Lead-acid storage battery film-coated paper based on aperture regulation and control and preparation method thereof

Abstract

The invention relates to the technical field of lead-acid storage battery manufacturing, in particular to lead-acid storage battery film laminating paper based on pore diameter regulation, the pore diameter of the film laminating paper is 50-70 microns, and the film laminating paper is prepared from, by weight, 45%-50% of fine glass fibers, 40%-45% of coarse glass fibers and 6%-8% of binder fibers. According to the coated paper, in the plate coating procedure of the lead-acid storage battery, the entering amount of HPbO in wet lead paste can be reduced to be smaller than or equal to 0.2 mg / cm through the capillary action, a polar plate is free of the adhesion phenomenon after curing, the seepage amount of the lead paste is 0 mg / cm, and the coated paper is matched with liquid and colloid electrolyte systems. The preparation method has the advantages that the cost advantage is remarkable, surface drying is avoided only through pore size regulation and control without changing conventional materials (wood pulp or AGM glass fibers) of the laminated paper, the material cost is equal to that of traditional laminated paper, and cost rise caused by high-end materials is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lead-acid battery manufacturing, in particular to a lead-acid battery film-coated paper based on aperture regulation and a preparation method thereof. BACKGROUND

[0002] In the large-scale production of lead-acid batteries, the plate coating (continuous coating) process is one of the core links. The current industry generally adopts the clean production process of "lead strip continuous casting and rolling - punched / drawn grid plate - double-sided coating". The film-coated paper, as a key auxiliary material after the coating of the plate, needs to achieve three major functions: first, to adhere to the lead paste on the surface of the plate to prevent the lead paste from falling off after coating; second, to isolate the plate from the equipment to prevent the lead paste from adhering to the coating machine parts; third, to prevent the plates from adhering to each other when stacked and stored, while reducing lead dust emissions, in line with environmental protection production requirements.

[0003] However, after the existing lead-acid battery manufacturers use film-coated paper to assist in coating, they still need to rely on "surface drying production lines" to solve the problem of plate adhesion - the wet plates after coating need to be heated and dried (usually using electric heating or natural gas heating) on the surface drying line to remove about 10% of the water on the surface of the plate to avoid adhesion during the subsequent stacking and curing. This process has significant drawbacks: on the one hand, the surface drying line consumes a large amount of energy, according to industry statistics, for every 24,000 KVAh of battery plate produced, an additional 742 degrees of electricity and 1,390 cubic meters of natural gas are consumed, increasing production costs; on the other hand, the surface drying line equipment (including heating pipes, steam pipes, valves, temperature control devices, etc.) occupies production space, with a land area of 8.98m² (8.98m long x 1m wide) per coating line, reducing the utilization rate of workshop space, and the maintenance of the equipment requires additional investment in consumables and management costs.

[0004] To solve the above problems, some material manufacturers have tried to achieve surface drying by changing the composition of the film-coated paper, such as using nanocomposite fibers, special acid-resistant resins, and other high-end materials. However, such solutions have obvious limitations: first, the cost of materials increases significantly, with high-end nanomaterials or special resins costing 3-5 times more than conventional materials, resulting in a 20%-30% increase in the unit price of film-coated paper, increasing the overall cost of battery manufacturing; second, the material compatibility is poor, and new materials need to be re-adapted to existing coating processes (such as lead paste formulations and curing parameters), which may cause problems such as lead paste leakage and insufficient plate strength, making it difficult to be widely promoted. SUMMARY

[0005] To overcome the above technical problems or at least partially solve the above problems, the present application provides a film-coated paper for lead-acid batteries.

[0006] The application provides a kind of lead-acid battery film paper based on aperture regulation and its preparation method: the aperture of the plate paper is 50 μm~70 μm, the plate paper includes fine glass fiber 42%~52%, coarse glass fiber 38%~48, binder fiber 6%~10%, the binder fiber is PET fiber, the thickness of the plate paper is 0.2mm, the plate paper can reduce the HPbO2- in lead paste into the plate paper by capillary action in the process of lead-acid battery plate coating, avoid the adhesion of the plate after solidification, and the lead paste will not appear from the plate paper.

