Mineral insulation heating cable with pipeline for heating and cooling new energy automobile battery pack

Abstract

The invention discloses a mineral insulated heating cable with a pipeline for heating and cooling a battery pack of a new energy automobile. The cable sequentially comprises an outer sheath, an insulating layer, a heating wire core and the pipeline from outside to inside, the outer sheath and the pipeline are formed by integrally drawing and reducing seamless metal pipes; the insulating layer is made of a powdery mineral insulating material, is filled in the outer sheath, and is a compact whole formed by drawing, reducing and annealing; the heating wire core is made of an alloy material with high resistivity and high surface load so as to meet the requirement of higher heating efficiency; the pipeline is a cooling liquid guide pipe and is resistant to corrosion of chloride ions and sulfur ions. According to the invention, the heat dissipation and heating component functions of the new energy battery are integrated in the same component, and the single crystal silicon nitride is used as a high-temperature insulating material in the mineral cable, so that the materials of the pipe and the heating wire core are optimized, the structure is simplified, the space is saved, the mechanical strength is increased, and the application prospect is very good.

Description

Technical field:

[0001] The present invention relates to the field of cable technology, and in particular to a mineral insulated heating cable with pipelines for heating and cooling a battery pack of a new energy vehicle. Background technology:

[0002] With the vigorous promotion of new energy vehicles, the safety requirements for automotive power batteries are also constantly improving and perfecting. Due to the characteristics of lithium-ion batteries, their ideal operating temperature is between 0-45℃. If the temperature is less than 0℃, the battery performance will be greatly reduced and may even fail to charge normally. If the temperature is greater than 45℃, the battery is prone to thermal runaway, and if it is greater than 75℃, it may even explode and catch fire.

[0003] The existing lithium battery heating methods mainly include: 1. Heating by the charger. In a low temperature environment, the charger can only perform low-rate discharge heating. Therefore, it takes about 2 to 5 hours to slowly heat up before charging can be performed, which is relatively safe. The disadvantage is that this method can only be used in a fixed place and the required preheating time is relatively long; 2. Heating by electric heating plate. This low-temperature heating method of electric heating plate is to stick the corresponding heating plate on the side of the battery cell, and then connect and control it through the protection board. The heat generated by the electric heating plate is directly transferred to the battery. As the temperature rises, the resistance increases, thereby achieving the purpose of heating. The disadvantage is that this low-temperature heating method requires a large number of electric heating components and joints, with a high failure rate and low overall technical content.

[0004] The existing lithium battery heat dissipation methods mainly include: 1. Using air convection, relying on natural convection at vehicle speed or using fans to generate forced convection to remove battery heat, and the structure is simple. The disadvantage is that the space in the car is limited, the various arrangements of the battery pack are compact, the central part has poor contact with the outside world, and the heat dissipation effect is not obvious. When the battery discharge reaches a certain level and the external ambient temperature is high, even if the wind speed is increased, the battery temperature cannot continue to drop, and the cooling range is limited; 2. Using liquid exchange, the liquid cooling effect is stronger than air cooling. The disadvantage is that the structure is more complicated, and the liquid that can directly contact the battery generally has poor flow performance and unsatisfactory heat transfer effect. However, many liquids cannot be in direct contact with the battery, and the liquid needs to be wrapped. Arranging pipes between the batteries will greatly occupy the battery pack space and reduce the battery capacity. Summary of the invention:

[0005] In order to more effectively achieve battery insulation and heat dissipation and solve the problems existing in existing lithium battery temperature control components, the present invention provides a new type of mineral insulated heating cable material, structure, preparation method and installation structure of a mineral insulated heating cable with a pipeline and an integrated coolant conduit for heating and cooling a new energy vehicle battery pack.

[0006] The technical solution of the present invention is as follows: a mineral insulated heating cable with pipeline for heating and cooling a battery pack of a new energy vehicle, the cable comprising an outer sheath, an insulating layer, a heating core and a pipeline from the outside to the inside;

[0007] The outer sheath and pipeline are both formed by integral drawing and shrinking of seamless metal pipes;

[0008] The outer sheath protects the internal heating wire core and pipeline when the car bumps or collides unexpectedly during normal driving, and has high tensile strength, yield strength and melting point;

[0009] The insulating layer is made of powdered mineral insulating material, which is filled inside the outer sheath and formed into a dense whole after drawing, shrinking and annealing;

[0010] The heating wire core is made of alloy material with high resistivity and high surface load to meet the requirements of higher heating efficiency;

[0011] The pipeline is a coolant conduit, and the pipeline is resistant to chloride ion and sulfur ion corrosion.

