bag-type puncture-resistant AGM separator. At the same time, it further improves the resilience, wear resistance and puncture resistance of the separator.

[0028] (4) In the present invention, since the reinforcing fibers are made of flexible chemical fibers, the integrity of the AGM separator can still be maintained after folding or stacking. Then, the edges of the separator are pressed and fitted together under a certain pressure and temperature by a hot pressing edge sealing machine. The temperature during hot pressing and edge sealing can be used to melt the cortex of the reinforcing fibers, thereby achieving edge sealing with the help of the melted cortex under a certain pressure, thereby obtaining a thin bag-type puncture-resistant AGM separator for use in starved lead-acid batteries. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] The present invention provides a thin bag-type puncture-resistant AGM separator, comprising the following raw materials in the following mass percentages: 50% to 70% of high-alkali glass fiber (for example, 50%, 52%, 54%, 55%, 56%, 58%, 60%, 62%, 64%, 65%, 66%, 68% or 70%) and 30% to 50% of reinforcing fiber (for example, 30%, 32%, 34%, 35%, 36%, 38%, 40%, 42%, 44%, 45%, 46%, 48% or 50%); the high-alkali glass fiber comprises high-alkali glass fiber with a beating degree of 29 to 44°SR and high-alkali glass fiber with a beating degree of 19 to 29°SR; the reinforcing fiber is a skin-core type dual-melting point fiber.

[0031] Specifically, the beating degree of 29-44°SR refers to any value between 29°SR and 44°SR, for example, 29°SR, 30°SR, 32°SR, 34°SR, 35°SR, 36°SR, 38°SR, 40°SR, 42°SR or 44°SR;

[0032] The beating degree of 19-29°SR refers to any value between 19°SR and 29°SR, for example, 19°SR, 20°SR, 22°SR, 24°SR, 25°SR, 26°SR, 28°SR or 29°SR.

[0033] In the present invention, low-beating glass fiber plays a skeleton role in the thin bag-type puncture-resistant AGM separator, ensuring the acid absorption capacity of the separator and increasing the ion and reaction material transfer channels in the separator; the puncture resistance of the prepared AGM separator is improved by adding reinforcing fibers, thereby avoiding the decrease in puncture strength caused by thinning of the separator and increase of low-beating glass fiber, and preventing lead dendrite puncture short circuit.

[0034] According to some preferred embodiments, a thin bag-type puncture-resistant AGM separator comprises the following raw materials in percentage by mass: 30% to 40% (for example, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%) of high alkali glass fiber with a beating degree of 29 to 44°SR, 20% to 40% (for example, 20%, 22%, 24%, 25%, 26%, 28%, 30%, 32%, 34%, 35%, 36%, 38% or 40%) of high alkali glass fiber with a beating degree of 19 to 29°SR, and 30% to 50% (for example, 30%, 32%, 34%, 35%, 36%, 38%, 40%, 42%, 44%, 45%, 46%, 48% or 50%) of reinforcing fiber.

[0035] The thin, bag-type, puncture-resistant AGM separator prepared by the present invention is used in starved lead-acid batteries. Therefore, it requires a certain electrolyte adsorption capacity. Glass fiber has superior adsorption capacity for acidic electrolytes compared to chemical fibers, so glass fiber is still the primary component in the formulation. Experimental studies have confirmed that by limiting the raw material composition, the separator's poor electrolyte adsorption capacity can be avoided when the glass fiber dosage is too low, while the separator's poor puncture resistance and even lead dendrite puncture short circuits can be avoided when the glass fiber dosage is too high. At the same time, by further limiting the mass percentage of high-alkali glass fibers with different low beating degrees in the thin bag-type puncture-resistant AGM separator, under the premise that the amount of other raw materials remains unchanged, it can further avoid the situation where the pore size of the pores in the separator is too large and the active substances of the plate penetrate into the separator when the amount of high-alkali glass fibers with a beating degree of 29 to 44°SR is less than 30%; it can also avoid the situation where the amount of high-alkali glass fibers with a beating degree of 29 to 44°SR is higher than 40%, which leads to an increase in the separator resistance and a decrease in the ion transfer efficiency and oxygen recombination capacity between the positive and negative electrodes.

