Microporous nano heat insulation plate based on quantitative flow casting and production process thereof

Abstract

The application discloses a kind of microporous nanometer heat insulation plate based on quantitative flow casting pressing method and production process thereof, comprising the steps of raw material preparation, raw material mixing, quantitative flow casting laying, constant temperature counter roller pressing and finished product processing.The application uses continuous flow casting pressing process to replace batch dry method mould pressing, eliminates intermittent links such as charging and demoulding, production efficiency is improved by 100% compared with dry method mould pressing, daily production capacity of single production line can reach more than 5000 square meters, which is suitable for large-scale battery production demand;Basalt fiber mesh cloth and organic polyester long and short fibers form a double reinforced structure, and the bending strength is improved by 30%;Quantitative flow casting and gradient roller pressing ensure that the product thickness deviation is ≤±0.1mm, the density uniformity is improved by 40%, and various performance indexes are stable and controllable;Continuous production reduces manual intervention, raw material utilization rate is improved from 85% to 98%, and existing dry method mould pressing mould loss is saved, and the comprehensive production cost is reduced by 20%-30%.

Description

Technical Field

[0001] This invention relates to the field of new energy battery thermal insulation material manufacturing technology, and in particular to a microporous nano thermal insulation board production process based on quantitative casting pressing method. Background Technology

[0002] With the explosive growth of the new energy vehicle industry, the demand for lithium battery production capacity continues to expand. As a core component for battery safety, the production efficiency and performance stability of cell insulation materials have become key factors restricting the industry's development. Microporous nano-insulation panels, due to their combination of extremely low thermal conductivity and lightweight advantages, have become the mainstream choice for cell insulation.

[0003] Current production of microporous nano-insulating panels primarily employs a dry molding process, where raw materials are mechanically mixed, molded in batches, and then cut to obtain the finished product. This process suffers from two major problems: first, poor production continuity, as the molding process involves loading, pressurizing, holding pressure, and demolding, resulting in long production cycles per batch and low efficiency, making it difficult to meet large-scale production demands; second, the disordered fiber arrangement within the product, lacking a continuous support structure, leads to insufficient bending strength and susceptibility to breakage during battery assembly. Although some research has improved performance by optimizing fiber ratios, it has not fundamentally solved the process efficiency problem. Therefore, developing a production process that combines high efficiency and high performance has become an urgent need for the industry.

[0004] Quantitative casting pressing technology is widely used in the board manufacturing industry due to its continuous production advantages. However, a technical solution combining it with basalt fiber mesh reinforcement for the production of microporous nano-insulation boards, achieving a dual improvement in efficiency and strength, has not yet been reported. Based on this, this invention develops a dedicated casting pressing process using a mature formula, filling a gap in the industry. Summary of the Invention

[0005] To address the problems of poor production continuity, low production efficiency, and insufficient bending strength in existing dry molding processes for microporous nano-insulation boards, this invention provides a microporous nano-insulation board production process based on quantitative casting pressing. While retaining the excellent thermal insulation performance of the original formula, this process doubles production efficiency and improves bending strength through continuous process design and the introduction of a reinforcing substrate, thus meeting the needs of large-scale production.

[0006] To achieve the above objectives, the present invention provides a manufacturing process for microporous nano-insulation panels based on a quantitative casting and pressing method, characterized by comprising the following steps: S1. Raw material preparation: Weigh out organic polyester long fibers, organic polyester short fibers, fumed silica, and silicon carbide according to the formula. The organic polyester long fibers have a diameter of 5-15 μm and a length of 5-15 mm, and the organic polyester short fibers have a diameter of 5-15 μm and a length of 0.5-2 mm. The mass ratio of organic polyester long fibers to organic polyester short fibers is 1:3 to 1:5; the mass ratio of fumed silica to silicon carbide is 3:1 to 5:1. The total amount of organic polyester long fibers and organic polyester short fibers added accounts for 8% to 15% of the total mass of raw materials. S2. Raw material mixing: Put all the raw materials prepared in step S1 into a high-speed mixer, with a mixing speed of 800-1200 r / min and a mixing time of 10-20 min, to obtain a uniform mixture. S3. Quantitative casting and spreading: The uniform mixture obtained in step S2 is fed into an automatic gravity casting device and spread evenly on a continuously conveyed basalt fiber mesh at a flow rate of 5-10 kg / min. The mixture on the basalt fiber mesh is scraped by a height-adjustable scraper to control the material spreading thickness to 2-10 mm to ensure uniform material distribution. S4. Constant temperature roller pressing: The basalt fiber mesh cloth with the mixed material evenly laid in step S3 is sequentially fed into three sets of constant temperature metal roller devices. The roller temperature is 80-120℃ and the roller pressure is 15-25MPa. The material is densified by three sets of continuous roller pressing to form a continuous slab with a thickness of 0.5-5mm. S5. Finished product processing: The continuous slab obtained in step S4 is naturally cooled to room temperature, and then cut according to the size of the battery cell using a CNC laser cutting machine to obtain the finished microporous nano heat insulation board.