[0012] The performance parameters of various commonly used high-temperature insulation materials are tested as follows:

[0013]

[0014]

[0015] Preferably, the insulating layer uses Si3N4 or single crystal α-Si3N4 as the insulating material.

[0016] A comprehensive analysis of copper-nickel alloys NC005, NC010, NC020; nickel-chromium alloys Cr15Ni60, Cr20Ni80, Cr30Ni70; iron-chromium-aluminum alloys 0Cr25Al5, 1C13Al4, 0Cr21Al6 electric heating alloys is conducted, while meeting the requirements of higher heating efficiency and taking into account the plasticity of the material, that is, the ductility required for mechanical drawing and shrinking, as well as the universality and economy of the material.

[0017]

[0018] Preferably, when the long-term operating temperature of the heating cable is ≥500°C, the heating core is made of copper-nickel alloy of NC005 or NC020.

[0019] Preferably, when the long-term operating temperature of the heating cable is ≥1000°C, the heating core is made of a nickel-chromium alloy of Cr20Ni80 or Cr15Ni60.

[0020] A method for preparing a mineral insulated heating cable with a pipeline for heating and cooling a battery pack of a new energy vehicle comprises the following steps:

[0021] S1. After design and selection, prepare the raw materials and clean them;

[0022] S2, firing a single crystal α-Si3N4 ceramic column as an insulating layer;

[0023] S3, assembling the heating wire core, pipeline, ceramic column and outer sheath embryo tube before drawing;

[0024] S4. Before drawing, the end is squeezed and compressed to facilitate entry into the steel mold;

[0025] S5. The first drawing process uses a linear drawing machine with a large deformation amount to initially compact the insulation layer and complete the coaxiality of the cable;

[0026] S6, annealing the semi-finished product to relieve stress in a tubular heating furnace;

[0027] S7, secondary drawing uses a combined drawing machine with a small deformation to complete the final shaping and mounting;

[0028] S8. Finished product inspection.

[0029] A mounting structure for a mineral insulated heating cable with a pipeline for heating and cooling a battery pack of a new energy vehicle comprises a battery pack shell and a bottom plate matched with the battery pack shell, wherein a battery cell is mounted in the battery pack shell, and the upper surface of the bottom plate is provided with evenly arranged continuous U-shaped grooves, and the mineral insulated cable with a pipeline is embedded in the continuous U-shaped grooves and forms a plate-type integral body with the bottom plate.

[0030] Preferably, the connection terminal of the mineral insulated cable with pipeline extends out of the bottom plate, and the extended end is connected to a control module.

[0031] The beneficial effects of the present invention are: integrating the heat dissipation and heating component functions of new energy batteries into the same component, using single crystal silicon nitride as a high-temperature insulating material in mineral cables, optimizing the pipe and heating wire core materials, simplifying the structure, saving space, and increasing mechanical strength, and having good application prospects. Description of the drawings:

[0032] Figure 1 It is a structural schematic diagram of the present invention;

[0033] Figure 2 The process flow chart of the method for preparing the mineral insulated cable with pipeline 8 of the present invention;

[0034] Figure 3 This is an installation structure diagram of a mineral insulated cable with pipeline 8 of the present invention;

[0035] Figure 4 It is a diagram of the installation structure of the base plate 6 and the mineral insulated cable with pipeline 8 in the present invention.

[0036] In the figure: 1. Outer sheath; 2. Insulation layer; 3. Heating wire core; 4. Pipeline; 5. Battery pack shell; 6. Bottom plate; 7. Battery cell; 8. Mineral insulated cable with pipeline; 9. Control module. Specific implementation method:

[0037] Combined with Figure 1 The present invention further describes a mineral insulated heating cable with pipelines for heating and cooling a battery pack of a new energy vehicle.

[0038] The present invention designs a special cable structure, which can integrate a heat dissipation pipeline while realizing efficient heating, so that a component can simultaneously meet the requirements of two working conditions of heat dissipation and heating of lithium batteries, and has the performance of high and low temperature resistance and impact resistance.

