Method and device for measuring heat conductivity coefficient of thermal insulation material

Abstract

The invention relates to the technical field of batteries, and particularly discloses a method and a device for measuring the heat conductivity coefficient of a thermal insulation material. The method comprises the following steps: placing a heating plate between a heat sink plate I and a heat sink plate II which are oppositely arranged, and respectively placing a to-be-tested material sheet and an incompressible contrast material sheet with a known heat conductivity coefficient on two sides of the heating plate; applying pressure to enable all the components to be tightly attached, and measuring the thickness of the to-be-measured material sheet; through heating of the heating plate, temperatures between the heating plate and the to-be-tested material sheet, between the to-be-tested material sheet and the first heat sink plate, and one side, far away from the to-be-tested material sheet, of the first heat sink plate are collected, temperatures between the heating plate and the comparison material sheet, between the comparison material sheet and the second heat sink plate, and one side, far away from the comparison material sheet, of the second heat sink plate are collected, and the environment temperature is collected; and calculating the heat conductivity coefficient of the to-be-tested material sheet according to a formula. The heat conductivity coefficient can be quickly calculated without waiting for steady-state heat transfer through a double-path comparison measurement mode, and the test period is greatly shortened.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a method and apparatus for measuring the thermal conductivity of insulating materials. Background Technology

[0002] In the design and development of new energy battery packs, suppressing the propagation of thermal runaway is one of the core safety indicators. To prevent the spread of thermal runaway from a single cell to adjacent cells or modules, the use of highly efficient thermal insulation materials between cells, between modules, and between modules and the casing is a crucial measure. The thermal conductivity of the insulation material directly determines its insulation performance; therefore, in practical engineering, materials with lower thermal conductivity are usually preferred.

[0003] Currently, thermal conductivity testing primarily relies on thermal conductivity meters based on the steady-state method. Based on Fourier's law of thermal conductivity, the thermal conductivity of a material is calculated by measuring the temperature difference or heat flow between its two surfaces. To ensure accurate and reliable measurements, thermal insulation is required for the test material in all directions except the thermally conductive direction. This results in a larger heat capacity of the test system, an increased time constant, and a longer time to reach steady state, thus extending the testing time. The time for the test system to reach steady state is approximately three hours.

[0004] In practical engineering, commonly used thermal insulation materials include aerogel, silicone foam, and nanosheets, among which aerogel and silicone foam are widely used due to their compressibility. However, during the assembly of battery modules or battery packs, these compressible materials are often inevitably compressed due to factors such as assembly tolerances, structural constraints, and manufacturing processes. Studies have shown that there are significant differences in the thermal conductivity of materials before and after compression, leading to a series of problems in practical engineering: for example, different materials with similar nominal thermal conductivity values ​​may produce contradictory actual thermal insulation results; it is difficult to verify whether the thermal conductivity of materials provided by suppliers matches the nominal value in their product manuals; and for compressible materials, the variation law of thermal conductivity at any compression ratio is still unclear, and there is a lack of rapid and effective testing methods. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a method and apparatus for measuring the thermal conductivity of insulation materials, which simplifies the structure of the testing system, eliminates the need for thermal protection of the testing system, and allows the testing system to reach steady state in about half an hour, thereby improving testing efficiency and enabling rapid measurement of the thermal conductivity of various incompressible materials and compressible materials at different compression ratios.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a method for measuring the thermal conductivity of insulation materials, which includes the following steps: A heating plate is placed between two heat sink plates arranged opposite to each other. Then, a material sheet to be tested and a control material sheet are placed on both sides of the heating plate. Pressure is applied to make the components fit tightly together and the thickness δ2 of the material sheet to be tested is measured. The control material sheet is incompressible and its thermal conductivity λ1 is known. The heating plate heats the test material sheet and the control material sheet, and the temperature T between the heating plate and the control material sheet is collected. 11 Compare the temperature T between the material sheet and the heat sink plate. 12 And the temperature T on the side of the heat sink plate furthest from the control material sheet. 13 The temperature T between the heating plate and the material sheet under test is collected. 21 The temperature T between the material sheet to be tested and the heat sink plate II 22 And the temperature T of the heat sink plate on the side furthest from the material sheet being tested. 23 And collect ambient temperature T amb ; The thermal conductivity λ of the material sheet under test is calculated using the following formula. x :

[0007] In the formula, δ1 is the thickness of the comparison material sheet.

