Internal and external thermal resistance estimation method for lithium battery

Abstract

The invention discloses an internal and external thermal resistance estimation method for a lithium battery, comprising the steps of: setting different environmental temperature gradients, wherein thelithium battery adopts different discharge rates for constant current discharge under each temperature gradient; recording the discharge currents, the internal temperatures of the battery and the surface temperatures of the battery when the lithium battery is in the thermal equilibrium at each temperature; and establishing a three-dimensional relational surface map of the discharge current, the environmental temperature and the internal temperature, that is, the heat balance surface, and combining the temperature difference between the inside and the outside and the temperature difference between the surface and the environment to accurately determine the internal and external thermal resistance. According to the internal and external thermal resistance estimation method for the lithium battery, the main factors affecting the internal and external thermal resistance of the lithium battery are fully analyzed, and the experiments are designed by controlling variables. By constructing athree-dimensional heat balance surface, it is easy to clarify the change of internal and external thermal resistance with various factors.

Description

technical field [0001] The invention relates to the technical field of power batteries, in particular to a method for estimating internal and external thermal resistance of a lithium battery. Background technique [0002] The thermal model of the lumped parameters of the power lithium battery is the main model used to describe the internal heat generation, heat conduction and heat dissipation process of the lithium battery. The internal thermal resistance in the thermal model parameters is used to represent the internal heat conduction rate of the lithium battery, and the external thermal resistance represents the internal heat transfer rate of the lithium battery. Ambient heat exchange rate. The existing experimental measurement methods for the internal and external thermal resistance of lithium batteries are not comprehensive and representative, so that the internal and external thermal resistance of lithium batteries cannot be accurately measured, and it also directly aff...

AI Technical Summary

Problems solved by technology

The existing experimental measurement methods for the internal and external thermal resistance of lithium batteries are not comprehensive and representative, so that the internal and external thermal resistance of lithium batteries cannot be accurately measured, and it also directly affects the accuracy of real-time estimation of the internal temperature of the battery.

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