New energy copper alloy energy storage cable

Abstract

The application discloses a new energy copper alloy energy storage cable and relates to the technical field of cable insulation. The new energy copper alloy energy storage cable comprises, from inside to outside, a copper alloy conductor, an insulation layer, a shielding layer and an outer sheath layer. The insulation layer comprises the following components in parts by weight: low-density polyethylene 65-75 parts, linear low-density polyethylene 25-35 parts, interface enrichment copper capturing agent 1.8-2.2 parts, long-chain flexible heat-conducting carrier 14-16 parts, antioxidant 0.4-0.6 parts, initiator A 0.08-0.12 parts and initiator B 1.8-2.2 parts. The application realizes rheological stability of the extrusion processing of the insulation material through a specific reaction regulation strategy, avoids surface roughness and scorching phenomena, constructs a barrier layer by utilizing an interface enrichment effect, effectively inhibits the aging problem induced by metal ions, further improves the toughness and anti-cracking capacity of the insulation layer at low temperature through flexible interface modification, and guarantees long-term reliable operation of the cable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable insulation, in particular to a new energy copper alloy energy storage cable. BACKGROUND

[0002] The energy storage cable is a key carrier connecting the battery cluster and the core equipment such as the converter, and is an indispensable energy transmission channel in the new energy storage system. It mainly builds an electrical isolation and mechanical protection system by extruding an insulation layer, a shielding layer and a sheath layer outside the metal conductor. In the manufacturing process of the cable, the high molecular matrix material and various functional additives are mixed in a high temperature melting state, and then coated on the surface of the conductor through a mold. Subsequently, cross-linking and curing are performed to shape. In order to meet the use requirements of high power density and complex environment of the energy storage system, inorganic fillers and specific chemical additives are often added to the insulation material to simultaneously achieve insulation protection, heat dissipation and anti-aging performance.

[0003] However, in the actual continuous extrusion production process, due to the differences in the reaction activity and rheological properties of the components in the insulation material system, unstable processing states often occur at the extruder cylinder or the die head. The internal early solidification or gelation of the material occurs before it is transported to the die, resulting in a rough and uneven granular surface of the extruded cable insulation layer, or causing abnormal fluctuations in the equipment pressure, making it difficult to control the thickness uniformity of the insulation layer. In addition, during the long-term power-on operation, ions on the surface of the metal conductor easily penetrate into the insulation layer, causing accelerated aging of the insulation medium. At the same time, the insulation layer filled with a large amount of inorganic substances often appears micro-cracks when starting or bending in a low temperature cold environment due to the inability to effectively dissipate internal stress, which seriously affects the operation reliability and safety of the energy storage cable throughout its life cycle. SUMMARY

[0004] The present application aims to provide a new energy copper alloy energy storage cable, which solves the problems in the background art.

[0005] To solve the above technical problems, the present application provides a new energy copper alloy energy storage cable, which comprises a copper alloy conductor, an insulation layer, a shielding layer and an outer sheath layer arranged in sequence from inside to outside.

[0006] The insulation layer comprises the following components by weight: low density polyethylene 65-75 parts, linear low density polyethylene 25-35 parts, interface-rich copper capturing agent 1.8-2.2 parts, long-chain flexible heat-conducting carrier 14-16 parts, antioxidant 0.4-0.6 parts, initiator A 0.08-0.12 parts, and initiator B 1.8-2.2 parts.

[0007] Initiator A is a peroxide initiator with a lower half-life temperature, used to initiate the grafting reaction; initiator B is a peroxide initiator with a higher half-life temperature, used to initiate the crosslinking reaction;

[0008] The interface enrichment copper capture agent is a silsesquioxane derivative containing a fluoralkyl side chain.

[0009] The long-chain flexible heat-conducting carrier is a boron nitride nanosheet with a long carbon chain grafted on the surface.

[0010] Preferably, the interface enrichment copper capture agent is processed by the following steps:

[0011] Step A1, skeleton construction: mix vinyltrimethoxysilane and trifluoropropyltrimethoxysilane in anhydrous ethanol, add acetic acid to the system to adjust the pH value to 4.5-5.5, add 60%-70% of the total amount of deionized water to the system at 45-50℃ in a water bath environment, and carry out pre-hydrolysis condensation reaction for 3-4 hours; then, add 3-glycidyloxypropyltrimethoxysilane to the system and adjust the pH value of the system to 5.5-6.0, add the remaining deionized water, and continue to react for 6-8 hours under constant temperature stirring at 45-50℃, to obtain an intermediate core containing vinyl, complete epoxy and fluoralkyl groups;

[0012] Step A2, functional modification: adjust the pH value of the system obtained in step A1 to neutral, slowly add an ethanol solution of hydrazine hydrate under high-speed stirring, and the molar amount of hydrazine hydrate is 2.0-2.5 times the molar amount of 3-glycidyloxypropyltrimethoxysilane added in step A1; after the addition is completed, the system is heated to 75-80℃, and ring-opening addition reaction is carried out under reflux condensation for 5-7 hours;

[0013] Step A3, purification and drying: after the reaction is completed, the product is treated by rotary evaporation to remove the solvent and excess reactants, the obtained solid is precipitated and washed 2-4 times with cold diethyl ether, and then transferred to a vacuum drying oven for drying to constant weight, to obtain the interface enrichment copper capture agent.

