Armoring and anti-corrosion integrated anti-corrosion power cable for energy storage system

Abstract

The invention relates to the technical field of wires and cables, discloses an armoring and anticorrosion integrated corrosion-resistant power cable for an energy storage system, and aims to solve the problems that in the prior art, an armoring layer and an anticorrosion layer are weak in interface bonding and easy to strip under the temperature difference circulation effect of the energy storage system, so that the protection function fails, and the service life of the cable is shortened. The cable sequentially comprises a conductor layer, a conductor shielding layer, an insulating layer, an insulating shielding layer, an inner sheath layer, an integrated functional layer and an outer sheath layer from inside to outside. The integrated functional layer is formed by compositing a base material subjected to mechanical micro-nano structuring and chemical activity modification and an integrated material containing functional filler, a gradient curing process is adopted to be matched with integrated co-extrusion forming, the interlayer bonding stability, corrosion resistance and mechanical strength are effectively improved, the integrated functional layer can adapt to the severe temperature difference environment of an energy storage system, surface layer cracking is reduced, and the service life of the integrated functional layer is prolonged. And long-term safe and stable operation of the energy storage system is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wire and cable, in particular to a kind of armored and corrosion integrated corrosion-resistant energy storage system power cable. BACKGROUND

[0002] With the rapid development of global energy storage industry, power cable for energy storage system as the core component of power transmission, its working environment is increasingly complex and demanding, often need to face high salt fog, severe temperature difference, microbial corrosion and other extreme conditions, which puts forward high requirements for the corrosion resistance, mechanical protection performance and structural stability of cable. Among them, the armored layer as the key structure of cable mechanical protection, the corrosion protection layer bears the core role of resisting corrosion medium erosion, and the performance and combination state of the two directly determine the service life and operation safety of the cable.

[0003] At present, the armored and corrosion function of power cable in the prior art is designed and prepared by layering, for example, a kind of cross-linked polyethylene insulated submarine power cable with publication number CN120340943A, by designing the cable body into a layered structure of insulating outer protective layer, tensile resistance layer, corrosion resistance layer, steel belt armored layer and insulating layer, setting conductor insulation shielding layer, conductor shielding layer and conductor water blocking layer inside, filling water blocking powder in the tensile resistance layer and steel belt armored layer and using spiral arranged compression steel belt and steel wire, the adaptation to the high pressure and corrosion environment of submarine is realized, and the problem of cable damage caused by longitudinal diffusion of seawater along the cable gap is solved; A kind of corrosion-resistant armored power cable with publication number CN219778551U, by setting the first corrosion-resistant layer of polytetrafluoroethylene material in the protective outer layer, and setting the shielding layer, insulating layer, second corrosion-resistant layer of FEP film material and wear-resistant layer outside each conductor in turn, and combining with copper wire braided armored layer, separation mechanism and tensioning silk ring, double corrosion-resistant protection is realized for all conductors inside the cable and single conductor after the protective outer layer is peeled off.

[0004] However, the surface of metal armored layer is easy to form inert passivation film naturally, which leads to significant lack of chemical compatibility between the metal armored layer and the high molecular corrosion protection layer, and cannot form stable chemical bond connection, but only relies on van der waals force to maintain the interface combination. The severe temperature difference cycle generated in the charging and discharging process of energy storage system will further aggravate the periodic tensile and shear stress generated by the difference in thermal expansion coefficient between the metal armored layer and the high molecular corrosion protection layer, leading to the gradual peeling of the interlayer interface and the formation of gap, and the external corrosion medium is easy to invade through the gap, causing the corrosion of armored layer, not only causing the synchronous failure of the mechanical protection performance and corrosion resistance of the cable, but also leading to the performance deterioration of the insulating layer due to corrosion pollution, greatly shortening the service life of the cable, and directly threatening the long-term safe and stable operation of the energy storage system. SUMMARY

[0005] The technical problem to be solved by the present application is that the existing technology has the shortcoming of poor interface combination between the armored layer and the corrosion-resistant layer.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme: a kind of armored and corrosion-resistant integrated corrosion-resistant energy storage system power cable, from inside to outside, including conductor layer, conductor shield layer, insulation layer, insulation shield layer, inner sheath layer, integrated functional layer and outer sheath layer;Integrated functional layer gives consideration to mechanical support protection and corrosion barrier function, which is made of armored base material treated by mechanical micro-nano structure and modified by chemical activity, and is compounded with integrated material, and the integrated material is tightly covered on the surface of the modified armored base material.

[0007] Preferably, the thickness of the integrated functional layer is 1.8-2.2mm.

[0008] Preferably, the mechanical micro-nano structure treatment is sand blasting treatment of the surface of the armored base material with white corundum sand with a particle size of 0.22mm, the sand blasting pressure is 0.35-0.4MPa, and the treatment time is 4.2-4.5min, so that the surface roughness Ra of the base material reaches 1.8-2.0μm.

[0009] Preferably, the chemical activity modification is to immerse the base material after sand blasting treatment in a treatment liquid, so as to introduce amino active groups on the surface of the base material and form a physical anchoring structure.

[0010] Preferably, the treatment liquid material includes, by weight: 1.8-2.2 parts of silane coupling agent KH-550, 0.5-0.9 parts of micro-nano alumina particles, 96.5-97.7 parts of ethanol-water solution, 0.04-0.06 parts of glacial acetic acid;The volume ratio of ethanol to water in the ethanol-water solution is 3:7.

[0011] Preferably, the integrated material includes, by weight: 75-80 parts of epoxy modified polyolefin, 3.5-4.1 parts of isocyanate curing agent, 0.6-0.8 parts of photoinitiator, 2.5-3.5 parts of nano zinc oxide, 6-7 parts of chopped glass fiber, 0.12-0.18 parts of calcium stearate, 2.2-2.5 parts of compatibilizer PE-g-MAH.

[0012] Preferably, the content of epoxy groups in the epoxy modified polyolefin is 7-8wt%, the water content is ≤0.05wt%;The water content of isocyanate curing agent is ≤0.02wt%;The water content of photoinitiator is ≤0.03wt%;The particle size of nano zinc oxide is 40-50nm, and the water content is ≤0.1wt%;The length of the chopped glass fiber is 0.3-0.4mm, and the water content is ≤0.1wt%;The water content of calcium stearate and compatibilizer PE-g-MAH is ≤0.05wt%.