[0039] The cable comprises an outer sheath 1, an insulating layer 2, a heating core 3 and a pipeline 4 from the outside to the inside.

[0040] Cable material design:

[0041] ① Outer sheath 1 tube material and internal pipeline 4 material: seamless tubes are used for overall drawing and shrinking, wrapping the internal insulation layer and wire core, and are optimized from several aspects such as material strength, elongation, corrosion resistance, and high temperature melting point.

[0042] A. Outer sheath 1: It protects the internal wire core and pipeline when the car is bumped or accidentally collided during normal driving. It needs to have high tensile strength, yield strength and melting point. After comprehensive evaluation, duplex stainless steel S31083 (2205) is preferred as the material of the outer sheath 1.

[0043] B. Internal integrated pipeline 4: It is mainly used as a coolant conduit and needs to be resistant to chloride and sulfur ion corrosion. At the same time, it is required to be ductile when the insulation layer and outer sheath are drawn and reduced during product manufacturing. After comprehensive evaluation, duplex stainless steel S31603 (SUS316L) is selected as the material for pipeline 4.

[0044] Test results of performance parameters of various commonly used alloy pipes

[0045]

[0046]

[0047] ②Insulation layer 2 material: Mineral insulation material is used in powder form and filled inside the metal pipe sheath. After drawing, shrinking, annealing and other processes, it forms a dense whole similar to ceramic. It is selected from several mineral insulation materials with excellent insulation performance, chemical stability, thermal conductivity, high temperature stability and other aspects.

[0048] Traditional mineral insulated cables use magnesium oxide (MgO) as the insulation layer. Its advantages include excellent insulation performance, high temperature stability and good thermal conductivity.

[0049] However, in addition to having the above properties, the insulating material of the present invention also needs to meet the requirements of chemical stability to ensure that it does not react with battery components under extreme conditions, and at the same time needs to have higher thermal conductivity to take away the battery heat as much as possible. After comprehensive evaluation of several commonly used insulating materials such as MgO, Al2O3, ordinary Si3N4, single crystal α-Si3N4, single crystal α-Si3N4 is preferred as the insulating layer 2 material.

[0050] Test results of performance parameters of various commonly used high-temperature insulation materials

[0051] Material Name Volume resistivity Thermal conductivity Melting point Reaction with water Reaction with inorganic acid Optional MgO <![CDATA[2.4×10 8 Ohm cm]]> 36W / m·k 2825℃ yes yes × <![CDATA[Al2O3]]> <![CDATA[1×10 13 Ohm cm]]> 30W / m·k 1545℃ no yes × <![CDATA[Ordinary Si3N4]]> <![CDATA[1×10 15 Ohm cm]]> 20W / / m·k 1900℃ no no √ <![CDATA[Single crystal α-Si3N4]]> <![CDATA[1×10 14 Ohm cm]]> 70W / m·k 1900℃ no no √

[0052] ③ Heating wire core 3 material: adopts alloy material with high resistivity and high surface load to meet higher heating efficiency requirements.

[0053] Comprehensive analysis: Copper-nickel alloys NC005, NC010, NC020; nickel-chromium alloys Cr15Ni60, Cr20Ni80, Cr30Ni70; iron-chromium-aluminum alloys 0Cr25Al5, 1C13Al4, 0Cr21Al6 and other electric heating alloys, while meeting higher heating efficiency, take into account the plasticity of the material (the ductility required for mechanical drawing and shrinking) as well as the universality and economy of the material.

[0054] Preferred copper-nickel alloy: NC005, NC020 (long-term use temperature ≥ 500°C)

[0055] Preferred nickel-chromium alloys: Cr20Ni80, Cr15Ni60 (long-term use temperature ≥1000℃)

[0056] Material Name Resistivity Elongation Melting point Optional NC005 0.05μΩ·m ≥45％ 1350℃ √ NC010 0.1μΩ·m ≥40.3％ 1350℃ NC020 0.25μΩ·m ≥37％ 1350℃ √ Cr15Ni60 1.11μΩ·m ≥25％ 1350℃ √ Cr20Ni80 1.13μΩ·m ≥20％ 1400℃ √ Cr30Ni70 1.18μΩ·m ≥20％ 1380℃ 0Cr25Al5 1.42μΩ·m ≥12％ 1500℃ 1C13Al4 1.25μΩ·m ≥12％ 1450℃ 0Cr21Al6 1.45μΩ·m ≥12％ 1500℃

