A flame retardant energy storage cable and a preparation method thereof

Abstract

The present invention discloses a flame-retardant energy storage cable and a preparation method thereof, and relates to the technical field of energy storage cables. The flame-retardant energy storage cable of the present invention comprises a copper wire bundle stranded conductor, an insulating layer, a shielding layer and an outer sheath from the inside to the outside, and the outer sheath material forming the outer sheath comprises at least the following raw materials in parts by mass: 45-65 parts of olefin copolymer, 15-20 parts of filler, 15-25 parts of composite flame retardant, 0.1-0.5 parts of antioxidant, 0.4-0.8 parts of lubricant, wherein the composite flame retardant is a magnesium-aluminum layered double hydroxide-arginine-ammonium polyphosphate composite flame retardant. The flame-retardant energy storage cable prepared in the present application has both large tensile strength and elongation at break, as well as excellent flame retardant properties.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage cables, and in particular to a flame-retardant energy storage cable and a preparation method thereof. Background Art

[0002] With the continuous development of society and the widespread application of electrification technology, all walks of life have higher and higher requirements for the quality and performance of wires and cables. Traditional cables have always been used only for power transmission. However, in some special fields, such as power energy storage systems, special energy storage cables are required to form connections between battery modules on the DC side of the system, between battery clusters, between battery clusters and junction boxes, or between battery clusters and energy storage converters, so as to achieve the storage and utilization of excess energy. The highest voltage level of energy storage cables is DC 1500V, and the highest continuous operating temperature of the conductor is 125℃. During use, it needs to face harsh conditions such as battery acid and alkali; severe cold; torsion; bending, and other harsh conditions, and withstand more severe tests. Therefore, the insulation materials for energy storage cables not only require conventional properties such as safety, environmental protection, halogen-free, low smoke, and good insulation, but also have higher requirements for special properties such as high flame retardancy, acid and alkali resistance, low temperature resistance, high temperature aging resistance, long life, and softness.

[0003] Energy storage cables are used in a variety of environments. Due to the limited thermal conductivity of the insulation and outer protection parts of energy storage cables, the purpose of rapid heat dissipation cannot be achieved. When the cable core works for a long time, the load of the cable increases, the core temperature increases, and the cable expands due to heat. Long-term use can easily cause the cable to spontaneously combust. Therefore, cables for energy storage batteries must not only have excellent insulation electrical properties and mechanical properties, but also must have characteristics such as sunlight resistance, low smoke and halogen-free flame retardancy, and environmental protection. At present, the insulation and sheath materials for cables used in energy storage systems mainly include PVC materials, TPE materials, cross-linked elastomers, and cross-linked polyolefin materials. Among them, polyolefins have the characteristics of low relative density, corrosion resistance, good water resistance, and electrical insulation, and are widely used in the cable industry. However, as a polymer organic material, polyolefins have poor flame retardant properties and are very easy to burn when encountering open flames, which seriously endangers people's lives and property safety.

[0004] In the prior art, halogen-free low-smoke polyolefin flame-retardant cable materials are environmentally friendly flame-retardant cable materials developed to meet the characteristics of halogen-free, non-toxic, low smoke emission, and flame retardancy. It is a cable material made by blending, plasticizing, and granulating olefin polymers as a base material, and inorganic materials containing crystalline water such as aluminum hydroxide and magnesium hydroxide as flame retardants. However, existing low-smoke, halogen-free, flame-retardant polyolefin cable materials often have contradictions that are difficult to balance between various properties. For example, if the flame retardant properties of the material are to be improved, a large amount of flame retardants must be added, and its mechanical properties, electrical properties, low temperature resistance, and softness will inevitably be affected; to meet the requirements of high temperature life, acid and alkali resistance, etc., sufficient cross-linking degree is required, and an increase in the cross-linking degree will reduce its toughness, affecting mechanical properties and softness. Therefore, how to meet the various physical and chemical properties required for this type of cable and good processing technology performance is an urgent problem to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a flame retardant energy storage cable and a preparation method thereof, to solve the following technical problems:

[0006] Existing flame-retardant energy storage cables have problems such as insufficient flame retardancy and difficulty in balancing flame retardancy and toughness.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A flame-retardant energy storage cable, comprising, from the inside to the outside, a copper wire bundle stranded conductor, an insulating layer, a shielding layer and an outer sheath, wherein the outer sheath material forming the outer sheath comprises at least the following raw materials in parts by weight: 45-65 parts of an olefin copolymer, 15-20 parts of a filler, 15-25 parts of a composite flame retardant, 0.1-0.5 parts of an antioxidant, and 0.4-0.8 parts of a lubricant; wherein the composite flame retardant is a magnesium-aluminum layered double hydroxide-arginine-ammonium polyphosphate composite flame retardant;