[0008] The method provided by this invention uses an incompressible comparison material with a known thermal conductivity as a reference and employs a dual-path comparison measurement method, utilizing a heat sink plate to establish a stable heat flow path with ambient temperature. This method shortens the time to reach steady state during testing, is more efficient, and only requires collecting temperature values ​​from multiple key points to quickly calculate the thermal conductivity of the material under test, significantly shortening the testing cycle. Simultaneously, by applying pressure and ensuring tight contact between components during testing, the actual state of the insulation material under compression during actual battery pack assembly can be simulated, thereby obtaining the thermal conductivity under compression conditions. This provides accurate and reliable data support for engineering design selection and material quality control.

[0009] As a further improvement to the above-mentioned solution of the present invention, heat sink plate one and heat sink plate two are the same size and made of the same material, and the opposite sides of heat sink plate one and heat sink plate two are smooth and flat. By limiting heat sink plate one and heat sink plate two to be the same size and material, and to have smooth and flat opposite sides, the symmetry and consistency of the heat conduction path on both sides are ensured, the influence of the difference in thermal resistance of the heat sink plate itself on the measurement results is eliminated, and the accuracy and repeatability of the test are improved.

[0010] As a further improvement to the above-described solution of the present invention, the test material sheet and the comparison material sheet are of the same size, and the comparison material sheet is an aluminum sheet, a stainless steel sheet, a mica sheet, or a nanoplate sheet. By limiting the size of the test material sheet and the comparison material sheet to be the same, the cross-sectional area of ​​the heat flow path on both sides is ensured to be consistent, simplifying the area parameter in the thermal conductivity calculation formula. Aluminum sheets (such as aluminum 3003, thermal conductivity 163 W / mK), stainless steel sheets (such as stainless steel 304, thermal conductivity 12.1 W / mK), mica sheets (thermal conductivity 0.1 W / mK), or nanoplate sheets (thermal conductivity 0.02 W / mK) are selected as comparison materials. These materials have known and stable thermal conductivity and are incompressible, providing a stable reference standard for measurement. For test material sheets with different thermal conductivity, the range of thermal conductivity of the material can be predicted based on the properties of the test material sheet, and a comparison material sheet with a relatively similar thermal conductivity can be selected for testing. In this way, when the temperature field is stable, the temperature fields of the comparison side and the test side are closer, thereby improving the correction accuracy of subsequent data processing.

[0011] As a further improvement to the above-mentioned solution of the present invention, the test material sheet, the comparison material sheet, the first heat sink plate, and the second heat sink plate are all square structures of the same size. The test material sheet is completely attached to the first heat sink plate, and the comparison material sheet is completely attached to the second heat sink plate. This further ensures that the test material sheet, the comparison material sheet, and the heat sink plates are completely attached, guaranteeing a tight contact interface, reducing the influence of contact thermal resistance on the measurement results, and making the heat flow direction closer to the ideal one-dimensional heat transfer model, thereby improving the accuracy of the measurement results.

[0012] As a further improvement to the above-described solution of the present invention, during the heating process, the test material sheet and the comparison material sheet are kept in a vertical state. Maintaining the test material sheet and the comparison material sheet in a vertical state during the heating process ensures that the outer wall surfaces of the heat sink and the comparison heat sink are under the same vertical wall convective heat transfer conditions, resulting in the same convective heat transfer coefficient and guaranteeing the accuracy of the measurement results.

[0013] This invention also provides a device for measuring the thermal conductivity of insulation materials, comprising a support, a heating plate, a first heat sink plate, a second heat sink plate, an adjusting component, a temperature acquisition component, a material sheet to be tested, and a comparison material sheet with known thermal conductivity and incompressibility. The first heat sink plate is mounted on the support via the adjusting component. The second heat sink plate is arranged opposite to the first heat sink plate and fixed on the support. The heating plate is positioned between the first and second heat sink plates. The material sheet to be tested is positioned between the heating plate and the first heat sink plate. The comparison material sheet is positioned between the heating plate and the second heat sink plate. The adjusting component drives the first heat sink plate towards the second heat sink plate to ensure tight contact between the components. The temperature acquisition component is used to collect the temperature T between the heating plate and the comparison material sheet. 11 Compare the temperature T between the material sheet and the heat sink plate. 12 The temperature T on the side of the heat sink plate furthest from the control material sheet.13 The temperature T between the heating plate and the material sheet being tested 21 The temperature T between the material sheet to be tested and the heat sink plate. 22 The temperature T of the side of the heat sink plate furthest from the material sheet being tested 23 and ambient temperature T amb .