[0007] Furthermore, in step S1, the organic polyester long fibers and organic polyester short fibers are one or a blend of two of polyethylene terephthalate (PET) fibers and polybutylene terephthalate (PBT) fibers. In step S1, the particle size of fumed silica is 10-50 nm and the specific surface area is 150-300 m² / g; the particle size of silicon carbide is 1-5 μm and the purity is ≥98%.

[0008] Furthermore, in step S2, the high-speed mixer is equipped with a spiral stirring paddle and dispersing teeth. The spiral stirring paddle rotates at a speed of 800-1000 r / min, and the dispersing teeth rotate at a speed of 1000-1200 r / min, thereby achieving material dispersion and uniform mixing.

[0009] Furthermore, in step S3, the thickness of the basalt fiber mesh is 0.5–1 mm, and the mass per unit area is set to 50–80 g / m². 2 The conveying speed is 0.5~1m / min, and the tensile strength is ≥800N / 5cm; The height-adjustable scraper can scrape to a height accurate to 0.1 mm.

[0010] Furthermore, in step S4, the three sets of constant-temperature metal rollers have a diameter of 500mm, and the pressure is set in a gradient according to the process sequence, namely 15-18MPa, 20-22MPa, and 23-25MPa, respectively. The material conveying linear speed between the rollers is kept consistent with the conveying speed of the basalt fiber mesh in S3.

[0011] Furthermore, in step S4, the roller surfaces of the three sets of constant temperature metal rollers are chrome-plated, with a roughness Ra≤0.8μm.

[0012] Furthermore, in step S4, the upper and lower rollers of the three sets of constant temperature metal rollers are equipped with circulating heat transfer oil, so that the temperature fluctuation range during roller pressing is ±2℃.

[0013] This invention utilizes a proven formula of "organic polyester long and short fibers + fumed silica + silicon carbide" to ensure stable thermal insulation performance. Unlike traditional mixing methods, it employs a high-speed mixer with a spiral agitator and dispersing teeth. The agitator tumbles the material as a whole, while the dispersing teeth break up powder agglomerates. The combination of high and low speeds (800–1200 r / min for the agitator and 1000–1200 r / min for the dispersing teeth) achieves uniform mixing within 10–20 minutes, increasing efficiency by 50% compared to traditional mixing methods while avoiding excessive fiber damage.

[0014] By introducing basalt fiber mesh with a thickness of 0.5–1 mm as a reinforcing substrate, its tensile strength is ≥800 N / 5 cm, forming a continuous supporting skeleton and solving the strength defects caused by uneven fiber dispersion in traditional processes. The mesh surface density is controlled at 50–80 g / m², providing sufficient strength without affecting thermal insulation performance; at the same time, the porous structure of the mesh allows the mixed materials to be embedded within it, forming a composite reinforcement structure of "mesh-fiber-powder".

[0015] The automatic gravity casting device, controlled by frequency conversion feeding, lays the mixed material at a stable flow rate of 5–10 kg / min onto a continuously conveyed basalt fiber mesh. Combined with a height-adjustable scraper (scraping height accurate to 0.1 mm), the material thickness is controlled between 2–10 mm, providing a precise allowance for the subsequent roll-pressed finished product thickness (0.5–5 mm). This process achieves quantitative and uniform material laying, avoiding product density differences caused by uneven material loading in traditional molding.

