Lithium ion battery internal temperature monitoring method

Abstract

The invention discloses a lithium ion battery internal temperature monitoring method. The monitoring method includes the following steps that a charge-discharge tester is used for carrying out charge-discharge tests on a lithium ion battery on different environment conditions to obtain a battery surface temperature change curve; related parameters such as battery internal resistance and an open-circuit voltage temperature coefficient are tested, and a lithium ion battery electric heating coupling model based on a variable heat production rate is set up; the temperature rise change of the discharge process of the battery is simulated to obtain a temperature change simulation curve; the experiment test temperature change curve and the simulation curve are analyzed and compared to optimize and verify the electric heating coupling model; the influence between the battery internal temperature and the battery surface temperature as well as the influence between the discharge currents and the discharge depth are analyzed, and a lithium ion battery internal temperature model is constructed; the battery internal temperature is monitored in real time according to the model. The lithium ion battery internal temperature monitoring method is simple and easy to implement, small in estimation error and capable of well meeting the requirement for monitoring the battery internal temperature in real time.

Description

Technical field [0001] The invention belongs to the technical field of lithium ion batteries, and more specifically, relates to a method for monitoring the internal temperature of a lithium ion battery. Background technique [0002] Lithium-ion batteries appeared in the early 1990s. In just over two decades, lithium-ion battery technology has achieved unprecedented development. At present, the performance of lithium-ion batteries is better than that of lead-acid batteries and nickel-hydrogen batteries in terms of specific energy, specific power, working voltage and service life, and has gradually become the development direction of power batteries. With the improvement of the safety performance and low-temperature discharge performance of lithium-ion batteries, more and more electric vehicles use lithium-ion power batteries as power sources, showing very broad application prospects. However, as a chemical power source, lithium-ion batteries are accompanied by complex chemical an...

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Problems solved by technology

[0003] At present, the traditional method of monitoring the temperature of lithium-ion batteries is to measure the surface temperature of the battery. The temperature measured in this way cannot accurately reflect the actual situation inside the battery and cannot provide accurate information for the internal temperature control of lithium-ion batteries.

In addition, there is also a built-in temperature sensor to measure the internal temperature of the battery, but this method can only be carried out during the battery production process and is not applicable to existing batteries

[0004] The internal temperature of lithium-ion batteries is an important factor affecting the performance of electric vehicles. However, the internal temperature of existing batteries cannot be directly measured. Most of them obtain the internal temperature field of batteries through three-dimensional thermal models. However, this method requires too much calculation and cannot be used in real vehicles. Apply on

In addition, a simple one-dimensional thermal model or lumped mass model can be used to estimate the internal temperature of the battery, but the model estimation accuracy is low and cannot meet the needs of actual vehicles

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