[0014] The measuring device provided by this invention has a simple structure and is easy to operate. Pressure can be applied to each component through adjustment mechanisms to simulate the actual working conditions of thermal insulation materials under different compression states. This device, in conjunction with a temperature acquisition unit, can quickly acquire multiple sets of temperature data, achieving efficient measurement of the thermal conductivity of compressible thermal insulation materials under compression conditions. This solves the problems of long testing cycles and the inability to simulate compression conditions in traditional testing equipment.

[0015] As a further improvement to the above-mentioned solution of the present invention, heat sink plate one and heat sink plate two are arranged vertically opposite each other. The adjusting component includes a screw and a connecting plate. The screw is arranged horizontally and is threadedly connected to the bracket. One end of the screw is rotatably connected to the connecting plate, and the other end is connected to a rotating wheel. The connecting plate is provided with multiple horizontally arranged mounting rods. Heat sink plate one is fixed on the multiple mounting rods, and the length of the mounting rods is not less than the height of heat sink plate one. Heat sink plate two is installed on the bracket through multiple horizontally arranged fixing rods, and the length of the fixing rods is not less than the height of heat sink plate two. By adopting the adjusting mechanism composed of screw and connecting plate, the precise adjustment of the position of heat sink plate one and stable pressure are achieved, ensuring the controllability and repeatability of the compression state during the test. The setting of the rotating wheel makes the operation more labor-saving and convenient. In order to achieve the purpose of natural convection in a large space on the outer surfaces of heat sink plate one and heat sink plate two, the length of the mounting rod should not be less than the height of heat sink plate one, the length of the fixing rod should not be less than the height of heat sink plate two, and the distance between the side of heat sink plate one and heat sink plate two and the bracket should not be less than half of its vertical length.

[0016] As a further improvement to the above-mentioned solution of the present invention, the temperature acquisition device includes thermocouple 1, thermocouple 2, thermocouple 3, thermocouple 4, thermocouple 5, thermocouple 6, and a thermometer for acquiring ambient temperature; mounting groove 1 and mounting groove 2 are respectively opened on opposite sides of heat sink plate 1 and heat sink plate 2, and thermocouple 1 and thermocouple 2 are respectively installed in mounting groove 1 and mounting groove 2; mounting groove 3 and mounting groove 4 are respectively opened on the side of heat sink plate 1 and heat sink plate 2 away from each other, and thermocouple 3 and thermocouple 4 are respectively installed in mounting groove 3 and mounting groove 4; mounting groove 5 is opened on the side of the heating plate facing heat sink plate 1, and thermocouple 5 is installed in mounting groove 3; mounting groove 6 is opened on the side of the heating plate facing heat sink plate 2, and thermocouple 6 is installed in mounting groove 4. That is, the temperature T between the heating plate and the control material sheet is acquired through thermocouple 6. 11 The temperature T between the comparison material sheet and the heat sink plate was collected by thermocouple 2. 12Temperature T on the side of heat sink plate two furthest from the control material sheet was collected by thermocouple four. 13 The temperature T between the heating plate and the material sheet under test is collected by thermocouple five. 21 The temperature T between the material under test and the heat sink plate is collected by thermocouple one. 22 Temperature T on the side of the heat sink plate furthest from the material being tested is collected by thermocouple 3. 23 The ambient temperature T was collected by a thermometer. amb Ideally, the thermometer should be placed outside the testing device and unaffected by any heat source. By creating mounting slots on the heat sink and heating plate and embedding thermocouples within them, accurate temperature acquisition at key locations is achieved. This ensures good contact between the temperature sensor and the measurement point while avoiding the sensor's influence on the flatness of the interface, thus guaranteeing the authenticity and reliability of the temperature data. Thermocouple 1, Thermocouple 2, Thermocouple 3, Thermocouple 4, Thermocouple 5, and Thermocouple 6 can be one or more, used to collect the temperature T between the heating plate and the comparison material sheet. 11 For example, thermocouples six are arranged at different positions on the heating plate, and the average temperature measured by multiple thermocouples six is ​​calculated as the temperature T between the heating plate and the control material sheet. 11 It should be noted that if there is only one thermocouple, taking thermocouple one as an example, it is preferable to place thermocouple one at the center of heat sink plate one.

