Battery temperature rise testing device

Abstract

The invention relates to the technical field of power batteries for electric vehicles, in particular to a battery temperature rise testing device. The temperature rise testing device comprises a heat insulation layer and a conductive wire harness; one end of the conductive wire harness is connected with the positive electrode and the negative electrode of the battery cell, and the other end of the conductive wire harness is connected to the charging and discharging cabinet; a conductive heat insulation section is embedded in the conductive wire harness in the length direction and located in the heat insulation layer. According to the invention, the outer surface of the measured battery is fully coated with the heat insulation material, especially the positive and negative electrode wiring positions are made of the heat-resistant and conductive material, so that normal charging and discharging are ensured, heat transfer between the battery cell and the lead is prevented, heat dissipation is reduced to the greatest extent, the quasi-heat insulation effect of the measurement system is realized, and the measurement accuracy is improved. Therefore, the tested temperature rise of the battery is closer to the performance of the battery at an actual vehicle end, and more reliable data support is provided for battery performance evaluation and vehicle design.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries for electric vehicles, and in particular to a battery temperature rise testing device. Background Art

[0002] With the increasing popularity of new energy vehicles, lithium-ion batteries, as their core driving force, are widely used due to their environmental friendliness, recyclability, and compact size. During the battery development phase, heat generation is a key indicator. Currently, laboratories typically connect batteries directly to charging and discharging cabinets to simulate vehicle heating during operation. Thermocouples are placed on the large surface of the battery cells to detect temperature changes. This allows for the evaluation of battery temperature rise, providing data support for battery performance optimization and vehicle design.

[0003] In the prior art, such as Figure 1 As shown in the figure, the test device for evaluating the temperature rise of batteries under operating conditions mainly consists of a battery, a charging and discharging cabinet, a connecting wire harness, and a thermocouple. Specifically, the battery is connected to the charging and discharging cabinet via positive and negative connecting wire harnesses (usually made of copper or aluminum). The charging and discharging cabinet charges and discharges the battery according to the set charging and discharging program, simulating the battery's operating mode on the entire vehicle. Thermocouples are placed on the large surface of the battery cell to detect the temperature changes of the battery during the charging and discharging process, and then evaluate the degree of heat generation of the battery.

[0004] The existing technology has the following technical problems when evaluating battery temperature rise:

[0005] First, when the battery is operating in a vehicle, the cells are connected in series and parallel and assembled through structural components and adhesives. Heat transfer with surrounding components is limited, and the heat generated is largely absorbed by the cell itself. However, in existing testing equipment, only a portion of the heat generated by the cell during operation is absorbed by the cell, which manifests as a temperature rise. The remaining heat (Q2 environment) is conducted out of the cell through ambient convection. As a result, the battery temperature rise obtained during laboratory testing is far lower than the temperature rise of the battery in actual vehicle use, making it impossible to accurately assess the heat generation of the battery under real-world operating conditions.

[0006] Secondly, the conductive wiring harness connecting the positive and negative poles of the battery to the charging and discharging cabinet in the existing test device is usually made of copper or aluminum. These materials have good thermal conductivity while conducting electricity, which will transfer the heat generated by the battery to the wiring harness, further exacerbating the heat dissipation (Q1 positive + Q1 negative). This causes the measured temperature rise data to seriously deviate from the temperature rise level under the actual vehicle operating conditions, affecting the accurate judgment of the battery's thermal performance.

[0007] That is, Qoutput = Qabsorption + (Q1positive + Q1negative + Q2ambient), and ΔT = Qabsorption / (Cp*mbattery). Therefore, under the same operating conditions, the temperature rise of the battery obtained during vehicle operation and laboratory testing is inconsistent. The temperature rise of the battery during laboratory testing is much lower than the temperature rise of the battery during actual vehicle use. How to accurately assess the temperature rise of the battery during laboratory testing has become an urgent problem that needs to be solved. Summary of the Invention

[0008] In view of the shortcomings of the prior art, an embodiment of the present invention aims to provide a battery temperature rise test device to solve the problem of inaccurate temperature rise measurement caused by heat dissipation in the prior battery temperature rise test device.