[0013] Preferably, the preparation step of the integrated functional layer comprises: S1: first, the surface of the armored substrate is mechanically micro-nano structured, then soaked in sodium hydroxide aqueous solution for degreasing, and finally the armored substrate is immersed in a treatment solution for chemical activation modification to obtain a modified substrate, which is dried for standby; S2: first, the raw materials of the integrated material are dried and pretreated respectively, then the epoxy modified polyolefin is premixed with the compatibilizer, the functional filler is dispersed, and then the curing agent and the photoinitiator are added and mixed at low speed to obtain an integrated composite layer base material; S3: the preheated modified substrate is sent into the center channel of the co-extruder, and the integrated composite layer base material is injected from the side feeding port to form an integrated structure synchronously; S4: the integrated structure is gradiently cured, and then wet grinding, washing and drying are carried out to obtain an integrated functional layer.

[0014] Preferably, in S3, the screw rotation speed of the co-extruder is 65-70 r / min, the barrel temperature is 140-150℃ in the first zone, 160-170℃ in the second zone, and 170-180℃ in the third zone, and the die temperature is 160-165℃; the armored substrate is preheated to 125-135℃ before co-extrusion, and the temperature is maintained for 30-40 min.

[0015] Preferably, in S4, the gradient curing comprises ultraviolet curing and thermal curing in sequence, wherein the ultraviolet curing is performed at a ultraviolet light wavelength of 265 nm, an irradiation intensity of 12.5-13.5 mW / cm 2 , and an irradiation time of 4 min; the thermal curing is performed at a temperature of 130℃ and a holding time of 20-25 min.

[0016] The technical effects and advantages of the present application are as follows: in the present application, an armored and corrosion integrated functional layer is constructed, the armored substrate is subjected to double activation treatment of surface mechanical micro-nano structuring and chemical activity modification, and is combined with an integrated material containing functional fillers to form an integrated structure with mechanical protection and corrosion resistance, effectively solving the problem of weak interface combination between the metal armored layer and the high polymer corrosion resistant layer in the prior art, realizing the synergistic effect of interface chemical combination and physical anchoring, improving the salt mist corrosion resistance, interface peeling strength and tensile strength of the cable, avoiding the failure of protection function caused by interlayer peeling, and prolonging the service life of the cable in harsh environment of energy storage system.

[0017] In the present application, the gradient curing process is adopted in combination with the integrated co-extrusion molding technology, the surface layer is rapidly cured and shaped by ultraviolet light initiation, and then the deep layer material is fully crosslinked by heat curing, which effectively avoids the defects of material surface cracking and insufficient deep layer crosslinking caused by single curing in the prior art, ensures the structural compactness of the integrated functional layer, and at the same time, the co-extrusion molding ensures the close adhesion of the functional layer and other layers of the cable, so that the whole cable has excellent temperature difference cycle performance, can adapt to the severe temperature difference generated by the charging and discharging of the energy storage system, reduce the surface cracking phenomenon, maintain the stability of the insulation resistance, and meet the long-term safe operation demand of the energy storage system. BRIEF DESCRIPTION OF DRAWINGS

[0018] The disclosure of the present application will be described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes, and are not intended to limit the scope of protection of the present application. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 Preparation flow diagram of the integrated functional layer of the present application; DETAILED DESCRIPTION

[0019] It is easy to understand that, according to the technical scheme of the present application, those skilled in the art can propose a plurality of structure modes and implementation modes which can be replaced with each other without changing the essential spirit of the present application. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical scheme of the present application, and should not be regarded as the whole or as the limitation or restriction of the technical scheme of the present application.

[0020] This invention provides a technical solution: a corrosion-resistant power cable for energy storage systems that integrates armor and corrosion protection, comprising the following layers from the inside out: Conductor layer: the foundation for current carrying of the cable, made of highly conductive copper or aluminum core, with thickness adjusted according to the cable's current carrying capacity requirements; Conductor shielding layer: made of semi-conductive cross-linked polyethylene (XLPE), 0.8-1mm thick, used to uniformly distribute the electric field on the conductor surface, eliminate electric field distortion on the conductor surface, and prevent electric field concentration from causing insulation breakdown; Insulation layer: made of XLPE, 3-5mm thick, used to block current leakage, ensure the cable's insulation performance, and prevent short-circuit accidents; Insulation shielding layer: made of semi-conductive cross-linked polyethylene (XLPE), 0.8-1mm thick, used to uniformly distribute the electric field on the conductor surface, eliminate electric field distortion on the conductor surface, and prevent electric field concentration from causing insulation breakdown; Insulation layer: made of semi-conductive cross-linked polyethylene (XLPE), 3-5mm thick, used to block current leakage, ensure the cable's insulation performance, and prevent short-circuit accidents; Insulation shielding layer: made of semi-conductive cross-linked polyethylene (XLPE), 0.8-1mm thick, used to uniformly distribute the electric field on the conductor surface, eliminate electric field distortion, and prevent short-circuit accidents; Conductive XLPE, 0.8-1mm thick, is used to uniformly shape the electric field on the surface of the insulation layer, forming an electric field closed loop with the conductor shielding layer, thus improving the stability of the insulation system; Inner sheath: High-density polyethylene (HDPE), 1.5-2mm thick, is used to protect the internal insulation shielding layer and prevent mechanical damage during subsequent processing and operation; Integrated functional layer: 1.8-2.2mm thick, combining the mechanical support and protection function of the existing armor layer with the corrosion barrier function of the anti-corrosion layer, is composed of modified substrate and integrated material; Outer sheath: Flame-retardant polyethylene (PE), 2-2.5mm thick, is used to enhance the mechanical protection capability of the cable.