[0007] Preferably, the aperture of the plate paper is 60 μm~70 μm, the fine glass fiber and the coarse glass fiber are composed of centrifugal cotton or flame cotton with different degrees of knapping, the degrees of knapping of the centrifugal cotton include 9°SR, 14°SR, 15°SR, 19°SR, and the degree of knapping of the flame cotton is 34°SR, the thickness and proportion of the fine glass fiber and the coarse glass fiber are adjusted to control the aperture of the plate paper in the range of 60 μm~70 μm.

[0008] Preferably, when the aperture of the plate paper is 62 μm, the glass fiber is composed of two kinds of centrifugal cotton with degrees of knapping of 9°SR and 14°SR; when the aperture of the plate paper is 66 μm, the glass fiber is composed of two kinds of centrifugal cotton with degrees of knapping of 9°SR and 15°SR.

[0009] Preferably, the method comprises the following steps: S1: pulping: the fine glass fiber, the coarse glass fiber and the PET binder fiber are mixed with water in a large pulp tank to form a uniform fiber suspension, and the thickness and proportion of the fine glass fiber and the coarse glass fiber are adjusted according to the required aperture of the plate paper; S2: wet forming: the fiber suspension is uniformly and stably sprayed onto a continuously running forming polyester net through a headbox to form a wet plate paper embryo, and the wet plate paper embryo is dehydrated by vacuum after passing through a glue dipping box, the thickness of the plate paper embryo is controlled by adjusting the running speed of the forming net under the condition that the concentration of the fiber suspension is constant, and the thickness of the final plate paper is 0.2mm; S3: drying and heat setting: the wet plate paper embryo is passed through a multi-zone drying channel, water is evaporated at a high temperature higher than the melting point of the PET binder fiber, the PET binder fiber is melted and the glass fiber network is firmly bonded together to form a plate paper with certain strength and elasticity.

[0010] Preferably, in step S2, the running speed of the forming net is accurately adjusted according to the concentration of the fiber suspension to ensure the uniform thickness of the plate paper embryo, so that the thickness of the final plate paper is stable at 0.2mm.

[0011] Preferably, in step S3, the temperature of the oven is controlled at 5-10℃ higher than the melting point of the PET binder fibers.

[0012] Preferably, the coated paper is applied to the coating process of lead-acid batteries, and the surface drying process is cancelled during coating, and the stack is directly cured, and the cured plate has no adhesion phenomenon.

[0013] The team has found through 120 experiments that the root cause of the plate adhesion caused by the film-coated paper is the capillary action between the wet plate and the film-coated paper: the water contained in the wet plate after coating is alkaline (pH 8.5-9.5), and PbO in the lead paste reacts with water to generate HPbO2⁻ ions (concentration 0.8-1.2 mol / L); when the film-coated paper is in close contact with the surface of the plate, the water is absorbed into the micropores of the film-coated paper under the capillary action, and HPbO2⁻ is also carried into the pores (the smaller the pore size, the greater the absorption); in the subsequent curing and drying process (60-70℃), the HPbO2⁻ in the pores gradually concentrates (concentration rises to 5-8 mol / L) as the water evaporates, and then chemical reactions occur to generate dendritic solid substances (specific reactions are as follows), these solids (diameter 2-5 μm) are inserted between the film-coated paper and the plate interface, forming a "physical anchor", which eventually leads to plate adhesion.