[0017] As a further improvement to the above-mentioned solution of the present invention, the heating plate includes an aluminum plate and a heating tube embedded in the aluminum plate. The aluminum plate has a square structure and its two sides are smooth and flat. The structure of the heating plate with the aluminum plate and the heating tube embedded ensures the temperature uniformity of the heating surface. The smooth and flat design on both sides ensures good adhesion between the heating plate and the test material sheet and the comparison material sheet, providing a guarantee for the formation of a stable and uniform heat flow.

[0018] As a further improvement to the above-mentioned solution of the present invention, heat sink plate one, heat sink plate two, the test material sheet, and the comparison material sheet are all square structures of the same size. One side of heat sink plate one and heat sink plate two are smooth and flat. The test material sheet is completely bonded to heat sink plate one, and the comparison material sheet is completely bonded to heat sink plate two. The comparison material sheet is an aluminum sheet, stainless steel sheet, mica sheet, or nanosheet. By comprehensively defining the size, shape, and bonding method of each component, the symmetry of the heat conduction path on both sides and the one-dimensional heat transfer characteristics are further ensured, eliminating the influence of contact thermal resistance and edge effects, and effectively improving the accuracy and stability of the measurement results. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a device for measuring the thermal conductivity of insulation materials according to an embodiment of the present invention; Figure 2This is a schematic diagram illustrating the principle of temperature point acquisition in a method for measuring the thermal conductivity of insulation materials according to an embodiment of the present invention. Figure 3 This is a partial structural schematic diagram of a device for measuring the thermal conductivity of insulation materials provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the heating plate in a thermal conductivity measuring device for thermal insulation materials provided in an embodiment of the present invention.

[0020] Reference numerals in the attached drawings: 1. Heat sink plate one; 2. Heat sink plate two; 3. Heating plate; 4. Test material sheet; 5. Comparison material sheet; 6. Support; 7. Screw; 8. Connecting plate; 9. Rotary wheel; 10. Mounting rod; 11. Mounting slot two; 12. Mounting slot three; 13. Mounting slot five; 14. Mounting slot six; 15. Fixing rod. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0023] Reference Figure 1 This embodiment first provides a device for measuring the thermal conductivity of insulation materials, used to quickly measure the thermal conductivity of compressible insulation materials under different compression states, and to quickly measure the thermal conductivity of incompressible insulation materials. The device includes a support 6, a heating plate 3, a heat sink plate 1, a heat sink plate 2, an adjustment component, a temperature acquisition component, a material sheet to be tested 4, and a comparison material sheet 5 with known thermal conductivity and incompressibility.

[0024] In this embodiment, heat sink plate 1 and heat sink plate 2 are the same size and made of the same material, preferably aluminum alloy with good thermal conductivity and stable heat capacity. The opposite sides of heat sink plate 1 and heat sink plate 2 are precision machined to ensure smoothness and flatness, thereby reducing contact thermal resistance. Heat sink plate 1 is mounted on bracket 6 via an adjusting member, and heat sink plate 2 is arranged opposite to heat sink plate 1 and fixed on bracket 6. Heating plate 3 is disposed between heat sink plate 1 and heat sink plate 2, the material sheet to be tested 4 is disposed between heating plate 3 and heat sink plate 1, and the comparison material sheet 5 is disposed between heating plate 3 and heat sink plate 2. The adjusting member drives heat sink plate 1 towards heat sink plate 2 to ensure tight contact between the components and to simulate the compression state of the material sheet to be tested 4 in actual applications.