[0021] It should be noted that in the above-mentioned layered structure, the integrated functional layer is the core of cable performance optimization. The material and proportion details of its components are as follows: The armor base material is made of low-carbon steel strip or wire with a carbon content of 0.12-0.18 wt% and a tensile strength ≥450 MPa. It is modified with a surface-modifying material, which includes 1.8-2.2 parts of a silane coupling agent (KH-550) containing active amino groups. Its hydrolysis products can undergo a condensation reaction with the hydroxyl groups on the base material surface and simultaneously form chemical bonds with the epoxy groups in the integrated material, thereby enhancing the base material's performance. The interfacial bonding force between the material and the composite material; 0.5-0.9 parts of micro-nano alumina particles with a particle size of 80-100nm can be embedded in the micro-nano concave structure on the surface of the mechanically treated substrate to form a physical anchoring effect and enhance the interlayer bonding stability; 96.5-97.7 parts of ethanol-water solution are used as the dispersion medium for the modified material, and the volume ratio of ethanol to water is controlled at 3:7 to ensure uniform hydrolysis of the coupling agent and stable dispersion of particles; 0.04-0.06 parts of glacial acetic acid are used to adjust the pH of the ethanol-water solution, which affects the hydrolysis reaction rate of KH-550 and ensures the reaction activity.

[0022] The integrated material tightly coats the surface of the modified substrate and is the core material for achieving synergistic improvement in anti-corrosion function and mechanical properties. The composition and functions of each component are as follows: 75-80 parts of epoxy-modified polyolefin (POE-g-GMA), with an epoxy group content of 7-8 wt% and a moisture content ≤0.05 wt%, serving as an anti-corrosion base material. Its epoxy groups can undergo ring-opening reactions with the amino groups on the surface of the modified substrate to form stable chemical bonds; 3.5-4.1 parts of isocyanate curing agent (MDI), with a moisture content ≤0.02 wt%, which can initiate cross-linking of the epoxy-modified polyolefin molecular chains, improving the structural stability and deformation resistance of the composite material; 0.6-0.8 parts of photoinitiator (type 1173), with a moisture content ≤0.03 wt%, which can initiate surface curing and shaping under ultraviolet light irradiation, preventing surface cracking and warping during deep curing; 2.5-3.5 parts of nano-zinc oxide, with a particle size of 40-50 nm, containing… The material contains ≤0.1wt% water, which adsorbs harmful ions in corrosive media through ion exchange, enhancing corrosion resistance and improving thermal stability to resist thermal stress caused by temperature cycling during charging and discharging in energy storage systems. 6-7 parts of chopped glass fibers, 0.3-0.4mm in length and ≤0.1wt% water, improve the tensile and compressive strength of the composite material, enhance armor protection, and prevent damage to the functional layer under mechanical stress. 0.12-0.18 parts of calcium stearate, as a dispersant, with ≤0.05wt% water, prevents the agglomeration of chopped glass fibers and nano-zinc oxide, ensuring uniform dispersion of various fillers in the base material. 2.2-2.5 parts of compatibilizer (PE-g-MAH), with ≤0.05wt% water, improves the interfacial compatibility between chopped glass fibers, nano-zinc oxide, and epoxy-modified polyolefins, enhancing the overall uniformity of the integrated material. It should be noted that all the above materials are commercially available.

[0023] This invention also provides a method for preparing an integrated functional layer for a corrosion-resistant energy storage system power cable that combines armor and corrosion protection. The process steps and parameter settings are described in detail below through specific embodiments.

[0024] Example 1: According to Figure 1As shown, this embodiment provides a method for preparing an integrated functional layer for a corrosion-resistant energy storage system power cable that combines armor and corrosion protection. The method includes the following steps: S1: Surface activation treatment of the armor substrate; S11: Mechanical micro-nano structuring treatment: Using a pressure-type sandblasting device, white corundum sand with a particle size of 0.22 mm is selected as the sandblasting medium. The sandblasting pressure is set to 0.4 MPa to perform surface treatment on low-carbon steel strips. The treatment time is 4.2 min, resulting in a surface roughness Ra of 2.0 μm for the substrate, thus destroying the dense inert passivation film on the surface. S12: Chemical degreasing treatment: The sandblasted substrate is immersed in a 6.5 wt% sodium hydroxide aqueous solution. The solution temperature is controlled at 56°C, and the immersion time is 13 min to remove oil and residual sand particles from the substrate surface. Subsequently, the substrate is repeatedly rinsed with deionized water until the pH value of the rinsing solution reaches 7.0. S13: Chemically active modification treatment: Weigh 97.25 parts of ethanol-water solution and place it in a container. Add 0.05 parts of glacial acetic acid to adjust the pH of the solution to 4.5, then add 2 parts of KH-550 and stir for 10 min to allow it to fully hydrolyze. Then add 0.7 parts of micro-nano alumina particles with a particle size of 90 nm and ultrasonically disperse for 5 min to ensure uniform particle dispersion and obtain the treatment solution. Immerse the degreased substrate in the treatment solution, control the temperature of the treatment solution at 36℃, and soak for 26 min to allow the hydroxyl groups generated by the hydrolysis of the coupling agent to undergo a condensation reaction with the hydroxyl groups on the surface of the substrate, and introduce amino active groups on the surface of the substrate. After the treatment is completed, place the modified substrate in an 88℃ oven to dry for 1.5 h for later use.

[0025] S2: Integrated material preparation; S21: Raw material pretreatment: Weigh 78 parts of epoxy-modified polyolefin, 3.8 parts of isocyanate curing agent, 3.0 parts of nano zinc oxide, 6.5 parts of chopped glass fiber, 0.15 parts of calcium stearate, 0.7 parts of photoinitiator, and 2.3 parts of compatibilizer. First, dry the epoxy-modified polyolefin, nano zinc oxide, and chopped glass fiber separately in an oven at 102℃ for 2 hours, controlling the moisture content of each raw material. S22: Base material premixing: Add the dried epoxy-modified polyolefin and compatibilizer to a high-speed mixer, set the mixer speed to 900 r / min, the temperature to 85℃, and mix for 12 minutes to achieve uniform dispersion. S23: Functional filler dispersion: Add the dried nano zinc oxide, chopped glass fiber, and calcium stearate sequentially to the mixer, adjust the mixer speed to 1300 r / min, maintain the temperature at 95℃, and mix for 22 minutes. High shear force breaks up filler agglomerates to ensure uniform dispersion of the filler. S24: Curing System Fusion: Reduce the temperature of the material in the mixer to 65℃, quickly add isocyanate curing agent and photoinitiator, set the speed to 400r / min, and stir at low speed for 6min to avoid premature cross-linking reaction of the curing agent, so as to obtain a uniform integrated composite layer base material.