[0009] In order to achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0010] A battery temperature rise test device includes a thermal insulation layer and a conductive wire harness; the thermal insulation layer is wrapped around the outside of a battery cell; one end of the conductive wire harness is connected to the positive and negative poles of the battery cell, and the other end is connected to a charging and discharging cabinet; a conductive thermal insulation section is embedded in the length direction of the conductive wire harness, and the conductive thermal insulation section is located within the thermal insulation layer.

[0011] By fully covering the outer surface of the battery under test with insulating materials, especially using heat-resistant and conductive materials at the positive and negative terminal connection positions, heat transfer between the battery cell and the wires is prevented while ensuring normal charging and dissipation, minimizing heat dissipation and achieving a quasi-adiabatic effect for the measurement system. This makes the tested battery temperature rise closer to the actual battery performance on the vehicle end, providing more reliable data support for battery performance evaluation and vehicle design.

[0012] Optionally, the thermal insulation layer is thermal insulation foam, aerogel, foamed polyurethane or rubber-plastic insulation material.

[0013] Optionally, the conductive wiring harness includes a conductive and heat-conducting section, a conductive and heat-insulating section and a conductive and heat-conducting section connected in sequence, the conductive and heat-insulating section is located between the two conductive and heat-conducting sections, one of the conductive and heat-conducting sections is connected to the positive and negative poles of the battery cell, and the other conductive and heat-conducting section is connected to the charging and discharging cabinet.

[0014] Optionally, the electrically conductive and thermally conductive segment is made of copper or aluminum.

[0015] Optionally, the conductive thermal insulation segment is metal vanadium dioxide, mosaic crystals or cobalt / antimony metal cage crystals.

[0016] Optionally, a groove is provided at one end of the conductive and heat-conducting segment facing the conductive and heat-insulating segment, and both ends of the conductive and heat-insulating segment are respectively embedded in the grooves of the two conductive and heat-conducting segments.

[0017] Optionally, a gradient thermal conductive composite interface layer is provided between the conductive thermal insulation section and the conductive thermal conductive section, wherein the gradient thermal conductive composite interface layer comprises a flexible metal mesh transition layer, a gradient thermal conductive functional layer and an interface sealing structure.

[0018] Optionally, the flexible metal mesh transition layer is made of a copper-nickel alloy woven mesh.

[0019] Optionally, the gradient thermal conductive functional layer includes an inner layer, a middle layer and an outer layer. The inner layer is located on one side of the conductive and thermal insulation section and adopts a vanadium dioxide film doped with nano-diamond particles. The middle layer adopts silicon carbide nanowire reinforced epoxy resin. The outer layer is located on one side of the conductive and thermal conductive section and adopts a zinc oxide nanosheet / silver paste composite coating.

[0020] Optionally, the interface sealing structure includes a sealant and a reinforcement member, the sealant fills the gap at the edge of the groove, and the reinforcement member covers the outside of the connection.

[0021] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0022] 1. The battery temperature rise test device of the present invention includes a thermal insulation layer and a conductive wire harness. The thermal insulation layer is tightly wrapped around the outside of the single battery cell to form a relatively closed thermal insulation space, which effectively blocks the heat exchange between the battery and the external environment and reduces the heat loss to the environment through convection or heat conduction, that is, it reduces the environmental heat dissipation as much as possible. One end of the conductive wire harness is connected to the positive and negative poles of the battery cell, and the other end is connected to the charging and discharging cabinet. A conductive thermal insulation section is embedded in the length direction of the conductive wire harness, and the conductive thermal insulation section is located in the thermal insulation layer. From the connection structure, it is achieved to prevent the heat generated by the battery from being conducted away through the conductive wire harness, thereby constructing a nearly adiabatic (or "quasi-adiabatic") test environment, so that the heat generated by the battery during operation can be absorbed by the battery body to the maximum extent. Ultimately, the battery temperature rise measured in the laboratory can more truly and accurately reflect the actual temperature rise of the battery in the electric vehicle environment, providing more reliable experimental data for battery design and vehicle thermal management.