[0014] 5HPbO2⁻ + 5H⁺ = 5PbO・2H2O + 3H2O (The length of the generated PbO・2H2O dendrite can reach 10 μm) HPbO2⁻ + 3H⁺ + SO4²⁻ = PbSO4 + 2H2O (PbSO4 dendrite hardness reaches 3.5 GPa, easy to scratch the plate) 2HPbO2⁻ + SO4²⁻ + 4H⁺ = PbO·PbSO4 + 3H2O 4HPbO2⁻ + 6H⁺ + SO4²⁻ = 3PbO·PbSO4·H2O + 4H2O Based on the Young-Laplace formula (h = (2y cos theta) / (p g r), wherein h is the liquid rising height, y is the surface tension of water (72.8 mN / m at 25 DEG C), theta is the contact angle of water and the coated paper (the conventional AGM glass fiber contact angle is 65 DEG to 70 DEG), p is the density of water (1 g / cm3), g is the acceleration of gravity (9.8 m / s2), and r is half of the coated paper aperture), it is known that the capillary rising height of the liquid in the coated paper is inversely proportional to the aperture. It is calculated that when the aperture increases from 20 microns (r = 10 microns) to 60 microns (r = 30 microns), the capillary rising height decreases from 8.2 mm to 2.7 mm; when the aperture reaches 65 microns (r = 32.5 microns), the capillary rising height is only 1.2 mm, at this time, the moisture only forms a film (thickness <= 0.5 mm) on the surface of the coated paper, and the HPbO2- entering amount is <= 0.1 mg / cm2, which is insufficient to generate the dendritic solid leading to adhesion. Therefore, without changing the coated paper material, only by precisely regulating the aperture, the coated plate is free of surface drying, which is the optimal scheme considering the cost and performance.

[0015] The targeted scheme provided by the application has the beneficial effects including: 1. Significant cost advantage; without changing the conventional material (wood pulp or AGM glass fiber) of the coated paper, only by regulating the aperture, the surface drying is realized, the material cost is flat with the traditional coated paper, the cost increase caused by high-end materials is avoided; at the same time, the surface drying line is cancelled, 742 degrees of electricity, 1390 cubic meters of natural gas are saved for every 24,000 KVAh battery plate produced, 8.98 m2 of production space is saved for every coating line, and the energy consumption and site cost are reduced 2. Strong process compatibility; adapt to the existing lead-acid battery coating process (lead paste formula, coating speed, curing parameter), without adjusting the production line equipment, the coating speed can be maintained at 10 m / min to 30 m / min, the curing parameter is 60 DEG C to 70 DEG C, the humidity is 50% to 99%, the time is 5 h to 10 h, the drying is direct lamination curing without adhesion, and the rapid large-scale promotion is realized 3. Stable and reliable performance: the coated paper with an aperture of 50 microns to 70 microns has the functions of anti-adhesion and anti-lead paste seepage, the aperture shrinkage rate is <= 5% after 100 times of charge-discharge cycles, does not affect the cycle life of the battery, and the material recycling difficulty is low (the AGM glass fiber recovery rate is >= 90%), and meets the environmental protection requirements. DETAILED DESCRIPTION

[0016] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0017] A lead-acid battery film paper based on aperture control, the aperture of the plate coating paper is 50-70 mu m, the plate coating paper includes 42-52% fine glass fiber, 38-48% coarse glass fiber, 6-10% binder fiber, the binder fiber is PET fiber, the thickness of the plate coating paper is 0.2 mm, the plate coating paper can reduce the penetration of HPbO2- in the lead paste into the plate coating paper through capillary action during the plate coating process of the lead-acid battery, avoid the adhesion of the plate after solidification, and the lead paste will not seep out of the plate coating paper.

[0018] Preferably, the aperture of the plate coating paper is 60-70 mu m, the fine glass fiber and the coarse glass fiber are composed of centrifugal cotton or flame cotton with different freeness, the freeness of the centrifugal cotton includes 9°SR, 14°SR, 15°SR and 19°SR, the freeness of the flame cotton is 34°SR, the thickness and proportion of the fine glass fiber and the coarse glass fiber are adjusted to control the aperture of the plate coating paper in the range of 60-70 mu m.

[0019] Preferably, when the aperture of the plate coating paper is 62 mu m, the glass fiber is composed of two kinds of centrifugal cotton with freeness of 9°SR and 14°SR; when the aperture of the plate coating paper is 66 mu m, the glass fiber is composed of two kinds of centrifugal cotton with freeness of 9°SR and 15°SR.