[0025] Specifically, heat sink plate 1 and heat sink plate 2 are arranged vertically opposite each other. The adjusting components include a screw 7, a connecting plate 8, and a guide rod (not shown). The screw 7 is horizontally arranged and threadedly connected to the bracket 6. One end of the screw 7 is rotatably connected to the connecting plate 8, and the other end is connected to a rotating wheel 9. Multiple horizontally arranged mounting rods 10 are provided on the connecting plate 8. Heat sink plate 1 is fixed to these mounting rods 10, and the length of each mounting rod 10 is not less than the height of heat sink plate 1. Correspondingly, heat sink plate 2 is mounted on the bracket 6 via multiple horizontally arranged fixing rods 11, and the length of each fixing rod 11 is not less than the height of heat sink plate 2. To achieve natural convection in a large space on the outer surfaces of heat sink plates 1 and 2, the length of each mounting rod 10 should be not less than the height of heat sink plate 1, the length of each fixing rod 11 should be not less than the height of heat sink plate 2, and the distance between the sides of heat sink plates 1 and 2 and the bracket 6 should be not less than half their vertical length. The guide rod is horizontally fixed on the bracket 6 and slides through the connecting plate 8. Through this structure, the operator can rotate the wheel 9 to drive the screw 7 to rotate, thereby driving the connecting plate 8 and the heat sink plate 1 to move horizontally along the guide rod axis, so as to achieve precise pressure and compression control of the test component.

[0026] Temperature acquisition devices are used to collect temperatures at multiple key points during the testing process. Specifically, the temperature acquisition devices include thermocouple one, thermocouple two, thermocouple three, thermocouple four, thermocouple five, thermocouple six, and a thermometer for collecting ambient temperature. Among these, [the following is a continuation of the previous sentence, likely related to temperature acquisition]. Figure 2 Thermocouple 6 is installed on the side of heating plate 3 facing heat sink plate 2 1, and is used to collect the temperature T between heating plate 3 and comparison material sheet 5. 11 Thermocouple 2 is installed on the side of heat sink plate 2 facing heating plate 3 to collect the temperature T between the comparison material sheet 5 and heat sink plate 2. 12 Thermocouple 4 is installed on the side of heat sink plate 2 away from heating plate 3 to collect the temperature T on the side of heat sink plate 2 away from the comparison material sheet 5. 13Accordingly, thermocouple 5 is installed on the side of heating plate 3 facing heat sink plate 1, for collecting the temperature T between heating plate 3 and the material sheet 4 under test. 21 Thermocouple 1 is installed on the side of heat sink 1 facing heating plate 3 to collect the temperature T between the material sheet 4 under test and heat sink 1. 22 Thermocouple 3 is installed on the side of heat sink 1 away from heating plate 3, and is used to collect the temperature T on the side of heat sink 1 away from the material sheet 4 to be tested. 23 The thermometer is placed outside the testing apparatus in a location unaffected by any heat source to collect ambient temperature T. amb .

[0027] To achieve accurate temperature acquisition, mounting slots for thermocouples are provided on heat sink 1, heat sink 2, and heating plate 3. Specifically, in conjunction with... Figure 3 , Figure 4 The heating plate 1 and heating plate 2 have mounting slots 1 and 2 11 respectively on opposite sides, where thermocouples 1 and 2 are installed. Mounting slots 3 and 4 are also provided on opposite sides of the heating plate 1 and heating plate 2, where thermocouples 3 and 4 are installed. Mounting slot 5 is provided on the side of heating plate 3 facing heating plate 1, where thermocouple 5 is installed. Mounting slot 6 is provided on the side of heating plate 3 facing heating plate 2, where thermocouple 6 is installed. The probes of each thermocouple are in good contact with the bottom surface of their respective mounting slots, and the thermocouple leads are led out from the side. The number of thermocouples 1, 2, 3, 4, 5, and 6 can be one or more. When multiple thermocouples are used, the temperature T between the heating plate and the control material sheet is collected. 11 For example, multiple thermocouples can be arranged at different positions on the heating plate 3, and the average temperature measured by the multiple thermocouples can be calculated as T. 11 If there is only one thermocouple, it is preferable to place the thermocouple at the center of the corresponding component to reduce the effect of edge effects.

[0028] Heating plate 3 includes an aluminum plate and heating tubes embedded within it. The aluminum plate has a square structure with smooth, flat sides to ensure good adhesion to the test material sheet 4 and the comparison material sheet 5. The aluminum plate has excellent thermal conductivity, enabling uniform temperature distribution on the heating surface and ensuring a stable and uniform heat flow. The power setting of heating plate 3 is approximately 0.05 W / cm² based on its area. 2 It is advisable.