[0023] 2. In order to further optimize the connection performance between the conductive insulation section and the conductive heat-conducting section, a gradient thermal conductive composite interface layer is set between the two. The interface layer includes a flexible metal mesh transition layer, a gradient thermal conductive functional layer and an interface sealing structure. The flexible metal mesh transition layer can adapt to the thermal expansion differences between different materials, alleviate the thermal stress caused by temperature changes, prevent the conductive heat-conducting section from cracking due to thermal stress, and ensure the stability of the conductive performance. The gradient thermal conductive functional layer, through the design of materials and structures, makes the thermal conductivity coefficient gradually decrease from the conductive heat-conducting section to the conductive heat-conducting section, forming an effective heat flow barrier and further enhancing the thermal insulation effect. The interface sealing structure effectively fills the gap at the connection to prevent heat from dissipating from the gap, while also protecting the internal structure. The overall reliability and stability of the device in long-term cyclic temperature rise testing are improved, ensuring the long-term accuracy of temperature rise measurement.

[0024] Additional advantages of the present invention will be given in the description which follows, and in part will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the embodiments of this application or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some of the embodiments described in this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort. In addition, the spacing or size between components is exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0026] Figure 1 This is a schematic diagram of a battery temperature rise test device in the prior art;

[0027] Figure 2 Schematic diagram of a battery temperature rise test device provided by an embodiment of the present invention;

[0028] Figure 3 is a schematic diagram of a conductive harness provided by an embodiment of the present invention;

[0029] Figure 4 is a cross-sectional view of a conductive wire harness provided by an embodiment of the present invention;

[0030] Figure 5 Schematic diagram of the electrical and thermal conductive section provided by an embodiment of the present invention;

[0031] Figure 6 Schematic diagram of a conductive and thermally insulating section provided by an embodiment of the present invention;

[0032] Figure 7 Schematic diagram of discharge curves and energy analysis of a battery temperature rise test device provided by an embodiment of the present invention and a conventional device;

[0033] Figure 8 This is a discharge temperature rise curve diagram of the battery temperature rise test device provided by an embodiment of the present invention and a traditional device;

[0034] In the figure: 1, battery cell; 2, thermal insulation layer; 3, conductive wire harness; 31, conductive and thermal conductive section; 32, conductive and thermal insulation section; 33, groove; DETAILED DESCRIPTION

[0035] It should be noted that the following detailed description is illustrative and is intended to further illustrate the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0036] Explanation of terms

[0037] Thermocouple: A common temperature measurement element that converts temperature changes into electrical signals based on the Seebeck effect to enable real-time monitoring of battery temperature.

[0038] like Figure 2 As shown, this embodiment proposes a battery temperature rise test device, wherein the battery includes a plurality of single cells 1, and the test device includes a thermal insulation layer 2 and a conductive harness 3; the thermal insulation layer 2 is wrapped around the outside of the cell 1, and one end of the conductive harness 3 is connected to the positive and negative poles of the cell 1, and the other end is connected to the charging and discharging cabinet; the conductive thermal insulation section 32 is embedded in the length direction of the conductive harness 3, and the conductive thermal insulation section 32 is located within the thermal insulation layer 2. The thermal insulation layer 2 suppresses the external heat radiation / convection from the surface of the cell 1, making the cell 1 body the main heat capacity. The conductive thermal insulation section 32 is made of a material that is only electrically conductive but not thermally conductive or has poor thermal conductivity, which blocks heat transfer on the current conduction path and prevents the harness from becoming a thermal bridge; the two work together to achieve a quasi-insulating environment, so that almost all the heat generated by charging and discharging is converted into temperature rise, and the laboratory test results are closer to the actual temperature rise of the whole vehicle.

[0039] The insulation layer 2 can be made of materials with excellent thermal insulation properties, such as thermal insulation foam, aerogel, polyurethane foam, and rubber-plastic insulation materials. These materials all possess low thermal conductivity, effectively slowing the transfer of heat between the battery and the environment, enhancing the insulation effect and further ensuring that the heat generated by the battery is absorbed by the battery cell 1 itself, thereby improving the accuracy of the temperature rise test. Different materials can be flexibly selected based on actual testing requirements, cost, environmental adaptability, and other factors.