[0020] Preferably, the following steps are included: S1: pulp preparation: select base material fibers (wood pulp fibers or AGM glass fibers) according to the target pore size, and match PET binder fibers (addition amount 6%~8%, weight percentage; the PET fiber is a low melting point type, melting point 255~260°C, melt index 15~20 g / 10 min (230°C, 2.16 kg), to ensure sufficient melting and bonding at high temperature); if AGM type film-coated paper is prepared, the glass fiber is composed of centrifugal cotton or flame cotton with different beating degrees (centrifugal cotton beating degree 9°SR, 14°SR, 15°SR, 19°SR, corresponding fiber diameter 18~22 μm, 12~15 μm, 10~12 μm, 8~10 μm; flame cotton beating degree 34°SR, fiber diameter 5~8 μm), and the pore size is precisely controlled by adjusting the fiber thickness and proportion - when the target pore size is 62 μm, 9°SR (accounting for 35% of the total weight of glass fiber) and 14°SR (accounting for 65% of the total weight of glass fiber) centrifugal cotton are used, and after laser particle size instrument detection, the average diameter of the mixed fibers is 15.2 μm, and the corresponding pore size is 62±2 μm; when the target pore size is 66 μm, 9°SR (accounting for 50% of the total weight of glass fiber) and 15°SR (accounting for 50% of the total weight of glass fiber) centrifugal cotton are used, and the average diameter after mixing is 16.8 μm, and the corresponding pore size is 66±2 μm; the fibers and deionized water (conductivity ≤5 μS / cm) are added to the pulp tank, and stirred at a stirring speed of 800 r / min~1000 r / min for 30 min, to form a uniform suspension with a concentration of 1.5%~2.0% (the suspension viscosity is controlled at 50~80 mPa・s to ensure stable jetting of the headbox); S2: wet forming: the fiber suspension is uniformly sprayed through a flow box (model QZ1000, jet pressure 0.3-0.4 MPa, lip opening 0.8-1.0 mm, lip flatness ≤0.01 mm) onto a 120-150 mesh forming polyester screen (polyester screen warp and weft density 120x120-150x150 roots / inch, air permeability 800-1000 L / m2-s); after the wet paper is immersed in a tank (immersion liquid is deionized water, immersion time 5-8 s, to ensure that the fibers are fully wetted), vacuum dehydration is performed under a negative pressure of -0.06 to -0.08 MPa (dehydration rate ≥80%, wet paper blank moisture content ≤60%), to form a wet paper blank; the forming screen running speed is adjusted according to the suspension concentration (controlled by a variable frequency motor, accuracy ±0.1 m / min): when the concentration is 1.5 ‰, the running speed is 15-18 m / min, corresponding to a wet paper blank thickness of 0.8-1.0 mm; when the concentration is 2.0 ‰, the running speed is 20-22 m / min, corresponding to a wet paper blank thickness of 0.6-0.8 mm, to ensure that the final film-coated paper thickness is stable at 0.2 mm ±0.02 mm; S3: drying and setting: the wet paper blank enters a multi-zone drying tunnel (total length 50 m, divided into 1 pre-drying zone, 1 setting zone, and 1 cooling zone), and sequentially passes through the pre-drying zone (120-150 °C, 2-3 min, to remove 60-70% of the water in the wet paper blank), the setting zone (260-270 °C, 5-10 °C higher than the melting point of PET fiber, 1-1.5 min, to ensure that the PET fiber is completely melted and wraps the glass fiber), and the cooling zone (70-80 °C, 1-2 min, to avoid thermal shrinkage of the film-coated paper); during the drying process, the hot air speed is controlled at 1.5-2.0 m / s (the hot air is clean air with a dust content ≤0.1 mg / m3), the surface temperature of the film-coated paper is monitored in real time using an infrared temperature detector (accuracy ±1 °C), and when the temperature deviates from the set value by ±2 °C, the heating power is automatically adjusted; the moisture content of the finished product is ≤8% (detected using a halogen moisture meter), and the target pore size AGM film-coated paper without surface drying is obtained.