[0029] In this embodiment, the test material sheet 4, the comparison material sheet 5, the first heat sink plate 1, and the second heat sink plate 2 are all square structures of the same size to ensure that the cross-sectional area of ​​the heat flow path on both sides is consistent. The test material sheet 4 is completely attached to the first heat sink plate 1, and the comparison material sheet 5 is completely attached to the second heat sink plate 2, thereby ensuring a tight contact interface and reducing contact thermal resistance. The comparison material sheet 5 is an incompressible material with a known and stable thermal conductivity λ1. Specifically, it can be made of aluminum sheet (such as aluminum 3003, thermal conductivity 163 W / m·K), stainless steel sheet (such as stainless steel 304, thermal conductivity 12.1 W / m·K), mica sheet (thermal conductivity 0.1 W / m·K), or nanoplate sheet (thermal conductivity 0.02 W / m·K), etc. When testing material sheet 4 with different thermal conductivity, a comparison material sheet 5 with a similar thermal conductivity can be selected for testing based on the predicted range of thermal conductivity of material sheet 4. This makes the temperature fields of the comparison side and the tested side closer when the temperature field is stable, thereby improving the correction accuracy of data processing.

[0030] Based on the above-mentioned measuring device, this embodiment also provides a method for measuring the thermal conductivity of thermal insulation materials. The method for measuring the thermal conductivity of thermal insulation materials of the present invention will be described in detail below with reference to the above-mentioned measuring device.

[0031] First, test preparation is carried out. Based on the estimated range of thermal conductivity of the material sheet 4 to be tested, a comparison material sheet 5 with a similar thermal conductivity is selected, and the thickness δ1 and thermal conductivity λ1 of the comparison material sheet 5 are recorded. The thickness of the material sheet 4 to be tested in its initial state is measured with vernier calipers, and then it is placed in the test position. During the test operation, the support 6 is laid down so that the heat sink plate 2 is horizontally arranged. The comparison material sheet 5, the heating plate 3, and the material sheet 4 to be tested are placed in sequence on one side of the heat sink plate 2. Then, the rotating wheel 9 is rotated, and the heat sink plate 1 is driven to move along the guide rod axis towards the heat sink plate 2 via the screw 7 and the connecting plate 8, so that the components fit tightly together, and pressure is applied as needed to achieve the preset compression amount. Then, the support 6 is restored to its original state for the next test.

[0032] After the testing device is installed, it is placed in a constant-temperature chamber with no significant airflow for testing. During the heating process, the test material sheet 4 and the control material sheet 5 are kept vertical to ensure that the outer walls of the heat sink and the control heat sink are under the same vertical wall convective heat transfer conditions, with the same convective heat transfer coefficient, thus ensuring the accuracy of the measurement results. During the test, to prevent insufficient pre-tightening force of the testing device from failing to support the weight of the heating plate, a pad with good insulation, such as bakelite, can be placed under the heating plate 3.

[0033] Heating plate 3 was energized and heated. Changes at various temperature probes were observed. After approximately 30 minutes, the temperature changes at each probe stabilized, and the temperature at each point was recorded. Specifically, the temperature T between heating plate 3 and the control material sheet 5 was collected using thermocouple 6.11 The temperature T between the comparison material sheet 5 and the heat sink plate 2 was collected by thermocouple 2. 12 The temperature T on the side of heat sink plate 2 away from the control material sheet 5 was collected by thermocouple 4. 13 The temperature T between the heating plate 3 and the material sheet 4 under test is collected by thermocouple 5. 21 The temperature T between the test material sheet 4 and the heat sink plate 1 is collected by thermocouple 1. 22 The temperature T on the side of the heat sink plate 1 furthest from the material sheet 4 under test is collected by thermocouple 3. 23 And the ambient temperature T was collected by a thermometer. amb .

[0034] According to the principles of heat transfer, the outer walls of heat sink 1 and heat sink 2 belong to a typical vertical flat plate large-space natural convection model, with a natural convection heat transfer coefficient of 5~15W / m. 2 The variation is small within the K range. When the thermal resistances of the comparison material 5 and the test material 4 are closer, the outer wall temperatures of heat sink 1 and heat sink 2 are also closer. Therefore, the heat transfer coefficients of the two outer wall surfaces can be considered relatively stable. h They are the same. Furthermore, since heat sink plate 1 and heat sink plate 2 have the same dimensions, their outer convection heat transfer area Ac is also the same.

