Lithium ion battery managing system and on-line measuring and diagnosing method for internal resistance of electric core monomer

Abstract

The invention discloses a lithium ion battery managing system and an on-line measuring and diagnosing method for internal resistance of an electric core monomer. The lithium ion battery managing system comprises a main control unit, an electric core sensing and monitoring unit and an electric current sensor, and adopts a manner of high-and-low voltage separation, wherein the electric core sensing and monitoring unit is used for monitoring and measuring the voltage of the electric core monomer of a lithium ion battery; the electric current sensor is used for measuring a bus electric current in a main return circuit of an electric circuit; and the main control unit is used for controlling the working pattern of a lithium ion battery set, and controlling the switching off and the switching on of a relay, the processing and the storing of data, the calculating, the processing and the transmitting of the internal resistance of the electric core monomer of the battery, and the diagnosing and the warning of the failure of an electric core. Through the adoption of the lithium ion battery managing system disclosed by the invention, on-line measuring of the internal resistance of the electric core monomer of the battery is realized, and the diagnosing of the failure and the aging of the electric core of the battery can be performed, so that the property and the condition of a lithium ion battery set can be more effectively monitored, effective basis is provided for the guarantee of the battery, reliable reference is provided for the exchanging of the electric core of the battery, important information is provided for the complete automobile strategy of an automobile, and the safety of the automobile, a driver and occupants are guaranteed.

Description

technical field [0001] The invention relates to the measurement of battery parameters, in particular to a lithium-ion battery management system and a method for online measurement and fault diagnosis of the internal resistance of a single battery cell. Background technique [0002] At present, lithium-ion power batteries have been used on a large scale in new energy vehicles. Due to the capacity and energy limitations of lithium-ion battery cells, grouping technology must be used to connect multiple batteries in series to realize lithium-ion power battery packs. Even the performance indicators of new energy vehicles; and the existing technology lacks effective measurement methods for the internal resistance of the grouped battery cells, which increases the health status of the battery cells and the difficulty of fault diagnosis. [0003] The performance of a lithium-ion battery is closely related to its health status. The internal resistance of the battery is a key indicator...

AI Technical Summary

Problems solved by technology

[0004] However, since lithium-ion batteries are in a group state, it is very complicated to measure the internal resistance of a single cell under the existing technology and conditions; and in the application environment of new energy vehicles, it is very difficult to measure the internal resistance of a single cell online

[0005] The existing internal resistance measurement methods are divided into direct current method and alternating current method; the direct current method is to connect the battery to a fixed device and the battery needs to be in a static state, charge and discharge a large current through an external load, and measure the voltage drop of the battery at the same time. The ratio of the voltage drop to the discharge current; the internal resistance of the battery can be obtained; however, because this method needs to be connected to a fixed measuring device, it is often necessary to disassemble the battery pack for measurement, which is very troublesome. If it is for the measurement of a single cell, It needs to be disassembled thoroughly, and it is not practical in daily use; the AC rule is widely applicable, but the measurement results are related to the waveform, frequency and current intensity of the signal used, and the measurement results have large errors; especially By applying an AC low-frequency small current signal to the battery, measure the feedback AC voltage signal, through the amplitude and phase of the AC voltage, and according to the input AC current signal, the impedance of the battery is obtained; but in the AC method, it cannot be used in the online environment. In addition, the AC method needs to add additional equipment and devices, which will increase the complexity and cost of the system, and the influence of noise cannot be ruled out. , the error of the measurement result is also very large; and the above method is mainly for the overall measurement of the battery pack after the cells are grouped. If the above method is applied to the measurement of the internal resistance of the monomer, it will further increase the difficulty and the feasibility is very low

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