A method for preparing a high-voltage cable in a new energy electric vehicle

Abstract

The invention discloses a high-voltage cable in a new energy electric vehicle and a preparation method thereof, comprising a conductor arranged inside the cable, the conductor being formed by multiple layers of strands being twisted, the strands being formed by a plurality of tinned copper wires being bundled, the direction of the strands being bundled being opposite to the direction of the strands being twisted, and the bundle pitch-diameter ratio being controlled within 20-25 times; a high-temperature resistant 180°C high-tear-resistant mixed silicone rubber insulation layer being extruded outside the conductor, a first high-temperature resistant isolation layer being wrapped outside the high-temperature resistant 180°C high-tear-resistant mixed silicone rubber insulation layer being wrapped, a shielding layer that can also serve as a negative electrode core being wrapped outside the first high-temperature resistant isolation layer in a sparsely wound manner, a second high-temperature resistant isolation layer being wrapped outside the shielding layer, and a high-temperature resistant 180°C high-tear-resistant mixed silicone rubber sheath layer being extruded outside the second high-temperature resistant isolation layer. The cable has the advantages of large transmission capacity, high temperature resistance, flexibility and tear resistance, bending resistance, cracking resistance, and good solvent corrosion resistance.

Description

Technical Field

[0001] The present invention relates to a method for preparing a novel in-vehicle high-voltage cable for new energy electric vehicles, which is mainly used as a connecting line for an in-vehicle high-voltage power system of a new energy electric vehicle with a rated voltage of DC1500V / AC1000 or below. Background Art

[0002] With the rapid development of my country's economy and the improvement of people's living standards, cars have gradually become common products entering thousands of households. It can be expected that in the near future, more and more families will own cars, and some families will even own more than two cars. Due to the sharp increase in traditional gasoline cars, the problem of air pollution caused by exhaust emissions has become more and more serious. New energy electric vehicles have developed rapidly with their energy saving and environmental protection. In recent years, with the breakthrough of new energy vehicle technology bottlenecks, its market has developed rapidly. As an important supporting product of new energy electric vehicles, although the high-voltage cables in new energy electric vehicles have developed rapidly in recent years and their performance has been continuously improved, there are still problems such as heavy cable body weight, poor flexibility and bending performance, cracking, and high temperature resistance. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a high-voltage cable for new energy electric vehicles with large transmission capacity, high temperature resistance, flexibility, tear resistance, bending resistance, crack resistance and solvent corrosion resistance.

[0004] The invention also discloses a method for preparing a novel high-voltage cable in a new energy electric vehicle.

[0005] To achieve the above objectives, the present invention adopts the following technical scheme: a high-voltage cable for a new energy electric vehicle, comprising a conductor arranged inside the cable, the conductor being twisted by multiple layers of strands, the strands being bundled by multiple tinned copper wires, the direction of the strands being bundled is opposite to the direction of the strands being twisted, and the bundle pitch-diameter ratio being controlled within 20-25 times; a high-temperature 180°C tear-resistant mixed silicone rubber insulation layer being extruded outside the conductor, a first high-temperature resistant isolation layer being wrapped outside the high-temperature 180°C tear-resistant mixed silicone rubber insulation layer, a shielding layer which can also serve as a negative electrode core being wrapped outside the first high-temperature resistant isolation layer in a sparsely wound manner, a second high-temperature resistant isolation layer being wrapped outside the shielding layer, and a high-temperature 180°C tear-resistant mixed silicone rubber sheath layer being extruded outside the second high-temperature resistant isolation layer.

[0006] As a further improvement, the conductor adopts Category 6 soft tinned conductor specified in GB / T3956-2008, whose single wire diameter is thinner than that of Category 6 soft conductor, with a single wire diameter of no more than 0.16 mm, and has more strands. At the same time, the bundling direction of each layer of strands is opposite to the twisting direction, thereby maintaining both the flexibility of the conductor and the stability of the structure.

[0007] As a further improvement, the conductor is formed by twisting three layers of strands, the twisting direction of each layer is opposite to the strand bundle direction of the layer, the pitch diameter ratio of the outermost layer is controlled at 10-14 times, and the pitch diameter ratio of the inner layer is controlled at 14-22 times.

[0008] As a further improvement, the first high temperature resistant isolation layer and the second high temperature resistant isolation layer are both ceramic silicone rubber belts.

[0009] As a further improvement, the shielding layer is composed of a plurality of bundled twisted soft copper strands, the gap between the plurality of bundled twisted soft copper strands is no more than 3 mm, the winding pitch-diameter ratio is controlled at 10 to 12 times, and the winding direction is left-handed.

[0010] As a further improvement, the soft copper strands are twisted from tinned soft copper wires with a diameter of 0.2-0.5 mm, the bundle diameter ratio is controlled at 15-20 times, and the direction is right-handed.