[0035] Based on the above principles, steady-state Fourier heat conduction formulas and convective heat transfer formulas are established for the comparison side and the test side, respectively.

[0036] The energy transferred from heating plate 3 to the control material 5 via heat conduction is equal to the energy transferred from heat sink plate 2 to the environment via convection heat transfer, which gives us Formula 1: Formula 1:

[0037] in, A 1 represents the heat transfer cross-sectional area, which is also the cross-sectional area of ​​the comparison material sheet. The heat Q1 transferred from the comparison material sheet is transferred to the environment through convection heat exchange from heat sink plate two. The middle part of the equation is the calculation formula for the heat conduction of the comparison material sheet, and the right side of the equation is the calculation formula for the heat exchange between heat sink plate two and the environment.

[0038] Similarly, the energy is transferred from the heating plate 3 to the material sheet 4 under test through heat conduction. The energy transferred to the environment by the heat sink plate 1 through convection heat transfer is equal to that transferred to the heat sink plate 1, so we can obtain formula 2: Formula 2:

[0039] in, A 2 represents the heat transfer cross-sectional area, which is also the cross-sectional area of ​​the material sheet being tested. A 1 =A2. The heat Q2 transferred from the material sheet under test is transferred to the environment through convection heat exchange from the heat sink plate-1. The middle part of the equation is the calculation formula for the heat conduction of the material sheet under test, and the right side of the equation is the calculation formula for the heat exchange between the heat sink plate-1 and the environment.

[0040] By combining formulas 1 and 2, we can eliminate identical terms. A 1 、A 2 h, Ac We can obtain:

[0041] After processing, the thermal conductivity of the material sheet 4 to be tested is... λ x The calculation formula is:

[0042] In the formula, λ 1 represents the thermal conductivity of the reference material sheet 5, in W / mk, which is a known quantity; δ1 represents the thickness of the reference material sheet 5, in m, which is a known quantity; δ2 represents the thickness of the material sheet 4 to be tested, in m, which was measured using vernier calipers; all temperature values ​​were collected.

[0043] The thermal conductivity of the insulation material under test under the current compression state can be quickly obtained through the above calculations.

[0044] In summary, the method and apparatus for measuring the thermal conductivity of insulation materials provided by this invention, by setting an incompressible comparison material with a known thermal conductivity as a reference, employs a dual-path comparison measurement method and utilizes a heat sink plate to establish a stable heat flow path with ambient temperature. Compared to other measurement devices, because the entire system requires no insulation and has a small system heat capacity time constant, it can quickly reach a steady state, significantly shortening the testing cycle. Simultaneously, by applying pressure and ensuring tight contact between components during the testing process, the actual state of the insulation material under compression during actual battery pack assembly can be simulated, thereby obtaining the thermal conductivity under compression. This provides accurate and reliable data support for engineering design selection and material quality control.

[0045] It should be noted that when a component is said to be "installed on" another component, it can be directly on the other component or it may be in a component that is centered on it. When a component is said to be "set on" another component, it can be directly set on the other component or it may also be in a component that is centered on it. When a component is said to be "fixed to" another component, it can be directly fixed to the other component or it may also be in a component that is centered on it.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for measuring the thermal conductivity of insulation materials, characterized in that, It includes the following steps: A heating plate is placed between two relatively arranged heat sink plates, and then a test material sheet and a control material sheet are placed on both sides of the heating plate. Pressure is applied to make the components fit tightly together and the thickness δ2 of the material sheet to be tested is measured. The comparison material sheet is incompressible and its thermal conductivity λ1 is known. The heating plate heats the test material sheet and the control material sheet, and the temperature T between the heating plate and the control material sheet is collected. 11 Compare the temperature T between the material sheet and the heat sink plate. 12 And the temperature T on the side of the heat sink plate furthest from the control material sheet. 13 The temperature T between the heating plate and the material sheet under test is collected. 21 The temperature T between the material sheet to be tested and the heat sink plate II 22 And the temperature T of the heat sink plate on the side furthest from the material sheet being tested. 23 And collect ambient temperature T amb ; The thermal conductivity λ of the material sheet under test is calculated using the following formula. x : In the formula, δ1 is the thickness of the comparison material sheet.

2. The method for measuring the thermal conductivity of insulation materials according to claim 1, characterized in that, Heat sink plate one and heat sink plate two are the same size and made of the same material. Both heat sink plate one and heat sink plate two have smooth and flat sides facing each other.