[0036] According to some preferred embodiments, the high alkali glass fiber with a beating degree of 29-44°SR is obtained by a flame process.

[0037] According to some preferred embodiments, the high alkali glass fiber with a beating degree of 19-29°SR is obtained by a centrifugal method.

[0038] In the present invention, due to the molecular forces between fibers, water molecules during hydrolysis have little impact on these forces, resulting in relatively poor dispersion. Centrifugally produced high-alkali glass fibers are more uniform in diameter and length, resulting in a smoother separator surface and improved thickness consistency. A higher degree of beating means larger size, weaker molecular forces, and better dispersion. During the separator molding process, they form a skeletal structure with the reinforcing fibers, ensuring the overall uniformity of the thin, bag-type, puncture-resistant AGM separator meets requirements.

[0039] The present invention has no special requirements for high-alkali glass fiber; existing products that meet the beating degree requirements can be used. Flame-grown high-alkali glass fiber primarily has an SR of 29-44°, while centrifugal-grown high-alkali glass fiber primarily has an SR of 19-29°. These production processes are relatively mature, and their application in the AGM separator industry is scalable and cost-effective.

[0040] According to some preferred embodiments, the raw material used for the core-sheath dual melting point fiber includes at least one of polyethylene terephthalate, polypropylene, and polyethylene.

[0041] According to some preferred embodiments, the sheath layer melting point of the sheath-core dual melting point fiber is lower than the core layer melting point.

[0042] According to some more preferred embodiments, the sheath melting point of the sheath-core dual-melting-point fiber is 100-165°C (for example, it can be 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C or 165°C), and the core layer melting point is not less than 180°C (for example, it can be 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 220°C, 240°C, 250°C, etc.).

[0043] In the present invention, the puncture resistance of the thin bag-type puncture-resistant AGM separator is improved by adding dual-melting-point reinforcing fibers. During the preparation process, the low-melting-point cortex will melt first, and the melted part will bond with the high-alkali glass fiber to form a mesh structure. At this time, the core layer has a higher melting point and plays the role of a skeleton fiber together with the high-alkali glass fiber in the thin bag-type puncture-resistant AGM separator, while further improving the resilience, wear resistance and puncture resistance of the separator.

[0044] Specifically, the core-sheath dual melting point fiber can be made of polyethylene with different melting points, polyethylene terephthalate with different melting points, polypropylene with different melting points, polyethylene and polyethylene terephthalate, polypropylene and polyethylene terephthalate, polyethylene and polypropylene.

[0045] The thickness of ordinary AGM separator 10kPa is usually designed to be above 1.0mm to ensure that it has a certain puncture resistance. The AGM separator prepared in the present invention improves the puncture resistance of the separator by using dual melting point reinforced fibers. Therefore, the thickness of the prepared AGM separator 10kPa can be designed to be between 0.6 and 1.0mm (for example, it can be 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm or 1.0mm), thereby obtaining lower resistance and more plate assembly quantities.

[0046] The present invention also provides a method for preparing a thin bag-type puncture-resistant AGM separator, which comprises:

[0047] (1) adding high alkali glass fiber with a beating degree of 29-44°SR, high alkali glass fiber with a beating degree of 19-29°SR, and reinforcing fiber to acidic decomposition water for decomposition to obtain a slurry;

[0048] (2) diluting the slurry and transferring it to a forming net and vacuum dehydrating it to obtain a wet fiber mat; transferring the wet fiber mat to an oven, heating it, and cooling it to obtain a separator;

[0049] (3) Fold the partition in half or stack them and perform heat pressing and edge sealing to obtain a thin bag-type puncture-resistant AGM partition.

