On-line Quantitative Diagnosis Method of Micro-short-circuit Fault of Battery

Abstract

The invention relates to a method for online quantitative-diagnosing a battery micro-short-circuit fault. The method comprises the following steps: pre-establishing a relation table of electric quantity and a charging-discharging voltage, and storing; in an online diagnostic process, performing table lookup or interpolation in the relation table on the voltage while the charge / discharge is over, to obtain the electric quantity of a battery while the charge / discharge is over, thereby estimating a micro-short-circuit current according to the change of the electric quantity along with the time, and judging whether a micro-short-circuit is existent and the severity degree according to the size of the micro-short-circuit current. In allusion to end conditions of a battery pack, such as fully charged, fully discharged, non-fully charged, and non-fully discharged, corresponding diagnostic methods are provided for forming an all-around diagnosis framework. In order to solve problems that the battery is aged and the diagnosis accuracy degree and the calculation precision of the micro-short-circuit current can be affected because the environment temperatures in the different times of the charging and discharging are different, a compensated solution scheme is implemented. The method for the micro-short-circuit current is capable of detecting the micro-short-circuit fault in advance, andoutputting the size of the micro-short-circuit current so as to estimate the severity degree of the fault, and providing the basis for measures, such as warning or answering.

Description

technical field [0001] The invention relates to a technology for diagnosing battery faults, in particular to a method for on-line quantitative diagnosis of battery micro-short circuit faults. Background technique [0002] Looking at the development history of electric vehicles, it can be found that humans have been developing electric vehicles since the 19th century, and have experienced several ups and downs, but they still have not become the mainstream means of transportation for humans. The main reason is that some shortcomings of electric vehicles are caused, mainly due to the short cruising range of electric vehicles, short battery cycle life, and poor safety. As the power source of electric vehicles, the battery pack is generally composed of hundreds of battery cells connected in series. The battery pack is generally equipped with a battery management system (BMS) to ensure the efficient and safe operation of these batteries. The battery short circuit is a common fau...

AI Technical Summary

Problems solved by technology

In the production process of the battery, if there are burrs or dust falling into the raw materials such as the current collector, then there is a hidden danger that the diaphragm will be damaged during the subsequent use of the battery, forming an internal micro-short circuit

Even for batteries without manufacturing defects, dendritic lithium branches are likely to form on the surface of the negative electrode of the battery if faced with abuses such as over-discharging, over-charging, ultra-high temperature, ultra-low temperature, and severe vibration during use, which may It will puncture the diaphragm and cause a micro short circuit inside the battery

As the degree of micro-short circuit increases, the self-discharge rate of the battery will gradually increase, and the calorific value will increase, which will lead to serious safety problems such as fire and even thermal runaway.

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