3. The method for measuring the thermal conductivity of insulation materials according to claim 2, characterized in that, The test material sheet and the comparison material sheet are the same size, and the comparison material sheet is an aluminum sheet, stainless steel sheet, mica sheet or nanoplate sheet.

4. The method for measuring the thermal conductivity of insulation materials according to claim 2, characterized in that, The test material sheet, the control material sheet, heat sink plate one, and heat sink plate two are all square structures of the same size. The test material sheet is completely attached to heat sink plate one, and the control material sheet is completely attached to heat sink plate two.

5. The method for measuring the thermal conductivity of insulation materials according to claim 1, characterized in that, During the heating process, both the test material and the control material are kept vertical.

6. A device for measuring the thermal conductivity of insulation materials, characterized in that, It includes a support, a heating plate, a first heat sink, a second heat sink, an adjusting mechanism, a temperature acquisition device, a material sheet to be tested, and a control material sheet with known thermal conductivity and incompressibility. The first heat sink is mounted on the support via the adjusting mechanism. The second heat sink is positioned opposite the first heat sink and fixed to the support. The heating plate is positioned between the first and second heat sinks. The material sheet to be tested is positioned between the heating plate and the first heat sink, and the control material sheet is positioned between the heating plate and the second heat sink. The adjusting mechanism drives the first heat sink towards the second heat sink to ensure tight contact between all components. The temperature acquisition device is used to collect the temperature T between the heating plate and the control material sheet. 11 Compare the temperature T between the material sheet and the heat sink plate. 12 The temperature T on the side of the heat sink plate furthest from the control material sheet. 13 The temperature T between the heating plate and the material sheet being tested 21 The temperature T between the material sheet to be tested and the heat sink plate. 22 The temperature T of the side of the heat sink plate furthest from the material sheet being tested 23 and ambient temperature T amb .

7. The thermal conductivity measuring device for thermal insulation materials according to claim 6, characterized in that, Heat sink plate 1 and heat sink plate 2 are arranged vertically opposite each other; the adjusting components include a screw and a connecting plate. The screw is arranged horizontally and is threadedly connected to the bracket. One end of the screw is rotatably connected to the connecting plate, and the other end is connected to a wheel. The connecting plate is provided with multiple horizontally arranged mounting rods. Heat sink plate 1 is fixed on the multiple mounting rods, and the length of the mounting rods is not less than the height of heat sink plate 1. Heat sink plate 2 is installed on the bracket through multiple horizontally arranged fixing rods, and the length of the fixing rods is not less than the height of heat sink plate 2.

8. The thermal conductivity measuring device for insulation materials according to claim 6, characterized in that, The temperature acquisition components include thermocouple 1, thermocouple 2, thermocouple 3, thermocouple 4, thermocouple 5, and thermocouple 6; mounting groove 1 and mounting groove 2 are respectively opened on opposite sides of heat sink plate 1 and heat sink plate 2, and thermocouple 1 and thermocouple 2 are installed in mounting groove 1 and mounting groove 2 respectively; mounting groove 3 and mounting groove 4 are respectively opened on opposite sides of heat sink plate 1 and heat sink plate 2, and thermocouple 3 and thermocouple 4 are installed in mounting groove 3 and mounting groove 4 respectively; mounting groove 5 is opened on the side of the heating plate facing heat sink plate 1 and thermocouple 5 is installed in mounting groove 3, and mounting groove 6 is opened on the side of the heating plate facing heat sink plate 2 and thermocouple 6 is installed in mounting groove 4.

9. The thermal conductivity measuring device for insulation materials according to claim 6, characterized in that, The heating plate includes an aluminum plate and a heating tube embedded in the aluminum plate. The aluminum plate has a square structure and its two sides are smooth and flat.

10. The thermal conductivity measuring device for thermal insulation materials according to claim 6, characterized in that, Heat sink plate 1, heat sink plate 2, test material sheet, and reference material sheet are all square structures of the same size. The opposite sides of heat sink plate 1 and heat sink plate 2 are smooth and flat. The test material sheet is completely attached to heat sink plate 1, and the reference material sheet is completely attached to heat sink plate 2. The reference material sheet is an aluminum sheet, stainless steel sheet, mica sheet, or nanosheet.

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