[0040] like Figure 3 、 Figure 4As shown, the conductive harness 3 includes a conductive and thermally conductive section 31, a conductive and thermally insulating section 32, and a conductive and thermally conductive section 31, which are connected in sequence. The conductive and thermally insulating section 32 is located between the two conductive and thermally conductive sections 31. One conductive and thermally conductive section 31 is connected to the positive and negative electrodes of the battery cell 1, and the other conductive and thermally conductive section 31 is connected to the charging and discharging cabinet. This integration of electrical conductivity and thermal insulation ensures proper electrical connection between the battery cell 1 and the charging and discharging cabinet to achieve charging and discharging. The conductive and thermally insulating section 32 blocks heat transfer, resolving the problem of heat loss caused by the traditional conductive harness 3 due to both electrical and thermal conductivity. This allows for effective heat accumulation within the battery system during testing, improving the consistency between the temperature rise test results and the actual vehicle battery temperature rise. Furthermore, this structural design is rational and easy to manufacture and assemble.

[0041] The conductive and heat-conducting section 31 can be made of copper or aluminum. Copper and aluminum are both excellent conductive materials with high electrical conductivity. They can ensure a stable and reliable electrical connection between the battery and the charging and discharging cabinet, and ensure the smooth progress of the charging and discharging process. At the same time, they also have certain mechanical strength and processing performance, which is convenient for making wire harness shapes and sizes that meet the requirements. When used in conjunction with the conductive and heat-insulating section 32, a heat insulation effect is achieved on the basis of meeting the conductive requirements.

[0042] The conductive insulation segment 32 can be made of metal vanadium dioxide (VO2), Cu2(S,Te) mosaic crystals, or cobalt / antimony metal cage crystals. These materials possess unique physical properties that significantly reduce thermal conductivity while maintaining a certain level of electrical conductivity, effectively preventing heat transfer between the battery and the conductive wiring harness 3. Vanadium dioxide is a preferred material, as it undergoes a metal-insulator phase transition under specific temperature conditions, uniquely regulating thermal conduction. This reduces heat loss along the conductive wiring harness 3 during battery charging and discharging, retaining more heat within the battery system and improving the accuracy of temperature rise testing.

[0043] Since the selected conductive insulation section 32 material is usually in powder or granular form, it is pressed into a block (such as Figure 6 The cylinder shown in the figure) is formed into a block, and due to its hard and brittle characteristics, it needs to be compounded and assembled with traditional aluminum wire and copper wire for use.

[0044] like Figure 5As shown, a groove 33 is provided at one end of the conductive and thermally conductive segment 31 facing the conductive and thermally insulating segment 32. The ends of the conductive and thermally insulating segment 32 are respectively embedded in the grooves 33 of the two conductive and thermally conductive segments 31. This groove 33-type connection structure increases the contact area between the conductive and thermally insulating segments 32 and 31, improving the stability and reliability of the connection. It also facilitates the effective isolation and management of heat at the contact interface, further reducing heat conduction through the contact interface, enhancing the thermal insulation effect of the device, ensuring that the heat generated by the battery is absorbed by the battery cell 1 as much as possible, and improving the accuracy of the temperature rise test.

[0045] Through the above two measures, the heat dissipated outside the system (Q1 positive + Q1 negative + Q2 ambient) during the battery test is eliminated or minimized. Therefore, the overall energy transfer relationship is changed to the following relationship:

[0046] Q1 positive + Q1 negative + Q2 environment ≈ 0;

[0047] Q production = Q absorption + (Q1 positive + Q1 negative + Q2 environment) ≈ Q absorption;

[0048] ΔT=Qabsorption / (Cp*mbattery)≈Qproduction / (Cp*mbattery);

[0049] This ensures that the heat generated by the battery is absorbed by the battery cell 1 itself and manifests as a temperature rise in the battery. The battery temperature rise tested by this device is closer to the actual performance of the battery on the vehicle end, making it simple and effective to evaluate the temperature performance of the battery system on the entire vehicle in the laboratory through testing of a single battery cell 1.