[0014] Preferably, in step A1, the molar ratio of vinyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane and trifluoropropyltrimethoxysilane is 9-11:3-5:0.8-1.2; in step A2, the molar ratio of the amount of hydrazine hydrate added to the molar amount of 3-glycidyloxypropyltrimethoxysilane added in step A1 is 1.8:1-2.2:1.

[0015] Preferably, the long-chain flexible heat-conducting carrier is processed by the following steps:

[0016] Step B1, high shear exfoliation: hexagonal boron nitride and urea are mixed in a mass ratio of 1:18-1:22, placed in a ball mill for high-energy ball milling treatment for 34-38 hours, the milled mixture is dispersed in deionized water, ultrasonic dispersion exfoliation is carried out, centrifugal separation is carried out to take the supernatant, and the supernatant is subjected to sedimentation separation and drying treatment to obtain hydroxylated boron nitride nanosheet powder;

[0017] Step B2, long-chain modification: the hydroxylated boron nitride nanosheet is dispersed in a xylene solvent, 10-undecylenic acid and p-toluenesulfonic acid are added, and after being mixed uniformly, heated to 115-125℃, the azeotropic dehydration reflux reaction is carried out in a device connected with a water trap, and the esterification reaction is carried out under the condition of keeping the condensation reflux state for 10-14 hours;

[0018] Step B3, product treatment: the reaction product is washed with alcohol to remove unreacted substances, centrifuged and dried in an oven at 75-85℃ to constant weight to obtain a long-chain flexible heat-conducting carrier.

[0019] Preferably, in step B2, the amount of 10-undecylenic acid added is 4.5%-5.5% of the mass of the hydroxylated boron nitride nanosheet.

[0020] Preferably, the insulation layer is formed by a double-source initiation stepwise grafting process, which includes the following steps:

[0021] Step C1, preparation of pre-grafted functional masterbatch: low-density polyethylene, linear low-density polyethylene, interface-rich copper-trapping agent, long-chain flexible heat-conducting carrier, antioxidant and initiator A are added to a high-speed mixer and mixed at a speed of 1100-1300 r / min for 4-6 minutes, and then put into a double-screw extruder;

[0022] The double-screw extruder is set to a gradient temperature curve so that the temperature of the material in the grafting reaction zone reaches 160-170℃, and the interface-rich copper-trapping agent and the long-chain flexible heat-conducting carrier are grafted onto the polyethylene molecular chain; a vacuum devolatilization section with a vacuum degree of -0.07 MPa to -0.09 MPa is set at the end of the double-screw extruder to remove small molecular byproducts, and the extruded granules are obtained; in this step, initiator B is strictly prohibited;

[0023] Step C2, cable extrusion: the pre-grafted functional masterbatch obtained in step C1 is mixed with initiator B and added to a single-screw cable extruder, and the temperature of the barrel and die head of the cable extruder is controlled at 115-130℃, and then coated on the outside of the copper alloy conductor after melt extrusion;

[0024] Step C3, high-temperature crosslinking: the copper alloy conductor coated with the insulating layer is sent into a catenary vulcanization pipe, and high-temperature crosslinking is carried out at a temperature of 250-270 DEG C and a pressure of 1.0-1.4 MPa in a nitrogen protective atmosphere, so that the initiator B is decomposed to initiate the main chain network crosslinking, and the insulating layer is obtained after cooling.

[0025] Preferably, in step C1, the temperatures of the five temperature zones of the twin-screw extruder from the feeding port to the discharging port are set to 125-135 DEG C, 140-150 DEG C, 155-165 DEG C, 160-170 DEG C and 145-155 DEG C, respectively; and the initiator A is selected from one of benzoyl peroxide or 1,1-bis(tert-butyl peroxy)-3,3,5-trimethylcyclohexane.

[0026] Preferably, in step C2, the initiator B is dicumyl peroxide, and is added through a side feeding port or is physically mixed with a pre-grafted functional masterbatch at room temperature; and the copper alloy conductor is composed of a plurality of copper alloy wire cores twisted together, and the copper alloy wire core comprises an aluminum alloy inner core and a copper cladding layer cladded on the outer part of the aluminum alloy inner core.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] By optimizing the reaction system and processing logic of the insulating material, the rheological stability problem of the composite material in the extrusion process is effectively solved. By stage-by-stage regulation of the reaction activity, the material maintains good thermoplastic flow state in the extrusion mixing stage, avoids the occurrence of local gelation or early solidification in the equipment, ensures the smoothness of the extrusion surface of the cable insulating layer, eliminates the appearance defects, and at the same time ensures the uniformity of the wall thickness of the insulating layer and the continuous stability of the production process, so as to obtain an insulating wire core with excellent processing quality.