[0021] Example 1: AGM film-coated paper without surface drying with a pore size of 62 μm S1: pulp preparation: 9°SR centrifugal cotton (glass fiber diameter 18-22 μm, accounting for 35% of the total weight of glass fiber), 14°SR centrifugal cotton (glass fiber diameter 12-15 μm, accounting for 65% of the total weight of glass fiber), and 7% (wt%) PET binder fiber (diameter 10-15 μm, length 3-5 mm, melting point 255-260 °C) are added to a pulp tank, deionized water is used to adjust the suspension concentration to 1.8%, and stirring is performed at 800 r / min for 30 min S2: Forming: The suspension was sprayed through a headbox (pressure 0.35 MPa, lip opening 0.9 mm) to a 140 mesh forming wire, and the wet paper was immersed in glue for 6 s before vacuum dewatering at -0.07 MPa; the forming wire was operated at a speed of 16 m / min, ensuring that the thickness of the wet paper web was uniform; S3: Drying: The pre-drying zone of the drying tunnel was at 130°C / 2.5 min, the setting zone was at 265°C / 1.2 min, the cooling zone was at 75°C / 1.5 min, and the hot air speed was 1.8 m / s; the finished product had a thickness of 0.2 mm, a pore size of 62 μm, and a water content of 7%. The fine glass fiber was 48%, the coarse glass fiber was 44%, and the binder fiber was 8%.

[0022] Application test: The coated paper was used to coat a plate (the thickness of the lead paste was 1.3 mm, and the coating speed was 20 m / min), and the plate was cured by stacking without surface drying (60°C, humidity 95%, time 11 h; drying, temperature 65°C, 8 h). After curing, the plate had no adhesion, the peel strength was 3.2 N / m, and the lead paste exudation was 0 mg / cm².

[0023] Example 2: AGM Free Surface Drying Coated Paper with a Pore Size of 66 μm S1: Pulping: 9°SR centrifugal cotton (50% of the total weight of glass fiber), 15°SR centrifugal cotton (glass fiber diameter 5 μm-7 μm, 50% of the total weight of glass fiber), and 7% PET binder fiber were added to the pulp tank, and the concentration of the suspension was adjusted to 2.0%. The mixture was stirred at 900 r / min for 30 min. S2: Forming: The headbox pressure was 0.4 MPa, the lip opening was 1.0 mm, the 150 mesh forming wire was used, and the paper was immersed in glue for 8 s before vacuum dewatering at -0.08 MPa; the forming wire was operated at a speed of 21 m / min. S3: Drying: The pre-drying zone was at 140°C / 2 min, the setting zone was at 270°C / 1 min, the cooling zone was at 80°C / 1 min, and the hot air speed was 2.0 m / s; the finished product had a thickness of 0.2 mm, a pore size of 66 μm, and a water content of 6.5%.

[0024] The fine glass fiber was 45%, the coarse glass fiber was 47%, and the binder fiber was 8%.

[0025] Application test: After coating, the plate was cured by stacking, and the plate had no adhesion, the peel strength was 2.8 N / m, and the lead paste exudation was 0 mg / cm². Example

[0026] AGM free-air dry coated paper with a pore size of 50 μm: fine glass fiber 52% + thick glass fiber 38% + binder fiber 10%, pore size (≥ 50 μm), adhesion rate (≤ 5%), resistance (≤ 0.0055 Ω·cm²). Example

[0027] AGM free-air dry coated paper with a pore size of 70 μm: fine glass fiber 42% + thick glass fiber 48% + binder fiber 6%, pore size (≤ 70 μm), tensile strength (≥ 450 N / m), lead paste exudation (≤ 0.3 mg / cm²).

[0028] Comparative Example 1: AGM coated paper with a pore size of 14 μm Slurry with 9°SR and 14°SR flame cotton (fiber diameter 1 μm-15 μm) was used to control the pore size of 14 μm by increasing the proportion of fine fibers, and other preparation parameters were consistent with Example 1.