[0009] The preparation method of the composite flame retardant comprises the following steps:

[0010] Dissolving magnesium salt and aluminum salt in deionized water to prepare a magnesium-aluminum salt solution;

[0011] Dissolve arginine in deionized water to prepare an alkaline solution;

[0012] Add ammonium polyphosphate to the magnesium aluminum salt solution to obtain a mixed solution, add the mixed solution to the alkaline solution to form a mixed reaction system, and continuously stir in a water bath at 80-85° C. for 20-24 hours. After stirring, repeatedly wash with deionized water and centrifuge for 3 times, and low-temperature dry at 50-60° C. to obtain a composite flame retardant.

[0013] As a further solution of the present invention: the mass percentage of the magnesium aluminum layered double hydroxide in the composite flame retardant is 55-75%, the mass percentage of the arginine is 10-15%, and the mass percentage of the ammonium polyphosphate is 15-30%.

[0014] As a further embodiment of the present invention: the mass ratio of magnesium salt to aluminum salt in the magnesium-aluminum salt solution is 2-3:1, and the magnesium salt is MgCl2·6H2O, the aluminum salt is AlCl3·6H2O, and the concentration of the alkaline solution is 0.02-0.03 g / mL.

[0015] As a further solution of the present invention: the mass ratio of the ammonium polyphosphate to the arginine in the mixed reaction system is 1:8-15.

[0016] As a further solution of the present invention: the preparation method of the outer sheath material comprises at least the following steps:

[0017] Prepare raw materials according to weight, add all raw materials into a mixer and mix evenly to obtain a mixture;

[0018] The mixed material is added into a twin-screw extruder and extruded at 120-140° C., and the extruded particles are irradiated to obtain the outer protective layer material.

[0019] As a further embodiment of the present invention: the olefin copolymer is selected from one or more of thermoplastic elastomer, linear low-density polyethylene, high-density polyethylene or ethylene-vinyl acetate copolymer, and the filler is selected from one or more of nano calcium carbonate, calcined kaolin, silica lime, fumed silica or talc.

[0020] As a further embodiment of the present invention: the antioxidant is selected from one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, tris[2.4-di-tert-butylphenyl]phosphite, disteardithiodipropionate, dilaurylthiodipropionate, 4.4'-bis(α.α-dimethylbenzyl)diphenylamine or 4,4'-thiobis(6-tert-butyl-3-methylphenol), and the lubricant is selected from one or more of zinc stearate, calcium stearate, magnesium stearate, polyethylene wax or ethylene bisstearamide.

[0021] A method for preparing a flame-retardant energy storage cable as described in any one of the above, comprising at least the following steps:

[0022] An insulating layer is formed on the surface of the copper wire bundle stranded conductor, and then a shielding layer is formed on the insulating layer. Finally, an outer sheath material is formed on the shielding layer to form an outer sheath.

[0023] As a further solution of the present invention: the copper wire bundle stranded conductor is a tinned copper wire stranded soft structure conductor, the insulating layer is a ceramic silicone rubber insulating layer, and the shielding layer is a tinned braided shielding layer.

[0024] Beneficial effects of the present invention:

[0025] In this application, magnesium aluminum layered double hydroxide and ammonium polyphosphate are compounded with arginine as a flame retardant, and are cross-linked with olefin copolymers, fillers, antioxidants and lubricants to prepare outer sheath materials, thereby preparing flame-retardant energy storage cables. Magnesium aluminum layered double hydroxide and ammonium polyphosphate have synergistic flame retardant effects in terms of heat release and smoke suppression performance. They can form a continuous carbon layer with high heat resistance and release non-combustible gases, reduce the concentration of combustible volatiles, and play a condensed phase and gas phase flame retardant effect. The added arginine can improve the dispersibility of magnesium aluminum layered double hydroxide and ammonium polyphosphate in the olefin copolymer matrix, which is beneficial to improving the heat resistance of the outer sheath, and also effectively improves the tensile strength and bending strength of the outer sheath. The flame-retardant energy storage cable prepared by the present application comprises a copper wire bundle twisted conductor, an insulating layer, a shielding layer and an outer sheath arranged in sequence. The copper wire bundle twisted conductor is a tinned copper wire stranded soft structure conductor, the insulating layer is a ceramic silicone rubber insulating layer, which has a good effect of resisting mechanical impact and isolating the cable core from external high temperature, the shielding layer is a tinned braided shielding layer, and the outer sheath is a radiation cross-linked polyolefin outer sheath. The flame-retardant energy storage cable prepared by the present application has high flame retardancy, and the tensile strength and bending strength are also improved, which can meet the requirements of mechanical properties, high softness, electrical insulation performance, flame retardancy, low smoke performance, life aging performance, acid and alkali resistance, low temperature resistance and processing technology performance of the energy storage cable.