[0016] Three sets of 500mm diameter constant-temperature metal rollers are used, with chrome-plated roller surfaces to ensure smoothness (Ra≤0.8μm) and prevent material adhesion. Internal heat-conducting oil circulation maintains a stable temperature of 80–120℃, which softens the organic polyester fibers, enhancing the bond between the fibers and powder, without causing fiber degradation. The pressure gradient of the three sets of constant-temperature metal rollers is set as follows: 15–18MPa (pre-pressurization and venting) → 20–22MPa (densification) → 23–25MPa (setting). Combined with a basalt fiber mesh with a stable linear velocity of 0.5–1m / min, continuous pressing is achieved, significantly improving efficiency compared to batch molding.

[0017] The continuous slab is naturally cooled to room temperature (avoiding internal stress caused by forced cooling) and then directly cut to the size of the battery cell using a CNC laser cutting machine, without the need for additional curing treatment, further simplifying the process.

[0018] The present invention also provides a microporous nano-insulation board prepared by the above-mentioned production process, wherein the microporous nano-insulation board has a density of 0.25-0.45 g / cm³, a bending angle of ≥120°, no cracks after 10 reciprocating bends, a powder shedding rate of ≤0.3%, and a thermal conductivity of ≤0.03 W / (m·K).

[0019] Furthermore, after being kept at 200℃ for 24 hours, the microporous nano heat insulation plate exhibits a dimensional change rate of ≤1% and a bending strength retention rate of ≥95%, making it suitable for heat insulation of square aluminum shells, soft-pack and cylindrical lithium battery cells.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses a continuous casting pressing process to replace batch dry molding, eliminating intermittent steps such as loading and demolding. The production efficiency is increased by 100% compared to dry molding, and the daily capacity of a single production line can reach more than 5,000 square meters, which is suitable for the needs of large-scale battery production.

[0021] 2. This invention uses basalt fiber mesh and organic polyester long and short fibers to form a double-reinforced structure, which increases the product's bending angle resistance from ≥90° to ≥120°, increases the bending strength by 30%, and reduces the breakage rate during assembly to below 0.1%.

[0022] 3. This invention uses quantitative casting and gradient rolling to ensure that the product thickness deviation is ≤ ±0.1mm, the density uniformity is improved by 40%, the thermal conductivity is kept ≤0.03W / (m·K), the powder shedding rate is ≤0.3%, and all performance indicators are stable and controllable.

[0023] 4. The continuous production of this invention reduces manual intervention, increases the raw material utilization rate from 85% to 98%, and eliminates the wear and tear of existing dry molding dies, reducing the overall production cost by 20% to 30%. Attached Figure Description

[0024] Figure 1 This is a process flow diagram of an embodiment of the present invention; Figure 2 This is a comparison chart of the production efficiency of the production process of Embodiment 1 of the present invention and the existing dry molding process. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In this embodiment of the invention, both the organic polyester long fibers and organic polyester short fibers are PET fibers (10 μm in diameter), fumed silica (30 nm in particle size, 200 m² / g in specific surface area), silicon carbide (3 μm in particle size, 99% purity), and basalt fiber mesh (0.8 mm in thickness, 60 g / m² in areal density, 900 N / 5 cm in tensile strength). Example 1: A manufacturing process for microporous nano-insulation panels based on quantitative casting pressing, comprising the following steps: S1. Raw material preparation: Weigh 86.4 kg of fumed silica, 21.6 kg of silicon carbide, 3 kg of PET long fibers (10 mm in length), and 9 kg of PET short fibers (1 mm in length), with the total fiber content being 10%. S2. Raw material mixing: Put all the raw materials prepared in step S1 into a high-speed mixer, with the stirring paddle speed at 900 r / min, the dispersing tooth speed at 1100 r / min, and the mixing time at 15 min to obtain a uniform mixture. S3. Quantitative casting and spreading: The uniform mixture obtained in step S2 is fed into an automatic gravity casting device and spread evenly on a basalt fiber mesh fabric that is continuously conveyed (conveyor speed is 0.8m / min) at a flow rate of 7kg / min. The mixture on the basalt fiber mesh fabric is scraped by a height-adjustable scraper. The scraper height is adjusted to 4mm to control the material spreading thickness to 4mm, ensuring uniform material distribution. S4. Constant temperature roller pressing: The basalt fiber mesh cloth with the mixed material evenly laid in step S3 is sequentially fed into three sets of constant temperature metal roller devices. The roller temperature is 100℃, and the roller pressing pressure of the three sets of rollers is 16 MPa, 21 MPa and 24 MPa respectively. The material conveying line speed between the rollers is 0.8m / min. The material is densified by the three sets of continuous roller pressing to form a continuous slab with a thickness of 1mm. S5. Finished product processing: The continuous slab obtained in step S4 is naturally cooled to room temperature (25°C), and then cut according to the size of the battery cell using a CNC laser cutting machine to obtain a microporous nano heat insulation board with a specification of 150mm×200mm×1mm.