[0057] A mounting structure for a mineral insulated heating cable with a pipeline for heating and cooling a battery pack of a new energy vehicle comprises a battery pack shell 5 and a bottom plate 6 matched with the battery pack shell 5, wherein a battery cell 7 is mounted in the battery pack shell 5, and a continuous U-shaped groove evenly arranged is provided on the upper end surface of the bottom plate 6. When combined with a new energy battery pack, the groove can be milled or CNC-machined on the battery pack bottom plate 6 according to the required cable cross-section size. A mineral insulated cable with a pipeline 8 is embedded in the continuous U-shaped groove and forms a plate-type integral body with the bottom plate 6, and a terminal of the mineral insulated cable with a pipeline extends out of the bottom plate 6, and the extended end is connected to a control module 9.

[0058] The above descriptions are only preferred embodiments of the present invention, and all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

Claims

1. A mineral insulated heating cable with pipeline for heating and cooling battery packs of new energy vehicles, characterized in that: The cable comprises an outer sheath, an insulating layer, a heating core and a pipeline in sequence from the outside to the inside; The outer sheath and pipeline are both formed by integral drawing and shrinking of seamless metal pipes; The outer sheath protects the internal heating wire core and pipeline when the car bumps or collides unexpectedly during normal driving, and has high tensile strength, yield strength and melting point; The insulating layer is made of powdered mineral insulating material, which is filled inside the outer sheath and formed into a dense whole after drawing, shrinking and annealing; The heating wire core is made of alloy material with high resistivity and high surface load to meet the requirements of higher heating efficiency; The pipeline is a coolant conduit, and the pipeline is resistant to chloride ion and sulfur ion corrosion.

2. A mineral insulated heating cable with pipeline for heating and cooling a battery pack of a new energy vehicle according to claim 1, characterized in that: The insulating layer uses Si3N4 or single crystal α-Si3N4 as insulating material.

3. The mineral insulated heating cable with pipeline for heating and cooling the battery pack of a new energy vehicle according to claim 1, characterized in that: When the long-term use temperature of the heating cable is ≥500°C, the heating wire core is made of copper-nickel alloy of NC005 or NC020.

4. The mineral insulated heating cable with pipeline for heating and cooling the battery pack of a new energy vehicle according to claim 1, characterized in that: When the long-term use temperature of the heating cable is ≥1000°C, the heating wire core is made of nickel-chromium alloy of Cr20Ni80 or Cr15Ni60.

5. The method for preparing a mineral insulated heating cable with pipeline for heating and cooling a battery pack of a new energy vehicle according to claim 1, characterized in that: The specific steps include: S1. After design and selection, prepare the raw materials and clean them; S2, firing a single crystal α-Si3N4 ceramic column as an insulating layer; S3, assembling the heating wire core, pipeline, ceramic column and outer sheath embryo tube before drawing; S4. Before drawing, the end is squeezed and compressed to facilitate entry into the steel mold; S5. The first drawing process uses a linear drawing machine with a large deformation amount to initially compact the insulation layer and complete the coaxiality of the cable; S6, annealing the semi-finished product to relieve stress in a tubular heating furnace; S7, secondary drawing uses a combined drawing machine with a small deformation to complete the final shaping and mounting; S8. Finished product inspection.

6. The installation structure of a mineral insulated heating cable with pipeline for heating and cooling a battery pack of a new energy vehicle according to claim 1, characterized in that: The invention comprises a battery pack shell and a bottom plate matched with the battery pack shell, wherein the battery pack shell is provided with a battery cell, and the upper surface of the bottom plate is provided with evenly arranged continuous U-shaped grooves, and the mineral insulated cable with pipeline is embedded in the continuous U-shaped grooves and forms a plate-type integral body with the bottom plate. The installation structure of a mineral insulated heating cable with pipeline for heating and cooling a battery pack of a new energy vehicle according to claim 6 is characterized in that: The connection terminal of the mineral insulated cable with pipeline extends out of the bottom plate, and the extended end is connected with a control module.

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