Irregular sample thermal conductivity test method

A test method and technology of thermal conductivity, which is applied in the field of thermal conductivity testing of irregular samples, and can solve problems such as irregular shapes and uneven materials

Active Publication Date: 2019-09-10
CHINA JILIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The technical problem to be solved by the present invention is: how to use a non-destructive method to test the thermal

Method used

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  • Irregular sample thermal conductivity test method
  • Irregular sample thermal conductivity test method
  • Irregular sample thermal conductivity test method

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Embodiment 1

[0029] In this embodiment, the test object has an irregular shape, and the material may be uneven, and its thermophysical properties are similar to those of ceramic materials. If conventional testing methods are used, it is difficult to non-destructively construct a heat transfer conforming to the test model, so its thermal conductivity cannot be tested.

[0030] The test method of this embodiment is as figure 1 As shown, a thermocouple 2 is fixed on the surface of the sample 1 to be tested, and the thermocouple 2 is connected to a temperature measuring instrument 3 to sample and record temperature data; in addition, a thermocouple 7 and a sample holder 8 are connected to the temperature measuring instrument 3 for measuring and recording the ambient temperature during the test . The testing process mainly includes three steps:

[0031] Step 1: Place the sample 1 to be tested in a constant temperature water bath 4 at a temperature of "room temperature + 20°C" for 1 hour, and ...

Embodiment 2

[0041] In this embodiment, the test object is a square lithium battery with a metal shell, and its irregular characteristics are mainly manifested in the macroscopic inhomogeneity, and its structure is as follows: image 3 As shown: the battery is composed of a metal shell 10 and an inner core 11 , and the inner core 11 is completely wrapped and sealed by the metal shell 10 . When the battery is in operation, the inner core 11 will generate heat, which needs to be transferred to the outer surface of the battery (that is, the outer surface of the metal casing 1 ) before it can be further transferred away through air or water circulation. The thermal conductivity of the heat from the inner core 11 to the outer surface of the metal shell 10 is very important to the thermal design. If the package of the lithium battery is not damaged, the heating and temperature measurement in the conventional test method are all on the metal shell 10, and the heat transfer mainly occurs on the fa...

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Abstract

The invention discloses a thermal conductivity test method aiming at lithium batteries and other irregular samples. According to the irregular sample thermal conductivity test method, a sample to be tested is placed in three states, that is, a constant temperature T0 state, a constant temperature T1 state with strong convection heat-changing coefficient on the surface and a surface adiabatic state, and an unsteady heat transfer process between the inner part of the sample to be tested and environments when heat is changed is constructed; stored energy of the sample to be tested is taken as a heat source or heat sink, internal and external heat transfer tests are achieved without damaging the sample, the thermal shielding effect caused by good thermal conductivity materials on the surface of uneven samples can be avoided, and the heating problem caused by an irregular shape of the sample can be solved. The thermal conductivity test method can be used in nondestructive tests of equivalent thermal conductivity coefficient of square lithium batteries with metal shells, and can further be used in nondestructive tests of thermal conductivity of an irregularly shaped sample difficult to be detected by other conventional methods.

Description

technical field [0001] The invention relates to a method for testing the thermal conductivity of materials, more specifically to a method for testing the thermal conductivity of irregular samples such as square lithium batteries. Background technique [0002] The thermal conductivity of materials is crucial to thermal design. Accurate testing of thermal conductivity of materials is the basis of system design and the basis of production quality control. The thermal conductivity of materials is generally expressed by thermal conductivity, and in a few cases, it is also characterized by thermal diffusivity parameters. In the case of known density and specific heat capacity, knowing one of the two can calculate the other. [0003] There are currently many methods and standards for thermal conductivity testing, but most of these methods are aimed at traditional materials, and generally require the test sample to be an isotropic homogeneous material. With the development of techn...

Claims

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Application Information

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IPC IPC(8): G01N25/20
CPCG01N25/20
Inventor 侯德鑫叶树亮
Owner CHINA JILIANG UNIV
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