[0026] S3: Integrated co-extrusion molding; S31: Substrate preheating: The armored substrate after surface activation treatment is placed in a preheating furnace, and the preheating temperature is set to 130℃ and held for 35 minutes to enhance the reactivity of amino groups on the substrate surface. S32: Co-extrusion molding: A three-layer concentric die twin-screw co-extruder is used. A guide ring is set inside the die to ensure the uniformity of the composite layer thickness. The screw speed is set to 65 r / min, the barrel temperature is 145℃ in zone 1, 165℃ in zone 2, and 175℃ in zone 3, and the die temperature is 165℃. The preheated armored substrate is continuously fed into the co-extruder through the central channel, and the integrated composite layer base material is injected from the side feed port, simultaneously coating the substrate surface to form an integrated structure with a thickness of 2.0 mm.

[0027] S4: Post-processing; S41: UV curing: The co-extruded integrated structure is fed into a UV curing oven, with the UV wavelength set to 265nm and the irradiation intensity to 12.5mW / cm². 2 The irradiation time is 4 minutes to achieve rapid surface curing and shaping, avoiding surface cracking during deep reactions. S42: Thermal curing: The UV-cured integrated structure is transferred to a hot air oven at 130℃ for 25 minutes to promote the chemical bonding of deep epoxy groups and amino groups and the full cross-linking of polymer chains, thereby improving the stability of the integrated structure. S43: Wet grinding and drying: The thermocured integrated structure is wet-ground using an 800-grit grinding wheel at a pressure of 0.08 MPa to remove tiny burrs at the die exit. After grinding, it is rinsed with deionized water and dried in a 60℃ oven for 30 minutes to obtain the integrated functional layer.

[0028] Example 2: This example provides a method for preparing an integrated functional layer for a corrosion-resistant energy storage system power cable that combines armor and corrosion protection. Compared with Example 1, the difference lies in adjusting the sandblasting process parameters of the substrate surface, as follows: a pressure-type sandblasting device is used, white corundum sand with a particle size of 0.22 mm is selected as the sandblasting medium, the sandblasting pressure is set to 0.35 MPa, and the surface of the low-carbon steel strip is treated for 4.5 min, so that the surface roughness Ra of the substrate reaches 1.8 μm, destroying the dense inert passivation film on the surface; the aim is to verify the influence of the micro-nano structure on the substrate surface on the subsequent physical anchoring effect and interfacial bonding force under low sandblasting pressure and low surface roughness conditions.

[0029] Example 3: This example provides a method for preparing an integrated functional layer for a corrosion-resistant energy storage system power cable that combines armor and corrosion protection. Compared with Example 1, the difference lies in adjusting the material ratio and parameters for chemical modification of the substrate surface, as follows: Weigh 97.05 parts of ethanol-water solution and place it in a container. Add 0.05 parts of glacial acetic acid to adjust the pH of the solution to 5.0, then add 2.2 parts of KH-550 and stir for 10 minutes to allow for complete hydrolysis. Then add 0.7 parts of micro-nano alumina particles with a particle size of 90 nm and ultrasonically disperse for 5 minutes. Immerse the degreased substrate in the treatment solution, controlling the temperature of the treatment solution at 36°C and the soaking time at 26 minutes. After treatment, dry it according to the conditions of Example 1 for later use. The aim is to verify the effect of high silane coupling agent dosage and higher pH value on improving the amino introduction efficiency and chemical bonding strength.

[0030] Example 4: This example provides a method for preparing an integrated functional layer for a corrosion-resistant energy storage system power cable that combines armor and corrosion protection. Compared with Example 1, the difference lies in adjusting the amount of epoxy-modified polyolefin in the integrated material, as follows: Weigh 75 parts of epoxy-modified polyolefin, 3.8 parts of isocyanate curing agent, 3.0 parts of nano zinc oxide, 6.5 parts of chopped glass fiber, 0.15 parts of calcium stearate, 0.7 parts of photoinitiator, and 2.3 parts of compatibilizer. Complete the raw material drying and subsequent mixing and curing steps according to the conditions of Example 1; the aim is to verify the effect of reducing the amount of anti-corrosion base material on the density of interfacial reaction sites and the support capacity of the anti-corrosion layer.

[0031] Example 5: This example provides a method for preparing an integrated functional layer for a corrosion-resistant energy storage system power cable that combines armor and corrosion protection. Compared with Example 1, the difference lies in adjusting the proportion of functional fillers in the integrated material, as follows: Weigh 78 parts of epoxy-modified polyolefin, 3.8 parts of isocyanate curing agent, 3.5 parts of nano zinc oxide, 6 parts of chopped glass fiber, 0.15 parts of calcium stearate, 0.7 parts of photoinitiator, and 2.3 parts of compatibilizer. Complete the raw material drying and subsequent mixing and curing steps according to the conditions of Example 1; the aim is to verify the effect of the corrosion-resistant filler ratio on the enhancement of the cable's corrosion resistance.

[0032] Example 6: This example provides a method for preparing an integrated functional layer of a corrosion-resistant power cable for an energy storage system that combines armor and corrosion protection. Compared with Example 1, the difference lies in adjusting the amount of isocyanate curing agent in the integrated material, as follows: Weigh 78 parts of epoxy-modified polyolefin, 4.1 parts of isocyanate curing agent, 3.0 parts of nano zinc oxide, 6.5 parts of chopped glass fiber, 0.15 parts of calcium stearate, 0.7 parts of photoinitiator, and 2.3 parts of compatibilizer. Complete the raw material drying and subsequent mixing and curing steps according to the conditions of Example 1; the aim is to verify the effect of high curing agent dosage on the crosslinking density, structural stability, and deformation resistance of the composite material.

[0033] Example 7: This example provides a method for preparing an integrated functional layer of a corrosion-resistant power cable for an energy storage system that combines armor and corrosion protection. Compared with Example 1, the difference lies in adjusting the process parameters of the integrated co-extrusion molding, as follows: A three-layer concentric die twin-screw co-extruder is used, with a guide ring installed inside the die. The screw speed is set to 70 r / min, the barrel temperature is 145℃ in zone 1, 165℃ in zone 2, and 175℃ in zone 3, and the die temperature is 160℃. The preheated armor substrate is continuously fed into the co-extruder through the central channel, and the integrated composite layer base material is injected from the side feed port, simultaneously coating to form an integrated structure with a thickness of 2.0 mm. This aims to verify the influence of a lower die temperature and a higher screw speed on the uniformity of the integrated structure coating and the interlayer adhesion.