[0029] An active protection mechanism is constructed at the combination interface between the insulating layer and the copper alloy conductor. By specific chemical structure design of the functional component, the polar amino group and the unreacted epoxy group in the molecular structure are used as anchor points to preferentially adsorb and complex on the surface of the metal copper alloy conductor. At the same time, a dense water and oil repellent barrier is formed at the metal interface by the fluoralkyl chain segment suspended on the side of the molecular chain due to its extremely low surface energy and hydrophobic property, which effectively inhibits the diffusion and migration of copper alloy conductor metal ions into the insulating matrix, and blocks the oxidation aging path caused by metal ion catalysis from the source, effectively delays the aging and degradation rate of the material without sacrificing the insulating performance, thereby ensuring the electrical safety and service life of the cable under long-term working conditions.

[0030] The mechanical toughness of the high-filled insulation composite in an extremely low temperature environment is improved, the interface compatibility between the filler and the polymer matrix is improved by constructing a flexible long-chain molecule buffer layer on the surface of the inorganic heat-conducting filler, and additional free volume is provided to buffer internal stress, so that the insulation layer can effectively dissipate low-temperature impact energy while maintaining high-efficiency heat conduction capacity, avoiding brittle fracture or micro-crack propagation of the material due to excessive rigidity, and ensuring the mechanical integrity of the cable during laying or operation in cold climates. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0032] Fig. 1 A columnar graph for comparing the thermal conductivity coefficients of the insulation layers of the examples and comparative examples of the present application is provided.

[0033] Fig. 2 An OIT test result comparison graph for verifying the influence of fluorine-containing side chains on the copper resistance of the insulation layer is provided. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0035] Example 1

[0036] Referring to Figs. 1-2 The present embodiment provides a new energy copper alloy energy storage cable, which comprises a copper alloy conductor, an insulation layer, a shielding layer and an outer sheath layer arranged in sequence from inside to outside. The insulation layer is a core functional layer, and its performance directly determines the service life of the cable under complex working conditions. In the present embodiment, the insulation layer comprises the following components by weight: low density polyethylene 70 parts, linear low density polyethylene 30 parts, interface-rich copper capturing agent 2.0 parts, long-chain flexible heat-conducting carrier 15 parts, antioxidant 0.5 parts, initiator A 0.1 parts (1,1-bis(tert-butyl peroxy)-3,3,5-trimethylcyclohexane is selected), initiator B 2.0 parts (dicumyl peroxide is selected).

[0037] The copper alloy conductor adopts a composite metal structure, specifically composed of a plurality of composite wire cores twisted together, and the copper alloy wire core is in the form of copper-clad aluminum in the microstructure, including an aluminum alloy inner core and a copper cladding layer metallurgically combined and cladded outside the aluminum alloy inner core, which is collectively referred to as a copper alloy copper alloy conductor in the technical context of the present application, aiming to take advantage of the excellent electrical conductivity of the copper layer and the lightweight advantage of the aluminum core, while cooperating with the interface enrichment type copper capturing agent of the present application, to specially solve the copper ion migration and galvanic corrosion problem that may be induced by the long-term electrochemical action of such a bimetallic interface;

[0038] In the present embodiment, the selection of the initiator is crucial to the success of the process; initiator A is selected as 1,1-bis(tert-butyl peroxy)-3,3,5-trimethylcyclohexane, which has a 1-minute half-life temperature of about 148℃, and can be quickly decomposed at the extrusion granulation temperature of 160-170℃ set in the present application, mainly for initiating grafting reaction without causing deep crosslinking of the polyethylene main chain; initiator B is selected as dicumyl peroxide, which has a 1-minute half-life temperature of about 171℃, and decomposes very little (in the latent period) at the granulation temperature, and only at a high temperature environment above 250℃ of the CV tube, it will quickly and completely decompose, thereby initiating the final crosslinking and curing; this selection strategy based on the difference in half-life temperature (ΔT≥20℃) ensures the step-by-step grafting and crosslinking; this dual-source initiation strategy aims to solve the scorching problem caused by the competition between grafting and crosslinking in the traditional one-step method;

[0039] The interface enrichment type copper capturing agent in the present embodiment is a silsesquioxane derivative containing a fluoroalkyl side chain, which is processed by the following steps: the raw materials used, vinyltrimethoxysilane, 3-glycidyl ether oxypropyltrimethoxysilane, and trifluoropropyltrimethoxysilane, are all commercially available products;

