Method of estimating secondary battery internal temperature based on electrochemical impedance

Abstract

The invention provides a method of estimating secondary battery internal temperature based on electrochemical impedance, and belongs to the secondary battery temperature measuring technology field. The method comprises steps that a plurality groups of electrochemical impedance spectroscopy data corresponding to various temperatures and various charge states of various secondary batteries in a stable condition are acquired; the frequency range of the electrochemical impedance spectroscopy characteristic quantity sensitive to the changes of the temperatures and insensitive to the changes of the charge states is determined, and the relation between the electrochemical impedance spectroscopy characteristic quantity and the ambient temperature at a selected frequency point in the frequency range is acquired; the single frequency electrochemical impedance spectroscopy of the battery at the frequency point is measured in actual environment, and the real part value of the electrochemical impedance spectroscopy at the frequency point is acquired; and the internal temperature of the battery is calculated by using the relation between the electrochemical impedance spectroscopy characteristic quantity of the battery and the temperature at the above mentioned frequency point. The method provided by the invention is advantageous in that an influence of a built-in sensor on a battery is prevented, and at the same time of guaranteeing high precision, the estimation rate of the temperature is improved, and experiment convenience is improved.

Description

technical field [0001] The invention belongs to the technical field of secondary battery temperature measurement, and in particular relates to a method for estimating the internal temperature of a secondary battery based on electrochemical impedance. Background technique [0002] Secondary batteries are currently widely used in various fields. The main secondary batteries on the market are lithium-ion batteries, lead-acid batteries and nickel-metal hydride batteries. In recent years, with the advancement of secondary battery preparation technology and production technology, the price has gradually decreased, and the output and sales of secondary batteries have grown rapidly. Among them, lithium-ion batteries have many advantages such as high specific energy, high working voltage, long cycle life, and environmental friendliness, and are more suitable for the main driving energy of pure electric vehicles, plug-in electric vehicles and hybrid electric vehicles. It has also bee...

AI Technical Summary

Problems solved by technology

The internal measurement usually obtains the temperature of the battery through a built-in micro temperature sensor. This method is relatively complicated and expensive. When it is necessary to measure the internal temperature of multiple batteries, a special design for the battery is required; in addition, this measurement method will affect Battery performance and lifespan

External measurement usually uses the thermocouple on the surface of the battery to obtain the current temperature of the battery. Due to the temperature difference between the inside and outside of the battery during use, the measurement results of this method cannot accurately reflect the actual temperature inside the battery; and when the number of batteries is large, it is necessary to More sensors to obtain temperature information, increasing the cost required to measure temperature

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