[0034] Example 8: This example provides a method for preparing an integrated functional layer for a corrosion-resistant power cable used in a corrosion-resistant energy storage system, combining armor and corrosion protection. The difference from Example 1 lies in adjusting the curing process parameters, specifically as follows: The co-extruded integrated structure is placed in an ultraviolet curing oven, with the ultraviolet wavelength set to 265nm and the irradiation intensity to 13.5mW / cm². 2 The irradiation time was 4 minutes; the integrated structure cured by UV was then transferred to a hot air oven, set at 130℃, and kept at that temperature for 20 minutes; the aim was to verify the effects of enhanced UV curing and shortened heat curing time on the surface integrity, curing efficiency, and deep bonding strength of the integrated structure.

[0035] Comparative Example 1: This comparative example adopts the existing traditional layered preparation process of armoring first and then corrosion protection, specifically including the following steps: the same low carbon steel strip as in Example 1 is selected, and only sandblasting and degreasing are performed, without chemical active modification steps; conventional polyethylene (PE) is used as the anti-corrosion coating material, and a PE coating with a thickness of 2.0 mm is applied to the surface of the armor layer by a single screw extruder at an extrusion temperature of 165℃; only 130℃ heat curing for 30 minutes is used, without UV curing steps, and the subsequent wet grinding and drying processes are consistent with those in Example 1.

[0036] Comparative Example 2: This comparative example omits the chemical activity modification step on the substrate surface, and only performs mechanical sandblasting and degreasing treatment. The degreased substrate is then directly used for subsequent co-extrusion molding. The remaining steps and parameters are consistent with those in Example 1, aiming to verify the necessity of the chemical modification step for the formation of interfacial chemical bonds and the stability of the bonding.

[0037] Comparative Example 3: This comparative example omits the UV curing step and adopts a single thermosetting process. The co-extruded integrated structure is directly transferred into a hot air oven, set at 130°C, and kept at that temperature for 30 minutes. After that, wet grinding and drying are completed according to the conditions of Example 1. The remaining steps and parameters are consistent with those of Example 1. The aim is to verify the advantages of gradient curing process over traditional single thermosetting in terms of surface integrity and deep curing effect.

[0038] Comparative Example 4: This comparative example removes nano-zinc oxide from the integrated material and reduces the amount of chopped glass fiber. The remaining steps and parameters are the same as in Example 1, as follows: 78 parts of epoxy-modified polyolefin, 3.8 parts of isocyanate curing agent, 5 parts of chopped glass fiber, 0.15 parts of calcium stearate, 0.7 parts of photoinitiator, and 2.3 parts of compatibilizer were weighed, and the raw material drying and subsequent mixing and curing steps were completed according to the conditions of Example 1; the aim was to verify the synergistic effect of nano-zinc oxide and chopped glass fiber on improving the corrosion resistance and mechanical strength of the cable.

[0039] To verify the core performance of the integrated functional layer, the integrated functional layers prepared in Examples 1-8 and Comparative Examples 1-4 were used as test objects. Systematic tests were carried out on interface peel strength, salt spray corrosion resistance time, tensile strength, surface cracking rate and structural compactness. The specific test plan is as follows.

[0040] In the interfacial peel strength test, referring to GB / T2790-1995 "Adhesives - 180° Peel Strength Test Method", a 180° peel method was adopted, the test rate was 50 mm / min, the test ambient temperature was 25℃±2℃, and the test specimen width was 25 mm, ensuring a smooth and continuous peeling process. In the salt spray corrosion resistance test, referring to GB / T10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test", a neutral salt spray test was adopted, with a 5 wt% sodium chloride aqueous solution, a solution pH of 7, a test temperature of 35℃±2℃, and continuous spraying until obvious corrosion appeared on the specimen surface, at which point the timing was stopped. In the tensile strength test, referring to GB / T1040.3-2006 "Determination of Tensile Properties of Plastics - Part 3: Test Conditions for Films and Sheets", the tensile rate was 5 mm / min, and the test ambient temperature was 25℃±2℃. The test specimens were dumbbell-shaped Type I specimens with a gauge length of 50 mm, a specimen width of 10 mm, and a thickness of 2.0 mm. For the surface cracking rate test, referring to GB / T1766-2008 "Rating Method for Aging of Paint and Varnish Coatings", the specimens were first subjected to a temperature difference cycle treatment of -40℃ to 125℃, with each cycle lasting 8 hours and a total of 1000 cycles. After the cycle, a visual rating method combined with image analysis was used to calculate the percentage of cracked area on the specimen surface relative to the total surface area. For the structural density test, referring to GB / T1034-2008 "Determination of Water Absorption of Plastics" and scanning electron microscopy, the specimens were immersed in deionized water at 25℃ for 24 hours. The mass change rate before and after immersion was calculated. An electron microscope was used to observe the specimen cross-section at a magnification of 1000x, and the percentage of pore area in the cross-section relative to the total area of ​​the observed region was statistically analyzed.

[0041] The specific test results are shown in Table 1:

[0042] According to the data in Table 1, the interfacial peel strength of Examples 1-8 is between 1.1 MPa and 1.5 MPa, maintaining a relatively high level overall. Among them, Example 3 has the highest interfacial peel strength, reaching 1.5 MPa, while Example 4 has the lowest, at 1.1 MPa. The interfacial peel strength of Comparative Examples 1-4 is between 0.5 MPa and 1.3 MPa, lower than most examples. Example 3 has the best interfacial peel strength because it increases the amount of KH-550 and raises the pH value of the treatment solution, introducing more amino active groups to the substrate surface. These groups chemically bond with the epoxy groups of the epoxy-modified polyolefin in the integrated material. At the same time, the physical anchoring effect formed by the micro-nano alumina particles is further enhanced, resulting in a stronger interfacial bond. For better adhesion, Example 4 showed relatively low interfacial peel strength because the amount of epoxy-modified polyolefin was reduced, leading to a decrease in the density of interfacial reaction sites and a weakening of chemical bonding. Comparative Example 2 had the lowest interfacial peel strength, at only 0.5 MPa. The core reason for this was the lack of a chemical modification step on the substrate surface. It relied solely on the physical structure formed by mechanical sandblasting to achieve bonding, without forming stable chemical bonds. The interfacial bonding force depended only on van der Waals forces, which was far lower than the synergistic effect of chemical bonding and physical anchoring in Example 1. Comparative Example 1 used a traditional layering process without chemical modification treatment, resulting in weak interfacial bonding force and a peel strength of only 0.7 MPa. This further demonstrates the key role of the dual surface activation treatment and integrated co-extrusion process in improving interfacial bonding force in this invention.