[0040] Step A1, skeleton construction: mix vinyltrimethoxysilane, 3-glycidyl ether oxypropyltrimethoxysilane, and trifluoropropyltrimethoxysilane in a molar ratio of 10:4:1 in anhydrous ethanol, add acetic acid to adjust the pH value to 5.0, avoid strong acid to destroy the epoxy ring, add deionized water dropwise under a water bath environment at 50℃, keep constant temperature stirring for 10 hours to construct the functionalized silsesquioxane intermediate;

[0041] Step A2, functional modification: after the reaction in step A1 is completed, the temperature of the system is lowered to room temperature, and a saturated sodium bicarbonate solution is used to adjust the pH of the system to 7.0-7.2 to terminate the acid-catalyzed hydrolysis process. Subsequently, under high-speed stirring at 800 r / min, a 20wt% hydrazine hydrate ethanol solution is slowly added dropwise, and the basicity of hydrazine hydrate itself is used to initiate the ring-opening reaction of the epoxy group. The molar amount of hydrazine hydrate is 2.2 times the molar amount of 3-glycidyloxypropyltrimethoxysilane added in step A1. After the dropwise addition is completed, the system is heated to 78°C, and the ring-opening addition reaction is carried out under a condensing reflux state for 6 hours to construct polar adsorption sites containing amino and hydroxyl groups;

[0042] Step A3, purification and drying: after the reaction is completed, the product is treated by rotary evaporation to remove the solvent and excess reactants. The obtained solid is precipitated and washed 3 times with cold diethyl ether, and then transferred to a vacuum drying oven for drying to constant weight to obtain an interface enrichment copper capture agent. The interface enrichment copper capture agent uses the strong polar adsorption of amino and epoxy groups to the metal surface, and the hydrophobic shielding effect of the fluoroalkyl group, thereby forming a dense protective layer on the surface of the copper alloy conductor;

[0043] The long-chain flexible heat-conducting carrier in the present embodiment is a boron nitride nanosheet with a long carbon chain grafted on the surface, which is processed by the following steps: the used hexagonal boron nitride has a particle size of 1-2 microns;

[0044] Step B1, mix hexagonal boron nitride and urea according to a mass ratio of 1:20, and place them in a ball mill for high-energy ball milling treatment for 36 hours. Disperse the milled mixture in deionized water, perform ultrasonic dispersion and exfoliation, remove the unexfoliated large particle precipitate by centrifugation at a speed of 3000 r / min, collect the supernatant, and perform high-speed centrifugation of the supernatant at 10000 r / min. Discard the liquid, wash the obtained solid precipitate with anhydrous ethanol 3 times, and place it in a vacuum drying oven at 80°C for drying for 12 hours to constant weight to obtain dry hydroxylated boron nitride nanosheet powder;

[0045] Step B2, long-chain modification: weigh the above dry hydroxylated boron nitride nanosheet powder, disperse it in a dimethylbenzene solvent, and perform ultrasonic dispersion for 30 minutes to form a uniform suspension. Then add 10-undecylenic acid and a catalyst p-toluenesulfonic acid. The addition amount of 10-undecylenic acid is 5.0% of the mass of the hydroxylated boron nitride nanosheet powder. After mixing uniformly, heat to 120°C, and perform esterification reaction under a condensing reflux state for 12 hours to promote the reaction to proceed in the forward direction by azeotropic dehydration;

[0046] Step B3, product treatment: the reaction product is washed with alcohol to remove unreacted substances, and after centrifugal separation, is placed in an oven at 80°C to dry to constant weight, to obtain a long-chain flexible heat-conductive carrier; the long-chain flexible heat-conductive carrier provides a free volume required for polymer chain segment movement in a low-temperature environment by introducing a long carbon chain, and relieves stress concentration caused by inorganic fillers;

[0047] In this embodiment, the forming method of the insulating layer adopts a two-source stepwise grafting process, which comprises the following steps:

[0048] Step C1, preparation of pre-grafting functional masterbatch: low-density polyethylene, linear low-density polyethylene, interface-rich copper capturing agent, long-chain flexible heat-conductive carrier, antioxidant and initiator A are added into a high-speed mixer and mixed at a speed of 1200 r / min for 5 minutes, and then are put into a double-screw extruder; the temperatures of the five temperature zones of the double-screw extruder from the feeding port to the discharging port are set to 130°C, 145°C, 160°C, 160°C and 150°C, respectively, so that the temperature of the material in the grafting reaction zone reaches 165°C, and the interface-rich copper capturing agent and the long-chain flexible heat-conductive carrier are grafted onto the polyethylene molecular chain; a vacuum devolatilization section with a vacuum degree of -0.08 MPa is arranged at the end of the double-screw extruder to remove small molecular byproducts, and the material is extruded and granulated to obtain a pre-grafting functional masterbatch; in this step, initiator B is strictly prohibited from being added;

[0049] Step C2, cable extrusion: the pre-grafting functional masterbatch obtained in step C1 is mixed with initiator B uniformly and added into a single-screw cable extruder, and the temperature of the barrel and the die head of the cable extruder is controlled to be 120-125°C, and then the cable extruder is extruded to coat the copper alloy conductor outside;