[0027] Performance testing was conducted on the finished microporous nano-insulation board. The results showed: density 0.35 g / cm³, bending angle 125°, no cracks after 10 repeated bends, powder shedding rate 0.2%, thermal conductivity 0.026 W / (m·K), and daily output of 4100 m³. 2 The production efficiency is 105% higher than that of dry molding, and the bending strength retention rate is 99% after being kept at 200℃ for 24 hours.

[0028] like Figure 2 As shown, the daily production capacity of the microporous nano-insulation board prepared by the production process of Embodiment 1 of the present invention is increased by (4100-2000) / 2000=105% compared with the daily production capacity of the microporous nano-insulation board prepared by the existing dry molding process.

[0029] Example 2: A manufacturing process for microporous nano-insulation panels based on quantitative casting pressing, comprising the following steps: S1. Raw material preparation: Weigh 90kg of fumed silica, 30kg of silicon carbide, 3.5kg of PET long fibers (10mm in length), and 14kg of PET short fibers (1mm in length), with a total fiber content of 12.7%. S2. Raw material mixing: Put all the raw materials prepared in step S1 into a high-speed mixer, with the stirring paddle speed at 850 r / min, the dispersing tooth speed at 1050 r / min, and the mixing time at 18 min, to obtain a uniform mixture. S3. Quantitative casting and spreading: The uniform mixture obtained in step S2 is fed into an automatic gravity casting device and spread evenly on a basalt fiber mesh fabric that is continuously conveyed (conveyor speed is 1m / min) at a flow rate of 6kg / min. The mixture on the basalt fiber mesh fabric is scraped by a height-adjustable scraper. The scraper height is adjusted to 3mm to control the material spreading thickness to 3mm, ensuring that the material is evenly distributed. S4. Constant temperature roller pressing: The basalt fiber mesh cloth with the mixed material evenly laid in step S3 is sequentially fed into three sets of constant temperature metal roller devices. The roller temperature is 90℃, and the roller pressing pressure of the three sets of rollers is 15 MPa, 20 MPa and 23 MPa respectively. The material conveying line speed between the rollers is 1m / min. The material is densified by the three sets of continuous roller pressing to form a continuous slab with a thickness of 0.75mm. S5. Finished product processing: The continuous slab obtained in step S4 is naturally cooled to room temperature (25°C), and then cut according to the cell size using a CNC laser cutting machine to obtain a microporous nano heat insulation board with a specification of 50mm×100mm×0.75mm.

[0030] Performance testing was conducted on the finished microporous nano-insulation board. The results showed: density 0.38 g / cm³, bending angle 130°, powder shedding rate 0.15%, thermal conductivity 0.025 W / (m·K), and daily output of 5000 m³. 2 Production efficiency increased by 150%, and the bending strength retention rate was 96% after being kept at 200℃ for 24 hours.