[0043] The salt spray resistance times of Examples 1-8 were all within the range of 1400h-1600h, with Example 5 showing the best performance, reaching 1600h, while Example 4 was relatively lower at 1400h. The salt spray resistance times of the comparative examples were concentrated between 800h and 1400h, with Comparative Example 2 having the lowest at 800h, while Comparative Examples 1 and 4 both reached 900h. Example 5 exhibited outstanding salt spray resistance due to its increased use of nano-zinc oxide. Nano-zinc oxide effectively adsorbs harmful ions such as chloride ions in the salt spray through ion exchange, blocking the penetration path of the corrosive medium into the substrate. Simultaneously, its uniform dispersion within the integrated material forms a dense anti-corrosion barrier. Example 4 has a shorter salt spray resistance time, which is related to the reduced amount of epoxy-modified polyolefin. Insufficient support of the anti-corrosion base material leads to a decrease in the density of the anti-corrosion layer, making it easier for corrosive media to penetrate. Comparative Example 4 has a salt spray resistance time of only 900 hours, which is due to the lack of adsorption of corrosive ions by nano zinc oxide, resulting in a significant reduction in anti-corrosion performance. Comparative Example 1, as an existing technology, uses a conventional PE anti-corrosion layer, which is prone to gaps at the interface with the armor layer. Corrosive media can quickly penetrate to the surface of the armor layer through these gaps, resulting in a salt spray resistance time of only 900 hours, which is far lower than the anti-corrosion effect of the examples. This fully demonstrates the significant advantages of the integrated composite material and interface modification process of the present invention in improving anti-corrosion performance.

[0044] The tensile strengths of Examples 1-8 ranged from 500 MPa to 530 MPa, with Example 6 having the highest tensile strength at 530 MPa and Example 4 having the lowest at 500 MPa. The tensile strengths of the comparative examples ranged from 460 MPa to 500 MPa, with Comparative Example 1 having the lowest at 460 MPa, and Comparative Example 3 being the same as Example 4 at 500 MPa. Example 6 exhibited the best tensile strength, attributed to its increased use of isocyanate curing agent. More curing agent promoted the formation of a denser cross-linked network of epoxy-modified polyolefin molecular chains, while the reinforcing effect of chopped glass fibers was fully utilized, resulting in improved overall mechanical properties of the integrated functional layer. Example 4 had the lowest tensile strength. The reason is that the amount of epoxy-modified polyolefin used is reduced, resulting in insufficient interfacial bonding sites between the substrate and the integrated material. Under stress, local stress concentration is likely to occur, leading to a decrease in overall tensile strength. Comparative Example 1 has the lowest tensile strength. It adopts a traditional layered structure, and the interfacial bonding between the armor layer and the anti-corrosion layer is weak. During the stretching process, interlayer slippage is likely to occur, and an effective mechanical synergy cannot be formed, resulting in low tensile strength. The tensile strength of Comparative Example 3 is 500 MPa, which is higher than that of Comparative Example 1 and Comparative Example 4, but lower than that of most examples. The main reason is that it adopts a single thermosetting process, resulting in insufficient cross-linking uniformity of the integrated material and differences in the curing degree between the surface layer and the deep layer, which affects the overall mechanical properties.

[0045] The surface cracking rates of Examples 1-8 were all controlled between 0.6% and 1.0%, with Example 8 having the lowest rate at 0.6% and Example 4 the highest at 1.0%. The surface cracking rates of the comparative examples ranged from 1.2% to 4.0%, with Comparative Example 1 having the highest rate at 4.0% and Comparative Example 4 the lowest at 1.2%. Example 8 had the lowest surface cracking rate, thanks to its enhanced UV curing strength and appropriately shortened thermal curing time. The rapid UV light-induced surface curing and shaping effectively avoided shrinkage cracking during deep thermal curing. Simultaneously, sufficient thermal curing time ensured adequate deep cross-linking reaction, and the integrated structure better resisted thermal stress during temperature cycling. Example 4 has a relatively high surface cracking rate, which is related to insufficient structural support caused by the reduced amount of epoxy-modified polyolefin. The thermal stress generated by temperature difference cycling easily causes micro-cracks in the weak points of the structure. Comparative Example 1 has the highest surface cracking rate. It only uses a single thermosetting treatment, and the interface between the anti-corrosion layer and the armor layer is not firmly bonded. During the severe temperature difference cycling, the periodic tensile and shear stress generated by the difference in the thermal expansion coefficients between the layers directly leads to interface peeling and surface cracking. The surface cracking rate of Comparative Example 3 is 3.5%, which is lower than that of Comparative Example 1, but much higher than that of the example. It lacks a UV curing step, the surface layer is not cured in time, and the surface layer is prone to shrinkage stress during thermosetting. The cracking phenomenon is more obvious after temperature difference cycling.

[0046] The water absorption rates of Examples 1-8 were all below 0.05 wt%, and the cross-sectional porosity was all below 0.8%. Example 5 had the lowest water absorption rate at 0.02 wt%, and Example 6 had the lowest cross-sectional porosity at 0.4%. The water absorption rates of the comparative examples ranged from 0.05 wt% to 0.12 wt%, and the cross-sectional porosity ranged from 1.2% to 2.5%. Comparative Example 1 had the highest water absorption rate and cross-sectional porosity, at 0.12 wt% and 2.5%, respectively. Example 5 had the lowest water absorption rate because more nano-zinc oxide was uniformly dispersed in the integrated material, filling the tiny voids inside the material and forming a good interfacial bond with the epoxy-modified polyolefin, effectively blocking... The water penetration pathway shows that Example 6 has the lowest cross-sectional porosity because the increased amount of curing agent promotes full cross-linking of the molecular chains of the integrated material, forming a denser structure and reducing the generation of internal pores. Comparative Example 1 has the worst structural density, with obvious interfacial gaps between the armor layer and the anti-corrosion layer. At the same time, the PE anti-corrosion layer itself has a low degree of cross-linking and more internal pores, resulting in significantly higher water absorption and porosity. The water absorption and porosity of Comparative Example 2 are 0.08wt% and 1.8%, respectively, which are higher than those of Example 6. Due to the lack of a chemical modification step, the interface between the substrate and the integrated material is not tightly bonded, which easily forms tiny gaps, allowing water to easily penetrate and increasing the structural porosity.