[0050] According to some preferred embodiments, in step (1):

[0051] The decomposition time is 10 to 20 minutes (for example, it can be 10 minutes, 11 minutes, 12 minutes, 15 minutes, 16 minutes, 18 minutes or 20 minutes), and the fiber concentration in the slurry is 10 to 15 g / L (for example, it can be 10 g / L, 10.5 g / L, 11 g / L, 11.5 g / L, 12 g / L, 12.5 g / L, 13 g / L, 13.5 g / L, 14 g / L, 14.5 g / L or 15 g / L).

[0052] In this invention, the AGM separator pulping process primarily utilizes hydraulic debonding. Fiber dispersion relies on the flow of water molecules and the mutual shearing forces between fibers. Therefore, considering the uniformity of fiber dispersion, the fiber concentration in the slurry is limited to ensure effective debonding. Experimental studies have shown that if the fiber concentration is too low, the fibers will not be able to shear each other, while if the fiber concentration is too high, the fibers will not be fully and evenly dispersed.

[0053] According to some preferred embodiments, in step (1):

[0054] The pH value of the acidic decomposition water is 2 to 3 (for example, it can be 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 or 3).

[0055] In the present invention, the pH value of the slurry is maintained at a low level by adjusting the pH of the acidic decomposition water, thereby weakening the molecular interaction force between the fibers and improving the dispersion effect.

[0056] According to some preferred embodiments, in step (1):

[0057] High alkali glass fiber with a beating degree of 29-44°SR and high alkali glass fiber with a beating degree of 19-29°SR are added to acidic debonding water and dispersed for 5-10 minutes (for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes or 10 minutes), and then reinforcing fiber is added and dispersed for 5-10 minutes (for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes or 10 minutes) for debonding.

[0058] In the present invention, the specific dispersing method when preparing the slurry can be centralized beating or multiple beatings. By first dispersing the high-alkali glass fiber and then adding the reinforcing fiber for dispersion, the high-alkali glass fiber and the reinforcing fiber are fully mixed.

[0059] It should be noted that the acidic degassing water in step (1) is preferably a mixed solution of white water and sulfuric acid (e.g., at a concentration of 65-85%), with a pH of 2-3. White water refers to recycled water from AGM separator manufacturing, which is initially a mixed solution of pure water and sulfuric acid. The present invention does not impose any specific restrictions on the amount of sulfuric acid used to adjust the pH of the acidic degassing water, as long as the pH of the acidic degassing water is adjusted to the target range.

[0060] According to some preferred embodiments, in step (2):

[0061] The fiber concentration in the diluted slurry is 1.4 to 3.6 g / L (for example, it can be 1.4 g / L, 1.5 g / L, 1.6 g / L, 1.8 g / L, 2.0 g / L, 2.2 g / L, 2.5 g / L, 2.8 g / L, 3.0 g / L, 3.2 g / L, 3.4 g / L, 3.5 g / L or 3.6 g / L).

[0062] According to some more preferred embodiments, step (2) further includes:

[0063] The decomposed pulp is diluted for the first time to obtain a prepared pulp with a fiber concentration of 2 to 5 g / L; the prepared pulp is then diluted for the second time to obtain a sizing pulp with a fiber concentration of 1.4 to 3.6 g / L.

[0064] In the present invention, in order to take into account both good fiber dispersion performance and high delamination efficiency, the fiber concentration in the slurry is limited to 10-15 g / L; the slurry is further diluted for the first time to ensure the fiber dispersion performance during preparation, and a second dilution is performed during sizing in step (2) to further ensure the fiber dispersion.

[0065] According to some preferred embodiments, in step (2):

[0066] The heating temperature is higher than the melting point of the sheath layer of the sheath-core dual-melting-point fiber and lower than the melting point of the core layer.