[0026] The present application adopts the method of co-precipitation and aging to prepare the composite flame retardant. The ammonium polyphosphate in the composite flame retardant is a flame retardant containing two flame retardant elements, nitrogen and phosphorus. The nitrogen element forms non-combustible gases such as CO2, NO2, and NH3 when heated, which can dilute the combustible gas, isolate the polymer from the oxygen in the air, and effectively prevent combustion. The phosphorus element reacts with the substrate to undergo a highly dehydrated carbonization reaction to form a stable insulating carbonized layer to isolate heat and oxygen and play a highly efficient flame retardant role. The formation of this high thermal stability and high-quality carbon layer further hinders the heat and fuel in the combustion zone, and hinders the release of combustible gases, thereby preventing further combustion of the polymer matrix, while exerting a condensed phase and gas phase flame retardant effect. In the present application, ammonium polyphosphate is modified by arginine, and by adding a sufficient amount of a composite flame retardant, the compatibility and dispersibility of the arginine-modified ammonium polyphosphate in an olefin polymer matrix are increased, the interaction force between molecules is increased, the probability of slippage between olefin molecular chains is reduced to a certain extent, and the mechanical properties of the polyethylene composite material are effectively improved. In addition, a sufficient amount of the composite flame retardant can effectively improve the tensile strength and bending strength of the composite material while ensuring the flame retardancy of the outer protective layer.

[0027] In the preparation process of the composite flame retardant of the present application, arginine is also used as an alkali source, so that the generated magnesium aluminum layered double hydroxide is a hexagonal two-dimensional nanosheet. In the flame retardant process of the composite flame retardant, the magnesium aluminum layered double hydroxide and ammonium polyphosphate have a synergistic flame retardant effect. Ammonium polyphosphate catalyzes the rapid decomposition of the magnesium aluminum layered double hydroxide when heated, reduces the surface temperature through endothermic effect, and releases CO2 and water vapor to dilute the concentration of combustible gas and weaken the fire. The composite flame retardant gas phase flame retardant produces a "cooling effect" and "dilution effect" working together. At the same time, nanoscale layered double hydroxide is a type of inorganic two-dimensional nanomaterial with a special spatial structure and interlayer ion exchangeability and properties similar to molecular sieves. It can be directly used as a rigid support for the flame retardant expansion layer, giving the material special flame retardant and smoke suppression properties, and does not contain any toxic substances. In the present application, arginine is used as an alkali source to generate nanosheet magnesium aluminum layered double hydroxide with high dispersion and relatively uniform particle size. The nanoscale dispersed magnesium aluminum layered double hydroxide flakes have strong barrier properties in the olefin polymer matrix. The polymer molecular chains entering the magnesium aluminum layered double hydroxide flakes restrict the polymer molecular chains entering the interlayers, thereby improving the flame retardant and smoke suppression properties of the polymer while also improving the heat resistance of the material. DETAILED DESCRIPTION

[0028] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example 1 The preparation method of the composite flame retardant comprises the following steps:

[0030] Weigh 5.5 g of MgCl2·6H2O and 2 g of AlCl3·6H2O and dissolve them in 100 mL of deionized water to prepare a magnesium-aluminum salt solution; weigh 12 g of arginine and dissolve it in 400 mL of deionized water to prepare an alkaline solution;

[0031] Add 2 g of ammonium polyphosphate to the above-mentioned magnesium aluminum salt solution to obtain a mixed solution, add the mixed solution to the above-mentioned saline-alkali solution, and stir continuously for 24 hours in a water bath at 80°C under N2 protection. After stirring, wash repeatedly with deionized water and centrifuge for 3 times, and dry at low temperature at 60°C to obtain a composite flame retardant.