[0011] A method for preparing a high-voltage cable in a new energy electric vehicle comprises the following steps:

[0012] 1) First, the conductor adopts the 6 types of soft tinned conductors specified in GB / T3956-2008, and adopts copper wire monofilaments with a diameter not greater than 0.16mm. The conductor production goes through several stages of wire drawing, annealing, tinning, wire bundling and re-twisting. First, the thicker copper wire monofilament is drawn into the required ultra-fine copper wire through a wire drawing machine, and then the copper wire surface is tinned through a tinning process, and the copper wire is annealed while tinning; then the tinned copper wire is bundled through a wire bundling machine, and the bundling direction is opposite to the re-twisting direction of the layer of re-twisted conductors. If the re-twisting direction of the layer of re-twisted conductors is right-handed, then the wire bundling is left-handed, and the wire bundling pitch-diameter ratio is controlled within 20-25 times; finally, the bundled strands are subjected to multi-layer re-twisting to form a conductor, and the twisting direction of each layer of the re-twisted conductor is kept opposite to the wire bundling direction of the layer of strands, and the outermost layer pitch-diameter ratio is controlled between 10-14 times, and the inner layer pitch-diameter ratio is controlled between 14-22 times;

[0013] 2) Extruded insulation layer: First, mix the original silicone rubber with 1.2% of 2,5-dimethyl-2,5-di-tert-butyl peroxyhexane vulcanizer on an open mill to ensure that the vulcanizer and silicone rubber are evenly mixed to obtain a mixed rubber. During this period, pay attention to the temperature of the roller of the open mill not exceeding 50°C, and cool it with cooling water in time. Then, the mixed rubber is evenly extruded on the conductor through a rubber extruder to form a wire core, and continuously vulcanized through a high-temperature and high-pressure steam pipeline; during the extrusion process, pay attention to the control of the temperature of the rubber extruder barrel, cool it with cooling water in time, and open the valve to pass water steam when the wire core passes through the vulcanization pipeline. The air pressure is controlled between 0.8 and 1.2 MPa, and the line speed is controlled between 11 and 17 m / min. Appropriate adjustments are made according to the designed thickness of the insulation layer to ensure sufficient vulcanization;

[0014] 3) The ceramic silicone rubber tape is tightly wrapped around the insulating core to form a first high temperature resistant isolation layer;

[0015] 4) The tinned soft copper wire with a diameter of 0.2~0.5mm is bundled and twisted into strands through a wire bundling machine. The specific number of strands can be determined according to the cross-sectional design of the negative conductor. The bundled wire pitch-diameter ratio is controlled between 15 and 20 times, and the direction is right-handed; then the bundled strands are evenly wound on the isolation layer through a metal wire armoring machine. The strands are evenly distributed, the gap is not more than 3mm, the winding pitch-diameter ratio is controlled between 10 and 12 times, and the winding direction is left-handed to form a shielding layer;

[0016] 5) Overlap the ceramic silicone rubber tape outside the shielding layer, with the overlap rate controlled between 10% and 20%. The wrapping direction is right, opposite to the winding direction of the shielding copper wire, to form a second high temperature resistant isolation layer;

[0017] 6) A high temperature resistant 180°C high tear resistant mixed silicone rubber sheath layer is extruded on the second high temperature resistant isolation layer. The specific production process is the same as the process of extruding the high temperature resistant 180°C high tear resistant mixed silicone rubber insulation layer in step 2).

[0018] The beneficial effects of the present invention are:

[0019] The conductor of the present invention adopts the sixth type of soft conductor specified in GB / T3956-2008. At the same time, since the bundle direction of each layer of strands is opposite to the re-twisting direction, the flexibility of the conductor is ensured on the one hand, and the stability of the conductor is ensured on the other hand, and it is not easy to be flattened and deformed, and the roundness of the cable is maintained;

[0020] The insulation uses high-temperature 180°C high-tear-resistant compound silicone rubber. First of all, the long-term working temperature of this material reaches 180°C. Compared with the ordinary thermoplastic elastomer cable with a long-term working temperature of 70°C or 90°C, the working temperature is increased by more than 110°C. In this way, only a smaller cable cross-section is needed to transmit the same current, which can effectively reduce the weight of the cable and thus reduce the weight of the entire car. At the same time, the silicone rubber material has high tear resistance and flexibility, which can meet the needs of long-term bending use without cracking; in general, the cable's heat resistance and long-term working safety and reliability are greatly improved compared to conventional thermoplastic elastomer cables. The production of the cable insulation and sheath adopts a high-temperature and high-pressure steam continuous vulcanization process. Compared with the conventional hot drying or boiling process, the quality of the cable insulation and sheath is guaranteed;