[0050] Step C3, high-temperature crosslinking: the copper alloy conductor coated with the insulating layer is sent into a catenary vulcanization pipe, and high-temperature crosslinking is carried out at a temperature of 260°C and a pressure of 1.2 MPa in a nitrogen protective atmosphere, so that initiator B decomposes to initiate main chain network crosslinking, and the insulating layer is obtained after cooling; this process realizes the time and space separation of grafting and crosslinking through accurate control of the temperature window;

[0051] In order to verify the structure of the above-mentioned modified material, Fourier transform infrared spectrum analysis is performed on the prepared interface-rich copper capturing agent and long-chain flexible heat-conductive carrier;

[0052] For the interface-rich copper capturing agent, a strong Si-O-Si anti-symmetrical stretching vibration wide peak appears near 1100cm - ¹, which confirms the formation of the inorganic siloxane skeleton; a characteristic epoxy group absorption peak is observed at 910cm - ¹, indicating that the epoxy ring structure is retained in step A1; an absorption peak of the Si-O-Si anti-symmetrical stretching vibration appears at 1210cm -¹ stretching vibration peak of C-F bond was detected, and the stretching vibration peak of -NH- and -OH near 3350 cm - ¹ near the stretching vibration peak of -NH- and -OH introduced by step A2 proved that the hydrazine hydrate successfully opened the ring addition modification of the epoxy group;

[0053] For long-chain flexible heat-conducting carriers, the spectrum in 1380 cm - ¹ and 810 cm - ¹ correspond to the B-N stretching and bending vibration peaks of boron nitride, respectively; significant asymmetric and symmetric methylene (-CH2-) stretching vibration peaks appear at 2920 cm - ¹ and 2850 cm - ¹, and the characteristic absorption peak of ester carbonyl (C=O) appears at 1735 cm - ¹, which confirms that 10-undecylenic acid is successfully grafted on the surface of boron nitride nanosheet through an ester bond.

[0054] Example 2

[0055] The new energy copper alloy energy storage cable provided by the embodiment includes an insulating layer, which comprises the following components by weight: 65 parts of low-density polyethylene, 35 parts of linear low-density polyethylene, 1.8 parts of interface-rich copper capturing agent, 14 parts of long-chain flexible heat-conducting carrier, 0.4 parts of antioxidant, 0.08 parts of initiator A, and 1.8 parts of initiator B; wherein the sources of low-density polyethylene, linear low-density polyethylene and antioxidant are the same as in Example 1; initiator A is selected from benzoyl peroxide; and initiator B is selected from dicumyl peroxide.

[0056] In the embodiment, the preparation parameters of the interface-rich copper capturing agent are adjusted as follows: in step A1, the molar amount ratio of vinyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane and trifluoropropyltrimethoxysilane is 9:3:0.8, the pH value is adjusted to 4.5, and the hydrolysis and condensation reaction is performed for 9 hours; in step A2, the molar ratio of the amount of hydrazine hydrate added to the initial amount of 3-glycidyloxypropyltrimethoxysilane is 1.8:1, a condenser is installed on the reaction system to prevent solvent evaporation, the temperature is set to 55°C, and the reaction is performed for 5 hours under constant temperature stirring; and in step A3, the cold ether is precipitated and washed twice; the above parameter settings not only ensure the basic functional group ratio, but also appropriately reduce the reaction energy consumption, which is suitable for production scenarios that are more sensitive to cost control.

[0057] In the embodiment, the preparation parameters of the long-chain flexible heat-conducting carrier are adjusted as follows: in step B1, the mass ratio of hexagonal boron nitride to urea is 1:18, and the ball milling treatment is performed for 34 hours; in step B2, the amount of 10-undecylenic acid added is 4.5%, and the temperature is heated to 115°C, and the reaction is performed for 10 hours; reducing the amount of acid aims to investigate the interfacial compatibility performance under a lower grafting rate.

[0058] In the molding method of the insulation layer in this embodiment: the high-speed mixing speed in step C1 is 1100 r / min, and the mixing time is 4 minutes; the five temperature zones of the twin-screw extruder are set to 125℃, 145℃, 160℃, 160℃, and 145℃, the grafting reaction zone temperature is 160℃, and the vacuum degree is -0.07MPa; the temperature of the cable extruder in step C2 is controlled at 115-120℃; the high-temperature crosslinking temperature in step C3 is 250℃, and the pressure is 1.0MPa; the lower processing temperature is beneficial to further protect the activity of the heat-sensitive additives.

