Battery low-temperature preheating and charging method

Abstract

The invention brings forward a battery low-temperature preheating and charging method which comprises the following steps: an equivalent circuit model of a battery is obtained; multiple electrochemical impedance spectroscopy EIS data corresponding to multiple temperatures and multiple charged states are obtained, and corresponding parameters of the equivalent circuit model are obtained according to the multiple electrochemical impedance spectroscopy EIS data; current temperature and current charged state of the battery are obtained, and the working condition state of the battery, including low-temperature starting condition and low-temperature charging condition, is judged according to the current temperature and the current charged state; when the working condition state is the low-temperature starting condition, first frequency and a first amplitude of alternating current are selected according to parameter values of the equivalent circuit model corresponding to the current temperature and the current charged state; alternating current is applied on the battery according to the first frequency and the first amplitude for preheating until the temperature of the battery reaches a first preset temperature so as to make the battery to be normally used. By the method of the embodiment, lithium precipitation is avoided, and heat production rate inside the battery is raised.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a low-temperature preheating and charging method for batteries. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, long cycle life, low self-discharge rate, and no memory effect. Compared with lead-acid batteries and nickel-metal hydride batteries, they are more suitable for pure electric vehicles, plug-in electric vehicles and hybrid vehicles. It is also the main driving power of mobile phones and notebook computers and other main energy storage components. Graphite is currently the most commonly used negative electrode material for lithium-ion batteries due to its low potential, high capacity density, small irreversible capacity, and low cost. However, at low temperatures, various types of impedance inside lithium-ion batteries with graphite negative electrodes increase significantly, making it difficult to use lithium-ion batteri...

AI Technical Summary

Problems solved by technology

According to this method, in the actual application process, in order to avoid the excessive development of Faraday current and cause lithium precipitation, a current with a short pulse duration is usually used, that is, only the ohmic impedance is used to generate heat. However, due to the small ohmic impedance, the generated heat Also small, it is difficult to meet the requirements of battery temperature rise

In addition, this method uses pulse current to preheat the battery. Since the pulse current contains multiple frequency components, the precise selection of heat generating components and heat generating positions cannot be realized, and the interior of the battery is a transient response. The lithium ion concentration distribution becomes complicated, and it is difficult to accurately estimate the Faraday current inside the battery, so the control of the preheating and charging process is not accurate enough

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