[0032] Example 2 Preparation method of composite flame retardant The preparation method comprises the following steps:

[0033] Weigh 6 g of MgCl2·6H2O and 2 g of AlCl3·6H2O and dissolve them in 100 mL of deionized water to prepare a magnesium-aluminum salt solution; weigh 13.5 g of arginine and dissolve it in 400 mL of deionized water to prepare an alkaline solution;

[0034] Add 3 g of ammonium polyphosphate to the above magnesium aluminum salt solution to obtain a mixed solution, add the mixed solution to the above saline-alkali solution, and stir continuously for 24 hours in a water bath at 80°C under N2 protection. After stirring, wash repeatedly with deionized water and centrifuge for 3 times, and dry at 60°C to obtain a composite flame retardant.

[0035] Embodiment 3 The method for preparing the outer sheath material comprises the following steps:

[0036] 64 parts by mass of olefin copolymer, 15 parts by mass of filler, 20 parts by mass of the composite flame retardant prepared in Example 1, 0.4 parts by mass of antioxidant, and 0.6 parts by mass of lubricant are added into a mixer and mixed evenly to obtain a mixture;

[0037] The mixed material is added into a twin-screw extruder and extruded at 120-140° C., and the extruded particles are irradiated to obtain an outer protective layer material.

[0038] The preparation method of the flame-retardant energy storage cable comprises the following steps:

[0039] A ceramic silicone rubber insulation layer is formed on the surface of a tinned copper wire stranded soft structure conductor;

[0040] A tinned wire braided layer is formed on the surface of the insulating layer to form a shielding layer;

[0041] The outer protective layer material prepared in this embodiment is then applied on the surface of the shielding layer to form an outer protective layer.

[0042] Embodiment 4 The method for preparing the outer sheath material comprises the following steps:

[0043] 64 parts by mass of olefin copolymer, 15 parts by mass of filler, 20 parts by mass of the composite flame retardant prepared in Example 2, 0.4 parts by mass of antioxidant, and 0.6 parts by mass of lubricant are added into a mixer and mixed evenly to obtain a mixture;

[0044] The mixed material is added into a twin-screw extruder and extruded at 120-140° C., and the extruded particles are irradiated to obtain an outer protective layer material.

[0045] In the preparation steps of the flame-retardant energy storage cable, compared with Example 3, this example only replaces the outer sheath material prepared in Example 3 and the like added in Example 3 with the outer sheath material prepared in this example, and the other components and preparation methods are exactly the same as those in Example 3.

[0046] Embodiment 5 The method for preparing the outer sheath material comprises the following steps:

[0047] 56 parts by mass of olefin copolymer, 18 parts by mass of filler, 25 parts by mass of the composite flame retardant prepared in Example 1, 0.4 parts by mass of antioxidant, and 0.6 parts by mass of lubricant are added into a mixer and mixed evenly to obtain a mixture;

[0048] The mixed material is added into a twin-screw extruder and extruded at 120-140° C., and the extruded particles are irradiated to obtain an outer protective layer material.

[0049] In the preparation steps of the flame-retardant energy storage cable, compared with Example 3, this example only replaces the mass of the outer sheath material prepared in Example 3 added in Example 3 with the outer sheath material prepared in this example, and the other components and preparation methods are exactly the same as those in Example 3.

[0050] Embodiment 6 The method for preparing the outer sheath material comprises the following steps:

[0051] 56 parts by mass of olefin copolymer, 18 parts by mass of filler, 25 parts by mass of the composite flame retardant prepared in Example 2, 0.4 parts by mass of antioxidant, and 0.6 parts by mass of lubricant are added into a mixer and mixed evenly to obtain a mixture;

[0052] The mixed material is added into a twin-screw extruder and extruded at 120-140° C., and the extruded particles are irradiated to obtain an outer protective layer material.

[0053] In the preparation steps of the flame-retardant energy storage cable, compared with Example 3, this example only replaces the mass of the outer sheath material prepared in Example 3 added in Example 3 with the outer sheath material prepared in this example, and the other components and preparation methods are exactly the same as those in Example 3.

[0054] Comparative Example 1 The preparation method of the flame retardant comprises the following steps:

[0055] 2 g of arginine and 4 g of ammonium polyphosphate were dissolved in 400 mL of deionized water. Under N2 protection, the mixture was stirred continuously in a water bath at 80 °C for 24 h. After stirring, the mixture was repeatedly washed with deionized water and centrifuged three times. The mixture was low-temperature dried at 60 °C to obtain a flame retardant.

[0056] In the preparation step of the outer sheath material, compared with Example 3, this comparative example only replaces the mass of the composite flame retardant prepared in Example 3 added in Example 3 with the flame retardant prepared in this comparative example, and the remaining components and preparation method are exactly the same as those in Example 3.