[0059] Example 3

[0060] This embodiment provides a new energy copper alloy energy storage cable, the insulation layer of which comprises the following components by weight: 75 parts low-density polyethylene, 25 parts linear low-density polyethylene, 2.2 parts interface-enriched copper scavenger, 16 parts long-chain flexible thermal conductive carrier, 0.6 parts antioxidant, 0.12 parts initiator A, and 2.2 parts initiator B; initiator A is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and its source is the same as in Example 1; the other resins and additives are also from the same source as in Example 1;

[0061] In this embodiment, the preparation parameters of the interface-enriched copper scavenger were adjusted as follows: In step A1, the molar ratio of vinyltrimethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, and trifluoropropyltrimethoxysilane was 11:5:1.2, the pH was adjusted to 3.5, and the hydrolysis-condensation reaction was carried out for 11 hours; in step A2, the ratio of hydrazine hydrate was 2.2:1, the reaction temperature was 65°C, and the reaction was carried out for 7 hours; in step A3, the mixture was washed 4 times; the higher amount of fluorine monomer added was intended to enhance the driving force of molecules toward the interface;

[0062] In this embodiment, the preparation parameters of the long-chain flexible thermal conductive carrier are adjusted as follows: in step B1, the mass ratio of hexagonal boron nitride to urea is 1:22, and the mixture is ball-milled for 38 hours; in step B2, the amount of 10-undecenoic acid added is 5.5%, and the mixture is heated to 125°C and reacted for 14 hours; increasing the grafting density of the long-chain acid aims to improve the toughness reserve of the material at low temperatures.

[0063] In the molding method of the insulating layer in this embodiment: Step C1: mixing speed 1300 r / min, mixing for 6 minutes; twin-screw temperature zone set to 135℃, 155℃, 170℃, 170℃, 155℃, grafting reaction zone temperature 170℃, vacuum degree -0.09MPa; Step C2: extrusion temperature 125-130℃; Step C3: crosslinking temperature 270℃, pressure 1.4MPa; this set of parameters is designed to verify the material stability under high processing efficiency.

[0064] Example 4

[0065] This embodiment provides a new energy copper alloy energy storage cable, the insulation layer of which comprises the following components by weight: 72 parts of low-density polyethylene, 28 parts of linear low-density polyethylene, 1.9 parts of interface enrichment copper scavenger, 14.5 parts of long-chain flexible thermal conductive carrier, 0.45 parts of antioxidant, 0.09 parts of initiator A, and 1.9 parts of initiator B; the raw materials are the same as in Embodiment 1;

[0066] This embodiment focuses on verifying the robustness of intermediate process parameters; in the preparation of the interface enrichment copper scavenger, the molar ratio of each raw material is taken as the lower middle value, the pH value is 2.8, and the hydrolysis time is 9.5 hours; the hydrazine hydrate ratio is 1.9:1, and the reaction time is 5.5 hours at 62°C; in the preparation of the long-chain flexible heat-conducting carrier, the ball milling time is 35 hours, the amount of 10-undecenoic acid is 4.8%, and the reaction time is 118°C for 11 hours.

[0067] In process step C1, the temperature of the grafting zone is finely adjusted to 162℃ and the vacuum degree is -0.075MPa; in step C2, the extrusion temperature is 118-122℃; in step C3, the crosslinking temperature is 255℃ and the pressure is 1.1MPa. This embodiment demonstrates the process tolerance of the present invention under parameter fine-tuning, ensuring the yield rate of industrial production.

[0068] Example 5

[0069] This embodiment provides a new energy copper alloy energy storage cable, the insulation layer of which comprises the following components by weight: 68 parts of low-density polyethylene, 32 parts of linear low-density polyethylene, 2.1 parts of interface enrichment copper scavenger, 15.5 parts of long-chain flexible thermal conductive carrier, 0.55 parts of antioxidant, 0.11 parts of initiator A, and 2.1 parts of initiator B; the raw materials are the same as in Embodiment 1;

[0070] This embodiment aims to investigate the dispersion effect under a higher filling amount; the interface enrichment copper scavenger was prepared using a higher hydrolysis temperature of 52°C, and the rest was the same as in Example 1; the long-chain flexible heat-conducting carrier was prepared using a higher ball milling ratio of 1:21, and the rest was the same as in Example 1.

[0071] In process step C1, the grafting zone temperature is set to 168°C to promote the surface grafting reaction of high-content filler, and the vacuum degree is -0.085MPa; in step C2, the extrusion temperature is 122-128°C; in step C3, the crosslinking temperature is 265°C and the pressure is 1.3MPa. This embodiment verifies that under a high filler load, excellent insulation performance can still be obtained by adjusting the process parameters.

[0072] Comparative Example 1

[0073] This comparative example provides a conventional method for preparing the insulation layer of an energy storage cable. The difference from Example 1 is that it does not use a dual-source initiation stepwise grafting process, but instead uses a traditional single-step mixing and extrusion process. Specifically, all raw materials (including DCP) are mixed in a mixer and then directly added to a single-screw extruder for extrusion. The extruder temperature is set to 130-140°C to balance plasticization and prevent premature decomposition of DCP. Subsequently, the material enters a CV tube for crosslinking. Since no pre-grafting is performed, the bonding between the filler and the matrix relies solely on physical dispersion. The types and sources of raw materials are the same as in Example 1.