[0031] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A manufacturing process for microporous nano-insulation panels based on quantitative casting and pressing, characterized in that, Includes the following steps: S1. Raw material preparation: Weigh out organic polyester long fibers, organic polyester short fibers, fumed silica, and silicon carbide according to the formula. The organic polyester long fibers have a diameter of 5-15 μm and a length of 5-15 mm, and the organic polyester short fibers have a diameter of 5-15 μm and a length of 0.5-2 mm. The mass ratio of organic polyester long fibers to organic polyester short fibers is 1:3 to 1:5; the mass ratio of fumed silica to silicon carbide is 3:1 to 5:

1. The total amount of organic polyester long fibers and organic polyester short fibers added accounts for 8% to 15% of the total mass of raw materials. S2. Raw material mixing: Put all the raw materials prepared in step S1 into a high-speed mixer, with a mixing speed of 800-1200 r / min and a mixing time of 10-20 min, to obtain a uniform mixture. S3. Quantitative casting and spreading: The uniform mixture obtained in step S2 is fed into an automatic gravity casting device and spread evenly on a continuously conveyed basalt fiber mesh at a flow rate of 5-10 kg / min. The mixture on the basalt fiber mesh is scraped by a height-adjustable scraper to control the material spreading thickness to 2-10 mm to ensure uniform material distribution. S4. Constant temperature roller pressing: The basalt fiber mesh cloth with the mixed material evenly laid in step S3 is sequentially fed into three sets of constant temperature metal roller devices. The roller temperature is 80-120℃ and the roller pressure is 15-25MPa. The material is densified by three sets of continuous roller pressing to form a continuous slab with a thickness of 0.5-5mm. S5. Finished product processing: The continuous slab obtained in step S4 is naturally cooled to room temperature, and then cut according to the size of the battery cell using a CNC laser cutting machine to obtain the finished microporous nano heat insulation board.

2. The production process of a microporous nano-insulation board based on quantitative casting and pressing method according to claim 1, characterized in that: In step S1, the organic polyester long fiber and organic polyester short fiber are one or a blend of two of polyethylene terephthalate (PET) fiber and polybutylene terephthalate (PBT) fiber. In step S1, the particle size of fumed silica is 10-50 nm and the specific surface area is 150-300 m² / g; the particle size of silicon carbide is 1-5 μm and the purity is ≥98%.

3. The production process of a microporous nano-insulation board based on quantitative casting and pressing method according to claim 1, characterized in that: In step S2, the high-speed mixer is equipped with a spiral stirring paddle and dispersing teeth. The spiral stirring paddle rotates at 800-1000 r / min, and the dispersing teeth rotate at 1000-1200 r / min, so as to achieve material dispersion and uniform mixing.

4. The production process of a microporous nano-insulation board based on quantitative casting and pressing method according to claim 1, characterized in that: In step S3, the thickness of the basalt fiber mesh is 0.5–1 mm, and the mass per unit area is set to 50–80 g / m². 2 The conveying speed is 0.5~1m / min, and the tensile strength is ≥800N / 5cm; The height-adjustable scraper can scrape to a height accurate to 0.1 mm.

5. The production process of a microporous nano-insulation board based on quantitative casting and pressing method according to claim 1, characterized in that: In step S4, the three sets of constant temperature metal rollers have a diameter of 500 mm, and the pressure is set in a gradient according to the process sequence, namely 15-18 MPa, 20-22 MPa, and 23-25 ​​MPa. The linear speed of the material conveying between the rollers is kept consistent with the conveying speed of the basalt fiber mesh in S3.

6. The production process of a microporous nano-insulation board based on quantitative casting and pressing method according to claim 1, characterized in that: In step S4, the roller surfaces of the three sets of constant temperature metal rollers are chrome-plated, with a roughness Ra≤0.8μm.

7. The production process of a microporous nano-insulation board based on quantitative casting and pressing method according to claim 1, characterized in that: In step S4, the upper and lower rollers of the three sets of constant temperature metal rollers are equipped with circulating heat transfer oil, so that the temperature fluctuation range during roller pressing is ±2℃.

8. A microporous nano-insulation plate prepared by the production process according to any one of claims 1 to 7, characterized in that: The microporous nano-insulation board has a density of 0.25–0.45 g / cm³, a bending angle of ≥120°, no cracks after 10 repeated bends, a powder shedding rate of ≤0.3%, and a thermal conductivity of ≤0.03 W / (m·K).

9. The microporous nano-insulation plate according to claim 8, characterized in that: The microporous nano-insulation plate exhibits a dimensional change rate of ≤1% and a bending strength retention rate of ≥95% after being kept at 200℃ for 24 hours. It is suitable for heat insulation of square aluminum shell, soft pack and cylindrical lithium battery cells.

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