Method for monitoring thermal runaway of lithium ion battery of electric vehicle

Abstract

The invention relates to a method for monitoring thermal runaway of a lithium ion battery of an electric vehicle. A voltage changing rate parameter when thermal runaway occurs in the lithium ion battery is monitored, and a battery voltage can be reduced abruptly, is maintained at a low voltage for 40-60 seconds and then is gradually raised to an initial voltage when the thermal runway occurs in the lithium ion battery; the fact that thermal runaway occurs in the battery can be judged by taking the battery voltage changing rate parameter as a monitoring object and is a first judgment method; abattery temperature rising rate changing parameter is monitored, the fact that thermal runaway occurs in the battery also can be judged when the battery temperature rising rate is larger than or equalto 10 DEG C per minute and is a second judgment method; and a battery management system (BMS) is used for monitoring, analyzing and judging the battery voltage changing parameter and the battery temperature rising rate parameter, the two methods are used as an independent condition or a logic combination condition and used as a technological basis for judgment on thermal runaway of the battery, and an early-warning signal can be given out in advance when thermal runaway occurs. By the method, the battery thermal runaway judgment time is greatly increased, and enough handling time is providedfor a person to escape and timely take a measure to prevent battery thermal runaway from being generated, propagating and being expanded.

Description

technical field [0001] The invention relates to a monitoring and early warning method for thermal runaway of a battery, in particular to a method for monitoring thermal runaway of a lithium-ion battery of an electric vehicle. Background technique [0002] With the catalysis of my country's new energy industry policy and the requirements of environmental protection status, electric vehicles are being actively promoted and used as a new environmentally friendly means of transportation to replace the original traditional energy vehicles. The power battery is an important source of power for electric vehicles, and the safety of the power battery is the first problem to be considered and solved in the development of electric vehicles. Lithium-ion batteries are currently the most practical power batteries for electric vehicles because of their high specific energy, high working voltage, low self-discharge rate, long cycle life and low environmental pollution. However, the safety ...

AI Technical Summary

Problems solved by technology

[0005] Tests have proved that once thermal runaway occurs in a lithium-ion battery, the temperature of the battery will rise sharply, and the temperature will suddenly rise from tens of degrees to hundreds of degrees in a short period of time, which will cause thermal runaway of adjacent batteries and form the expansion of thermal runaway. Cause more serious disasters, and bring greater difficulty to block thermal runaway of batteries and expansion of thermal runaway

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