[0074] Comparative Example 2

[0075] The difference between this comparative example and Example 1 is that trifluoropropyltrimethoxysilane is not added during the preparation of the interface-enriched copper scavenger, i.e., no fluoroalkyl side chain is introduced; the remaining steps and formulation are consistent with Example 1; the aim is to verify the effect of fluoroalkyl side chain on the migration and enrichment of copper ion scavengers to the interface and their resistance to copper damage.

[0076] Comparative Example 3

[0077] The difference between this comparative example and Example 1 is that, in the preparation of the long-chain flexible thermal conductive carrier, the short-chain silane coupling agent KH-570 (methacryloyloxypropyltrimethoxysilane) was used to replace 10-undecenoic acid for modification; the remaining steps and formulations were consistent with those of Example 1; the aim was to verify the specific effect of the long carbon chain structure in improving low-temperature brittleness.

[0078] To objectively verify the beneficial effects of the technical solution of this invention, the cable insulation materials prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to performance tests. The test items included: oxidation induction period (under copper catalysis, reflecting copper damage resistance life), thermal conductivity, low-temperature impact embrittlement temperature, and observation of extrusion surface quality. The test results are shown in the table below.

[0079] Table 1

[0080]

[0081] Results analysis:

[0082] As can be seen from the data in the table above, Examples 1-5 all exhibited excellent comprehensive performance. In terms of copper scavenging resistance, the OIT values ​​of the Example groups all exceeded 100 minutes, which was significantly better than Comparative Example 1 (conventional process) and Comparative Example 2 (fluorine-free modification). By comparing Example 1 and Comparative Example 2, it can be seen that after removing trifluoropropyltrimethoxysilane, although the formulation still contains copper-catching groups, the OIT value dropped significantly to 65 minutes. This proves that the fluoroalkyl side chain in this invention plays a key role in driving the copper scavenger to enrich at the interface of the copper alloy conductor, thus achieving source blocking of copper scavenging.

[0083] In terms of low-temperature performance, the embrittlement temperature of the example group was as low as -64°C, while that of Comparative Example 3 using a short-chain coupling agent was only -52°C, and that of Comparative Example 1 using a conventional process was only -48°C. This shows that the long-chain flexible heat-conducting carrier used in this invention effectively increases the flexibility of the molecular chain segments at low temperatures by introducing long carbon chains, thus overcoming the matrix embrittlement problem caused by inorganic filler filling.

[0084] Regarding processing quality, the surfaces of the Example Group were smooth, while those of Comparative Example 1 showed rough particles; this verifies the effectiveness of the dual-source initiation stepwise grafting process, which avoids early crosslinking (scorching) during extrusion by separating the grafting and crosslinking reactions on the temperature axis, thus ensuring excellent rheological processing performance.

[0085] In summary, this invention, through specific formula design and process control, effectively balances low-temperature mechanical properties and processing stability while improving the thermal conductivity and copper-damage resistance life of cables.

[0086] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A new energy copper alloy energy storage cable, characterized in that, It includes a copper alloy conductor, an insulation layer, a shielding layer and an outer sheath layer arranged sequentially from the inside out; the copper alloy conductor is made of multiple copper alloy wire cores twisted together, and the copper alloy wire core includes an aluminum alloy inner core and a copper cladding layer covering the outside of the aluminum alloy inner core; The insulation layer comprises the following components in parts by weight: 65-75 parts low-density polyethylene, 25-35 parts linear low-density polyethylene, 1.8-2.2 parts interface-enriched copper scavenger, 14-16 parts long-chain flexible thermal conductive carrier, 0.4-0.6 parts antioxidant, 0.08-0.12 parts initiator A, and 1.8-2.2 parts initiator B; Initiator A is selected from benzoyl peroxide or 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, and is used to initiate the grafting reaction; Initiator B is dicumyl peroxide, and is used to initiate the crosslinking reaction. The interface enrichment type copper scavenger is a silsesquioxane derivative containing fluoroalkyl side chains; The long-chain flexible thermal conductive carrier is boron nitride nanosheets with long carbon chains grafted on their surface; The method for forming the insulating layer employs a dual-source initiation stepwise grafting process, which includes the following steps: Step C1: Preparation of pre-grafted functional masterbatch: Low-density polyethylene, linear low-density polyethylene, interfacial enrichment copper scavenger, long-chain flexible thermal carrier, antioxidant and initiator A are added to a high-speed mixer and mixed at 1100-1300 r / min for 4-6 minutes, and then fed into a twin-screw extruder. The twin-screw extruder is set with a gradient heating curve so that the temperature of the material in the grafting reaction zone reaches 160-170℃, initiating the grafting of the interfacial enrichment copper scavenger and the long-chain flexible heat-conducting carrier onto the polyethylene molecular chain; a vacuum devolatilization section with a vacuum degree of -0.07MPa to -0.09MPa is set at the end of the twin-screw extruder to remove small molecule by-products, and the pre-grafted functional masterbatch is obtained by extrusion granulation; the addition of initiator B is strictly prohibited in this step; Step C2, cable extrusion: Mix the pre-grafted functional masterbatch obtained in step C1 with initiator B evenly, add it to a single-screw cable extruder, control the temperature of the extruder body and die head to 115-130℃, and after melt extrusion, coat the outside of the copper alloy conductor. Step C3, High-temperature crosslinking: The copper alloy conductor coated with the insulating layer is fed into a catenary vulcanizing tube. Under a nitrogen protective atmosphere, high-temperature crosslinking is carried out at a temperature of 250-270℃ and a pressure of 1.0-1.4MPa, which causes the initiator B to decompose and initiate the main chain network crosslinking. After cooling, the insulating layer is obtained.