[0047] This invention also provides a method for preparing a corrosion-resistant power cable for an integrated armored and corrosion-resistant energy storage system, specifically including the following steps: S1: Selecting high-conductivity copper or aluminum rods, and preparing a conductor layer through wire drawing and stranding processes; S2: Using a three-layer co-extrusion process, sequentially and continuously extruding a conductor shielding layer, an insulation layer, and an insulation shielding layer on the outer layer of the conductor, controlling the extrusion temperature at 130-145℃ to ensure uniform thickness of each layer and tight interface adhesion, and cooling and shaping after cross-linking treatment; S3: Using a single-screw extruder, extruding a high-density polyethylene inner sheath layer on the outside of the insulation shielding layer at an extrusion temperature of 16℃. S4: Preheat the surface of the inner sheath layer to 120-125℃, uniformly coat a layer of EVA hot melt adhesive, and then bond the integrated functional layer to the inner sheath layer through a hot press roller. Set the temperature to 145℃, the pressure to 0.25MPa, and maintain the temperature and pressure for 12 minutes to achieve tight bonding between the layers. S5: Extrude a flame-retardant polyethylene outer sheath layer on the outside of the integrated functional layer. The extrusion temperature is 165-175℃, the thickness is controlled at 2.0-2.5mm, and after extrusion, it is cooled and shaped in a water cooling tank to obtain the finished cable.

[0048] To verify the core performance of the entire cable, the integrated functional layers prepared in Examples 1-8 and Comparative Examples 1-4 were used in the preparation of the entire cable. Systematic tests were conducted on the cable's temperature difference cycling performance, insulation resistance change rate, mechanical protection performance, and flame retardant performance. The specific test plan is as follows: In the temperature difference cycling performance test, referring to GB / T2951.41-2018 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers - Part 41: Environmental Stress Cracking Test" and GB / T2951.31-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers - Part 31: High Temperature Aging Test Method", a temperature difference cycling treatment of -40℃ to 125℃ was adopted, with a single cycle period of 8 hours and a cumulative cycle of 1500 cycles. After the cycle, the appearance of the entire cable was observed for cracking and interlayer peeling, and the interface peel strength retention rate was tested. In the insulation resistance change rate test, the test environment temperature was controlled at 25℃±2℃. With a relative humidity of 60%±5%, the initial value of the insulation resistance of the entire cable was measured using a 1000VDC megohmmeter. After 1500 temperature differential cycles and 1500h of salt spray corrosion, the insulation resistance was measured again, and the resistance change rate was calculated. In the mechanical protection performance test, a 1kg hammer was used to impact the entire cable sample from a height of 1m with an impact point spacing of 50mm. The sample was observed for damage and insulation layer breakdown. At 25℃, a pressure of 1000N was applied to the entire cable and held for 1min. After release, the entire cable was observed for permanent deformation and interlayer separation. In the flame retardant performance test, referring to GB / T18380.12-2008 "Cables and Optical Cables Under Flame Conditions - Part 12: Vertical Flame Propagation Test of Single Insulated Wires and Cables - 1kW Premixed Flame Test Method", the entire cable sample was vertically burned with a 1kW premixed flame for 60s. After extinguishing, the afterflame time and smoldering time of the sample were observed, and the char length was measured.

[0049] The specific test results are shown in Table 2:

[0050] According to the data in Table 2, the cables of Examples 1-8 exhibited excellent resistance to temperature difference cycling. Except for Example 4, which showed the first peeling after 950 cycles, the other examples could withstand 1000 temperature difference cycles without interfacial peeling. The resistance to temperature difference cycling of the comparative examples was significantly deteriorated. Comparative Example 1 peeled after only 400 cycles, and Comparative Example 2 after 550 cycles. Example 3, due to the strongest interfacial bonding force of the integrated functional layer, was able to resist interlayer thermal stress during temperature difference cycling and did not peel. Example 4, due to the reduced amount of epoxy-modified polyolefin, had insufficient bonding sites between the integrated functional layer and the inner sheath layer, and peeled prematurely under thermal stress. Comparative Example 1 used a traditional layering process, with interlayer bonding relying solely on van der Waals forces. The difference in thermal expansion and contraction during temperature difference cycling led to stress concentration between layers, resulting in rapid peeling. Comparative Example 2 lacked a chemical modification step, resulting in weak interfacial bonding force and a significant decrease in resistance to temperature difference cycling.

[0051] The insulation resistance change rate of Examples 1-8 was controlled between 2.5% and 4.5%, with Example 5 having the lowest at 2.5% and Example 4 having the highest at 4.5%. The insulation resistance change rate of the comparative examples was between 5.2% and 12.5%, with Comparative Example 1 having the highest at 12.5%. Example 5 had the lowest resistance change rate because the integrated functional layer had the best corrosion resistance and no corrosive medium intruded after salt spray corrosion, so the insulation layer was not contaminated. Example 4 had a slight decrease in insulation resistance due to insufficient density of the anti-corrosion layer and the infiltration of a small amount of corrosive medium. Comparative Example 1 had gaps that easily formed between layers, allowing corrosive medium to quickly intrude and damage the insulation layer, resulting in a significantly higher resistance change rate. Comparative Example 4 lacked nano zinc oxide, weakening its anti-corrosion performance and affecting the insulation layer with a resistance change rate of 10.5%.