[0057] In the preparation steps of the flame-retardant energy storage cable, compared with Example 3, this comparative example only replaces the mass of the outer sheath material prepared in Example 3 added in Example 3 with the outer sheath material prepared in this comparative example, and the other components and preparation method are exactly the same as those in Example 3.

[0058] Comparative Example 2 The preparation method of the flame retardant comprises the following steps:

[0059] Weigh 6 g of MgCl2·6H2O and 2.5 g of AlCl3·6H2O and dissolve them in 100 mL of deionized water to prepare a magnesium-aluminum salt solution; weigh 12 g of arginine and dissolve it in 400 mL of deionized water to prepare an alkaline solution;

[0060] The magnesium aluminum salt solution was added to the above saline-alkali solution, and stirred continuously for 24 hours in a water bath at 80°C under N2 protection. After stirring, the solution was repeatedly washed and centrifuged with deionized water for 3 times, and low-temperature dried at 60°C to obtain a flame retardant.

[0061] In the preparation step of the outer sheath material, compared with Example 3, this comparative example only replaces the mass of the composite flame retardant prepared in Example 3 added in Example 3 with the flame retardant prepared in this comparative example, and the remaining components and preparation method are exactly the same as those in Example 3.

[0062] In the preparation steps of the flame-retardant energy storage cable, compared with Example 3, this comparative example only replaces the mass of the outer sheath material prepared in Example 3 added in Example 3 with the outer sheath material prepared in this comparative example, and the other components and preparation method are exactly the same as those in Example 3.

[0063] Comparative Example 3 In the preparation steps of the composite flame retardant, the components and the preparation method are completely consistent with those in Example 3.

[0064] The method for preparing the outer sheath material comprises the following steps:

[0065] 74 parts by mass of olefin copolymer, 15 parts by mass of filler, 10 parts by mass of the composite flame retardant prepared in Example 1, 0.4 parts by mass of antioxidant, and 0.6 parts by mass of lubricant are added into a mixer and mixed evenly to obtain a mixture;

[0066] The mixed material is added into a twin-screw extruder and extruded at 120-140°C, and the extruded particles are irradiated to obtain the outer sheath material.

[0067] In the preparation steps of the flame-retardant energy storage cable, compared with Example 3, this comparative example only replaces the mass of the outer sheath material prepared in Example 3 added in Example 3 with the outer sheath material prepared in this comparative example, and the other components and preparation method are exactly the same as those in Example 3.

[0068] Comparative Example 4 The preparation method of the flame retardant comprises the following steps:

[0069] 2 g of ammonium polyphosphate and 7 g of magnesium aluminum layered double hydroxide were directly mixed to obtain a flame retardant.

[0070] In the preparation step of the outer sheath material, compared with Example 3, this comparative example only replaces the mass of the composite flame retardant prepared in Example 3 added in Example 3 with the flame retardant prepared in this comparative example, and the remaining components and preparation method are exactly the same as those in Example 3.

[0071] In the preparation steps of the flame-retardant energy storage cable, compared with Example 3, this comparative example only replaces the mass of the outer sheath material prepared in Example 3 added in Example 3 with the outer sheath material prepared in this comparative example, and the other components and preparation method are exactly the same as those in Example 3.

[0072] Performance Testing

[0073] The limiting oxygen index (LOI) test was carried out according to GB / T 2406-2008, and the outer sheath specimens obtained in Examples 3-6 and Comparative Examples 1-4 were tested using a Jiangning HC-2 oxygen index analyzer; the test results are shown in Table 1;

[0074] Vertical combustion test: According to GB / T 2408-2008, the outer sheath specimens obtained in Examples 3-6 and Comparative Examples 1-4 were subjected to UL-94 vertical combustion test using Jiangning CZF-III vertical combustion test machine; the test results are shown in Table 1;

[0075] Mechanical properties test: The tensile strength and fracture growth rate of the outer sheath specimens obtained in Examples 3-6 and Comparative Examples 1-4 were tested in accordance with GB / T 2567-2008; the test results are shown in Table 1;

[0076] Table 1: Statistical table of performance test data of test pieces of Examples 3-6 and Comparative Examples 1-4

[0077]