2. The new energy copper alloy energy storage cable according to claim 1, characterized in that, Interface-enriched copper scavengers are obtained through the following steps: Step A1, framework construction: Vinyltrimethoxysilane and trifluoropropyltrimethoxysilane were mixed in anhydrous ethanol. Acetic acid was added to the system to adjust the pH to 4.5-5.

5. Deionized water, accounting for 60%-70% of the total formulation, was added dropwise in a water bath at 45-50°C to carry out a pre-hydrolysis condensation reaction for 3-4 hours. Subsequently, 3-glycidyl etheroxypropyltrimethoxysilane was added to the system, and the pH was adjusted to 5.5-6.

0. The remaining deionized water was added dropwise, and the reaction was continued for 6-8 hours with stirring at a constant temperature of 45-50°C to obtain an intermediate core containing vinyl groups, complete epoxy groups, and fluoroalkyl groups. Step A2, Functionalization Modification: Adjust the pH of the system obtained in Step A1 to neutral, and slowly add an ethanol solution of hydrazine hydrate dropwise under high-speed stirring. The molar amount of hydrazine hydrate is 2.0-2.5 times the molar amount of 3-glycidyl etheroxypropyltrimethoxysilane added in Step A1. After the addition is complete, heat the system to 75-80℃ and carry out the ring-opening addition reaction under reflux for 5-7 hours. Step A3, purification and drying: After the reaction is completed, the product is subjected to rotary evaporation to remove the solvent and excess reactants. The obtained solid is washed 2-4 times with cold diethyl ether precipitation, and then transferred to a vacuum drying oven to dry to constant weight to obtain an interface-enriched copper scavenger.

3. The new energy copper alloy energy storage cable according to claim 2, characterized in that, In step A1, the molar ratio of vinyltrimethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, and trifluoropropyltrimethoxysilane is 9-11:3-5:0.8-1.2; in step A2, the molar ratio of the amount of hydrazine hydrate added to the amount of 3-glycidyl etheroxypropyltrimethoxysilane added in step A1 is 1.8:1-2.2:

1.

4. The new energy copper alloy energy storage cable according to claim 1, characterized in that, The long-chain flexible thermal conductive medium is obtained by the following steps: Step B1, High-shear exfoliation: Hexagonal boron nitride and urea are mixed at a mass ratio of 1:18-1:22 and placed in a ball mill for high-energy ball milling for 34-38 hours. The ball-milled mixture is dispersed in deionized water and ultrasonically dispersed and exfoliated. The supernatant is centrifuged and then precipitated and dried to obtain hydroxylated boron nitride nanosheet powder. Step B2, Long-chain modification: Disperse hydroxylated boron nitride nanosheets in xylene solvent, add 10-undecenoic acid and p-toluenesulfonic acid, mix evenly and heat to 115-125℃, carry out azeotropic dehydration reflux reaction in a device connected to a water separator, and carry out esterification reaction for 10-14 hours under reflux condensation. Step B3, Product Processing: The reaction product is washed with alcohol to remove unreacted substances, centrifuged, and then dried in an oven at 75-85℃ to constant weight to obtain a long-chain flexible thermal conductive carrier.

5. A new energy copper alloy energy storage cable according to claim 4, characterized in that, In step B2, the amount of 10-undecenoic acid added is 4.5%-5.5% of the mass of the hydroxylated boron nitride nanosheets.

6. The new energy copper alloy energy storage cable according to claim 1, characterized in that, In step C1, the temperatures of the five temperature zones of the twin-screw extruder from the feed inlet to the discharge outlet are set sequentially to 125-135℃, 140-150℃, 155-165℃, 160-170℃, and 145-155℃.

7. A new energy copper alloy energy storage cable according to claim 1, characterized in that, In step C2, initiator B is added either through a side feed port or by physical mixing with the pre-grafted functional masterbatch at room temperature.

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