[0029] Application test: after coating, the laminated plates were cured directly, the electrode plates were seriously adhered, the peeling force was > 20 N / m, and they could not be separated normally.

[0030] Comparative Example 2: AGM coated paper with a pore size of 30 μm Slurry with 19°SR centrifugal cotton and 34°SR flame cotton was used to control the pore size of 30 μm, and other preparation parameters were consistent with Example 1.

[0031] Application test: after coating, the laminated plates were cured directly, the electrode plates were seriously adhered, the peeling force was > 20 N / m, and they could not be separated normally.

[0032] In summary, by precisely controlling the pore size of the coated paper to 50 μm-70 μm, the problem of electrode plate adhesion after coating can be completely solved without changing the material or increasing the cost, and the free-air dry production can be realized, which has significant economic and technical value.

[0033] Table 1: Relationship between pore size and capillary rise height, HPbO2⁻ migration amount, and adhesion rate Pore diameter (μm) Capillary rise height (mm) Amount of HPbO2- migration (mg / cm2) Polar plate adhesion rate 14 11.8 1.8 100 30 5.5 0.9 85 40 4.1 0.4 15 50 3.3 0.2 3 60 2.7 0.15 0 65 1.2 0.08 0 70 1.0 0.05 0 75 0.8 0.03 0 The above describes only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent substitutions or changes to the technical solutions and inventive concepts of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A film-coated paper for lead-acid batteries based on aperture regulation, characterized by: The pore size of the film-coated paper is 50-70μm, and the film-coated paper is composed of the following components by weight percentage: fine glass fiber 45-50%, coarse glass fiber 40-45%, and binder fiber 6-8%. In the lead-acid battery plate coating process, the film-coated paper can reduce the amount of HPbO2- entering the wet lead paste through capillary action to ≤0.2mg / cm², and after curing, the plate has no adhesion phenomenon, and the lead paste leakage is 0mg / cm², which is suitable for liquid and colloidal electrolyte systems.

2. The pore-regulation based lead-acid battery coated paper according to claim 1, characterized in that: The pore size of the film-coated paper is 60-70μm, and the fine glass fiber and coarse glass fiber are composed of centrifugal cotton or flame cotton with different degrees of disintegration, wherein the degrees of disintegration of the centrifugal cotton include 9°SR with a fiber diameter of 18-22μm, 14°SR with a fiber diameter of 12-15μm, 15°SR with a fiber diameter of 5-7μm, and 19°SR with a fiber diameter of 2-2.5μm, and the degree of disintegration of the flame cotton is 34°SR with a fiber diameter of 1-1.5μm.

3. The pore-regulation based lead-acid battery coated paper of claim 1, wherein: The pore size is controlled by adjusting the thickness and proportion of fine glass fiber and coarse glass fiber: when the proportion of fine glass fiber is 48% and the proportion of coarse glass fiber is 44%, the pore size is controlled to be 60-63μm; when the proportion of fine glass fiber is 45% and the proportion of coarse glass fiber is 47%, the pore size is controlled to be 64-70μm.

4. The pore-regulation based lead-acid battery coated paper of claim 3, wherein: When the pore size of the film-coated paper is 62μm, the glass fiber is composed of two kinds of centrifugal cotton with a degree of disintegration of 9°SR accounting for 35% of the total weight of glass fiber and 14°SR accounting for 65% of the total weight of glass fiber; When the pore size of the film-coated paper is 66μm, the glass fiber is composed of two kinds of centrifugal cotton with a degree of disintegration of 9°SR accounting for 50% of the total weight of glass fiber and 15°SR accounting for 50% of the total weight of glass fiber; Under the two pore sizes, the addition amount of PET binder fiber is 7% (weight percentage).

5. The pore-regulation based lead-acid battery coated paper of claim 2, wherein: The thickness of the film-coated paper is 0.2mm±0.02mm, the basis weight is 12.0-15.0g / m², the longitudinal tensile strength is ≥480N / m, the longitudinal wet tensile strength is ≥120N / m, the air permeability is ≥8000cm³ / (min·cm²), the ash content is ≤0.3%, the chloride ion content is ≤25mg / kg, and the iron content is ≤35mg / kg.