[0067] In the present invention, the wet fiber felt after forming is continuously conveyed into an oven and heated in the oven. The heating causes the cortex of the reinforcing fiber to reach the melting point and melt, thereby enhancing the bonding with the high-alkali glass fiber and forming a network structure. The fiber felt is then taken out of the oven and cooled and solidified to obtain a partition.

[0068] According to some preferred embodiments, in step (3):

[0069] The temperature of the hot-pressing edge sealing is higher than the melting point of the sheath layer of the sheath-core dual-melting-point fiber and lower than the melting point of the core layer.

[0070] According to some preferred embodiments, in step (3):

[0071] The temperature of hot pressing and edge sealing is 100-200°C (for example, it can be 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C), and the pressure is 0.1-0.5MPa (for example, it can be 0.1MPa, 0.15MPa, 0.2MPa, 0.25MPa, 0.3MPa, 0.35MPa, 0.4MPa, 0.45MPa or 0.5MPa).

[0072] In the present invention, since the reinforcing fibers are made of flexible chemical fibers, the integrity of the AGM separator can still be guaranteed after folding or stacking. Then, the edges of the separator are pressed and fitted together under a certain pressure and temperature through a hot pressing edge sealing machine. The temperature during hot pressing edge sealing can be used to melt the cortex of the reinforcing fibers, thereby achieving edge sealing with the help of the melted cortex under a certain pressure to obtain a thin bag-type puncture-resistant AGM separator.

[0073] Unless otherwise specified, the raw materials used in the present invention can be products that can be directly purchased on the market or synthesized by existing methods;

[0074] In the present invention, “and / or” appearing between multiple technical features means that these technical features are connected in an “and / or” relationship, indicating that it can be any one of these technical features, or a combination of any two or more of these technical features.

[0075] The present invention will be further described below by way of examples, but the protection scope of the present invention is not limited to these examples.

[0076] Example 1

[0077] A thin bag-type puncture-resistant AGM separator, comprising the following raw materials in the following mass percentages: 30% flame-made high-alkali glass fiber with a beating degree of 29°SR, 40% centrifugal-made high-alkali glass fiber with a beating degree of 19°SR, and 30% reinforcing fiber; the reinforcing fiber is a sheath-core dual-melting-point fiber with a polyethylene sheath and a polyethylene terephthalate core;

[0078] Preparation method of thin bag-type puncture-resistant AGM separator:

[0079] (1) According to the above amount, flame-made high-alkali glass fiber with a beating degree of 29°SR, centrifugal-made high-alkali glass fiber with a beating degree of 19°SR, and reinforcing fiber were added to acidic decomposition water (a mixed solution of white water and sulfuric acid) with a pH of 2 and decomposition was continued for 6 minutes, and then the reinforcing fiber was added and decomposition was continued for 6 minutes to obtain a slurry with a fiber concentration of 12 g / L;

[0080] (2) After the slurry is diluted (fiber concentration is 3.0g / L), it is evenly distributed on the polyester forming net through the slurry distributor and the headbox, and after vacuum dehydration, it is forwarded from the forming net to the oven for drying. In the oven, the wet fiber felt after forming and dehydration is conveyed into the oven, and then conveyed to the oven outlet through the transmission device inside the oven. The oven is heated by the burner to the melting point temperature of polyethylene + 10°C, so that the moisture in the wet fiber felt is evaporated when passing through the oven. At the same time, the cortex of the reinforcing fiber melts after reaching the melting point and cools and solidifies after leaving the oven to obtain a separator.

[0081] (3) The dried separator is cut into sheets according to the required size, and then the sheet separator is folded in half or stacked and sent to a hot pressing edge sealing machine. The edges of the separator are pressed and fitted at 150°C and 0.5MPa to achieve edge sealing. After cooling and solidification, a thin bag-type puncture-resistant AGM separator that can completely cover the plate is made.

