Method for monitoring impedance of connectors in power battery pack

Abstract

The invention provides a method for monitoring the impedance of connectors in a power battery pack, which is used for monitoring the impedance change of the connectors among battery cells or battery packs in an automobile power battery pack. In the method, parts such as the battery cells or the battery packs, the connectors, an operational amplifier, a current monitor, a microprocessor, a display unit, a data output interface, an electric output interface and the like are provided. When an electric automobile is used, the state change of the connectors is continuously monitored, so that an owner can timely discover the potential safety problem of the automobile power battery pack; meanwhile, maintenance personnel also can find a defective connector according to impedance data provided by the invention and quickly replace the connector.

Description

Technical field [0001] The invention relates to an impedance monitoring method of a connector in a power battery pack. Background technique [0002] The main problems in the development of the current power lithium battery power system are: the safety and service life of the power batteries are significantly reduced after the power batteries are grouped, and even battery burning and explosion accidents may occur in serious cases. The main reasons for the above problems are power lithium battery group technology, group application technology and battery management system (BMS). [0003] The main reason for the safety and life of the battery is the deviation of a certain part of the battery pack, such as internal short circuit, high current discharge, overcharge, increase in cell impedance, and increase in connector impedance. Due to the thermal effect of current, these will The temperature of the battery pack will rise. When the temperature of the battery pack is high, it will caus...

AI Technical Summary

Problems solved by technology

[0002] The main problem in the development of the current power lithium battery power system is: the safety and service life of the power battery are significantly reduced after the power battery is grouped, and even accidents such as battery combustion and explosion occur in severe cases.

[0003] The cause of battery safety and life is mainly the deviation of a certain part of the battery pack, such as internal short circuit, high current discharge, overcharge, increase in cell impedance and connector impedance, etc., due to the thermal effect of the current, these will It causes the temperature of the battery pack to rise. When the temperature of the battery pack is high, it will cause a series of side reactions, which will cause thermal damage to the battery. For example, the liquid electrolyte in the battery is flammable, and the electrolyte will first produce a large amount of gas when it is heated. The relatively large air pressure is generated in the limited internal space. Once the air pressure is large enough to break the battery shell, the battery will rupture, burn or explode.

[0004] There are many reasons for the increase in the impedance of the connector, such as poor contact of the connector, poor elasticity of the conductor in the jack connector, ineffective transmission of the nut-type tension, and problems with the material of the connector. Impedance increases, due to the thermal effect of the current, the impedance of the connector increases, and its heat generation gradually increases, causing hidden dangers inside the battery pack

Taking the poor contact of the connector as an example, the most common cause is the action of external forces, such as impact, vibration, friction, etc. Especially when the car is driving, due to changes in road conditions, these external forces may occur continuously, and the constant external force , will cause the contact surface of the connector to be damaged or even deformed, and the change of the connection end surface will damage the conductor or medium change in the connector, resulting in an increase in contact resistance and a decrease in the electrical performance of the connector

In addition, if the connector is exposed to the air for a long time, there will be dust deposition on the end surface, which will affect the heat dissipation ability of the connector. At the same time, the increase in dust will cause the connection end surface to become larger, which will increase the contact resistance in disguise, heat deposition and impedance. , which will deteriorate the electrical performance of the connector

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