[0021] The cable's isolation layer is made of high-temperature resistant ceramic silicone rubber material, which not only has excellent insulation performance and plays an isolation role, but also has a heat-resistant temperature of more than 180°C, which is consistent with the cable's operating temperature, and also has a fire-proof function;

[0022] The shielding of the cable changes the traditional braided shielding method and adopts the strand winding method; first of all, the shielding method of strand winding not only has the same shielding effect as braided shielding, but also meets the needs of cable electromagnetic compatibility. At the same time, the shielding layer adopts strand bundle twisting and then winding multiple strands of strands. A larger cross-section can be designed, and its effective shielding cross-section can be close to or reach the conductor cross-section, which can be used as a negative pole or neutral wire. This can reduce the use of one cable, so that one cable can achieve the effect of two cables, which can effectively save the interior space of the car and further reduce the weight of the cable, thereby reducing the design weight of the entire vehicle and achieving the lightweight design goal of the car. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the present invention. DETAILED DESCRIPTION

[0024] like Figure 1 As shown, a high-voltage cable for a new energy electric vehicle includes a conductor arranged inside the cable, wherein the conductor 1 is formed by twisting multiple layers of strands, wherein the strands are bundled by multiple tinned copper wires, and the direction of the bundle is opposite to the direction of the strands twisting, and the bundle pitch ratio is controlled within 20-25 times;

[0025] A high temperature resistant 180°C high tear resistant mixed silicone rubber insulation layer 2 is extruded outside the conductor, a first high temperature resistant isolation layer 3 is wrapped outside the high temperature resistant 180°C high tear resistant mixed silicone rubber insulation layer, a shielding layer 4 which can also serve as a negative electrode core is wound in a sparse winding manner outside the first high temperature resistant isolation layer, a second high temperature resistant isolation layer 5 is wrapped outside the shielding layer, and a high temperature resistant 180°C high tear resistant mixed silicone rubber sheath layer 6 is extruded outside the second high temperature resistant isolation layer.

[0026] A method for preparing a rail transit DC traction combined flexible cable, the specific steps are as follows:

[0027] 1) First, the conductor adopts the 6 types of soft tinned conductors specified in GB / T3956-2008, and adopts copper wire monofilaments with a diameter not greater than 0.16mm. The conductor production goes through several stages of wire drawing, annealing, tinning, wire bundling and re-twisting. First, the thicker copper wire monofilament is drawn into the required ultra-fine copper wire through a wire drawing machine, and then the copper wire surface is tinned through a tinning process, and the copper wire is annealed while tinning; then the tinned copper wire is bundled through a wire bundling machine, and the bundling direction is opposite to the re-twisting direction of the layer of re-twisted conductors. If the re-twisting direction of the layer of re-twisted conductors is right-handed, then the wire bundling is left-handed, and the wire bundling pitch-diameter ratio is controlled within 20-25 times; finally, the bundled strands are subjected to multi-layer re-twisting to form a conductor, and the twisting direction of each layer of the re-twisted conductor is kept opposite to the wire bundling direction of the layer of strands, and the outermost layer pitch-diameter ratio is controlled between 10-14 times, and the inner layer pitch-diameter ratio is controlled between 14-22 times;

[0028] 2) Extruded insulation layer: First, mix the original silicone rubber with 1.2% of 2,5-dimethyl-2,5-di-tert-butyl peroxyhexane vulcanizer on an open mill to ensure that the vulcanizer and silicone rubber are evenly mixed to obtain a mixed rubber. During this period, pay attention to the temperature of the roller of the open mill not exceeding 50°C, and cool it with cooling water in time. Then, the mixed rubber is evenly extruded on the conductor through a rubber extruder to form a wire core, and continuously vulcanized through a high-temperature and high-pressure steam pipeline; during the extrusion process, pay attention to the control of the temperature of the rubber extruder barrel, cool it with cooling water in time, and open the valve to pass water steam when the wire core passes through the vulcanization pipeline. The air pressure is controlled between 0.8 and 1.2 MPa, and the line speed is controlled between 11 and 17 m / min. Appropriate adjustments are made according to the designed thickness of the insulation layer to ensure sufficient vulcanization;

[0029] 3) The ceramic silicone rubber tape is tightly wrapped around the insulating core to form a first high temperature resistant isolation layer;

[0030] 4) The tinned soft copper wire with a diameter of 0.2~0.5mm is bundled into strands through a wire bundling machine. The specific number of strands can be determined according to the cross-sectional design of the negative conductor. For example: the main line conductor is 50mm 2 , the insulation outer diameter is 13.0mm, the wrapping outer diameter is 13.5mm, and the negative conductor is also required to be 50mm 2 , then the negative conductor design structure is: 19*21*0.4mm, that is, the number of strands is 19, the number of monofilaments per strand is 21, and the calculated cross-section is 50.1mm 2 , the wire winding gap is 0.47mm, the wire bundle pitch ratio is controlled between 15 and 20 times, and the direction is right-handed; then the bundled wires are evenly wound on the isolation layer through a metal wire armoring machine, the wires are evenly arranged, the gap is no more than 3mm, the winding pitch ratio is controlled between 10 and 12 times, and the winding direction is left-handed to form a shielding layer;