[0082] Example 2

[0083] A thin bag-type puncture-resistant AGM separator comprises the following raw materials in the following percentages by mass: 35% flame-made high-alkali glass fiber with a beating degree of 34°SR, 35% centrifugally-made high-alkali glass fiber with a beating degree of 24°SR, and 30% reinforcing fiber; the reinforcing fiber is a sheath-core dual-melting-point fiber with a sheath layer of low-melting-point polyethylene terephthalate and a core layer of high-melting-point polyethylene terephthalate;

[0084] Preparation method of thin bag-type puncture-resistant AGM separator:

[0085] (1) According to the above dosage, flame-made high-alkali glass fiber with a beating degree of 34°SR, centrifugal-made high-alkali glass fiber with a beating degree of 24°SR, and reinforcing fiber were added to acidic decomposition water (a mixed solution of white water and sulfuric acid) with a pH of 2.5 and decomposition was continued for 5 minutes. Then, the reinforcing fiber was added and decomposition was continued for 5 minutes to obtain a slurry with a fiber concentration of 14 g / L;

[0086] (2) After the slurry is diluted (fiber concentration is 3.2g / L), it is evenly flowed onto the polyester forming net through the slurry distributor and the headbox, and after vacuum dehydration, it is forwarded from the forming net to the oven for drying. In the oven, the wet fiber felt after forming and dehydration is conveyed into the oven, and then conveyed to the oven outlet through the transmission device inside the oven. The oven is heated by the burner to the melting point temperature of 130℃ + 10℃, so that the moisture in the wet fiber felt is evaporated when passing through the oven, and at the same time, the cortex of the reinforcing fiber melts after reaching the melting point and cools and solidifies after leaving the oven to obtain a partition;

[0087] (3) The dried separator is cut into sheets according to the required size, and then the sheet separator is folded in half or stacked and sent to a hot pressing edge sealing machine. The edges of the separator are pressed and fitted at 160°C and 0.4MPa to achieve edge sealing. After cooling and solidification, a thin bag-type puncture-resistant AGM separator that can completely cover the plate is made.

[0088] Example 3

[0089] A thin, bag-type, puncture-resistant AGM separator, comprising the following raw materials by weight: 30% flame-grown high-alkali glass fiber with a beating degree of 44°SR, 35% centrifugal-grown high-alkali glass fiber with a beating degree of 19°SR, and 35% reinforcing fiber. The reinforcing fiber is a sheath-core dual-melting-point fiber with a polyethylene sheath and a polypropylene core.

[0090] Preparation method of thin bag-type puncture-resistant AGM separator:

[0091] (1) According to the above dosage, flame-made high-alkali glass fiber with a beating degree of 44°SR, centrifugal-made high-alkali glass fiber with a beating degree of 19°SR, and reinforcing fiber were added to acidic decomposition water (a mixed solution of white water and sulfuric acid) with a pH of 2.6 and decomposition was carried out for 7 minutes. Then, the reinforcing fiber was added and decomposition was continued for 5 minutes to obtain a slurry with a fiber concentration of 14 g / L;

[0092] (2) After the slurry is diluted (fiber concentration is 3.2g / L), it is evenly flowed onto the polyester forming net through the slurry distributor and the headbox, and after vacuum dehydration, it is forwarded from the forming net to the oven for drying. In the oven, the wet fiber felt after forming and dehydration is conveyed into the oven, and then conveyed to the oven outlet through the transmission device inside the oven. The oven is heated by the burner to the melting point temperature of 110℃ + 10℃, so that the moisture in the wet fiber felt is evaporated when passing through the oven. At the same time, the cortex of the reinforcing fiber melts after reaching the melting point and cools and solidifies after leaving the oven to obtain a partition;

[0093] (3) The dried separator is cut into sheets according to the required size, and then the sheet separator is folded in half or stacked and sent to a hot pressing edge sealing machine. The edges of the separator are pressed and fitted at 140°C and 0.5MPa to achieve edge sealing. After cooling and solidification, a thin bag-type puncture-resistant AGM separator that can completely cover the plate is made.