[0052] Examples 1-8 exhibit good mechanical protection performance. Except for Example 4, which showed slight deformation after being flattened, the other examples showed no damage or deformation after impact and flattening. Comparative Example 1 showed damage after impact and severe deformation after flattening. Comparative Example 4 showed damage after impact and significant deformation after flattening. Example 6, due to the highest tensile strength of its integrated functional layer, has strong mechanical support capabilities and can effectively resist impact and flattening stress. Example 4, due to a slight decrease in the mechanical properties of its integrated functional layer, showed slight deformation after flattening. Comparative Example 1 uses a traditional layered structure with weak interlayer bonding, which cannot effectively withstand mechanical stress, resulting in damage and severe deformation. Comparative Example 4 has reduced chopped glass fiber content, resulting in insufficient mechanical reinforcement and deteriorated mechanical protection performance.

[0053] The flame retardant performance of Examples 1-8 all met the qualified standards, with afterflame time ≤10s and smoldering time ≤20s. Example 8 performed best, with afterflame time 6s and smoldering time 12s. The flame retardant performance of the comparative examples was unqualified, with afterflame time ≥18s and smoldering time ≥28s. Comparative example 1 had afterflame time of 25s and smoldering time of 40s. Due to the dense structure of the integrated functional layer, Example 8 could effectively block the spread of flames in synergy with the outer sheath layer. Due to the insufficient density of the integrated functional layer, the flame retardant synergy effect of Example 4 was slightly reduced, but it still met the standard. The gaps between the layers of Comparative example 1 easily formed flame channels, resulting in poor flame retardant effect. The material structure of Comparative example 4 was loose, allowing flames to easily penetrate, and the flame retardant performance was significantly deteriorated.

[0054] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A corrosion-resistant power cable for an energy storage system that integrates armor and corrosion protection, characterized in that, From the inside out, it includes a conductor layer, a conductor shielding layer, an insulation layer, an insulation shielding layer, an inner sheath layer, an integrated functional layer, and an outer sheath layer. The integrated functional layer combines mechanical support and protection with corrosion barrier functions. It is composed of an armor substrate that has undergone mechanical micro-nano structuring and chemical activity modification, and an integrated material. The integrated material tightly covers the surface of the modified armor substrate.

2. The power cable for a corrosion-resistant energy storage system with integrated armor and corrosion protection as described in claim 1, characterized in that: The thickness of the integrated functional layer is 1.8-2.2 mm.

3. The power cable for a corrosion-resistant energy storage system with integrated armor and corrosion protection as described in claim 1, characterized in that: The mechanical micro-nano structuring process involves sandblasting the surface of the armored substrate with white corundum abrasive with a particle size of 0.22 mm. The sandblasting pressure is 0.35-0.4 MPa, and the processing time is 4.2-4.5 min, so that the surface roughness Ra of the substrate reaches 1.8-2.0 μm.

4. The power cable for a corrosion-resistant energy storage system with integrated armor and corrosion protection as described in claim 1, characterized in that: The chemically active modification involves immersing the sandblasted substrate in a treatment solution to introduce amino active groups onto the substrate surface, thereby forming a physical anchoring structure.

5. The power cable for a corrosion-resistant energy storage system with integrated armor and corrosion protection as described in claim 4, characterized in that: The treatment liquid material comprises, by weight, 1.8-2.2 parts of silane coupling agent KH-550, 0.5-0.9 parts of micro-nano alumina particles, 96.5-97.7 parts of ethanol-water solution, and 0.04-0.06 parts of glacial acetic acid; wherein the volume ratio of ethanol to water in the ethanol-water solution is 3:

7.

6. The power cable for a corrosion-resistant energy storage system with integrated armor and corrosion protection as described in claim 1, characterized in that: The integrated material comprises, by weight: 75-80 parts epoxy-modified polyolefin, 3.5-4.1 parts isocyanate curing agent, 0.6-0.8 parts photoinitiator, 2.5-3.5 parts nano zinc oxide, 6-7 parts chopped glass fiber, 0.12-0.18 parts calcium stearate, and 2.2-2.5 parts compatibilizer PE-g-MAH.

7. The power cable for a corrosion-resistant energy storage system with integrated armor and corrosion protection as described in claim 6, characterized in that: The epoxy-modified polyolefin contains 7-8 wt% epoxy groups and has a moisture content ≤0.05 wt%; the isocyanate curing agent has a moisture content ≤0.02 wt%; the photoinitiator has a moisture content ≤0.03 wt%; the nano zinc oxide has a particle size of 40-50 nm and a moisture content ≤0.1 wt%; the chopped glass fiber has a length of 0.3-0.4 mm and a moisture content ≤0.1 wt%; and the calcium stearate and compatibilizer PE-g-MAH both have a moisture content ≤0.05 wt%.

8. The power cable for a corrosion-resistant energy storage system with integrated armor and corrosion protection as described in claim 1, characterized in that: The preparation steps of the integrated functional layer include: S1: First, the surface of the armor substrate is mechanically micro-nano-structured, then degreased by soaking in sodium hydroxide aqueous solution, and finally the armor substrate is immersed in the treatment solution for chemical activation modification to obtain the modified substrate, which is then dried for later use. S2: First, dry and pre-treat the raw materials of the integrated material separately, then premix the epoxy-modified polyolefin with the compatibilizer, add the functional filler for dispersion, cool down and add the curing agent and photoinitiator for low-speed mixing to obtain the integrated composite layer base material; S3: The preheated modified substrate is fed into the central channel of the co-extruder, and the integrated composite layer base material is injected from the side feed port to simultaneously coat and form an integrated structure; S4: The integrated structure is subjected to gradient curing, followed by wet grinding, rinsing, and drying to obtain the integrated functional layer.

9. The power cable for a corrosion-resistant energy storage system with integrated armor and corrosion protection as described in claim 8, characterized in that: In S3, the screw speed of the co-extruder is 65-70 r / min, the barrel temperature is 140-150℃ in zone 1, 160-170℃ in zone 2, and 170-180℃ in zone 3, and the die temperature is 160-165℃; before co-extrusion, the armored substrate is preheated to 125-135℃ and kept at that temperature for 30-40 min.

10. The power cable for a corrosion-resistant energy storage system with integrated armor and corrosion protection as described in claim 8, characterized in that: In step S4, the gradient curing sequentially includes ultraviolet curing and thermal curing, wherein the ultraviolet light wavelength for ultraviolet curing is 265 nm, and the irradiation intensity is 12.5-13.5 mW / cm². 2 The irradiation time is 4 minutes; the heat curing temperature is 130℃, and the heat holding time is 20-25 minutes.

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