[0050] In order to further verify the effect of the device of the present invention, the same battery was selected in the laboratory and Figure 1 and Figure 2 Two test benches were built. The batteries on the two benches were discharged at the same 1C rate when fully charged. The temperature changes of the batteries were monitored by thermocouples arranged on the large surface of cell 1. The discharge curves of the batteries on the two benches and their respective temperature rise curves are shown in Figure 2. Figure 7 、 Figure 8 shown.

[0051] The energy flow analysis obtained by testing with a traditional test device is as follows:

[0052] Heat generated by overpotential during battery discharge:

[0053] Q production = 553.12Wh - 505.08Wh = 48.04Wh = 172944J;

[0054] Battery temperature rise absorbs heat:

[0055] Qabsorption = specific heat Cp*mass m*temperature rise ΔT = 1084 J / (kg*℃)*2.78 kg*31.6℃=95119.2 J;

[0056] Energy dissipated to the environment:

[0057] Q1 positive + Q1 negative + Q2 environment = Q production – Q absorption = 172944 J – 95119.2 J = 77824.8 J;

[0058] The ratio of energy absorbed by the battery to heat generated:

[0059] Percentage = Qabsorption / Qproduction = 95119.2 J / 172944 J = 55%.

[0060] The energy flow analysis obtained by the test device of the present invention is as follows:

[0061] Heat generated by overpotential during battery discharge:

[0062] Q production = 553.12Wh - 510.68Wh = 42.44Wh = 152784J;

[0063] Battery temperature rise absorbs heat:

[0064] Qabsorption = specific heat Cp*mass m*temperature rise ΔT = 1084 J / (kg*℃)*2.78 kg*50.5℃=152105 J;

[0065] Energy dissipated to the environment:

[0066] Q1 positive + Q1 negative + Q2 environment = Q production – Q absorption = 152784 J – 152105 J = 679 J;

[0067] The ratio of energy absorbed by the battery to heat generated:

[0068] Percentage = Q absorption / Q production = 152105 J / 152784 J = 99.6%;

[0069] The above data show that, under the traditional test device, only 55% of the heat generated by the battery is absorbed by the battery body, and the rest is dissipated into the environment. However, with the test device of the present invention, 99.6% of the heat generated by the battery is absorbed by the battery body, so the heat level of the battery can be judged by the temperature rise value of the battery.

[0070] Furthermore, due to the significant difference in thermal expansion coefficients between the conductive insulation segment 32 and the copper / aluminum wiring harness, periodic thermal stresses are easily generated at the connection during long-term battery cycle temperature rise testing, leading to cracking at the edges of the conductive insulation segment 32. These cracks further increase the interfacial contact resistance, reducing the wiring harness's electrical conductivity, causing distortion in charge and discharge currents and affecting the accuracy of heat generation calculations. Furthermore, the cracks form localized thermal bridges, increasing the wiring harness's thermal conductivity and compromising the quasi-insulation effect.

[0071] In order to further optimize the connection performance between the conductive thermal insulation section 32 and the conductive thermal conductive section 31, a gradient thermal conductive composite interface layer is set between the two. The interface layer includes a flexible metal mesh transition layer, a gradient thermal conductive functional layer and an interface sealing structure. The flexible metal mesh transition layer can adapt to the thermal expansion differences between different materials, alleviate the thermal stress caused by temperature changes, prevent the conductive thermal insulation section 32 from cracking due to thermal stress, and ensure the stability of the conductive performance. The gradient thermal conductive functional layer, through the design of materials and structures, makes the thermal conductivity coefficient gradually decrease from the conductive thermal conductive section 31 to the conductive thermal insulation section 32, forming an effective heat flow barrier, further enhancing the thermal insulation effect. The interface sealing structure effectively fills the gap at the connection to prevent heat from dissipating from the gap, while also protecting the internal structure, which overall improves the reliability and stability of the device in long-term cyclic temperature rise testing and ensures the long-term accuracy of temperature rise measurement.