[0094] Example 4

[0095] Example 4 is basically the same as Example 2, except that:

[0096] A thin bag-type puncture-resistant AGM separator comprises the following raw materials in the following mass percentages: 25% flame-produced high-alkali glass fiber with a beating degree of 34°SR, 25% centrifugally produced high-alkali glass fiber with a beating degree of 29°SR, and 50% reinforcing fiber; the reinforcing fiber is a sheath-core type dual-melting-point fiber with a sheath layer of low-melting-point polyethylene terephthalate and a core layer of high-melting-point polyethylene terephthalate.

[0097] Example 5

[0098] Example 5 is basically the same as Example 2, except that:

[0099] A thin bag-type puncture-resistant AGM separator comprises the following raw materials in the following mass percentages: 33% flame-produced high-alkali glass fiber with a beating degree of 34°SR, 33% centrifugally produced high-alkali glass fiber with a beating degree of 24°SR, and 34% reinforcing fiber; the reinforcing fiber is a sheath-core dual-melting-point fiber with a sheath layer of low-melting-point polyethylene terephthalate and a core layer of high-melting-point polyethylene terephthalate.

[0100] Example 6

[0101] Example 6 is basically the same as Example 2, except that:

[0102] A thin, bag-type, puncture-resistant AGM separator comprises the following raw materials by weight: 30% flame-grown high-alkali glass fiber with a beating degree of 44°SR, 30% centrifugally produced high-alkali glass fiber with a beating degree of 29°SR, and 40% reinforcing fiber. The reinforcing fiber is a sheath-core dual-melting-point fiber with a polyethylene sheath and a polypropylene core.

[0103] Comparative Example 1

[0104] Comparative Example 1 is substantially the same as Example 2, except that:

[0105] The raw materials for preparing the thin bag-type puncture-resistant AGM separator do not contain reinforcing fibers, and no reinforcing fibers are added during the preparation of the thin bag-type puncture-resistant AGM separator.

[0106] Comparative Example 2

[0107] Comparative Example 2 is substantially the same as Example 2, except that:

[0108] The raw material for preparing thin bag-type puncture-resistant AGM separators is not a sheath-core dual-melting-point fiber, but a low-melting-point polyethylene terephthalate fiber containing only the sheath material.

[0109] Comparative Example 3

[0110] Comparative Example 3 is substantially the same as Example 2, except that:

[0111] The raw materials for preparing the thin bag-type puncture-resistant AGM separators all use high-alkali glass fibers produced by the flame process, that is, high-alkali glass fibers produced by the centrifugal process are not used.

[0112] Comparative Example 4

[0113] Comparative Example 4 is substantially the same as Example 2, except that:

[0114] The amount of reinforcing fiber used in the raw materials for preparing the thin bag-type puncture-resistant AGM separator is 25%.

[0115] Comparative Example 5

[0116] Comparative Example 5 is substantially the same as Example 2, except that:

[0117] The amount of reinforcing fiber used in the raw materials for preparing the thin bag-type puncture-resistant AGM separator is 60%.

[0118] The present invention compares the performance of the AGM separators prepared in each embodiment and each comparative example. The performance testing methods of the AGM separators refer to the national standard GB / T28535-2018 lead-acid battery separator. The performance of the obtained separator products is shown in Table 1:

[0119] Table 1

[0120]

[0121] It can be seen from the experimental data in Table 1 that the acid absorption capacity and resistance of the thin bag-type puncture-resistant AGM separator prepared by the present invention are further ensured by air permeability. The surface of the separator is improved and the thickness consistency is improved by adding high-alkali glass fiber with low beating degree and high-alkali glass fiber produced by centrifugal method in pulping. At the same time, the low-beating degree fiber provides a skeleton structure for the separator, thereby improving the air permeability and porosity of the separator; at the same time, the addition of skin-core dual-melting point fiber plays the role of bonding the fibers and enhancing the puncture resistance of the separator, so that the prepared AGM separator 10kPa has excellent puncture resistance when the thickness is less than 1.0mm, and the skin-core dual-melting point fiber can also melt the skin layer during hot pressing and sealing to obtain a tightly fitted special-shaped edge, thereby increasing the contact area of ​​the edge to improve the bonding force to obtain a thin bag-type puncture-resistant AGM separator.