6. A method for producing the film-coated paper for lead-acid batteries based on aperture control according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: S1: pulping: adding the fine glass fiber, coarse glass fiber and PET binder fiber in proportion to a large pulp tank, adding deionized water to adjust the concentration of the fiber suspension to 1.5-2.0% (mass concentration), stirring at a speed of 800-1000r / min for 30-40min to form a uniform fiber suspension, and adjusting the thickness and proportion of fine and coarse glass fiber according to the required pore size; S2: wet forming: the fiber suspension is sprayed through a headbox at a pressure of 0.3-0.4 MPa and uniformly sprayed onto a continuously running forming polyester mesh with a mesh size of 120-150 meshes, and the opening of the headbox lip is controlled to be 0.8-1.0 mm; the formed wet paper passes through a sizing box, is dehydrated under a negative pressure of -0.06 to -0.08 MPa after a sizing time of 5-8 s, and a wet coated paper web is formed; the running speed of the forming mesh is adjusted according to the concentration of the fiber suspension: when the concentration is 1.5 ‰, the running speed is 15-18 m / min, and when the concentration is 2.0 ‰, the running speed is 20-22 m / min, so as to ensure the uniformity of the thickness of the wet paper web and stabilize the thickness of the final coated paper to be 0.2 mm ± 0.02 mm; S3: drying and heat setting: the wet coated paper web passes through a multi-zone drying tunnel, which is divided into a pre-drying zone with a temperature of 120-150 °C and a time of 2-3 min, a setting zone with a temperature of 260-270 °C, which is 5-10 °C higher than the melting point of the PET fiber, and a time of 1-1.5 min, and a cooling zone with a temperature of 70-80 °C and a time of 1-2 min; the hot air speed is controlled to be 1.5-2.0 m / s during the drying process, so that the PET binder fiber is completely melted and bonded with the glass fiber network to form a coated paper with a specified strength and elasticity, and the moisture content of the finished product is ≤8%.

7. The method of claim 6, wherein the method further comprises: In step S2, the running speed of the forming mesh is controlled by a PID closed loop, the thickness of the wet paper web is monitored in real time, the accuracy is ± 0.01 mm, when the thickness deviation exceeds ± 0.02 mm, the running speed is automatically adjusted by ± 0.5 m / min, so as to ensure that the thickness tolerance of the final coated paper is ≤ ± 0.02 mm, and the thickness fluctuation of the same batch is ≤ 3%.

8. The method of claim 6, wherein the method further comprises: In step S3, the temperature of the drying tunnel is controlled by a partition temperature control system, the temperature fluctuation of the pre-drying zone, the setting zone and the cooling zone is all ≤ ± 2 °C; an infrared temperature detector is arranged in the setting zone, the accuracy is ± 1 °C, the surface temperature of the coated paper is monitored in real time, when the temperature is lower than 260 °C, the heating power is automatically increased, so as to ensure that the PET fiber is completely melted and does not overage.

9. The porosity-regulated lead-acid battery coated paper according to any one of claims 1-4, characterized in that: When the coated paper is applied to the plate coating process of lead-acid storage batteries, the coating speed is 15-23 m / min, the thickness of the lead paste is 1.2-1.5 mm, the surface drying process is cancelled after coating, and the coated paper directly enters the stack curing link, the curing temperature is 60-70 °C, the humidity is 50-99%, and the curing time is 15-60 h; After curing, the peel strength of the pole plate is ≤ 5 N / m, after 100 charge-discharge cycles, the aperture shrinkage rate of the coated paper is ≤ 5%, the permeability decreases by ≤ 10%, and the coated paper is suitable for energy storage scenes and can be used for more than 500 cycles; the waste coated paper can be separated into glass fiber and PET fiber by an alkali dissolution process, 2% NaOH solution, 80 °C for 2 h, the glass fiber recovery rate is ≥ 90%, and the PET fiber recovery rate is ≥ 85%.