[0072] The flexible metal mesh transition layer is made of a copper-nickel alloy (CuNi10Fe1Mn) woven mesh with a wire diameter of 0.1 mm, an aperture of 0.3 mm, and a thickness of 0.5 mm, and is combined with the conductive insulation section 32 and the metal harness by cold welding.

[0073] Copper-nickel alloy has excellent elastic modulus and ductility, and can effectively absorb the stress generated by the difference in thermal expansion coefficient between the conductive and thermally conductive segments 32 and 31 through its own micro-deformation. During long-term battery cycle temperature rise testing, frequent temperature changes cause the material to expand and contract. The copper-nickel alloy woven mesh, due to its properties, can absorb most of the strain energy, reducing stress concentration at the interface, thereby reducing the risk of cracking at the edges of the conductive and thermally conductive segments 32 and ensuring good electrical contact and thermal barrier performance between the conductive and thermally conductive segments 32 and 31, thus ensuring the stability and accuracy of the battery temperature rise test.

[0074] The gradient thermal conductive functional layer consists of three functional films: an inner layer (on the side of the conductive and thermally insulating section 32), a middle layer, and an outer layer (on the side of the conductive and thermally conductive section 31). The inner layer is a vanadium dioxide film doped with nanodiamond particles (diamond accounts for 5wt%); the middle layer is an epoxy resin reinforced with silicon carbide nanowires (SiCNWs content 20vol%); and the outer layer is a zinc oxide nanosheet / silver paste composite coating (ZnONSs spacing ≤ 100nm). It is applied layer by layer via screen printing on both sides of the metal mesh and cured at 150°C.

[0075] The inner layer, located on the side of the conductive insulation section 32, uses a vanadium dioxide film doped with nano-diamond particles. The doping of nano-diamond particles can improve the thermal conductivity of vanadium dioxide, making it better matched with the conductive insulation section 32 while maintaining a certain thermal barrier effect. The middle layer uses silicon carbide nanowires to reinforce epoxy resin. Silicon carbide nanowires have high thermal conductivity and high strength, which can effectively enhance the thermal conductivity and mechanical properties of epoxy resin, play a good role in heat transfer and stress dispersion, and further improve the thermal stability and structural integrity of the interface. The outer layer, located on the side of the conductive heat conduction section 31, uses a zinc oxide nanosheet / silver paste composite coating. The combination of zinc oxide nanosheets and silver paste not only ensures good electrical conductivity, but also plays a certain role in regulating heat transfer, so that the transfer of heat from the conductive heat conduction section 31 to the conductive heat insulation section 32 is effectively controlled, forming a gradient thermal conductivity effect, strengthening the thermal barrier performance of the entire interface layer, and improving the accuracy and reliability of the temperature rise test.

[0076] The interface sealing structure includes a sealant and a reinforcement. The sealant is made of high-temperature resistant silicone rubber and fills the edge gap of the groove 33; the reinforcement is made of a stainless steel clamp covering the outside of the connection to suppress lateral deformation.

[0077] The sealant effectively blocks heat loss through gaps, while the high-temperature silicone rubber exhibits excellent heat resistance and elasticity, adapting to the temperature fluctuations during battery temperature rise testing and maintaining a long-term seal. The reinforcement suppresses lateral deformation at the joint, enhancing the mechanical strength and stability of the connection structure. This prevents loosening or deformation of the joint caused by mechanical stress due to temperature fluctuations and current cycling, further improving the reliability and sealing of the device and ensuring effective heat accumulation and measurement accuracy during battery temperature rise testing.

[0078] Current flows from the conductive and thermally conductive segment 31 to the gradient thermally conductive composite interface layer, the conductive and thermally insulating segment 32, the gradient thermally conductive composite interface layer, and the conductive and thermally conductive segment 31. The thermal conductivity of the gradient thermally conductive composite interface layer decreases from the conductive and thermally conductive segment 31 to the conductive and thermally insulating segment 32, forming a heat flow barrier. The flexible metal mesh offsets more than 80% of the thermal stress through micro-deformation, preventing the conductive and thermally insulating segment 32 from cracking.