[0031] 5) Overlap the ceramic silicone rubber tape outside the shielding layer, with the overlap rate controlled between 10% and 20%. The wrapping direction is right, opposite to the winding direction of the shielding copper wire, to form a second high temperature resistant isolation layer;

[0032] 6) A high temperature resistant 180°C high tear resistant mixed silicone rubber sheath layer is extruded on the second high temperature resistant isolation layer. The specific production process is the same as the process of extruding the high temperature resistant 180°C high tear resistant mixed silicone rubber insulation layer in step 2).

[0033] The present invention has many specific application paths. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principle of the present invention. These improvements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a high-voltage cable in a new energy electric vehicle, characterized in that: The following steps are involved: 1) Preparing the conductor arranged in the cable: First, the conductor adopts the 6 types of soft tinned conductors specified in GB / T3956-2008, and adopts copper wire monofilaments with a diameter not greater than 0.16 mm. The conductor production goes through several stages of wire drawing, annealing, tinning, wire bundling, and re-twisting. The thicker copper wire monofilaments are first drawn into the required ultra-fine copper wires through a wire drawing machine, and then the copper wire surface is tinned through a tinning process, and the copper wire is annealed while being tinned; Then the tinned copper wire is bundled through a wire bundling machine, and the bundling direction is opposite to the re-twisting direction of the layer of double-twisted conductor. If the re-twisting direction of the layer of double-twisted conductor is right-handed, then the bundling is left-handed, and the bundle pitch ratio is controlled within 20-25 times; finally, the bundled strands are subjected to multi-layer re-twisting to form a conductor, and the twisting direction of each layer of the double-twisted conductor is kept opposite to the bundling direction of the layer of strands, and the outermost layer pitch ratio is controlled between 10-14 times, and the inner layer pitch ratio is controlled between 14-22 times; 2) Extruding a high-temperature 180°C resistant and tear-resistant mixed silicone rubber insulation layer on the outside of the conductor: First, the silicone rubber raw rubber and 1.2% of 2,5-dimethyl-2,5-di-tert-butyl peroxyhexane vulcanizer are mixed on an open mill to ensure that the vulcanizer and silicone rubber are evenly mixed to obtain a mixed rubber. During the process, it is noted that the temperature of the roller of the open mill does not exceed 50°C, and cooling water is passed in time to cool it down. Then, the mixed rubber is evenly extruded on the conductor through a rubber extruder to form a wire core, and continuously vulcanized through a high-temperature and high-pressure water vapor pipeline; During the extrusion process, attention should be paid to the control of the temperature of the rubber extruder barrel, and cooling water should be passed in time to cool it down. When the wire core passes through the vulcanization pipeline, the valve is opened in time to pass water vapor, and the air pressure is controlled between 0.8 and 1.2 MPa, and the line speed is controlled between 11 and 17 m / min. Appropriate adjustments are made according to the designed thickness of the insulation layer to ensure sufficient vulcanization; 3) The ceramic silicone rubber tape is tightly wrapped around the high temperature resistant 180° C. high tear resistance mixed silicone rubber insulation layer to form the first high temperature resistant isolation layer; 4) A shielding layer that can also serve as a negative electrode core is wound outside the first high-temperature resistant isolation layer in a sparse winding manner: tinned soft copper wires with a diameter of 0.2-0.5 mm are bundled and twisted into strands through a wire bundling machine. The specific number of strands can be determined according to the cross-sectional design of the negative electrode conductor. The bundled wire pitch-diameter ratio is controlled between 15 and 20 times, and the direction is right-handed; then the bundled strands are evenly wound on the isolation layer through a metal wire armoring machine. The strands are evenly arranged and distributed, the gap is not greater than 3 mm, the winding pitch-diameter ratio is controlled between 10 and 12 times, and the winding direction is left-handed to form the shielding layer; 5) Overlapping and wrapping the ceramic silicone rubber tape outside the shielding layer, with the overlap rate controlled between 10% and 20%, with the wrapping direction being right, opposite to the winding direction of the shielding copper wire, to form the second high temperature resistant isolation layer; 6) Extruding a high temperature resistant 180°C high tear resistant mixed silicone rubber sheath layer outside the second high temperature resistant isolation layer, the specific production process is the same as the process of extruding the high temperature resistant 180°C high tear resistant mixed silicone rubber insulation layer in step 2).

Images