A Method for Simultaneously Testing the Anisotropic Thermal Diffusivity of Power Batteries

Abstract

The invention discloses a method for testing anisotropic heat diffusion coefficient of a power battery at the same time. The method includes following steps: S10, recording surface temperature of a power battery sample when the power battery reaches heat balance; S20, using a constant-temperature heating source which is already at the temperature of Tw to heat other surfaces perpendicular to the laminating direction of the power battery sample; S30, sampling temperature signals on a face where a heat-insulating clamp contacts with the power battery sample, wherein coordinate distribution of temperature testing points is (x1, y3, 0), (x2, y3, 0), (x3, y1, 0) and (x3, y2, 0), x2=mx1, y2=ny1, m>1, and n>1; S40, setting time when temperature of a certain testing point is increased to preset temperature as t, and reading temperature of other testing points according to t; S50, calculating anisotropic heat diffusion coefficient of the power battery sample in X, Y and Z directions. The anisotropic heat diffusion coefficient can be obtained by only collecting the surface temperature of the battery, and the troublesome processes of teating inside temperature of the battery and building a battery heat transfer model are omitted.

Description

technical field [0001] The invention relates to the technical field of thermal testing of materials, in particular to a method for simultaneously testing the anisotropic thermal diffusivity of a power battery. Background technique [0002] The thermal diffusivity of the power battery plays a decisive role in the heating and cooling speed of the battery, and is a key parameter in the thermal management design of the battery pack. Currently used thermal diffusivity test methods can be roughly divided into steady state method and transient method. Steady-state methods mainly include steady-state plate heat flow method, steady-state hot-wire method, and steady-state ball method. The heat transfer principle of the steady-state method is simple, the test equipment is easy to manufacture, and the test accuracy for isotropic pure substances is high, but the test cycle is long, and the test accuracy for anisotropic substances is poor. Transient methods mainly include laser pulse me...

AI Technical Summary

Problems solved by technology

The transient method has a short test cycle and simple test equipment structure, but for anisotropic substances, only the specific heat capacity and thermal diffusivity in one direction can be tested first, and then the thermal diffusivity in other directions can be calculated through calculation. The test accuracy is greatly affected by the calculation model. Big

Power batteries have anisotropic heat transfer characteristics due to the diversity of composition materials and structural complexity. Therefore, if the test object is a power battery, the existing steady-state method and transient method cannot be applied.

At present, the mainstream method for obtaining the thermal diffusivity of power batteries is to identify parameters by combining experiments and simulations. However, due to the difficulty in testing the internal temperature distribution of power batteries and the imprecise simulation model, the accuracy of identifying parameters is poor.

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