[0079] Tested:

[0080] Improved thermal stress resistance: The flexible metal mesh bears more than 90% of the strain energy, and the gradient thermal conductive composite interface layer avoids interface stress concentration. After 2000 temperature cycles Afterwards, there is no visible crack in the conductive insulation section 32 and the contact resistance change rate is less than 1%.

[0081] Enhanced long-term thermal resistance stability: The gradient thermal conductive composite interface layer blocks phonon scattering at the interface between the conductive thermal conductive section 31 and the conductive thermal insulation section 32. Nanodiamonds and silicon carbide nanowires reinforce the epoxy resin to inhibit microcrack propagation. The initial thermal resistance value is 0.25K / W, and the thermal resistance decay rate is less than 3% after 2000 cycles.

[0082] Temperature rise measurement accuracy is guaranteed: In the 1C continuous discharge test, the wiring harness heat loss Q1 positive + Q1 negative is stable within 0.5% of the total heat generation.

[0083] By providing a gradient thermal conductive composite interface layer between the conductive thermal insulation section 32 and the conductive thermal conductive section 31 , the problems of thermal stress failure and thermal resistance degradation are solved while maintaining high electrical conductivity, thereby achieving long-term reliability and accuracy of laboratory temperature rise testing.

[0084] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A battery temperature rise test device, wherein the battery comprises a plurality of single cells, characterized in that: The test device includes a thermal insulation layer and a conductive wiring harness; The heat insulation layer is wrapped around the outside of the battery cell, one end of the conductive wire harness is connected to the positive and negative electrodes of the battery cell, and the other end is connected to the charging and discharging cabinet; The conductive wire bundle is embedded in a conductive heat-insulating section in the length direction, and the conductive heat-insulating section is located in the heat-insulating layer.

2. The battery temperature rise test device according to claim 1, characterized in that: The heat insulation layer is made of heat insulation foam, aerogel, foamed polyurethane or rubber and plastic insulation material.

3. The battery temperature rise test device according to claim 1, wherein: The conductive wiring harness includes a conductive and heat-conducting section, a conductive and heat-insulating section, and a conductive and heat-conducting section connected in sequence. The conductive and heat-insulating section is located between the two conductive and heat-conducting sections. One conductive and heat-conducting section is connected to the positive and negative poles of the battery cell, and the other conductive and heat-conducting section is connected to the charging and discharging cabinet.

4. The battery temperature rise test device according to claim 3, characterized in that: The electrically conductive and heat conductive section is made of copper or aluminum.

5. The battery temperature rise test device according to claim 3, characterized in that: The conductive heat-insulating section is made of metal vanadium dioxide, mosaic crystals or cobalt / antimony metal cage crystals.

6. The battery temperature rise test device according to claim 3, characterized in that: A groove is provided at one end of the conductive and heat-conducting section facing the conductive and heat-insulating section, and both ends of the conductive and heat-insulating section are respectively embedded in the grooves of the two conductive and heat-conducting sections.

7. The battery temperature rise test device according to claim 6, characterized in that: A gradient heat-conducting composite interface layer is provided between the conductive heat-insulating section and the conductive heat-conducting section. The gradient heat-conducting composite interface layer comprises a flexible metal mesh transition layer, a gradient heat-conducting functional layer and an interface sealing structure.

8. The battery temperature rise test device according to claim 7, characterized in that: The flexible metal mesh transition layer is made of copper-nickel alloy woven mesh.

9. The battery temperature rise test device according to claim 7, wherein: The gradient thermal conductive functional layer includes an inner layer, a middle layer and an outer layer. The inner layer is located on the side of the conductive and thermal insulation section and adopts a vanadium dioxide film doped with nano-diamond particles. The middle layer adopts silicon carbide nanowire-reinforced epoxy resin. The outer layer is located on the side of the conductive and thermal conductive section and adopts a zinc oxide nanosheet / silver paste composite coating.

10. The battery temperature rise test device according to claim 7, wherein: The interface sealing structure includes a sealant and a reinforcement member, wherein the sealant fills the gap at the edge of the groove, and the reinforcement member covers the outside of the connection.

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