[0078] As can be seen from Table 1, the magnesium aluminum layered double hydroxide-arginine-ammonium polyphosphate obtained in the present application is used as a composite flame retardant to prepare the outer sheath of the energy storage cable, which gives the energy storage cable excellent flame retardant properties, and while the flame retardant properties are improved, the mechanical properties are also improved. In Comparative Example 1, arginine-modified ammonium polyphosphate is used as a modifier, and in Comparative Example 2, arginine is used as an alkali source to prepare the magnesium aluminum layered double hydroxide, the mechanical properties of the obtained outer sheath are improved, but the flame retardant properties are not greatly improved. In Comparative Example 3, less composite flame retardant is added, and in Comparative Example 4, ammonium polyphosphate and magnesium aluminum layered double hydroxide are simply mixed to prepare a flame retardant, and the mechanical properties of the obtained outer sheath are greatly reduced, and the flame retardant properties are not improved.

[0079] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A flame-retardant energy storage cable, characterized in that: The invention comprises, from the inside to the outside, a copper wire bundle stranded conductor, an insulating layer, a shielding layer and an outer sheath, wherein the outer sheath material forming the outer sheath comprises at least the following raw materials in parts by weight: 45-65 parts of an olefin copolymer, 15-20 parts of a filler, 15-25 parts of a composite flame retardant, 0.1-0.5 parts of an antioxidant, and 0.4-0.8 parts of a lubricant; wherein the composite flame retardant is a magnesium aluminum layered double hydroxide-arginine-ammonium polyphosphate composite flame retardant; The preparation method of the composite flame retardant comprises the following steps: Dissolving magnesium salt and aluminum salt in deionized water to prepare a magnesium-aluminum salt solution; Dissolve arginine in deionized water to prepare an alkaline solution; Adding ammonium polyphosphate to the magnesium aluminum salt solution to obtain a mixed solution, adding the mixed solution to the alkaline solution to form a mixed reaction system, stirring continuously in a water bath at 80-85° C. for 20-24 hours, and after the stirring is completed, repeatedly washing with deionized water and centrifuging for 3 times, and low-temperature drying at 50-60° C. to obtain a composite flame retardant; The mass ratio of magnesium salt to aluminum salt in the magnesium-aluminum salt solution is 2-3:1, the magnesium salt is MgCl2·6H2O, the aluminum salt is AlCl3·6H2O, and the concentration of the alkaline solution is 0.02-0.03 g / mL; The mass ratio of the ammonium polyphosphate to the arginine in the mixed reaction system is 1:8-15.

2. The flame-retardant energy storage cable according to claim 1, characterized in that: The mass percentage of the magnesium aluminum layered double hydroxide in the composite flame retardant is 55-75%, the mass percentage of arginine in the composite flame retardant is 10-15%, and the mass percentage of ammonium polyphosphate in the composite flame retardant is 15-30%.

3. The flame-retardant energy storage cable according to claim 1, characterized in that: The method for preparing the outer sheath material comprises at least the following steps: Prepare raw materials according to the weight of the components, add all the raw materials into a mixer and mix them evenly to obtain a mixture; The mixed material is added into a twin-screw extruder and extruded at 120-140° C., and the extruded particles are irradiated to obtain the outer protective layer material.

4. The flame-retardant energy storage cable according to claim 1, characterized in that: The olefin copolymer is selected from one or more of thermoplastic elastomer, linear low-density polyethylene, high-density polyethylene or ethylene-vinyl acetate copolymer, and the filler is selected from one or more of nano calcium carbonate, calcined kaolin, silica lime, fumed silica or talc.

5. The flame-retardant energy storage cable according to claim 1, characterized in that: The antioxidant is selected from one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, tris[2.4-di-tert-butylphenyl]phosphite, distearyl thiodipropionate, dilauryl thiodipropionate, 4.4'-bis(α.α-dimethylbenzyl)diphenylamine or 4,4'-thiobis(6-tert-butyl-3-methylphenol), and the lubricant is selected from one or more of zinc stearate, calcium stearate, magnesium stearate, polyethylene wax or ethylene bisstearamide.

6. A method for preparing a flame-retardant energy storage cable as claimed in any one of claims 1 to 5, characterized in that: At least the following steps are included: An insulating layer is formed on the surface of the copper wire bundle stranded conductor, and then a shielding layer is formed on the insulating layer. Finally, an outer sheath material is formed on the shielding layer to form an outer sheath.

7. The method for preparing a flame-retardant energy storage cable according to claim 6, characterized in that: The copper wire bundle stranded conductor is a tinned copper wire stranded soft structure conductor, the insulating layer is a ceramic silicone rubber insulating layer, and the shielding layer is a tinned braided shielding layer.

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