[0122] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A thin bag-type puncture-resistant AGM separator, characterized in that: The invention comprises the following raw materials in the following mass percentages: 50% to 70% high alkali glass fiber and 30% to 50% reinforcing fiber; the high alkali glass fiber comprises high alkali glass fiber with a beating degree of 29 to 44°SR and high alkali glass fiber with a beating degree of 19 to 29°SR; the reinforcing fiber is a sheath-core type dual-melting-point fiber; the sheath layer melting point of the sheath-core type dual-melting-point fiber is 100 to 165°C, and the core layer melting point is not less than 180°C.

2. The thin bag-type puncture-resistant AGM separator according to claim 1, characterized in that: The invention comprises the following raw materials in percentage by mass: 30% to 40% of high alkali glass fiber with a beating degree of 29 to 44°SR, 20% to 40% of high alkali glass fiber with a beating degree of 19 to 29°SR, and 30% to 50% of reinforcing fiber.

3. The thin bag-type puncture-resistant AGM separator according to claim 1, characterized in that: High alkali glass fiber with a beating degree of 29~44°SR is obtained by flame production.

4. The thin bag-type puncture-resistant AGM separator according to claim 1, characterized in that: High alkali glass fiber with a beating degree of 19~29°SR is obtained by centrifugal method.

5. The thin bag-type puncture-resistant AGM separator according to claim 1, characterized in that: The raw material used for the core-sheath dual-melting-point fiber includes at least one of polyethylene terephthalate, polypropylene and polyethylene.

6. A method for preparing the thin bag-type puncture-resistant AGM separator according to any one of claims 1 to 5, characterized in that: include: (1) adding high alkali glass fiber with a beating degree of 29-44°SR, high alkali glass fiber with a beating degree of 19-29°SR, and reinforcing fiber into acidic decomposition water for decomposition to obtain a slurry; (2) diluting the slurry and conveying it onto a forming net, and vacuum dehydrating the slurry to obtain a wet fiber felt; conveying the wet fiber felt to an oven, heating it, and cooling it to obtain a separator; (3) Folding the partition in half or stacking the partitions and performing heat pressing and edge sealing to obtain the thin bag-type puncture-resistant AGM partition.

7. The preparation method according to claim 6, characterized in that In step (1): The decomposition time is 10-20 minutes, and the fiber concentration in the slurry is 10-15 g / L.

8. The preparation method according to claim 6, characterized in that In step (1): The pH value of the acidic decomposition water is 2-3.

9. The preparation method according to claim 6, characterized in that In step (1): High alkali glass fiber with a beating degree of 29-44°SR and high alkali glass fiber with a beating degree of 19-29°SR are added to acidic decomposition water and dispersed for 5-10 minutes, and then the reinforcing fiber is added and dispersed for 5-10 minutes for decomposition.

10. The preparation method according to claim 6, characterized in that In step (2): The fiber concentration in the diluted slurry is 1.4~3.6g / L.

11. The preparation method according to claim 6, characterized in that In step (2): The heating temperature is higher than the melting point of the sheath layer of the sheath-core dual-melting-point fiber and lower than the melting point of the core layer.

12. The preparation method according to any one of claims 6 to 9, characterized in that: In step (3): The temperature of the hot pressing edge sealing is higher than the melting point of the sheath layer of the sheath-core dual-melting-point fiber and lower than the melting point of the core layer.

13. The preparation method according to any one of claims 6 to 9, characterized in that: In step (3): The temperature of the hot pressing edge sealing is 100-200° C., and the pressure is 0.1-0.5 MPa.

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